United States Nuclear Regulatory Commission - Protecting People and the Environment

Service Water System Problems Affecting Safety-Related Equipment (Generic Letter 89-13, Supplement 1)

ACCESSION #: 9003300128                                                        
                                                                               
                                UNITED STATES                                  
                         NUCLEAR REGULATORY COMMISSION                         
                             WASHINGTON, D.C.  20555                           
                                                                               
                                April 4, 1990                              
                                                                               
                                                                               
TO:       ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS FOR        
          NUCLEAR POWER PLANTS                                                 
                                                                              
SUBJECT:  SERVICE WATER SYSTEM PROBLEMS AFFECTING SAFETY-RELATED               
          EQUIPMENT (GENERIC LETTER 89-13, SUPPLEMENT 1)                       
                                                                               
On July 18, 1989, the U.S. Nuclear Regulatory Commission (NRC) issued          
Generic Letter 89-13, "Service Water System Problems Affecting Safety-         
Related Equipment."  On October 23, 1989, the NRC announced in the             
Federal Register  that it would hold four workshops on this generic            
letter.  The NRC conducted these workshops in Philadelphia, Atlanta,           
Chicago, and Denver on November 28 and 30 and December 5 and 7, 1989,          
respectively.  The NRC answered written questions submitted through            
appropriate project managers in the Office of Nuclear Reactor Regulation       
before the first workshop and questions submitted at each workshop.            
Transcripts of these meetings are available in the NRC Public Document         
Room, 2120 L Street NW, Washington, DC.                                        
                                                                               
This supplement contains the questions and answers read into the               
transcripts during the workshops, except for the following changes.            
Questions received in the general, Action I, and Action II categories          
have been grouped according to topic.  In addition, the NRC staff              
modified some answers after the workshops with the aim of furnishing           
additional guidance.  Please contact the project manager if you have           
questions on this matter.                                                      
                                                                               
                                    Sincerely,                                 
                                                                               
                                    original signed by:                        
                                                                               
                                    James G. Partlow                           
                                    Associate Director for Projects            
                                    Office of Nuclear Reactor Regulation       
                                                                               
Enclosures:                                                                    
1.  Questions and Answers                                                      
2.  List of Recently Issued NRC Generic Letters                                
                                                                               
Technical Contact:  C. Vernon Hodge, NRR                                       
                    (301) 492-1169                                             
                                                                               
                                                                               
.                                  Enclosure 1                                  
                                                                               
                              QUESTIONS AND ANSWERS                            
                                                                               
                                                            Page               
                                                                               
       I. GENERAL                                             2                
                                                                               
          A.   Reporting Requirements                         2                
          B.   Backfit                                        4                
          C.   Inspections                                    5                
          D.   Miscellaneous                                  7                
                                                                               
      II. ACTION I - BIOFOULING                               8                
                                                                               
          A.   Terms                                          8                
          B.   Inspection of Intake Structure                10                
          C.   Biocide Guidance                              14                
          D.   Fire Protection Systems                       16                
                                                                               
     III. ACTION II - HEAT TRANSFER TESTING                  18                
                                                                               
          A.   Testing Method                                18                
          B.   Maintenance of Heat Exchangers                23                
          C.   Number of Heat Exchangers To Be Tested        26                
          D.   Frequency of Testing or Maintenance           28                
          E.   Schedule                                      29                
          F.   Closed-Cycle Systems                          31                
          G.   Miscellaneous                                 33                
                                                                               
      IV. ACTION III - ROUTINE INSPECTION AND MAINTENANCE    34                
                                                                               
       V. ACTION IV - SINGLE-FAILURE WALKDOWN                36                
                                                                               
      VI. ACTION V - PROCEDURES REVIEW                       39                
                                                                               
                                                                               
.Generic Letter 89-13               -2-                                         
Supplement 1                                                                   
                                                                               
I.   GENERAL                                                                   
                                                                                
 A.   Reporting Requirements                                                    
                                                                                
 1.   If we are looking into several options to determine which one is the      
      most beneficial, however, [if] we have not made a decision by the         
      date that our response is due, would it be acceptable to explain          
      this and confirm that whatever option is chosen will be completed on      
      time?  (Wisconsin Public Service)                                         
                                                                                
      Answer                                                                    
                                                                                
      Yes.  The purpose of the 180-day response was to obtain the               
      commitments, plans, and schedules of licensees and applicants to          
      implement the recommended actions of the generic letter (GL) or           
      their equally effective alternatives.  The licensee's or applicant's      
      decision-making process should be made a part of the plans and            
      schedules and submitted to the NRC when the response is due.  If          
      other circumstances prevent such submittal, such as the regulatory        
      requirements of the technical specifications or outside government        
      agencies, the licensee or applicant should arrange any adjustments        
      of the schedule with the appropriate Office of Nuclear Reactor            
      Regulation (NRR) project manager.                                         
                                                                                
 2.   What was the basis (experience) used to determine the schedule of         
      completion for Items 2 and 4?  Do these schedules consider utilities      
      with more than one plant?  (Northeast Utilities)                          
                                                                                
      Answer                                                                    
                                                                                
      The basis for the schedule was an appearance of reasonableness.  The      
      schedules given apply to single units.  Schedules are intended to be      
      flexible and should be reported to the staff in the licensee's or         
      applicant's response with justification if the recommended schedule       
      in Generic Letter 89-13 is not used.  The licensee or applicant           
      should arrange any adjustments of the schedule with the appropriate       
      NRR project manager.                                                      
                                                                                
 3.   If the CCWS [component cooling water system] is part of the scope         
      for Items IV, V of the generic letter, would it be possible to            
      modify the completion date commitments to fit this into our already       
      existing SSFI [safety system functional inspection] schedule?             
      (Wisconsin Public Service)                                                
                                                                                
      Answer                                                                    
                                                                                
      Yes.  See the answer to Question I.A.1.  Also, this request appears       
      to be reasonable for good cause.  The licensee or applicant should        
      arrange any adjustments of the schedule with the appropriate NRR          
      project manager.                                                          
                                                                                
 4.   Can we defer the Unit 2 required action dates so that they coincide       
      with those of Unit 1 (i.e., October 1990 to April 1991 for Unit 2)?       
      (Houston Lighting and Power)                                              
                                                                         
                                                                         
.Generic Letter 89-13               -3-                                          
Supplement 1                                                                    
                                                                                
     Answer                                                                     
                                                                                
     Yes, with appropriate justification and arrangement with the               
     appropriate project manager.                                               
                                                                                
5.   For Action Items 4 and 5 of the GL 89-13, HL&P [Houston Lighting and       
     Power] plans to utilize the information gathered from a safety             
     system functional inspection (SSFI) for the essential cooling water        
     (ECW) and component cooling water (CCW) systems.                           
                                                                                
     The SSFI for the ECW system supports the GL 89-13 reporting                
     requirements; however, the CCW SSFI is scheduled for 1990.  Is it          
     acceptable to separate the reporting for the ECW and CCW systems,          
     that is, extend the CCW portion of GL 89-13?  (Houston Lighting and        
     Power)                                                                     
                                                                                
     Answer                                                                     
                                                                                
     Yes.  See the answers to Questions I.A.1 and I.A.3.                        
                                                                                
6.   The SSFI method currently being used to satisfy Recommended Actions        
     IV and V is manhour intensive.  Can program deficiencies identified        
     in the open-loop system be applied horizontally to the closed-loop         
     systems in lieu of an additional SSFI?  (Houston Lighting and Power)       
                                                                                
     Answer                                                                     
                                                                                
     Yes.  A licensee or applicant may extend identified deficiencies,          
     based on other actions already taken (such as an SSFI) on the open-        
     loop system, to the closed-loop system, provided the licensee or           
     applicant confirms that existing configuration control programs have       
     been applied to the closed-loop system.      
                                   
                                                                                
.Generic Letter 89-13               -4-                                          
Supplement 1    
                                                                
                                                                                
B.   Backfit                                                                    
                                                                                
1.   The actions proposed by GL 89-13 constitute new staff positions.  To       
     perform the testing and inspection requested by the GL, it may well        
     be necessary for licensees to make significant plant modifications.        
     For example, licensees will likely be forced to install new                
     instrumentation in order to perform tests and to monitor test              
     results.  Furthermore, changes will be required of procedures.  An         
     additional requirement of a walkdown has been made.  The proposed          
     tests may be beyond the licensing basis of the plant.  These               
     requirements seem to fit the definition of a backfit under 10 CFR          
     50.109(a)(1).  Therefore, why were the requirements in the GL              
     promulgated under the provisions of Section 50.54(f)?  (Nuclear            
     Utility Backfitting and Reform Group [NUBARG])                             
                                                                                
     Answer                                                                     
                                                                                
     The NRC concluded that it was not assured that licensees and               
     applicants are in compliance with existing regulations, namely             
     General Design Criteria 44, 45, and 46 of Appendix A of 10 CFR Part        
     50 and Appendix B of that part.  The recommended actions in this           
     generic letter do represent new staff positions and are considered a       
     backfit in accordance with NRC procedures.  This backfit is to bring       
     facilities into compliance with existing requirements.  The                
     regulatory request for information under 10 CFR 50.54(f) represented       
     by the generic letter is designed to gain this assurance.                  
                                                                                
2.   Was a backfit analysis of the testing and inspection requirements          
     per formed?  Will the staff make that analysis available to the            
     public?  In particular, did the staff's backfitting analysis, if           
     any, justify the need for actions on closed systems?  (NUBARG)             
                                                                                
     Answer                                                                     
                                                                                
     The staff performed an analysis for review by the NRC Committee to         
     Review Generic Requirements (CRGR).  Because the CRGR reviews all          
     proposed bulletins and generic letters, among other proposed staff         
     actions, this may properly be referred to as a regulatory analysis         
     pursuant to 10 CFR 50.54(f).  The CRGR analysis is available in the        
     NRC public document room (Accession No. 8907180077).                       
                                                                                
     Indeed, the staff was not able to justify inclusion of closed              
     systems in the recommended actions of the generic letter, as it had        
     once proposed to do.  Accordingly, the generic letter was issued           
     without the requirement for reporting heat transfer capability of          
     closed-cycle heat exchangers.    
                                               
                                                                                
.Generic Letter 89-13               -5-                                          
Supplement 1   
                                                                 
                                                                                
C.   Inspections                                                                
                                                                                
1.   What level of detail should be included in the descriptions of             
     existing and proposed programs? (Philadelphia Electric)                    
                                                                                
     Answer                                                                     
                                                                                
     The level of detail retained in plant records should be sufficient         
     to demonstrate that the heat removal requirements of the service           
     water system are satisfied.  Each recommended action delineated in         
     the generic letter or equivalent should be addressed in sufficient         
     detail to demonstrate the licensee's evaluation of the action.  It         
     should be noted that this information should be available in               
     appropriate plant records but need not be submitted to the NRC.            
                                                                                
2.   Generic Letter 89-13 provides the licensee with a great deal of            
     leeway in defining their programs.  This leeway is desirable and           
     justifiable given the wide variation in conditions that may prevail.       
     It is anticipated that the main mechanism for judging compliance           
     with the generic letter will be NRC site inspections.  During such         
     inspections, what will be the basis for judging the acceptability of       
     the program?  What is being done to promote consistency in                 
     interpretations among regions? (Duke Power)                                
                                                                                
     Answer                                                                     
                                                                                
     The engineering judgment of the inspector, based on the addressee's        
     documentation for the program, will be relied upon to determine            
     accept ability of the program.  The purpose of the generic letter is       
     for licensees and applicants to assure that the heat removal               
     requirements for the service water system are satisfied.  This is          
     required by regulations, particularly General Design Criteria 44,          
     45, and 46 of Appendix A of 10 CFR Part 50 and Appendix B of that          
     part.                                                                      
                                                                                
     The workshops constitute to date the NRC effort to promote                 
     consistency among the regions regarding Generic Letter 89-13.  The         
     NRC will issue the questions and answers submitted before and during       
     the workshops as a supplement to Generic Letter 89-13 within the           
     next two months.  The traditional method of issuing a temporary            
     instruction for inspection from headquarters to regional offices           
     will not be used for this generic letter. At this time, only audits        
     of implementation of Generic Letter 89-13 are planned rather than          
     systematic inspections.  If an event or problem related to the             
     service water system occurs at a particular plant, that plant's            
     actions in response to Generic Letter 89-13 will be reviewed to            
     determine if inadequacies in the implementation of the Generic             
     Letter contributed to the event or problem.  The supplement to             
     Generic Letter 89-13 will also reference the transcripts for these         
     workshops, which will be placed in the NRC public document room.           
     Authors of the generic letter will be available by telephone to            
     licensees, applicants, and inspectors to address questions on              
     implementation of the Generic Letter. 
                                          
                                                                                
.Generic Letter 89-13               -6-                                          
Supplement 1     
                                                               
                                                                                
3.   Many of your responses this morning (Workshop II in Atlanta on             
     November 30, 1989) fall back to the standard NRC position that the         
     licensee should provide adequate assurance that they have a program        
     or actions in place to satisfy the generic letter concerns.  This          
     position could create a problem later when the inspector shows up to       
     review our program.  What kind of guidance will the NRR and RES            
     [Office of Nuclear Regulatory Research] staff be providing to the          
     inspector?  If you don't provide specific instruction in something         
     like a TI [temporary instruction], the accept ability of a given           
     program will be left to the opinion of an individual inspector.            
     When will this type of guidance be available?  (Florida Power)             
                                                                                
     Answer                                                                     
                                                                                
     Both the kind of guidance and the schedule are discussed in the            
     answer to the previous question, C.2.                                      
                                                                                
4.   When does the NRC envision inspections to begin on this letter?            
     (Florida Power)                                                            
                                                                                
     Answer                                                                     
                                                                                
     At this time, only audits of implementation of Generic Letter 89-13        
     are planned rather than systematic inspections.  The schedules for         
     such audits have not been determined at this time. 
                             
                                                                                
.Generic Letter 89-13               -7-                                          
Supplement 1    
                                                                
                                                                                
D.   Miscellaneous                                                              
                                                                                
1.   Similar regional meetings regarding Generic Letter 89-04 were              
     conducted in the June 1989 time frame.  To date, the minutes from          
     these meetings have not been received.  When can we expect the             
     minutes from the Generic Letter 89-13 meetings?  (Duke Power)              
                                                                                
     Answer                                                                     
                                                                                
     Concerning Generic Letter 89-04, the minutes were issued by letter         
     dated October 25, 1989, signed by James Partlow, Associate Director        
     for Projects, Office of Nuclear Reactor Regulation.  The minutes are       
     being distributed to all licensees and applicants, meeting                 
     attendees, NRR project managers, and the NRC public document room.         
                                                                                
     Concerning Generic Letter 89-13, see the answer to Question I.C.2.         
     To repeat, the NRC will issue the questions and answers submitted          
     before and during the workshops as a supplement to Generic Letter          
     89-13 within the next two months.  The supplement to Generic Letter        
     89-13 will also reference the transcripts for these workshops, which       
     will be placed in the NRC public document room.                            
                                                                                
2.   Do Recommended Actions IV and V apply to closed cooling systems?           
     (Kansas Gas and Electric)                                                  
                                                                                
     Answer                                                                     
                                                                                
     Yes.  The generic letter defines service water systems as including        
     both open-cycle portions and intermediate closed-cycle loops that          
     function to remove heat from safety-related structures, systems, or        
     components to the ultimate heat sink.  Recommended Actions I, II,          
     and III specifically apply to open-cycle portions of the service           
     water system.  Recommended Action II can be extended to the closed-        
     cycle portions as conditions warrant. Whether a cooling loop is open       
     or closed is not specified for Actions IV and V. 
                               
                                                                                
.Generic Letter 89-13               -8-                                          
Supplement 1     
                                                               
                                                                                
II.  ACTION I - BIOFOULING                                                      
                                                                                
A.   Terms                                                                      
                                                                                
1.   What is the definition of layup?  (Philadelphia Electric)                  
                                                                                
     Answer                                                                     
                                                                                
     Layup is the treatment of a system that is isolated or in a standby        
     condition under stagnant flow conditions to prevent corrosion.             
     Refer to "Plant Layup and Equipment Preservation Sourcebook," EPRI         
     NP-5106 (March 1987).  Those service water cooling loops normally          
     operated with water in the system, even in a standby condition,            
     should contain chlorinated or equivalently treated water rather than       
     untreated water.                                                           
                                                                                
2.   What constitutes an infrequently used component?  (Philadelphia            
     Electric)                                                                  
                                                                                
     Answer                                                                     
                                                                                
     Paragraph C in Enclosure 1 in the generic letter states that               
     redundant and infrequently used cooling loops should be flushed and        
     flow tested periodically at the maximum design flow to ensure that         
     they are not fouled or clogged.  This recommended action refers to         
     emergency core cooling system loops or other safety-related cooling        
     loops that are normally in the standby condition.  The next sentence       
     states that other components in the service water system should be         
     tested on a regular schedule to ensure that they are not fouled or         
     clogged.  This recommended action refers to pumps, pipes, valves,          
     strainers, or other components even in loops in which water is             
     normally flowing.  Often inadequate flow may exist in these loops          
     and not be detected without such testing.                                  
                                                                                
     Consider a system in which water is normally flowing that has              
     parallel branches in which the states of the components in the             
     branches are not often changed.  For example, branch throttle valves       
     initially set before the plant began operation may not be controlled       
     by procedure.  Subsequent changes in the throttle valve positions          
     for various reasons or clogging of them or other components in the         
     branches would upset the initial system flow balance without               
     detection.                                                                 
                                                                                
3.   Redundant and infrequently used cooling loops:  (Unidentified)             
                                                                                
     a.   Define infrequently used.                                             
                                                                                
          Answer                                                                
                                                                                
          The wording "infrequently used cooling loops" is intended to          
          apply to those normally in a standby mode under stagnant flow         
          conditions.  The Generic Letter 89-13 program should address          
          means for ensuring that fouling does not occur under such             
          conditions.   
          
                                                                  
.Generic Letter 89-13               -9-                                          
Supplement 1 
                                                                   
                                                                                
     b.   If performance testing is done on all heat exchangers                 
          periodically, will this satisfy the intent of the                     
          recommendation?                                                       
                                                                                
     Answer                                                                     
                                                                                
     Yes.  Periodic performance monitoring of all safety-related heat           
     exchangers is acceptable, provided it ensures heat transfer                
     capability, not merely flow or pressure drop.                              
                                                                                
4.   Recommendation I of Generic Letter 89-13 states that "initial              
     activities should be completed before plant startup following the          
     first refueling outage beginning nine months or more after the date        
     of this letter."  What is the intent of the phrase, "initial               
     activities"?  Does it mean:                                                
                                                                                
     The first "round" of activities (inspections, flushes, biocide             
     treatment, etc.) has been completed; or,                                   
                                                                                
     The mechanisms have been put in place which will culminate in the          
     implementation of the program (biocide discharge permits submitted,        
     procedures written and approved)?  (Duke Power)                            
                                                                                
     Answer                                                                     
                                                                                
     Both these possibilities could be included in the intent of the            
     phrase. For those activities involving an outside governmental             
     agency, the licensee or applicant should arrange a needed adjustment       
     in the schedule with the appropriate NRR project manager.  For those       
     activities involving procedural changes or new procedures, "initial        
     activities" refers to those inspections or other activities by which       
     the need for procedural changes or new procedures is identified.  
              
                                                                                
.Generic Letter 89-13              -10-                                          
Supplement 1                                                                    
                                                                                
B.   Inspection of Intake Structure                                             
                                                                                
1.   When determining whether a plant has clams in its source water, does       
     consideration need to be given to the presence of clams in the plant       
     vicinity (local environment) or solely in the water body (source of        
     cooling water)?  (Philadelphia Electric)                                   
                                                                                
     Answer                                                                     
                                                                                
     The purpose of this recommended action is to enable a licensee or          
     applicant to know if the service water system might be subject to          
     biofouling. All potential sources of water for the service water           
     system should be examined annually for the presence of biofouling          
     species.  If no waters in the local environment of a plant can get         
     inside piping and components to cause biofouling degradation of the        
     heat transfer function of the service water system, then such waters       
     do not need to be sampled.                                                 
                                                                                
2.   Enclosure 1 to Generic Letter 89-13 recommends varying requirements        
     for service water systems based on intake structure configuration          
     and location.  In a service water system in which the suction point        
     of the service water pumps is in the collecting basin for the              
     ultimate heat sink (cooling tower) would the basin be considered the       
     intake structure or would the source of basin makeup water be              
     considered the intake structure? (Mississippi Power and Light)             
                                                                                
     Answer                                                                     
                                                                                
     Each licensee or applicant should define the scope of the intake           
     structure.  The NRC considers that an intake structure would contain       
     all the waters eventually used in the system.  See the answer to           
     Question II.B.1.                                                           
                                                                                
3.   Does the visual inspection of the intake structure apply to the            
     intake piping as well?  If so, will NRC give guidance as to                
     replacement criteria of piping?  If not, is [American National             
     Standards Institute Standard] B31.1 for wall thinning the                  
     appropriate criteria?  (Wisconsin Public Service)                          
                                                                                
     Answer                                                                     
                                                                                
     Visual inspection of the intake structure may apply to the intake          
     piping. The minimum wall thickness is defined by the code of record        
     that was used to design the piping system.  Before 1971, ANSI B31.1        
     was applicable. Since 1971, ASME Code Section 3 applies to piping          
     design and fabrication.                                                    
                                                                                
4.   When stating we should be aware of other plants (refer to                  
     Philadelphia workshop transcript, p. 21), facilities, etc., that use       
     the same service water source (e.g., river) and their biofouling           
     problems, how far does that extend?  Within 5 miles?  50 miles?            
     Please clarify.  (Unidentified)    
                                             
                                                                                
.Generic Letter 89-13              -11-                                          
Supplement 1                                                                    
                                                                                
     Answer                                                                     
                                                                                
     The NRC cannot place a quantitative range on biofouling awareness.         
     Conditions at each site would determine an appropriate program or          
     how far away to monitor for biofouling.  The licensee or applicant         
     should use the best available site-specific information and                
     establish an appropriate monitoring program.                               
                                                                                
5.   Refer to Action Item I in Gen. Ltr 89-13.  If the current sampling         
     program, which was initiated to detect Asiatic clams, has not found        
     any mollusk infestation do the sampling methods need to be modified        
     to detect Zebra mussels?  (Niagara Mohawk Power)                           
                                                                                
     Answer                                                                     
                                                                                
     The recommended sampling methods in Recommended Action I are               
     intended to be general enough to enable licensees and applicants to        
     become aware of macrobiofouling agents early enough to prevent the         
     associated fouling problem from adversely affecting the safety-            
     related function of the service water system.  See Information             
     Notice 89-76, "Biofouling Agent: Zebra Mussel."                            
                                                                                
6.   Inspection of intake structure each refuel cycle.  Could inspection        
     of other intake structures (fossil units) on the same body of water        
     that have been in place and in service for up to 40 years be used to       
     justify either to extend the frequency of inspection or maybe no           
     inspection at all? (Unidentified)                                          
                                                                                
     Answer                                                                     
                                                                                
     The inspection of the intake structure should not be restricted to         
     potential macroinvertebrate fouling.  If the program in place at the       
     fossil unit mentioned has been shown to be effective to date for           
     detecting of fouling, including biofouling, mud, and silt, then it         
     may be sufficient for future monitoring.  However, the licensee or         
     applicant should be aware of and should consider possible rapid            
     changes in environmental conditions and ensure that its program            
     includes the best available site-specific information.                     
                                                                                
7.   If it can be shown that the introduction of mollusks into the              
     service water system is not plausible based on service water system        
     design and makeup water system design, can the requirements of             
     Generic Letter 89-13 concerning both inspection for and  control of        
     mollusks be waived? (Mississippi Power and Light)                          
                                                                                
     Answer                                                                     
                                                                                
     The purpose of the generic letter is for licensees and applicants to       
     assure that the heat removal requirements for the service water            
     system are satisfied.  If this can be done by the proposed program,        
     then it is acceptable. 
                                                         
                                                                                
.Generic Letter 89-13              -12-                                          
Supplement 1         
                                                           
                                                                                
8.   If yearly inspection of a plant's service water intake structure           
     shows no indication of Asiatic clams, and testing results indicate         
     that corrosion is not microbiologically influenced, is it acceptable       
     to continue with the annual inspections for clams and perform              
     maintenance and testing as required in Actions II and III of GL            
     89-13, in lieu of a chlorination injection program?  (Commonwealth         
     Edison)                                                                    
                                                                                
     Answer                                                                     
                                                                                
     This appears to be reasonable for good cause shown.  See the answers       
     to the previous two questions.                                             
                                                                                
9.   Larva sampling is difficult to do.  We already have a sampling             
     commitment, but we don't want to do this and can justify not doing         
     it.  (Kansas Gas and Electric)                                             
                                                                                
     Answer                                                                     
                                                                                
     An equally effective course of action with justification is                
     acceptable. However, the earlier that a licensee or applicant can          
     identify the presence of a biofouling species in a source body of          
     water for the service water system, the better chance it will have         
     to control the situation and prevent a potential safety problem.           
                                                                                
10.  Does the generic letter imply that biofouling monitoring methods are       
     required?  Are sidestream or inline monitoring methods necessary?          
     Does the NRC have a preference concerning the methods of visual, UT        
     [ultrasonic testing], radiography, or electrochemical (Corrator)           
     probes to monitor for biofouling?  (South Carolina Electric and Gas)       
                                                                                
     Answer                                                                     
                                                                                
     Biofouling monitoring of the source water would generally be               
     necessary. Licensees and applicants may use, however, equally              
     effective programs for Recommended Action I.  Sidestream or inline         
     monitoring is effective and could be used for this purpose.  The NRC       
     has no preference concerning methods for biofouling monitoring or          
     nondestructive service water system examination provided the               
     selected method is effective.                                              
                                                                                
11.  For NTOL [near-term operating license] plants, when does GL 89-13          
     have to be implemented?  (Unidentified)                                    
                                                                                
     Answer                                                                     
                                                                                
     As stated in Generic Letter 89-13, both licensees and applicants           
     should observe the same schedule.  The licensee or applicant should        
     arrange any justified adjustments of the schedule with the                 
     appropriate NRR project manager.                                           
                                                                                
 12. On Item C, Enclosure 1, since macroscopic biological fouling and MIC       
     [microbiologically influenced corrosion] have not been problems at         
     CNS [Cooper Nuclear Station], does that exempt us from the                 
     recommendation for chlorinating systems using raw water before             
     layup?  (Nebraska Public Power District)   
     
                                     
.Generic Letter 89-13              -13-                                          
Supplement 1                                                                    
                                                                                
     Answer                                                                     
                                                                                
     Yes, if appropriate justification is provided.                             
                                                                                
13.  Is periodic maintenance adequate to address layup without                  
     chlorination? (Nebraska Public Power District)                             
                                                                                
     Answer                                                                     
                                                                                
     Yes, if appropriate justification is provided.                             
                                                                                
14.  On Item D, Enclosure 1, in lieu of taking annual water samples to          
     determine if Asiatic clams have populated the water source, could we       
     perform annual visual inspections of sample heat exchangers cooled         
     by river water? (Nebraska Public Power District)                           
                                                                                
     Answer                                                                     
                                                                                
     The purpose of sampling the water source itself was to ensure that         
     means of potential fouling were identified early.  However, if the         
     best avail able site-specific information does not indicate a means        
     of biofouling, then visual examination of a sample of service water        
     system heat exchangers may be sufficient, with proper justification,       
     to detect fouling.    
     
                                                          
                                                                                
.Generic Letter 89-13              -14-                                          
Supplement 1                                                                    
                                                                                
C.   Biocide Guidance                                                           
                                                                                
1.   Enclosure 1 to Generic Letter 89-13 describes an acceptable program,       
     to the NRC, to implement Recommendation No. I of the generic letter.       
     This program includes biocide treatment regardless of whether the          
     plant is susceptible to macroscopic biological fouling or not.  Will       
     a program that does not include biocide treatment be acceptable to         
     the NRC?  (Duke Power)                                                     
                                                                                
     Answer                                                                     
                                                                                
     Yes, if good cause is shown.  Note the guidance in Paragraph B of          
     Enclosure 1 to Generic Letter 89-13.  Chlorination or equally              
     effective treatment is included for freshwater plants without clams        
     because it can help prevent microbiologically influenced corrosion.        
                                                                                
2.   With regards to Enclosure 1 of the generic letter; (Wisconsin Public       
     Service)                                                                   
                                                                                
     a.   Will NRC give guidance on use of biocides other than chlorine?        
                                                                                
          Answer                                                                
                                                                                
     No.  The NRC is interested in the effective heat transfer of the           
     systems.  It is not in a position to consult on the various biocide        
     treatments.  Refer to "Plant Layup and Equipment Preservation              
     Sourcebook," EPRI NP-5106 (March 1987).                                    
                                                                                
     b.   Do we need to continuously chlorinate, if under our inspection        
          program, we find no evidence of macroscopic fouling?  Do WPDES        
          [sic; National Pollutant Discharge Elimination System]                
          discharge limits take precedence to this?                             
                                                                                
          Answer                                                                
                                                                                
          No.  The program described in Enclosure 1 represents an               
          acceptable program for implementing Recommended Action I.  A          
          licensee or applicant can choose to pursue an equally effective       
          alternative course of action if justified.  Precautions should        
          be taken to obey Federal, State, and local environmental              
          regulations regarding the use of biocides.  This includes the         
          National Pollutant Discharge Elimination System (NPDES)               
          discharge limits administered by the U.S. Environmental               
          Protection Agency, which were referenced in the question.             
                                                                                
     c.   Is demineralized water acceptable for use in wet layup of             
          stagnant SW [service water] piping?   
          
                                          
                                                                                
.Generic Letter 89-13              -15-                                          
Supplement 1                                                                    
                                                                                
Answer                                                                          
                                                                                
          This question must be decided by the licensee or applicant.           
          The result should be that the heat removal requirements for the       
          service water system are satisfied.  To accomplish this, the          
          NRC recommends that such piping be flushed and flow tested            
          periodically to ensure that clogging is absent and that               
          chlorinated or equivalently treated water will be used to fill        
          service water loops before layup to help prevent MIC.  We note        
          also that industry recommends treatment of service water              
          systems during outages to prevent microbes.  See EPRI NP-5106.        
                                                                                
3.   Some State regulations do not permit the use of biocides above the         
     minimum detectable level, yet Enclosure 1 to the GL appears to             
     require biocides while cautioning plants not to violate State and          
     local regulations.  Since it is not possible in some jurisdictions         
     to use any biocides without  violating State and local regulations,        
     what alternatives to biocides are acceptable to the staff? (Nuclear        
     Utility Backfit Action Reform Group [NUBARG])                              
                                                                                
     Answer                                                                     
                                                                                
     An alternative course of action is acceptable if the heat removal          
     requirements for the service water system are satisfied.  Biocides         
     can be deactivated before discharge.  The treated biocides must meet       
     NPDES discharge limits.  At least one utility (Trojan) is                  
     deactivating the biocides before discharge.  See the answers to the        
     previous two questions.  
     
                                                       
                                                                                
.Generic Letter 89-13              -16-                                          
Supplement 1       
                                                             
                                                                                
D.   Fire Protection Systems                                                    
                                                                                
1.   To what extent should fire protection systems be addressed in              
     response to the generic letter?  (Philadelphia Electric)                   
                                                                                
     Answer                                                                     
                                                                                
     The generic letter is not designed to focus on fire protection             
     systems, which are not safety-related, but to incidentally include         
     them if they use untreated water that could be subject to the              
     service water system problems described in the generic letter.             
                                                                                
2.   We use well water (raw water) as a source to the fresh water/fire          
     protection storage tanks.  Do we need to chlorinate these tanks or         
     do we need to conduct full-flow surveillance tests on all fire             
     protection piping runs? We presently only surveil the fire pumps for       
     flow, not the piping runs. We do not presently chlorinate these            
     tanks.  The SW system per se is not used to fill these tanks;              
     separate well pumps are used.  (Public Service Electric and Gas)           
                                                                                
     Answer                                                                     
                                                                                
     The recommended program described in Enclosure 1 of the generic            
     letter was developed under a government-sponsored research program.        
     If a licensee or applicant chooses an alternative course of action         
     from that recommended in Enclosure 1, it should assess the                 
     potentials for macroscopic biofouling and microbiologically                
     influenced corrosion (MIC) and justify that the alternative course         
     of action will result in satisfaction of the heat removal                  
     requirements for the service water system.                                 
                                                                                
     Paragraph B of Enclosure 1 of the generic letter recommends                
     chlorination whenever the potential for a macroscopic biological           
     fouling species exists.  Such a potential may not exist for these          
     wells, but the potential for MIC should also be considered.                
                                                                                
     Paragraph C of Enclosure 1 of the generic letter recommends periodic       
     flow testing of infrequently used loops at the maximum design flow         
     to ensure that they are not fouled or clogged.  If the fire                
     protection piping runs are subject to biofouling but the water is          
     not treated to protect against biofouling, then full-flow testing of       
     the runs may be appropriate to ensure that the potential for               
     clogging is minimal.  This paragraph also recommends chlorination to       
     help prevent MIC.  
     
                                                             
                                                                                
.Generic Letter 89-13              -17-                                          
Supplement 1    
                                                                
                                                                                
3.   Do Generic Letter 89-13 requirements apply to the fire protection          
     systems which are not fed by either the service water system or the        
     service water Intake?  (South Carolina Electric and Gas)                   
                                                                                
     Answer                                                                     
                                                                                
     The generic letter is not designed to focus on fire protection             
     systems, but to incidentally include them if they use untreated            
     water that could be subject to the service water system problems           
     described in the generic letter.                                           
                                                                                
4.   What is the basis for requiring treatment of fire protection systems       
     that use raw service water as a source (Enclosure 1, Section C)?           
     (NUBARG)                                                                   
                                                                                
     Answer                                                                     
                                                                                
     See the answers to the previous two questions.                             
                                                                                
5.   For a fire protection system supplied by raw water which meets flow        
     requirements and does not provide safety-related cooling, are any          
     actions required?  (Iowa Electric Light and Power)                         
                                                                                
     Answer                                                                     
                                                                                
     No.  See the answer to Question II.D.1.    
     
                                     
                                                                                
.Generic Letter 89-13              -18-                                          
Supplement 1    
                                                                
                                                                                
III. ACTION II - HEAT TRANSFER TESTING                                          
                                                                                
A.   Testing Method                                                             
                                                                                
1.   Should the proposed heat exchanger heat transfer testing method be         
     provided for prior NRC review and approval?  (Philadelphia Electric)       
                                                                                
     Answer                                                                     
                                                                                
     No.                                                                        
                                                                                
2.   Has the NRC reviewed the EPRI SWWG [Electric Power Research                
     Institute Service Water Working Group] document prepared by Duke           
     Power and Toledo Edison describing several methods of heat transfer        
     testing?  If so, is the temperature effectiveness method acceptable?       
     Which methods are accept able?  (Philadelphia Electric)                    
                                                                                
     Answer                                                                     
                                                                                
     The staff has not formally reviewed this document but has received a       
     draft copy.  A method of heat transfer testing is acceptable for           
     purposes of satisfying the generic letter if it can assure that the        
     heat removal requirements for the service water system are                 
     satisfied.                                                                 
                                                                                
3.   If the pressure drop across a heat exchanger at design flow is less        
     than or equal to the manufacturer's specification, is heat transfer        
     testing required, provided the baffles have been inspected to ensure       
     that the flow is not bypassing the coils?  (Philadelphia Electric)         
                                                                                
     Answer                                                                     
                                                                                
     The objective is not to satisfy the manufacturer's specification for       
     flow in a heat exchanger so much as it is to ensure that the heat          
     removal requirements for the service water system are satisfied.  If       
     the latter assurance can be achieved by showing design flow to be          
     necessary and sufficient, then heat transfer testing would be              
     superfluous.                                                               
                                                                                
4.   Page 5, paragraph 3.  What is meant by "The relevant temperatures          
     should be verified to be within the design limits?"  Does this imply       
     testing should be conducted with the design-basis heat load?  Is it        
     acceptable to conduct testing for all heat exchangers at off normal        
     conditions, provided accurate and relevant data can be acquired, and       
     analytical methods used to determine the heat transfer capacity at         
     design conditions?  (Portland General Electric)                            
                                                                                
     Answer                                                                     
                                                                                
     Enclosure 2 of the generic letter discusses in detail verifying            
     various parameters to be within design limits.  Testing with design-       
     basis heat loads is recommended ideally.  If testing can be done           
     under design conditions, it should be done under those conditions.         
     Realizing this may not be practicable in nonaccident circumstances,        
     the next best step is to    
     
                                                    
                                                                                
.Generic Letter 89-13              -19-                                          
Supplement 1                                                                    
                                                                                
     conduct tests under off-design conditions and analytically correct         
     the results to the design conditions.  Such a procedure is                 
     acceptable if it is necessary but not if testing under design              
     conditions is practicable.                                                 
                                                                                
5.   For heat exchangers that cannot be tested at the design heat removal       
     rate, what is the NRC-recommended method to extrapolate the test           
     data to design conditions?  Does the NRC have any additional               
     recommendations for extrapolating test data taken at very low loads        
     (less than 10% design load) to design conditions?  (Southern               
     California Edison)                                                         
                                                                                
     Answer                                                                     
                                                                                
     The staff does not have a recommended method of extrapolation.             
     However, the EPRI service water system working group has been              
     developing such guidance as have some licensees such as Duke Power.        
     These may be places to start when developing appropriate testing           
     programs.                                                                  
                                                                                
6.   Recommended Action II requires that "the relevant temperatures             
     should be verified to be within design limits."  Also, Enclosure 2,        
     Item II.A states, "Perform functional testing with the heat                
     exchanger operating, if practical, at its design heat removal rate         
     to verify its capabilities. Temperature and flow compensation should       
     be made in the calculations to adjust the results to the design            
     conditions."                                                               
                                                                                
     It is not practical to test the heat exchangers at design heat             
     removal rates.  Also, we are unable to find a method which has the         
     requisite level of precision to adjust the test results to design          
     conditions.                                                                
                                                                                
     Please discuss an acceptable method to adjust the test results to          
     the design conditions.  Also provide the scientific bases, or a            
     reference, for the proposed method.                                        
                                                                                
     Also, the heat removal test cannot be performed on the containment         
     spray heat exchangers because there is no heat source.  The only           
     test that can be performed is a pressure drop test.  Is this               
     acceptable?  If not, what is recommended?  (Indiana and Michigan           
     Power)                                                                     
                                                                                
     Answer                                                                     
                                                                                
     As mentioned previously, the NRC does not have a recommended test          
     method. See the answer to the previous question.  With regard to the       
     testing of containment spray heat exchangers, as of all safety-            
     related heat exchangers, a pressure drop test alone is not                 
     sufficient to satisfy the indicated heat transfer capability               
     concerns.  If it is not practicable to test a heat exchanger, then         
     the licensee or applicant may propose a program of periodic                
     inspection, maintenance, and cleaning as an alternative.  We are           
     aware, however, of one licensee who was able to test the containment       
     spray heat exchanger by heating the refueling water storage tank           
     water approximately 10 F and then performing temperature monitoring        
     tests as well as pressure drop tests.
     
     
.Generic Letter 89-13              -20-                                          
Supplement 1                                                                    
                                                                                
7.   To what degree should a utility endeavor to monitor real-time              
     corrosion rates of the service water system?  Is trending of heat          
     exchanger performance and visual inspections sufficient                    
     documentation of the component's internal condition?  (South               
     Carolina Electric and Gas)                                                 
                                                                                
     Answer                                                                     
                                                                                
     It is not necessary to determine numerical real-time corrosion rates       
     in the service water system.  The licensee's or applicant's                
     monitoring program should be sufficient to identify degradation and        
     to take the necessary corrective action before system performance is       
     unacceptably affected.  Trending of data is a recommended approach         
     to monitoring system performance.                                          
                                                                                
8.   Is the NRC staff stating that a technical evaluation of a heat             
     exchanger's capability to perform its design safety function cannot        
     be used in lieu of initial testing?  Therefore, all heat exchangers        
     must be tested and even maintenance/cleaning cannot be used in lieu        
     of initial testing because it would require a technical evaluation         
     to determine maintenance/cleaning frequency.  Also, when considering       
     several identical heat exchangers in one loop, do all the heat             
     exchangers require testing or maintenance/cleaning?  (Philadelphia         
     Electric)                                                                  
                                                                                
     Answer                                                                     
                                                                                
     No, the initial heat exchanger "test" program may consist of both          
     performance testing of some heat exchangers and maintenance and            
     cleaning of others.  The initial test program was intended to ensure       
     that the licensee or applicant has established a baseline for all          
     safety-related heat exchangers served by the service water system          
     and, therefore, is confident that they can perform their heat              
     removal function.  As further clarification, if there are several          
     identical heat exchangers in one service water loop, a licensee or         
     applicant may perform testing or develop a maintenance and cleaning        
     program for these heat exchangers based on the most limiting one as        
     part of its initial "test" program.  Justification for the basis of        
     comparable service conditions should be included in the evaluation         
     when all identical heat exchangers are not tested.                         
                                                                                
9.   Refer to Action Item II of Gen. Ltr 89-13.  Can the test program           
     include data taken during routine operating intervals, with minimum        
     load on heat exchangers, and extrapolated to substantiate adequate         
     HX [heat exchanger] performance?  Or when does the NRC consider it         
     impractical to test a HX at the design heat removal rate?  (Niagara        
     Mohawk Power)                                                              
                                                                                
     Answer                                                                     
                                                                                
     Yes, if testing under design conditions is not practicable.  See the       
     answers to Questions III.A.4, III.A.5, and III.A.6 above.  The             
     licensee or applicant should determine whether such testing is             
     practicable.  See the answer to Question III.A.14.  
                            
                                                                                
.Generic Letter 89-13              -21-                                          
Supplement 1                                                                    
                                                                                
10.  In Enclosure 2 of the generic letter, a statement is made that             
     testing should be done with necessary and sufficient                       
     instrumentation.  Flow measurement is one of the two key parameters        
     when measuring heat exchanger performance.  It is also the most            
     difficult since most plants never provided means to measure                
     individual flow rates to service water users. In general, orifice          
     plates, venturi tubes, pitot tubes and flow nozzles are the only           
     recognized traceable type of flow measuring devices, all of which          
     require intrusive elements.  To be able to utilize such devices            
     would require plant system modifications at great expense to the           
     utility and its customers.  A less expensive alternative to this           
     would be to use non-intrusive, non-traceable devices such as               
     transit-time ultrasonic flow meters which with current technology          
     give very reliable results.  Trending of data taken with such              
     devices would appear to be equally effective for detecting                 
     degradation in cooling water systems.  Would the NRC recognize the         
     value and benefit of using such devices and accept programs which          
     utilize them? (Detroit Edison)                                             
                                                                                
     Answer                                                                     
                                                                                
     Yes.                                                                       
                                                                                
11.  Thermographic cameras could potentially be used to scan the tubes on       
     air to water heat exchangers to see temperature profiles of the            
     tubes and detect tube blockage or sediment in the tubes.  Will the         
     NRC accept such qualitative checks rather than quantitative                
     measurements to prove that a heat exchanger is not fouled?  (Detroit       
     Edison)                                                                    
                                                                                
     Answer                                                                     
                                                                                
     Yes.  However, additional means should be included in the program to       
     ensure adequate heat transfer.                                             
                                                                                
12.  If off-the-shelf software is reviewed for technical adequacy and           
     subsequently utilized to perform heat exchanger performance                
     calculations, will it be acceptable to the NRC?  (Detroit Edison)          
                                                                                
     Answer                                                                     
                                                                                
     Yes.                                                                       
                                                                                
13.  If a heat exchanger performance test reveals that a heat exchanger         
     is in a degraded condition, the first obvious question will be as to       
     what the impact of the degraded condition is on system operability.        
     Will a heat exchanger performance program be considered the same as        
     the plant's surveillance program with the same ramifications for           
     questioning plant/system operability?  If so, is the NRC considering       
     asking the licensees to include limiting condition for operation           
     statements in their technical specifications?  (Detroit Edison)    
             
                                                                                
.Generic Letter 89-13              -22-                                          
Supplement 1                                                                    
                                                                                
     Answer                                                                     
                                                                                
     If a heat exchanger's heat transfer capability is shown to be              
     degraded below levels needed for performance of its safety-related         
     function, it is considered inoperable.  The staff does not intend          
     that elements of these programs be included in plant technical             
     specifications.                                                            
                                                                                
14.  Restate what you would consider acceptable as "impractical                 
     conditions for testing."  What are "acceptable alternatives,"              
     especially for utilities not privy to EPRI information?  (Portland         
     General Electric)                                                          
                                                                                
     Answer                                                                     
                                                                                
     An impractical condition would be a situation where flow or the            
     means of applying a heat load cannot be achieved because of system         
     configuration. An acceptable alternative is a periodic inspection or       
     maintenance program for such heat exchangers.  Impracticality itself       
     is not a sufficient reason for excluding any heat exchanger from           
     some verification of performance.                                          
                                                                                
15.  What if performable HX testing conditions (off design) cannot be           
     used to demonstrate acceptable heat transfer (i.e., low delta T            
     combined with instrument accuracies)?  Is maintenance inspection our       
     only alternative? (Portland General Electric)                              
                                                                                
     Answer                                                                     
                                                                                
     If reasonable results cannot be obtained from performance testing,         
     then inspection or maintenance is an appropriate alternative.  A           
     licensee may, however, be able to justify another acceptable               
     alternative.                                                               
                                                                                
16.  If the utility performs a baseline test that exceeds the design            
     requirements but is below the mfg [manufacturer's] rating for this         
     component HX, does the NRC consider this as a concern in that              
     "design margin" has been lowered?  (Arkansas Power and Light)              
                                                                                
     Answer                                                                     
                                                                                
     No.  The staff's concern is not that a licensee or applicant               
     maintain the initially specified design margin.  If the licensee or        
     applicant chooses to operate with a reduced margin, this is                
     acceptable provided the safety-related heat removal requirements are       
     satisfied.   
                                                                   
                                                                                
.Generic Letter 89-13              -23-                                          
Supplement 1                                                                    
                                                                                
B.   Maintenance of Heat Exchangers                                             
                                                                                
1.   To what extent can routine maintenance/cleaning of heat exchangers         
     replace testing?  (Philadelphia Electric)                                  
                                                                                
     Answer                                                                     
                                                                                
     A licensee or applicant should determine the appropriate frequency         
     of testing or maintenance activities to ensure that the heat removal       
     requirements for the service water system are satisfied.  For a            
     given heat exchanger, a licensee or applicant may elect to clean,          
     replace, repair, or otherwise maintain it initially before beginning       
     a routine testing program.  If the licensee or applicant elects to         
     not implement a routine testing program for the heat exchanger, then       
     a routine maintenance program may be necessary to provide the sought       
     assurance.  In the absence of a routine test program, no basis may         
     be available for detecting potential degradation of heat transfer          
     performance.  In the absence of such a basis, the frequency of             
     maintenance may have to be a maximum value to provide the sought           
     assurance.                                                                 
                                                                                
2.   Page 5, paragraph 4.  If the maintenance period is known why can't a       
     test be performed before maintenance to establish a data point for         
     the required testing or maintenance?  If the overall maintenance           
     period has been 3 or more fuel cycles could this be used to                
     establish the test frequency?  Is it necessary to retest a heat            
     exchanger after maintenance if the work performed was a restoration        
     only (i.e., cleaning not tube plugging) and testing had previously         
     been conducted with clean heat transfer surfaces? (Portland General        
     Electric)                                                                  
                                                                                
     Answer                                                                     
                                                                                
     All these steps are acceptable alternatives to the program outlined        
     in Enclosure 2 in the generic letter.  The justifications that these       
     alternative procedures ensure that the heat removal requirements for       
     the service water system are satisfied should be documented and            
     retained in appropriate plant records.                                     
                                                                                
3.   Recommended Action II paragraph 5 states that frequent regular             
     maintenance is an acceptable alternative to testing.  What is meant        
     by "frequent regular maintenance"?  Does this mean more frequently         
     than if testing were performed?  This paragraph further states that        
     this alternative might apply to small heat exchangers, . . . located       
     in low radiation areas. . . . Would low radiation areas be defined         
     by ALARA [as low as is reasonably achievable] practices or less than       
     100 mr/hr?  (Unidentified)                                                 
                                                                                
     Answer                                                                     
                                                                                
     The licensee or applicant is to establish the frequency of periodic        
     testing or regular maintenance once sufficient data have been              
     collected. The frequency should ensure that unacceptable degradation       
     does not occur between testing or maintenance cycles.  Low radiation       
     areas as intended in Generic Letter 89-13 are included in the              
     licensee's ALARA program so that                                           


.Generic Letter 89-13              -24-                                          
Supplement 1                                                                    
                                                                                
     radiation levels will not preclude personnel access for maintenance        
     and cleaning of heat exchangers.                                           
                                                                                
4.   GL 89-13 seems to imply that periodic maintenance (i.e., cleaning)         
     of small accessible heat exchangers is acceptable in lieu of               
     performance testing.  If so, is a refueling maintenance frequency          
     acceptable? (Northeast Utilities)                                          
                                                                                
     Answer                                                                     
                                                                                
     Yes.  This is an acceptable initial frequency and may be acceptable        
     in the long-term with justification based on data from a minimum of        
     three refueling outages.                                                   
                                                                                
5.   If maintenance is performed in lieu of testing for degraded                
     performance of the heat exchanger, how extensive does the                  
     maintenance have to be?  That is, does maintenance have to be              
     performed on both sides of the HX or just on the service water side?       
     (Niagara Mohawk Power)                                                     
                                                                                
     Answer                                                                     
                                                                                
     Maintenance should be extensive enough to assure the heat removal          
     requirements of the service water system are satisfied.  See the           
     answers to Questions III.B.1 and III.F.1.                                  
                                                                                
6.   Would a program involving inspection and maintenance activities in         
     lieu of a performance test program be an acceptable program for all        
     heat exchangers and components? (Nuclear Utility Backfit Action            
     Reform Group [NUBARG])                                                     
                                                                                
     Answer                                                                     
                                                                                
     Yes, if justification is provided.                                         
                                                                                
7.   Clarification of Item IV. B., Enclosure 2, on periodic visual              
     inspection of small heat exchangers such as seal coolers.  Are they        
     included in the class to be inspected when the pump is inspected?          
     (Nebraska Public Power District)                                           
                                                                                
     Answer                                                                     
                                                                                

     If the seal coolers in question are integral parts of larger               
     components, such as pumps, then the coolers may be inspected               
     visually during the regularly scheduled disassembly of the larger          
     component.  If not, then the seal coolers should be treated                
     separately.  Once it has been established that a small heat                
     exchanger such as a seal cooler is performing satisfactorily, the          
     licensee or applicant may choose to justify an extended program of         
     periodic inspection (e.g., up to 5 years) on the basis of existing         
     operating conditions, such as the cooling of loops not subject to          
     fouling mechanisms.  
                                                           
                                                                                
.Generic Letter 89-13              -25-                                          
Supplement 1                                                                    
                                                                                
8.   ANO [Arkansas Nuclear One] is scheduled to chemically clean the            
     entire SW system in the fall of 1990.  Does this constitute an             
     acceptable method to restore thermal performance in lieu of                
     performance testing for the first outage?  (Arkansas Power and             
     Light)                                                                     
                                                                                
     Answer                                                                     
                                                                                
     The licensee or applicant should justify such an approach to satisfy       
     this part of the generic letter.  Since chemical cleaning is a             
     corrective action, some followup verification such as visual               
     examination or limited performance testing may be appropriate.   
               
                                                                                
.Generic Letter 89-13              -26-                                          
Supplement 1                                                                    
                                                                                
C.   Number of Heat Exchangers To Be Tested                                     
                                                                                
1.   Is it acceptable to determine the most restrictive heat exchangers         
     in each group for testing in lieu of testing every heat exchanger?         
     (Philadelphia Electric)                                                    
                                                                                
     Answer                                                                     
                                                                                
     The purpose of the generic letter is for licensees and applicants to       
     assure that the heat removal requirements for the service water            
     system are satisfied.  If this can be done by the proposed program,        
     then it is acceptable.                                                     
                                                                                
2.   How much detail does the NRC expect for the response to Action II?         
     Would the proposed test/maintenance/inspection method for each             
     heat exchanger be necessary?  (Public Service Electric and Gas)            
                                                                                
     Answer                                                                     
                                                                                
     Specific details of the licensee's or applicant's program in               
     response to Action II should be developed and retained as part of          
     plant records. Those heat exchangers not being included in programs        
     under Action II should be identified and the basis given for their         
     exclusion.  Grouping of heat exchangers into categories based on the       
     approach to be used would be acceptable.                                   
                                                                                
3.   Enclosure 2, page 2.  The term "all heat exchangers" is used.  Does        
     this imply every heat exchanger of a given design must be tested or        
     where more than one identical heat exchanger is used can one               
     representative unit be selected?  (Portland General Electric)              
                                                                                
     Answer                                                                     
                                                                                
     Recommended Action II calls for the testing of the heat transfer           
     capability of all safety-related heat exchangers cooled by service         
     water.  The service water system is defined as the system or systems       
     that transfer heat from safety-related structures, systems, or             
     components to the ultimate heat sink.  Each heat exchanger,                
     regardless of redundancy, should be tested or maintained initially         
     to establish that the heat removal requirements for the service            
     water system are satisfied.  Existence of identical conditions then        
     can be used to determine the best test or maintenance frequencies to       
     ensure that the heat removal requirements for the service water            
     system are satisfied.                                                      
                                                                                
4.   We would like to limit heat exchanger performance testing to one           
     unit since the two units are identical.  Is this an acceptable             
     approach? (Houston Lighting and Power)                                     
                                                                                
     Answer                                                                     
                                                                                
     Not totally.  See the answer to the previous question.    
                      
                                                                                
.Generic Letter 89-13              -27-                                          
Supplement 1     
                                                               
                                                                                
5.   Is it acceptable to eliminate heat exchangers from the testing             
     requirement of Action II if they are in parallel and/or in series          
     with other heat exchangers which are tested and operated under             
     similar service conditions  (e.g., velocity, temperature, process          
     fluid) (Ref. EPRI Heat Exchanger Performance Monitoring Guidelines         
     for Service Water Systems)? (Common wealth Edison)                         
                                                                                
     Answer                                                                     
                                                                                
     Not totally.  See the answer to Question III.C.3.       
                        
                                                                                
.Generic Letter 89-13              -28-                                          
Supplement 1     
                                                               
                                                                                
D.   Frequency of Testing or Maintenance                                        
                                                                                
1.   Recommendation No. III [sic] does not specify a frequency for heat         
     exchanger inspections.  Is it the NRC's intent that the utility            
     establish the frequency of these inspections?  (GPU Nuclear)               
                                                                                
     Answer                                                                     
                                                                                
     Yes.  Recommended Action II indicates limits.  Initially, tests            
     should be conducted at least once every fuel cycle.  More frequent         
     testing may be necessary to enable a conclusion that the heat              
     removal requirements for the service water system are satisfied.           
     After about three tests, a licensee or applicant may be in a               
     position to set a different testing frequency.  However, the finally       
     determined testing frequency should not be less than once every 5          
     years.                                                                     
                                                                                
2.   Page 6, paragraph 1.  Why were three tests chosen?  Could a                
     different number, more or less, be appropriate?  (Portland General         
     Electric)                                                                  
                                                                                
     Answer                                                                     
                                                                                
     The number three is the minimum number needed to establish a trend.        
     A larger number would be appropriate, but a smaller number is              
     insufficient.                                                              
                                                                                
3.   Page 5, paragraph 5.  What is meant by frequent regular maintenance?       
     Can frequency be determined in a similar method as test frequency?         
     (Portland General Electric)                                                
                                                                                
     Answer                                                                     
                                                                                
     Frequent regular maintenance is an acceptable alternative to               
     Recommended Action II, which calls for heat exchanger performance          
     testing.  For small heat exchangers such as lube oil coolers,              
     testing might be excessively burdensome compared with maintenance of       
     the heat exchangers.  A licensee or applicant can choose to                
     routinely maintain the heat exchangers instead of testing them.            
     Either the frequency of maintenance or the frequency of testing            
     should be determined to ensure that the equipment will perform the         
     intended safety functions during the intervals between maintenances        
     or tests.         
                                                              
                                                                                
.Generic Letter 89-13              -29-                                          
Supplement 1     
                                                               
                                                                                
E.   Schedule                                                                   
                                                                                
1.   In an effort to minimize the amount of time that a single, redundant       
     division of safety-related equipment is out of service some                
     utilities employ a "divisional outage" concept for major planned           
     plant outages.  By utilizing this concept significant maintenance          
     work activities, i.e., system flow balance test, standby D/G [diesel       
     generator] teardowns, electrical distribution bus work, etc., are          
     performed on an alternating outage schedule for each division.  This       
     permits comprehensive maintenance on each division to be performed         
     while reducing the overall impact on redundant safety system               
     availability.                                                              
                                                                                
     The ability of a utility to implement and maintain a service water         
     heat removal capability monitoring program would be significantly          
     enhanced by the installation of permanent plant monitoring                 
     equipment.  Installation of dedicated monitoring equipment would           
     also reduce the impact of future testing on service water and heat         
     exchanger availability.                                                    
                                                                                
     For a utility that employs the "divisional outage" concept and             
     wishes to install permanent plant equipment to perform the system          
     testing identified in Generic Letter 89-13, is it permissible to           
     defer baseline data acquisition for one division of the service            
     water system until the second refueling outage following the               
     issuance of the generic letter?  (Mississippi Power and Light)             
                                                                                
     Answer                                                                     
                                                                                
     This request appears to be reasonable for good cause.  Any request         
     for an adjusted schedule should be arranged through the appropriate        
     project manager in the Office of Nuclear Reactor Regulation (NRR) of       
     the NRC.                                                                   
                                                                                
2.   In reference to Recommended Action II of Generic Letter 89-13.             
     (Niagara Mohawk Power)                                                     
                                                                                
     Asking an item of clarification   Do all safety-related heat               
     exchangers connected to or cooled by service water or raw water have       
     to be tested or verified clean by maintenance, to insure                   
     satisfaction of the heat removal requirements, prior to plant              
     startup following the first refueling outage beginning 9 months or         
     more after the issuance of Gen. Ltr 89-13?                                 
                                                                                
     Answer                                                                     
                                                                                
     Yes.                                                                       
                                                                                
     Reason for asking   If a heat exchanger was cleaned 13 or possibly         
     18 months prior to issuance of Gen. Ltr 89-13 and found to be clean        
     or tested and found acceptable and the current program does not call       
     for recleaning or testing for 3 years then the program would have to       
     be revised.  Also trend data may already exist indicating that there       
     is no need to clean or test on less than a 5-year interval.  [This         
     would also hold] if the heat exchanger is part of a larger component       
     that is not scheduled for maintenance. 
     
                                         
.Generic Letter 89-13              -30-                                          
Supplement 1                                                                    
                                                                                
     Answer                                                                     
                                                                                
     The generic letter is designed to provide flexibility in determining       
     a justifiable alternative program for testing.  The goal of the            
     letter is to ensure that the heat removal requirements for the             
     service water system are satisfied.  
                                           
                                                                                
.Generic Letter 89-13              -31-                                          
Supplement 1  
                                                                  
                                                                                
F.   Closed-Cycle Systems                                                       
                                                                                
1.   What is really required by the sentence on adequacy of chemistry           
     control programs in the first paragraph of page 5 of the generic           
     letter?  (Kansas Gas and Electric)                                         
                                                                                
     Answer                                                                     
                                                                                
     Even though a closed cooling loop may contain water with controlled        
     chemistry, the loop might be contaminated as a result of inleakage,        
     inadequate chemistry controls, or materials in the system before the       
     current chemistry control program became effective.  An example of         
     this was recently disclosed at the EPRI Service Water System               
     Reliability Improvement Seminar at Charlotte, North Carolina, on           
     November 6-8, 1989. In the internal study discussed there, optical         
     examination of the primary side of the decay heat removal (DHR) heat       
     exchanger (HX) tubes disclosed no fouling.  The tubes were shiny           
     bright.  Optical examination of the closed component cooling water         
     (CCW) HX, however, disclosed significant fouling.  The tubes did not       
     reflect any light.  The problem was a paraffin-based packing               
     material inadvertently left in the system when the plant was being         
     constructed.                                                               
                                                                                
     Suppose the licensee in this case can argue that it has a chemistry        
     control program for water circulating through the CCW HX, but cannot       
     show that the program has been in place since the system was filled        
     initially. A proper response to the generic letter then would              
     include testing the CCW HX.  At any point in the program, if a             
     finding of degraded heat transfer cannot be explained or remedied by       
     maintenance in the open-cycle portion of the system, as would be           
     possible in this case, the CCW HX should be tested and, depending on       
     those results, the DHR HX should be tested.  The process should be         
     continued until the problem is remedied.                                   
                                                                                
2.   Does our CCWS [component cooling water system] need to be addressed        
     as part of our response?  We have recently shown, through eddy             
     current testing of the CCW HTX's [heat exchangers], that the               
     physical barrier between SW [service water] and CCW is adequate.           
     Makeup to the CCW is via makeup water.  (Wisconsin Public Service)         
                                                                                
     Answer                                                                     
                                                                                
     Not necessarily.  See the answer to the previous question.                 
                                                                                
3.   Page 5, paragraph 1.  What level of documentation is required to           
     justify excluding closed-cycle system heat exchangers from testing         
     to verify heat transfer capability?  (Portland General Electric)
                
                                                                                
.Generic Letter 89-13              -32-                                          
Supplement 1       
                                                             
                                                                                
     Answer                                                                     
                                                                                
     The goal of the generic letter is to obtain assurance that the heat        
     removal requirements for the service water system are satisfied.  To       
     exclude a closed-cycle system heat exchanger from testing, a               
     licensee or applicant should show that the chemistry of the primary        
     fluid and the heat transfer characteristics of the heat exchanger          
     have been controlled since the system was first filled.                    
                                                                                
4.   The ACRS [Advisory Committee on Reactor Safeguards] June 14, 1989,         
     letter to the Commission noted five areas of concern with which            
     NUBARG agrees. Some of the concerns were accommodated in the GL;           
     however, we are interested to know the resolution of the following.        
     (Nuclear Utility Backfit Action Reform Group [NUBARG])                     
                                                                                
     a.   An intermediate closed cooling water system is exempt from the        
          GL provided it is not subject to significant sources of               
          contamination, is chemistry controlled, and does not reject           
          heat directly to a heat sink.  However, the adequacy of the           
          chemistry control program must be verified over the total             
          operating history of the plant.  The ACRS questioned whether          
          the absence of an adequate water chemistry control system over        
          any part of the operating history of a closed-cycle system was        
          adequate justification for including the system within the            
          scope of the GL.  How did the staff resolve this concern?             
                                                                                
          Answer                                                                
                                                                                
          The staff relaxed its position on including closed-cycle              
          cooling systems in Recommended Action II but added the                
          precautionary recommendation that if degradation of heat              
          transfer could not be explained or remedied by maintenance of         
          the open-cycle part of the service water system, then testing         
          may have to be selectively extended to the closed-cycle part of       
          the system.  See the answer to Question III.F.1.                      
                                                                                
     b.   Are plants required to review closed cooling water system             
          operating logs for the history of the plant to verify adequate        
          chemistry control?                                                    
                                                                                
          Answer                                                                
                                                                                
          Licensees and applicants are required to assure that the              
          safety-related heat removal requirements for the service water        
          system are satisfied.  If review of closed cooling water system       
          operating logs for the history of the plant can help provide          
          this assurance, then that review would be an acceptable part of       
          the program. 
                                                                   
                                                                                
.Generic Letter 89-13              -33-                                          
Supplement 1   
                                                                 
                                                                                
G.   Miscellaneous                                                              
                                                                                
1.   Do both emergency service water systems and normal service water           
     systems need to be reviewed?  (Kansas Gas and Electric)                    
                                                                                
     Answer                                                                     
                                                                                
     In some cases this may be necessary.  The NRC is concerned about the       
     safety-related effects of both systems.  Sometimes the mode of             
     operation of a service water system is changed under emergency             
     conditions.  This change may result in the introduction of                 
     uncontrolled water and thus the potential introduction of biofouling       
     agents, corrosion products, and silt that may adversely affect the         
     heat transfer performance of the system.                                   
                                                                                
2.   Page 6, paragraph 1.  The generic letter does not specifically             
     address testing of automatic safety features actuation which may be        
     required to provide the required service water flow to safety-             
     related heat exchangers. Does the NRC have any recommendations on          
     functional tests of systems? (Portland General Electric)                   
                                                                                
     Answer                                                                     
                                                                                
     The generic letter was written with the tacit assumption that all          
     other regulatory conditions would be observed.  In particular,             
     functional testing required by technical specifications must be            
     accomplished independently of the recommended actions of the generic       
     letter.  Where there is overlap, credit may be taken for the               
     functional tests required by the technical specifications.  The            
     procedures, results, and considerations of such tests should be            
     documented with the response to the generic letter and retained in         
     appropriate plant records.                                                 
                                                                                
3.   Recommended Action II paragraph 4 states tests should be performed         
     following corrective action.  Would bulleting tubes be considered as       
     corrective actions?  (Unidentified)                                        
                                                                                
     Answer                                                                     
                                                                                
     Yes.                                                                       
                                                                                
4.   Generic Letter 89-13 states that tests should be performed on heat         
     ex changers before and after "corrective action" is performed.  What       
     is meant by "corrective action"?  (Southern California Edison)             
                                                                                
     Answer                                                                     
                                                                                
     Corrective action is any action that improves the condition of the         
     heat exchanger. 
                                                                
                                                                                
.Generic Letter 89-13              -34-                                          
Supplement 1  
                                                                  
                                                                                
IV.  ACTION III - ROUTINE INSPECTION AND MAINTENANCE                            
                                                                                
A.   Recommendation III states, "Ensure by establishing a routine               
     inspection and maintenance program . . . that corrosion, erosion . .       
     . cannot degrade the performance of the safety-related systems             
     supplied by service water." [Emphasis added.]  It would seem               
     unrealistic to assume that a program could be developed that will          
     ensure absolutely no degradation of the system.  Could you clarify         
     that the intent here is to establish a program which will ensure           
     that the system cannot degrade to the point at which its ability to        
     perform its safety function is impaired?  (Duke Power)                     
                                                                                
     Answer                                                                     
                                                                                
     The NRC staff concurs in this interpretation.                              
                                                                                
B.   Must all safety-related service water piping be cleaned or only the        
     piping that is susceptible to corrosion buildup, i.e., low flow            
     areas?  Nondestructive examinations would be used to confirm the           
     areas needed to be cleaned.  (Wisconsin Public Service)                    
                                                                                
     Answer                                                                     
                                                                                
     Recommended Action III is intended to provide assurance that the           
     performance of open-cycle service water piping and components is not       
     degraded as a result of corrosion, erosion, protective coating             
     failure, silting, and biofouling.  Once this assurance is made, the        
     routine maintenance and inspection program can concentrate on those        
     piping segments that are susceptible to these problems.                    
                                                                                
C.   Would it be considered acceptable to omit from inspection piping           
     which is practically inaccessible (i.e., underground piping) based         
     on inspections of practically accessible piping?  (Philadelphia            
     Electric)                                                                  
                                                                                
     Answer                                                                     
                                                                                
     Inaccessibility itself would not be a sufficient reason for not            
     inspecting piping.  However, if additional justification including         
     operational data and prior history is available, along with an             
     evaluation that clearly shows that inspections would not be                
     necessary, then inspection could be omitted.                               
                                                                                
D.   Refer to Item III.  Does the maintenance program have to include           
     sampling of any crud or sediment found to determine its source;            
     e.g., during routine maintenance a small amount of sediment was            
     cleaned from a heat exchanger and the only documentation stated that       
     it appeared to be a normal corrosion deposit?  (Niagara Mohawk             
     Power)    
                                                                      
                                                                                
.Generic Letter 89-13              -35-                                          
Supplement 1   
                                                                 
                                                                                
     Answer                                                                     
                                                                                
     If the maintenance program can ensure that the heat removal                
     requirements for the service water system are met, then it is              
     acceptable.  The better the root cause analysis of a problem is,           
     however, the more effective will be the corrective action.                 
                                                                                
E.   Refer to Item III.  If minimum fouling is found during maintenance         
     it should be acceptable to assume that the heat exchanger can still        
     perform to the original design specification.  Does the NRC have a         
     problem with this assumption?  (Niagara Mohawk Power)                      
                                                                                
     Answer                                                                     
                                                                                
     The NRC staff cannot judge the adequacy of heat transfer capability        
     based on the broad statement of "minimum" fouling.  The licensee or        
     applicant must determine what fouling level requires corrective            
     action and justify the approach taken.                                     
                                                                                
F.   Under Specific Action III(A) on page 6 of the GL, what constitutes         
     excessive accumulations of biofouling agents, corrosion products,          
     and silt? (Nuclear Utility Backfit Action Reform Group [NUBARG])           
                                                                                
     Answer                                                                     
                                                                                
     The staff does not have a quantitative criterion for this parameter.       
     If such accumulations degrade the heat transfer capability of the          
     system such that the system cannot perform its safety-related              
     function as shown by performance trend data, then such accumulations       
     are excessive.                                                             
                                                                                
G.   Are plant work requests adequate relevant documentation to support         
     the inspection and maintenance documentation requirement of Specific       
     Action III?  (NUBARG)                                                      
                                                                                
     Answer                                                                     
                                                                                
     Yes, as long as they can be made available to an NRC inspector.            
                                                                                
H.   Programs acceptable to the NRC in response to GL 89-13 Actions I and       
     II were identified.  What are some examples of acceptable inspection       
     and maintenance programs in response to Action III?  (Commonwealth         
     Edison)                                                                    
                                                                                
     Answer                                                                     
                                                                                
     The NRC has not defined an acceptable program for Action III.              
     However, the generic letter is designed to give the licensee or            
     applicant sufficient flexibility in developing an appropriate              
     program.  
                                                                      
                                                                                
.Generic Letter 89-13              -36-                                          
Supplement 1   
                                                                 
                                                                                
V.   ACTION IV - SINGLE-FAILURE WALKDOWN                                        
                                                                                
A.   To what extent does this walkdown have to be performed?  We are            
     presently conducting a design-basis documentation reconstitution           
     effort.  A system walkdown is performed only if a problem is               
     identified during documentation review.  Walkdowns are not conducted       
     all the time and are not full scope. Is the intent to complete             
     walkdowns as required to ensure the system meets the licensing basis       
     for the plant or to verify the as-built condition? (Public Service         
     Electric and Gas)                                                          
                                                                                
     Answer                                                                     
                                                                                
     The intent of the recommended action is to verify that the as-built        
     condition of the system is sufficient to ensure performance of the         
     intend ed function of the service water system.  A design-basis            
     reconstitution suffices for the walkdown inspection recommended            
     here.                                                                      
                                                                                
B.   A service water system walkdown inspection was completed in 1986 at        
     our plant.  Can we take credit for that effort for this action or          
     must we repeat it now to meet the 2-year criterion?  (Niagara Mohawk       
     Power)                                                                     
                                                                                
     Answer                                                                     
                                                                                
     You may take credit for the 1986 walkdown to meet this recommended         
     action. The suggested time of 2 years to qualify the word "recent"         
     was not meant to be rigidly interpreted.  The NRC is interested in         
     the walkdown being done now or recently, not in the distant past.          
                                                                                
C.   Does the system walkdown take into account piping, valves, and in-         
     line components?  What about cabling walkdown?  Is our 79-14               
     walkdown sufficient to address this?  (Wisconsin Public Service)           
                                                                                
     Answer                                                                     
                                                                                
     The system walkdown should ensure that the system's safety-related         
     function can be accomplished in the event of failure of a single           
     active component.  Cabling walkdowns are thus not in the scope of          
     Generic Letter 89-13.  The intent of Recommended Action IV is to           
     make maximum use of other pertinent activities in reviewing the            
     system, but it is not sufficient to depend on 10-year-old reviews to       
     ascertain the condition of the system today.  However, the staff           
     understands that Bulletin 79-14, "Seismic Analyses for As-Built            
     Safety-Related Piping Systems," is not closed at all plants;               
     therefore, if the walkdowns have been done recently, they would be         
     acceptable.  Activities included in the Individual Plant Examination       
     (IPE) program may also constitute an acceptable response to this           
     recommended action.                                                        
                                                                                
D.   Recommendation No. IV discusses system walkdown inspections.  GPU          
     Nuclear assumes that the intent of the walkdown is down to the level       
     of the flow diagram only.  Does the NRC agree with this assumption         
     or do we intend for a more detailed walkdown?  (GPU Nuclear)  
                  
                                                                                
.Generic Letter 89-13              -37-                                          
Supplement 1      
                                                              
                                                                                
     Answer                                                                     
                                                                                
     See the answer to the previous question.  Single-failure                   
     inadequacies can occur in control systems as well as equipment in          
     which water flows.  The staff notes that single-failure inadequacies       
     have been found at some plants apart from routine surveillance             
     procedures.                                                                
                                                                                
E.   Page 6, paragraph IV.  Are there any specific requirements which are       
     new that should be added into existing single-failure analysis?            
     Explain what is meant by "reconstitution of the design basis of the        
     system is not intended."  (Portland General Electric)                      
                                                                                
     Answer                                                                     
                                                                                
     As discussed in the answers to the next two questions, the staff           
     does not intend that the licensing basis of a given plant be               
     changed.  Recommended Action IV for single-failure walkdown was not        
     designed to incorporate any new feature into existing single-              
     failure analysis techniques.  The phrase "reconstitution of the            
     design basis of the system is not intended" refers to excessively          
     difficult determinations of design data.  For example, this may be         
     the case for small skid-mounted heat exchangers that were purchased        
     as piece parts of larger units of equipment and for which the vendor       
     may not have provided design data to the licensee or applicant.  It        
     would be enough to demonstrate that the equipment module of which          
     the heat exchanger is a part could do its job.                             
                                                                                
F.   Please elaborate on the requirements of Item 4.  Specifically, what        
     is intended by confirmation of the performance of the service water        
     system in accordance with the design basis, without a reconstitution       
     of the design basis?  Also, is it intended by this requirement to          
     perform a complete single-failure analysis of the service water            
     system?  (Northeast Utilities)                                             
                                                                                
     Answer                                                                     
                                                                                
     The licensee or applicant is expected to confirm that the installed        
     as-built system satisfies the design requirements stated in the            
     plant's licensing basis, that is, the final safety analysis report         
     (FSAR), the technical specifications, and licensing documentation.         
     See the answers to Questions V.C and V.D.                                  
                                                                                
G.   The generic letter states that the licensee should verify that the         
     service water system is in accordance with the licensing basis of          
     the plant.  Is the licensing basis, in the context of this generic         
     letter, considered to be the FSAR and tech specs [technical                
     specifications] or will a more expansive interpretation be used?           
     (Wisconsin Electric Power)                                                 
                                                                                
     Answer                                                                     
                                                                                
     The licensing basis is as defined in the FSAR, technical                   
     specifications, and other licensing documentation.  It is not the          
     staff's intent that the licensing basis be redefined when addressing       
     Generic Letter 89-13.   
     
                                                        
.Generic Letter 89-13              -38-                                          
Supplement 1                                                                    
                                                                                
H.   With regard to Action IV which requests confirmation that the              
     service water system will perform its intended function in                 

     accordance with the licensing basis for the plant, which specific          
     licensing basis must be reconfirmed at this time?  Only the single         
     active failure review? (Commonwealth Edison)                               
                                                                                
     Answer                                                                     

                                                                                
     The licensing basis is considered to include the FSAR, technical           
     specifications, and licensing documentation.  See the answers to the       
     previous two questions.                                                    
                                                                                
I.   Action item 4 of GL 89-13 states that system walkdown inspections          
     are required to confirm the as-built configuration of the service          
     water systems.  As a recently licensed plant, we are confident that        
     our configuration control program satisfies this requirement.  We          
     believe system walkdowns are unnecessary for STPEGS [South Texas           
     Project Electric Generating Station].  (Houston Lighting and Power)        
                                                                                
     Answer                                                                     
                                                                                
     This position appears to be reasonable for good cause.  Ongoing            
     programs that contain results pertinent to Generic Letter 89-13            
     should be referenced in the response as justification for an equally       
     effective program and retained in appropriate plant records.               
                                                                                
J.   If other design-related issues are being addressed by other                
     regulatory actions is it acceptable to exclude them from the scope         
     of review for Action IV?  (Commonwealth Edison)                            
                                                                                
     Answer                                                                     
                                                                                
     Yes.  See the answer to the previous question.                             
                                                                                
K.   Should the single-failure analysis of the SW system include motive         
     power (electrical/pneumatic, etc.) to active components (motor,            
     valve, etc.)? If so, should it be limited only to the delivery of          
     the motive power to the component, and not the single-failure              
     reliability of the motive power sources (i.e., do not need to do           
     single-failure analysis on motive power system)?  (Carolina Power          
     and Light)                                                                 
                                                                                
     Answer                                                                     
                                                                                
     The licensee or applicant should consider single failures in power-        
     operated equipment or components that are part of the service water        
     system.  Single failures in power supply systems themselves do not         
     need to be considered under Generic Letter 89-13.  
                             
                                                                                
.Generic Letter 89-13              -39-                                          
Supplement 1                                                                    
                                                                                
VI.  ACTION V - PROCEDURES REVIEW                                               
                                                                                
A.   Please discuss what constitutes the desired response for Action Item       

     5. (Confirming the adequacy of maintenance practices, operating and        
     emergency procedures, and training that involves the service water         
     system).  The letter states that the confirmation "should include"         
     recent reviews of practices, procedures, and training modules.             
     Please provide some guidance for performing an adequate review.            
     Also, are there other actions which the NRC recommends as part of          
     the confirmation?  (South Carolina Electric and Gas)                       
                                                                                
     Answer                                                                     
                                                                                
     The staff has no specific guidance on what procedures, training, and       
     maintenance practices should be evaluated or revised.  The intent of       
     this item is to increase personnel awareness of the importance of          
     the service water system with the aim of reducing human errors.            
     Refer to the wording in Action Item V in Generic Letter 89-13.             
     Personnel or procedural errors were identified in the Office for           
     Analysis and Evaluation of Operational Data (AEOD) case study              
     (NUREG-1275, Volume 3, November 1988) discussed in the generic             
     letter as a significant cause of service water system failures and         
     degradations.  One acceptable response would be to review those            
     maintenance practices, operating and emergency procedures, and             
     training modules that pertain to the events listed in the appendices       
     in the AEOD case study.                                                    
                                                                                

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