United States Nuclear Regulatory Commission - Protecting People and the Environment

Guidance on Developing Acceptable Inservice Testing Programs (Generic Letter 89-04)

 April 3, 1989

TO:       ALL HOLDERS OF LIGHT WATER REACTOR OPERATING LICENSES AND 
          CONSTRUCTION PERMITS

SUBJECT:  GUIDANCE ON DEVELOPING ACCEPTABLE INSERVICE TESTING PROGRAMS 
          (GENERIC LETTER NO. 89-04)

BACKGROUND

Paragraph 50.55a(g) of 10 CFR Part 50, "Domestic Licensing of Production and 
Utilization Facilities," requires that certain ASME Code Class 1, 2, and 3 
pumps and valves be designed to enable inservice testing and that testing be 
performed to assess operational readiness in accordance with the Section XI 
requirements of the ASME Boiler and Pressure Vessel Code.  The inservice 
testing of ASME Code Class 1, 2, and 3 pumps and valves should be viewed as 
one part of a broad effort to ensure operational readiness of equipment rather 
than viewed in the narrow sense as compliance with 10 CFR 50.55a(g).  The 
intent of the testing is to detect degradation affecting operation and assess 
whether adequate margins are maintained.  While this letter has been written 
to provide guidance reIative to meeting the requirements of 10 CFR 50.55a(g), 
it is only one part of other ongoing industry and regulatory activities.  
Recent efforts have been undertaken by the nuclear industry and NRC sponsored 
research to provide information and techniques for enhanced assurance of 
equipment operability.  NRC staff concerns regarding equipment operability led 
to the issuance of Bulletin 85-03, dated November 15, 1985, and Bulletin 
85-03, Supplement 1, dated April 27, 1988.  An expansion of the requirements 
of this bulletin in the form of a generic letter is being considered by NRC.  
In addition, NRC is considering rulemaking on IST to develop requirements to 
address the inadequacies in the current scope and methods of testing per 10 
CFR 50.55a(g).

Light Water Reactor (LWR) licensees have submitted to the NRC inservice 
testing (IST) programs for pumps and valves pursuant to 10 CFR 50.55a(g).  The 
editions and addenda applicable to IST program intervals are outlined in 10 
CFR 50.55a(g)(4). If the licensee believes that conformance with certain code 
requirements is impractical, that conformance to the Code would cause 
unreasonable hardship without a compensating increase in safety or that a 
proposed alternative provides an acceptable level of quality and safety, 10 
CFR 50.55a allows the licensee to request relief from the Code by notifying 
the Commission and submitting infor-mation to support this determination.  
Following the evaluation of this infor-mation, the Commission may grant relief 
and may impose alternative requirements.

All IST programs contain requests for relief from various Code requirements.  
In addition, the surveillance requirements of technical specification (T.S.) 
4.0.5 for most plants state that this testing of pumps and valves must be 
performed in accordance with ASME Section XI except where specific written 
relief has been granted by the Commission.  Because of the general nature of 
the IST sections of the ASME Code which does not consider plant specific 
designs and the resulting difficulty in complying with all the ASME Code 
requirements, utilities frequently revise their programs as more experience 
with IST is acquired.  Programs at most plants are revised several times 
during the

89033000105
.                                      - 2 -


10 year interval between the program updates required by 10 CFR 50.55a.  This 
trend appears to be continuing even after the programs are updated at the end 
of the first 10 year interval.  The number of program revisions during these 
10 year intervals resulted in the need for frequent review by the NRC of 
licensee's proposed requests for relief from the ASME Section XI requirements 
and required additional interaction by the NRC with utilities before a Safety 
Evaluation Report (SER) could be issued.

Through reviews and inspections, the NRC staff has identified a number of 
generic deficiencies that affect plant safety and have frequently appeared as 
IST program-matic weaknesses.  These programmatic weaknesses can be attributed 
to a lack of understanding in the following areas:  (1) Code testing 
requirements, (2) technical specification requirements, and (3) acceptable 
alternatives to Code requirements. In order to remedy these generic IST 
deficiencies, to clarify the status of current programs with respect to 
applicable T.S. and 10 CFR 50.55a requirements, and to alleviate the problem 
with respect to review of program revisions, the NRC has established the 
following guidance.

NRC GUIDANCE ON IST PROBLEMS AND IMPLEMENTATION OF IST PROGRAM/REVISIONS  
A.   Introduction


Together with the technical specification requirements, IST Programs are 
intended to ensure the operational readiness of certain safety related pumps 
and valves. The NRC staff has reviewed and has under review a number of 
licensee IST programs and relief requests.  Based on the review of these 
programs, and on recent IST inspections, the staff has identified a number of 
generic deficiencies that potentially affect plant safety.  These weaknesses 
adversely impact the basic objective of the ASME Code, Section XI, IST 
requirements.  Attachment 1 to this Generic Letter contains positions that 
describe these deficiencies and explain certain ASME Code and T.S. 
requirements and certain alternatives to the ASME Code that the staff 
considers acceptable.

In addition to the generic deficiencies listed in Attachment 1, the staff has 
concerns regarding the operability of motor operated valve actuators.  These 
concerns are addressed in Bulletin 85-03, dated November 15, 1985, Bulletin 
85-03, Supplement 1, dated April 27, 1988, and Generic Issue II.E.6.1, 
"In-Situ Testing of Valves."

B.   Programs Currently Under NRC Review

For plants listed in Table 1, the NRC will be issuing an SER in the near 
future. These plants need not respond with the confirmation letter discussed 
below.  After receipt of the SER, plants in this category should follow the 
guidance in Part C of this generic letter.  For other utilities not listed on 
either Table 1 or 2, this letter constitutes the required approval for 
implementation of IST program relief requests provided the utility reviews its 
program and amends it as necessary to:  (1) conform with the Code requirements 
explained in Attachment 1, Positions 1, 3, 5, and 11; (2) conform with the 
T.S. requirements explained in Attachment 1, Positions 4 and 8; and (3) 
conform with the applicable Code requirement or the staff approved 
alternatives in Attachment 1, Positions 1, 2, 6, 7, 9, and 10.
.                                      - 3 -


     Based on the staff's experience the positions contained in Attachment 1 
can be implemented at all plants.  However, should licensees be unable to 
comply with one of these positions because of design considerations or 
personnel hazard, as opposed to inconvenience, any alternative testing must 
fulfill the basic test objective of detecting component degradation.  
Alternative testing should be individually evaluated by the licensee and the 
licensee's plant safety review committee (or equivalent).  When evaluating 
testing, licensees should address the following:

     1.  Maintenance history of the individual (specific) component,
     2.  Maintenance history of the related components in a similar 
         environment,
     3.  Component vendor records of degradation at other facilities, and
     4.  Records on degradation of the same or like component from other 
         utilities.

Licensees may utilize in-plant records, the NPRDS and other referenceable 
sources to compile data to address the above four areas.  A lack of service 
experience or test results by itself is not sufficient to justify the 
alternative test.

The alternative test is not considered acceptable unless the above data is 
sufficient to justify its adequacy for detecting degradation and ensuring 
continued operability.  Justification for the alternative test should be 
documented and retained in the IST program.

For plants not listed on either Table 1 or 2, currently submitted IST program 
relief requests are hereby approved for licensees who have not received an SER
provided that they (1) review their most recently submitted IST programs and 
implementation procedures against the positions delineated in Attachment 1 and 
(2) within 6 months of the date of this letter confirm in writing their 
conformance with the stated positions.  In cases where conformance with the 
stated positions would result in equipment modifications, the licensee should 
provide in his confirmation letter a schedule for completing the required 
modifications.  All modifications must be completed within 18 months of the 
date of the confirmatory letter, whichever occurs later.  Changes to the IST 
programs as a result of this generic letter, should be submitted to the NRC 
along with the confirmation letter.  Approval is granted provided the programs 
are consistent with the positions taken in Attachment 1 or, for positions that 
necessitate a plant modification, will be consistent with Attachment 1 on the 
schedule noted above.  Where a deviation needs to be taken from a specific 
position in Attachment 1, the approval is granted provided the adequacy of the
proposed alternative testing for detecting degradation is justified as 
discussed above.

C.   Programs With Completed NRC Reviews

For the plants listed in Table 2 the staff has completed its review of the IST 
program and issued an SER.  These plants need not respond with the 
confirmation letter discussed above.  The status of the relief requests 
approved in the SER is not affected by this letter.  The relief requests that 
were approved in the SER may continue to be implemented, and those that were 
denied should be
.                                      - 4 -


resolved in accordance with the guidance in the SER.  The technical positions 
found in Attachment 1 of this generic letter were used by the staff in reviews 
of IST programs.

If licensees have modified or plan to modify their IST program beyond that 
which was the basis for the staff's SER, the guidance in Part D below should 
be used.

D.   Program Updates/Revisions

If the licensees modify their IST program beyond that currently submitted to 
the NRC, they should review the modifications against the positions found in 
Attachment 1.  For IST program changes for which specific positions are 
provided in Attachment 1, licensees should follow the guidance in Section B 
above.  For IST program changes in areas not covered by Attachment 1, the 
provisions of 10 CFR 50.55(a)g should be followed.  The modified program 
should comply with the disposition of relief requests in any applicable SER 
based on a previously submitted IST program.

E.   Implementing Procedures

IST programs contain basic information on the pumps and valves being tested, 
the type of tests being performed, and the frequency of testing, but not the 
procedures being followed.  The positions in Attachment 1 primarily address 
generic short-comings in IST programs.  However, each of these positions, as 
well as other areas of the ASME Code, are dependent upon the adequacy of the 
implementing procedures. This letter provides guidance to be taken relative to 
the positions in Attachment 1 to correct deficiencies in the IST programs.  
The implementing procedures for these positions should likewise be reviewed 
and amended to address any deficiencies related to implementation of these 
positions.

F.   Inspection and Enforcement

The NRC may conduct inspections to determine licensee conformance with the 
provisions of the approval granted by this letter.  Enforcement action against 
licensees may result in cases where the program and procedures are not in 
confor-mance with 10 CFR 50.55a(g), as explained in this guidance.  The areas 
covered in Attachment 1 will be the focus of future IST inspections.  Aspects 
of the IST programs not addressed by Attachment 1 may also be inspected.

IST PROGRAM APPROVAL

This generic letter approves currently submitted IST program relief requests 
for licensees who have not received an SER provided that they (1) review their 
most recently submitted IST programs and implementation procedures against the                                          
positions delineated in Attachment 1 and (2) within 6 months of the date of 
this letter confirm in writing their conformance with the stated positions.  
Since the IST program reviews for licensees listed on Table 1 are nearly 
complete, they will receive relief request approvals by separate 
correspondence.

By addressing the technical areas identified in Attachment 1, the staff has 
concluded that certain significant deficiencies in the IST programs and in IST 
relief requests will be corrected.  Other deficiencies related to assurance of

.                                      - 5 -


the operational readiness of pumps and valves have been or will be the subject 
of regulatory actions such as generic letters and rulemaking.  Provided the 
provisions of this letter are followed, the staff has determined that relief 
is granted to follow the alternative testing delineated in positions 1, 2, 6, 
7, 9, and 10, pursuant to 10 CFR 50.55a(g)(6)(i), is authorized by law, and 
will not endanger life or property or the common defense and security and is 
otherwise in the public interest.  In making this determination the staff has 
considered the impracticality of performing the required testing considering 
the burden if the requirements were imposed.

This request is covered by Office of Management and Budget Clearance Number 
3150-0011 which expires December 31, 1989.  The estimated average burden hours 
is 700 man-hours per owner response, including assessment of the new recom-
mendations, searching data sources, gathering and analyzing the data, and 
preparing the required letters.  These estimated average burden hours pertain 
only to these identified response-related matters and do not include the time 
for actual implementation of the requested actions.  Comments on the accuracy 
of this estimate and suggestions to reduce the burden may be directed to the 
Office of Management and Budget, Room 3208, New Executive Office Building, 
Washington, D.C. 20503, and the U.S. Nuclear Regulatory Commission, Records 
and Reports Management Branch, Office of Administration and Resources Manage-
ment, Washington, D.C. 20555.

                              Sincerely,




                              Steven A. Varga, Acting
                              Associate Director for Projects
                              Office of Nuclear Reactor Regulation

Enclosures:
Tables 1 and 2 w/Attachment 1
.
                                     TABLE 1

                  PLANTS WITH SERs TO BE ISSUED IN NEAR FUTURE


Beaver Valley 1                    Peach Bottom 2&3
Braidwood 1&2                      Rancho Seco
Brunswick                          River Bend
Calvert Cliffs 1&2                 Robinson 2
Clinton                            Seabrook 1
Comanche Peak                      SONGS 2&3
D.C. Cook 1&2                      St. Lucie 2
Farley 1&2                         Summer
Ft. Calhoun                        Surry 1&2
Hatch 1&2                          Vogtle 1
Hope Creek                         Waterford 3
Kewaunee                           Wolf Creek
Limerick 1&2                       WNP 2
McGuire 1&2                        Zion 1&2
Millstone 2
Nine Mile Point 1
Nine Mile Point 2

.
                                     TABLE 2


                    PLANTS WITH CURRENT IST PROGRAMS REVIEWED
                                 AND SER ISSUED


Browns Ferry 1,2&3
Byron 1&2
Davis Besse 1
Diablo Canyon 1&2
Calloway
Fermi 2
Millstone 3
Palo Verde 1,2&3
Prairie Island 1&2
Sequoyah 1&2
Shearon Harris
South Texas 1&2
TMI 1
Vogtle 2
.
                                  ATTACHMENT 1

                    POTENTIAL GENERIC DEFICIENCIES RELATED TO
                           IST PROGRAMS AND PROCEDURES


1.   Full Flow Testing of Check Valves

     Section XI of the ASME Code requires check valves to be exercised to the 
     positions in which they perform their safety functions.  A check valve's 
     full-stroke to the open position may be verified by passing the maximum 
     required accident condition flow through the valve.  This is considered 
     by the staff as an acceptable full-stroke.  Any flow rate less than this 
     will be considered a partial-stroke exercise.  A valid full-stroke 
     exercise by flow requires that the flow through the valve be known.  
     Knowledge of only the total flow through multiple parallel lines does not 
     provide verification of flow rates through the individual valves and is 
     not a valid full-stroke exercise.

     Full flow testing of a check valve as described above may be impractical 
     to perform for certain valves.  It may be possible to qualify other 
     techniques to confirm that the valve is exercised to the position 
     required to perform its safety function.  To substantiate the 
     acceptability of any alternative technique for meeting the ASME Code 
     requirements, licensees must as a minimum address and document the 
     following items in the IST program:

     1.   The impracticality of performing a full flow test,

     2.   A description of the alternative technique used and a summary of the 
          procedures being followed,

     3.   A description of the method and results of the program to qualify 
          the alternative technique for meeting the ASME Code,

     4.   A description of the instrumentation used and the maintenance and 
          calibration of the instrumentation,

     5.   A description of the basis used to verify that the baseline data has 
          been generated when the valve is known to be in good working order, 
          such as recent inspection and maintenance of the valve internals, 
          and

     6.   A description of the basis for the acceptance criteria for the 
          alternative testing and a description of corrective actions to be 
          taken if the acceptance criteria are not met.

     An acceptable alternative to this full-stroke exercising requirement is 
     stated in position 2 below.

.                                      - 2 -

2.   Alternative to Full Flow Testing of Check Valves.

     The most common method to full-stroke exercise a check valve open (where 
     disk position is not observable) is to pass the maximum required accident 
     flow through the valve.  However, for some check valves, licensees cannot 
     practically establish or verify sufficient flow to full-stroke exercise 
     the valves open.  Some examples of such valves are, in PWRs, the contain-
     ment spray header check valves and combined LPSI and safety injection 
     accumulator header check valves and, in BWRs, the HPCI or RCIC check 
     valves in the pump suction from the suppression pool.  In most commercial 
     facili-ties, establishing design accident flow through these valves for 
     testing cou1d result in damage to major plant equipment.

     The NRC staff position is that valve disassembly and inspection can be 
     used as a positive means of determining that a valve's disk will full-
     stroke exercise open or of verifying closure capability, as permitted by 
     IWV-3522.  If possible, partial valve stroking quarterly or during cold 
     shutdowns, or after reassembly must be performed.

     The staff has established the following positions regarding testing check
     valves by disassembly:

     a.   During valve testing by disassembly, the valve internals should be 
          visually inspected for worn or corroded parts, and the valve disk 
          should be manually exercised.

     b.   Due to the scope of this testing, the personnel hazards involved and 
          system operating restrictions, valve disassembly and inspection may 
          be performed during reactor refueling outages.  Since this fre-quency 
          differs from the Code required frequency, this deviation must be 
          specifically noted in the IST program.

     c.   Where the licensee determines that it is burdensome to disassemble
          and inspect all applicable valves each refueling outage, a sample
          disassembly and inspection plan for groups of identical valves in 
          similar applications may be employed.  The NRC guidelines for this
          plan are explained below:

             The sample disassembly and inspection program involves grouping 
             similar valves and testing one valve in each group during each 
             refueling outage.  The sampling technique requires that each 
             valve in the group be the same design (manufacturer, size, model 
             number, and materials of construction) and have the same service 
             conditions including valve orientation.  Additionally, at each 
             disassembly the licensee must verify that the disassembled valve 
             is capable of full-stroking and that the internals of the valve 
             are structurally sound (no loose or corroded parts).  Also, if 
             the disassembly is to verify the full-stroke capability of the 
             valve, the disk should be manually exercised.

.                                      - 3 -

             A different valve of each group is required to be disassembled, 
             inspected, and manually full-stroke exercised at each successive 
             refueling outage, until the entire group has been tested.  If the 
             disassembled valve is not capable of being full-stroke exercised 
             or there is binding or failure of valve internals, the remaining 
             valves in that group must also be disassembled, inspected, and 
             manually full-stroke exercised during the same outage.  Once this 
             is completed, the sequence of disassembly must be repeated unless 
             extension of the interval can be justified.

     Extending the valve sample disassembly and inspection interval from disas-
     sembly of one valve in the group every refueling outage or expanding the 
     group size would increase the time between testing of any particular 
     valve in the group.  With four valves in a group and an 18-month reactor 
     cycle, each valve would be disassembled and inspected every six years.  
     If the fuel cycle is increased to 24 months, each valve in a four-valve 
     sample group would be disassembled and inspected only once every 8 years.

     Extension of the valve disassembly/inspection interval from that allowed 
     by the Code (quarterly or cold shutdown frequency) to longer than once 
     every 6 years is a substantial change which may not be justified by the 
     valve failure rate data for all valve groupings.  When disassembly/ 
     inspection data for a valve group show a greater than 25% failure rate, 
     the licensee should determine whether the group size should be decreased 
     or whether more valves from the group should be disassembled during every 
     refueling outage.

     Extension of the valve disassembly/inspection interval to one valve every 
     other refueling outage or expansion of the group size above four valves 
     should only be considered in cases of extreme hardship where the 
     extension is supported by actual in-plant data from previous testing.  In 
     order to support extension of the valve disassembly/inspection intervals 
     to longer than once every 6 years, licensees should develop the following 
     information:

     a.   Disassemble and inspect each valve in the valve grouping and document 
          in detail the condition of each valve and the valve's capability to 
          be full-stroked.

     b.   A review of industry experience, for example, as documented in 
          NPRDS, regarding the same type of valve used in similar service.

     c.   A review of the installation of each valve addressing the "EPRI 
          Applications Guidelines for Check Valves in Nuclear Power Plants" 
          for problematic locations.

3.   Back Flow Testing of Check Valves.

     Section XI requires that Category C check valves (valves that are self 
     actuated in response to a system characteristic) performing a safety 
     function in the closed position to prevent reversed flow be tested in a 
     manner that proves that the disk travels to the seat promptly on 
     cessation or reversal of flow.  In addition, for category A/C check 
     valves (valves that

.                                      - 4 -

     have a specified leak rate limit and are self actuated in response to a 
     system characteristic), seat leakage must be limited to a specific 
     maximum amount in the closed position for fulfillment of their function.  
     Verifica-tion that a Category C valve is in the closed position can be 
     done by vis-ual observation, by an electrical signal initiated by a 
     position-indicating device, by observation of appropriate pressure 
     indication in the system, by leak testing, or by other positive means.

     Examples of ASME Code Class check valves that perform a safety function 
     in the closed position that are frequently not back flow tested are:


     a.   main feedwater header check valves
     b.   pump discharge check valves on parallel pumps
     c.   keep full check valves
     d.   check valves in steam supply lines to turbine driven AFW pumps
     e.   main steam non-return valves
     f.   CVCS volume control tank outlet check valves

4.   Pressure Isolation Valves

     a.   General

          Pressure isolation valves (PIVs) are defined as two normally closed 
          valves in series that isolate the reactor coolant system (RCS) from 
          an attached low pressure system.  PIVs are located at all RCS low 
          pressure system interfaces.  The 10 CFR 50.2 contains the definition 
          of the RCPB.  PIVs are within the reactor coolant pressure boundary 
          (RCPB).

          The following summary is based upon the staff's review of responses 
          to Generic Letter 87-06, Periodic Verification of Leak Tight 
          Integrity of Pressure Isolation Valves.  All plants licensed since 
          1979 have a full list of PIVs in the plant Technical Specifications 
          (TS) along with leak test requirements and limiting conditions for 
          operation (LCOs). The plants licensed prior to 1979 fall into 
          several categories.  Some pre-1979 plants have a full list of PIVs 
          along with leak test requirements and LCOs in the plant TS.  Some 
          pre-1979 plants have only Event V PIVs (see below) in the plant TS.  
          Some pre-1979 plants have no TS requirements regarding PIVs.

          All PIVs listed in plant TS should be listed in the IST program as 
          Category A or A/C valves.  The TS requirements should be referenced 
          in the IST program.

     b.   Event V PIVs

          Event V PIVs are defined as two check valves in series at a low 
          pressure/RCS interface whose failure may result in a LOCA that by-
          passes containment.  Event V refers to the scenario described for 
          this event in the WASH-1400 study.

.                                      - 5 -

          On April 20, 1981, the NRC issued an Order to 32 PWRs and 2 BWRs 
          which required that these licensees conduct leak rate testing of 
          their PIVs, based on plant-specific NRC supplied lists of PIVs, and 
          required licensees to modify their TS accordingly.  These orders are
          known as the "Event V Orders" and the valves listed therein are the 
          "Event V" PIVs.  The Event V PIVs are a subset of PIVs.

          Based upon the results of recent inspections, it has been determined 
          that the following implementation problem still exists with respect 
          to testing of PIVs.  The staff has determined that in some cases the 
          procedures are inadequate to assure that these valves are 
          individually leak tested and evaluated against the leakage limits 
          specified in the TS; in other cases, the procedures were adequate 
          but were not being followed.  Specifically, some check valves were 
          tested in series as opposed to individually and some check valves 
          were not tested when required.

          Licensees should review their testing procedures to ensure the Event 
          V PIVs are individually leak rate tested.

5.   Limiting Values of Full-Stroke Times for Power Operated Valves

     The Code intent with respect to measuring the full-stroke times of power 
     operated valves is to verify operability and to detect valve degradation. 
     Measurement of full stroke times for air operating valves fulfills this 
     intent.  However, reviews of operating experience have identified several 
     problems with motor operated valves (MOVs) including limitations with 
     stroke time as a measure of operational readiness of the MOV.  As a 
     result, the industry has made extensive efforts to improve the knowledge 
     and under-standing of operational characteristics of motor operated 
     valves.  This effort has been conducted by industry groups (NUMARC, INPO, 
     NMAC, EPRI), individual licensees, equipment vendors, and national 
     standards groups.

     We believe the information and knowledge developed by these groups should 
     be reviewed and utilized.  Some of the information publicly available 
     includes an INPO white paper titled, "Motor-Operated Valve Performance 
     Update," issued October 4, 1988.  This document identifies MOV problem 
     areas and provides the key elements for a comprehensive MOV program. 
     Another document is the "Technical Repair Guidelines for the Limitorque 
     Model SMB-000 Valve Actuator," issued by the Nuclear Maintenance Applica-
     tion Center (NMAC) in January 1989.  This guide addresses several areas 
     such as setting torque and limit switches, preventive maintenance, 
     actuator failure modes, failure analysis to determine root cause and 
     corrective action, and preoperational and post-maintenance testing.

     NRC staff concerns regarding MOV operability led to the issuance of 
     Bulletin 85-03 and Bulletin 85-03, Supplement 1.  Expansion of this 
     bulletin in the form of a generic letter is being considered by the NRC.

.                                      - 6 -

     In spite of the limitations of stroke time testing of MOVs, IWV-3413(a) 
     of the ASME Code requires that the licensee specify the limiting value 
     of full-stroke time of each power operated valve.  The corrective actions
     of IWV-3417(b) must be followed when these limiting values are exceeded. 
     The Code does not provide any requirements or guidelines for establishing 
     these limits nor does it identify the relationship that should exist 
     between these limits and any limits identified for the relevant valves in 
     the plant TS or safety analysis.

     The purpose of the limiting value of full-stroke time is to establish a 
     value for taking corrective action on a degraded valve before the valve 
     reaches the point where there is a high probability of failure to perform 
     its safety function if called upon.  The NRC has, therefore, established 
     the guidelines described below regarding limiting values of full-stroke 
     time for power operated valves.

          The limiting value of full-stroke time should be based on the valve 
          reference or average stroke time of a valve when it is known to be 
          in good condition and operating properly.  The limiting value should 
          be a reasonable deviation from this reference stroke time based on 
          the valve size, valve type, and actuator type.  The deviation should 
          not be so restrictive that it results in a valve being declared 
          inoperable due to reasonable stroke time variations.  However, the 
          deviation used to establish the limit should be such that corrective 
          action would be taken for a valve that may not perform its intended 
          function.

     When the TS or safety analysis limit for a valve is less than the value 
     established using the above guidelines, the TS or safety analysis limit 
     should be used as the limiting value of full-stroke time.

     When the TS or safety analysis limit for a valve is greater than 
     the value established using the above guidelines, the limiting value 
     of full-stroke time should be based on the above guidelines instead of 
     the TS or safety analysis limit.

6.   Stroke Time Measurements for Rapid-Acting Valves

     The Code requires the following for power operated valves with stroke 
     times 10 seconds or less:  (a) Limiting values of full-stroke times shall 
     be specified [IWV-3413(a)], (b) Valve stroke times shall be measured to 
     (at least) the nearest second [IWV-3413(b)] and (c) If the stroke time 
     increases by 50% or more from the previous test, then the test frequency 
     shall be increased to once each month until corrective action is taken 
     [IWV-3417(a)].  Paragraph IWV-3417(b) specifies corrective actions that 
     must be taken.

     With reference to (c) above, measuring changes in stroke times from a 
     reference value as opposed to measuring changes from the previous test 
     is an acceptable (and possibly better) alternative to the staff.  
     However, since this is different from the Code requirement, this 
     deviation should be documented in the IST program.

.                                      - 7 -

     Most plants have many power operated valves that are capable of stroking 
     in 2 seconds or less such as small solenoid operated valves.  Licensees 
     encounter difficulty in applying the Code 50% increase of stroke time 
     corrective action requirements for these valves.  The purpose of this 
     requirement is to detect and evaluate degradation of a valve.  For valves 
     with stroke times in this range, much of the difference in stroke times 
     from test to test comes from inconsistencies in the operator or timing 
     device used to gather the data. These differences are compounded by 
     rounding the results as allowed by the Code.  Thus, the results may not 
     be representative of actual valve degradation.

     The following discussion illustrates the problem that may exist when 
     complying with the Code requirements for many of these rapid-acting 
     valves: 

          A valve may have a stroke time of 1.49 seconds during one test and a
          stroke time during the following test of 1.51 seconds.  If stroke 
          times are rounded to the nearest second as allowed by the Code, the 
          difference between these tests would exceed the 50% criteria and 
          would require an increased frequency of testing until corrective 
          action is taken.  This can result from a stroke time difference of 
          0.02 seconds, which is usually not indicative of significant valve 
          degradation.

     Power operated valves with normal stroke times of 2 seconds or less are 
     referred to by the staff as "rapid-acting valves."  Relief may be granted 
     from the requirements of Section XI, Paragraph IWV-3417(a) for these 
     valves provided the licensee assigns a maximum limiting value of 
     full-stroke time of 2 seconds to these valves and, upon exceeding this 
     limit, declares the valve inoperable and takes corrective action in 
     accordance with IWV-3417(b).

     An acceptable alternative to the Code stroke timing requirements is the 
     above stated rapid-acting valve position.  Since this represents a devi-
     ation from the Code requirements, it should be specifically documented in 
     the IST program.

7.   Testing Individual Control Rod Scram Valves in Boiling Water Reactors
     (BWRs)

     BWRs are equipped with bottom-entry hydraulically driven control rod 
     drive mechanisms with high-pressure water providing the hydraulic power.  
     Each control rod is operated by a hydraulic control unit (HCU), which 
     consists of valves and an accumulator.  The HCU is supplied charging and 
     cooling water from the control rod drive pumps, and the control rod 
     operating cylinder exhausts to the scram discharge volume.  Various 
     valves in the control rod drive system perform an active function in 
     scramming the control rods to rapidly shut down the reactor.

     The NRC has determined that those ASME Code Class valves that must change
     position to provide the scram function should be included in the IST 
     program and be tested in accordance with the requirements of Section XI 
     except where relief has been granted in a previously issued Safety 
     Evaluation Report or as discussed below.

.                                      - 8 -

     The control rod drive system valves that perform an active safety 
     function in scramming the reactor are the scram discharge volume vent and
     drain valves, the scram inlet and outlet valves, the scram discharge 
     header check valves, the charging water header check valves, and the 
     cooling water header check valves.  With the exception of the scram 
     discharge volume vent and drain valves, exercising the other valves 
     quarterly during power operations could result in the rapid insertion of 
     one or more control rods more frequently than desired.

     Licensees should test these control rod drive system valves at the 
     Code-specified frequency if they can be practically tested at that 
     frequency.

     However, for those control rod drive system valves where testing could 
     result in the rapid insertion of one or more control rods, the rod scram 
     test frequency identified in the facility TS may be used as the valve 
     testing frequency to minimize rapid reactivity transients and wear of the 
     control rod drive mechanisms.  This alternate test frequency should be 
     clearly stated and documented in the IST program.

     Industry experience has shown that normal control rod motion may verify 
     the cooling water header check valve moving to its safety function 
     position.  This can be demonstrated because rod motion may not occur if 
     this check valve were to fail in the open position. If this test method 
     is used at the Code required frequency, the licensee should clearly 
     explain in the IST program that this is how these valves are being 
     verified to close quarterly.

     Closure verification of the charging water header check valves requires 
     that the control rod drive pumps be stopped to depressurize the charging 
     water header.  This test should not be performed during power operation 
     because stopping the pumps results in loss of cooling water to all 
     control rod drive mechanisms and seal damage could result.  Additionally, 
     this test cannot be performed during each cold shutdown because the 
     control rod drive pumps supply seal water to the reactor recirculation 
     pumps and one of the recirculation pumps is usually kept running.  
     Therefore, the HCU accumulator pressure decay test as identified in the 
     facility TS may be used as the charging water header check valve 
     alternate testing frequency for the reasons stated above.  If this test 
     is not addressed in the licensee's TS this closure verification should be 
     performed at least during each refueling outage, and this alternate test 
     frequency should be specifically documented in the IST program.

     The scram inlet and outlet valves are power operated valves that 
     full-stroke in milliseconds and are not equipped with indication for both 
     positions, therefore, measuring their full-stroke time as required by the 
     Code may be impractical.  Verifying that the associated control rod meets 
     the scram insertion time limits

.                                      - 9 -

     defined in the plant TS can be an acceptable alternate method of 
     detecting degradation of these valves.  Also, trending the stroke times 
     of these valves may be impractical and unnecessary since they are 
     indirectly stroke timed and no meaningful correlation between the scram 
     time and valve stroke time may be obtained, and furthermore, conservative 
     limits are placed on the control rod scram insertion times.  If the above 
     test is used to verify the operability of scram inlet and outlet valves, 
     it should be specifically documented in the IST program.

8.  Starting Point for Time Period in TS ACTION Statements

     ASME Section XI, IWP-3220, states "All test data shall be analyzed within 
     96 hours after completion of a test."  IWP-3230(c) states, in part, "If 
     the deviations fall within the 'Required Action Range' of Table 
     IWP-3100-2, the pump shall be declared inoperative,...."

     In many cases pumps or valves covered by ASME, Section XI, Subsections 
     IWP and IWV, are also in systems covered by TS and, if declared 
     inoperable, would result in the plant entering an ACTION statement.  
     These ACTION statements generally have a time period after which, if the 
     equipment is still inoperable, the plant is required to undergo some 
     specific action such as commence plant shutdown.

     The potential exists for a conflict between the aforementioned data 
     analysis interval versus the TS ACTION statement time period.  Section 
     XI, IWP-6000 requires the reference values, limits, and acceptance 
     criteria to be included in the test plans or records of tests.  With this 
     information available, the shift individual(s) responsible for conducting 
     the test (i.e., shift supervisor, reactor operator) should be able to 
     make a timely determination as to whether or not the data meets the 
     requirements.

     When the data is determined to be within the Required Action Range of 
     Table IWP-3100-2 the pump is inoperable and the TS ACTION statement time 
     starts.  The provisions in IWP-3230(d) to recalibrate the instruments 
     involved and rerun the test to show the pump is still capable of 
     fulfilling its function are an alternative to replacement or repair, not 
     an additional action that can be taken before declaring the pump 
     inoperable.

     The above position, which has been stated in terms of pump testing, is 
     equally valid for valve testing.

     In summary, it is the staff's position that as soon as the data is recog-
     nized as being within the Required Action Range for pumps or exceeding 
     the limiting value of full-stroke time for valves, the associated 
     component must be declared inoperable and the TS ACTION time must be 
     started.

.                                     - 10 -

9.   Pump Testing using Minimum-flow Return Line With or Without Flow
     Measuring Devices

     An inservice pump test requires that the pump parameters shown in Table 
     IWP-3100-1 be measured and evaluated to determine pump condition and 
     detect degradation.  Pump differential pressure and flow rate are two 
     parameters that are measured and evaluated together to determine pump 
     hydraulic performance.

     Certain safety-related systems are designed such that the minimum-flow 
     return lines are the only flow paths that can be utilized for quarterly 
     pump testing.  Furthermore, some of these systems, do not have any flow 
     path that can be utilized for pump testing during any plant operating 
     mode except the minimum-flow return lines.  In these cases, pumping 
     through the path designed for fulfilling the intended system safety 
     function could result in damage to plant equipment.  Minimum-flow lines 
     are not designed for pump testing purposes and few have installed flow 
     measuring devices.

     In cases where flow can only be established through a non-instrumented 
     minimum-flow path during quarterly pump testing and a path exists at cold 
     shutdowns or refueling outages to perform a test of the pump under full 
     or substantial flow conditions, the staff has determined that the 
     increased interval is an acceptable alternative to the Code requirements 
     provided that pump differential pressure, flow rate, and bearing 
     vibration measurements are taken during this testing and that quarterly 
     testing also measuring at least pump differential pressure and vibration 
     is continued.  Data from both of these testing frequencies should be 
     trended as required by IWP-6000.  Since the above position is a deviation 
     from the Code required testing, it should be documented in the IST 
     program.

     In cases where only the minimum-flow return line is available for pump 
     testing, regardless of the test interval, the staff's position is that 
     flow instrumentation which meets the requirements of IWP-4110 and 4120 
     must be installed in the mini-flow return line.  Installation of this 
     instrumentation is necessary to provide flow rate measurements during 
     pump testing so this data can be evaluated with the measured pump differ-
     ential pressure to monitor for pump hydraulic degradation.

     NRC Bulletin 88-04, dated May 5, 1988, advised licensees of the potential
     for pump damage while running pumps in the minimum-flow condition.  The 
     above guidelines for meeting the Code or performing alternative testing 
     is not intended to supersede the thrust of this Bulletin.  Licensees 
     should ensure that if pumps are tested in the low flow condition, the 
     flow is sufficient to prevent damage to the pump.

.                                     - 11 -

10.  Containment Isolation Valve Testing

     All containment isolation valves (CIVs) that are included in the Appendix 
     J, program should be included in the ISI program as Category A or A/C 
     valves. The staff has determined that the leak test procedures and 
     requirements for containment isolation valves specified in 10 CFR 50, 
     Appendix J are equivalent to the requirements of IWV-3421 through 3425.  
     However, the licensee must comply with the Analysis of Leakage Rates and 
     Corrective Action requirements of Paragraph IWV-3426 and 3427(a).

     IWV-3427(b) specifies additional requirements on increased test 
     frequencies for valve sizes of six inches and larger and repairs or 
     replacement over the requirements of IWV-3427(a).  Based on input from 
     many utilities and staff review of testing data at some plants, the 
     usefulness of IWV-3427(b) does not justify the burden of complying with 
     this requirement.  Since this position represents a deviation from the 
     Code requirements, it should be documented in the IST program.

11.  IST Program Scope

     The 10 CFR 50.55a requires that inservice testing be performed on certain 
     ASME Code Class 1, 2, and 3 pumps and valves.  Section XI Subsections 
     IWP-1100 and IWV-1100 defines the scope of pumps and valves to be tested 
     in terms of plant shutdowns and accident mitigation.  The plant's FSAR 
     (or equivalent) provides definitions of the necessary equipment to meet 
     these functions.  The staff has noted during past IST program reviews and 
     inspections that licensees do not always include the necessary equipment 
     in their IST programs.  Licensees should review their IST programs to 
     ensure adequate scope.  Examples that are frequently erroneously omitted 
     from IST programs are:

     a.   BWR scram system valves,
     b.   control room chilled water system pumps and valves,
     c.   accumulator motor operated isolation valves, or accumulator
          vent valves,
     d.   auxiliary pressurizer spray system valves,
     e.   boric acid transfer pumps,
     f.   valves in emergency boration flow path,
     g.   control valves that have a required fail-safe position,
     h.   valves in mini-flow lines.

     It should be recognized that the above examples of pumps and valves do 
     not meet the IWP/and IWV scope statement requirements for all plants.

     The intent of 10 CFR 50 Appendix A, GDC-1, and Appendix B, Criterion XI, 
     is that all components, such as pumps and valves, necessary for safe 
     operation are to be tested to demonstrate that they will perform 
     satisfactorily in service.  Therefore, while 10 CFR 50.55a delineates the
     testing requirements for ASME Code Class 1, 2, and 3 pumps and valves, 
     the testing of pumps and valves is not to be limited to only those 
     covered by 10 CFR 50.55a.

Page Last Reviewed/Updated Friday, June 28, 2013