United States Nuclear Regulatory Commission - Protecting People and the Environment

"Consideration of the Results of NRC-Sponsored Tests of Motor-Operated Valves" (Generic Letter 89-10, Supplement 3)


October 25, 1990 


TO:       ALL LICENSEES OF OPERATING NUCLEAR POWER PLANTS AND HOLDERS OF      
          CONSTRUCTION PERMITS FOR NUCLEAR POWER PLANTS

SUBJECT:  GENERIC LETTER 89-10, SUPPLEMENT 3, "CONSIDERATION OF THE RESULTS 
          OF NRC-SPONSORED TESTS OF MOTOR-OPERATED VALVES"


BACKGROUND

In Generic Letter 89-10 (June 28, 1989), "Safety-Related Motor-Operated 
Valve Testing and Surveillance," the staff of the U.S. Nuclear Regulatory 
Commission (NRC) requested holders of operating licenses and construction 
permits to establish a program to provide for the testing, inspection, and 
maintenance of safety-related motor-operated valves (MOVs) and certain other 
MOVs in safety-related systems.  Supplement 1 to Generic Letter 89-10 (June 
13, 1990) provides the results of public workshops held to discuss the 
generic letter and to answer questions on the staff positions regarding its 
implementation.  In Supplement 2 (August 3, 1990) the NRC staff stated that 
inspections of program descriptions would not commence until January 1, 
1991, and, thus, the program descriptions need not be available on site 
until that date.

In parallel with the NRC staff's activities leading to Generic Letter 89-10, 
the staff performed tests of MOVs as part of an ongoing research effort.  
The tests were conducted on 6-inch and 10-inch gate valves typically used to 
provide containment isolation in the steam supply lines of the High Pressure 
Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems, 
and in the supply line for the Reactor Water Cleanup (RWCU) system at 
boiling water reactor (BWR) nuclear power plants.  On June 5, 1990, the 
staff issued Information Notice 90-40, "Results of NRC-Sponsored Testing of 
Motor-Operated Valves."  

As discussed in Information Notice 90-40, the NRC-sponsored tests revealed 
that, regardless of fluid conditions, the tested valves required more thrust 
for opening and closing under various differential pressure and flow 
conditions than would have been predicted from standard industry 
calculations using typical friction factors.  Thus, although the 
NRC-sponsored tests focused on the HPCI, RCIC and RWCU containment isolation 
valves at BWR plants, the information obtained from those tests may be 
applicable to valves used in other systems at BWR and pressurized water 
reactor (PWR) plants.  For example, calculations using low valve friction 
factors may underestimate thrust requirements for opening and closing 
valves.





9010220146 
.

                                    - 2 -                 October 25, 1990 

In response to a staff request, the BWR Owners' Group obtained information 
from the BWR licensees regarding the capability of MOVs used to provide 
containment isolation in the steam lines of the HPCI and RCIC systems, and 
in the supply line of the RWCU system.  The staff's review of the 
NRC-sponsored test results and the MOV data provided by the BWR Owners' 
Group indicates that deficiencies might exist in those MOVs.  

DISCUSSION

In Generic Letter 89-10, the NRC staff requested that licensees and 
construction permit holders complete the programs established in response to 
the generic letter (excluding the periodic verification of MOV switch 
settings) by June 28, 1994, or within 3 refueling outages after December 28, 
1989 (or operating license issuance for construction permit holders), 
whichever is later.  While recommending that licensees and permit holders 
consider the safety significance of MOVs in developing their programs, the 
staff did not have sufficient information at that time to recommend that 
licensees and permit holders establish any particular priority for MOVs 
within the generic letter program.  The information recently obtained from 
the NRC-sponsored tests, however, may affect the priorities being 
established by licensees and permit holders for implementing their generic 
letter programs.  From its evaluation of the MOV data provided by the BWR 
Owners' Group and the results of the NRC-sponsored tests, the staff has 
determined that correction of any deficiencies in the HPCI, RCIC and RWCU 
MOVs described herein need to be given high priority in the implementation 
of generic letter programs.  While such deficiencies may not need to be 
corrected immediately, the staff has determined by means of a safety 
assessment (Enclosure 1) that any MOV deficiencies should be corrected 
within 18 months or by the end of the first refueling outage, following 
issuance of this generic letter supplement, whichever is later.  The staff's 
review of a generic safety assessment performed by the BWR Owners' Group 
(Enclosure 2) confirmed that this time period is acceptable for correcting 
any deficiencies in those MOVs.  If a BWR licensee believes that there are 
MOVs with potential deficiencies at its facility that have greater safety 
significance than the HPCI, RCIC, and RWCU MOVs described herein, the 
licensee should determine the appropriate priority for completing the 
generic letter program for those valves.


REQUESTED ACTIONS

BWR licensees are requested to assess the applicability of the data from the 
NRC-sponsored MOV tests, to determine the "as-is" capability of the HPCI, 
RCIC, and RWCU MOVs described herein, and to identify any deficiencies in 
those MOVs.  Where applicable, BWR licensees should also evaluate the MOVs 
used for containment isolation in lines to the isolation condensers.  
Elements that a BWR licensee may consider in determining whether the 
NRC-sponsored test data are inapplicable to its HPCI, RCIC and RWCU MOVs 
include valve size, type and manufacturer; disk type; design-basis 
differential pressure and flow conditions; internal dimensions and 
clearances; and disk and guide surface materials.
.

                                    - 3 -                 October 25, 1990 

BWR licensees are requested to perform a plant-specific safety assessment to 
verify that the generic safety assessments performed by the NRC staff and 
the BWR Owners' Group are applicable.  In performing the plant-specific 
safety assessment, BWR licensees should address factors such as 
consideration of functional valve test results; operating procedures and 
emergency operating procedures; the conduct of training; current torque 
switch bypass settings including the potential for motor overload on a first 
attempt to close the valve; leak detection capabilities; inspection programs 
for erosion-corrosion and intergranular stress corrosion cracking (including 
response to Generic Letter 88-01, "NRC Position on IGSCC in BWR Austenitic 
Stainless Steel Piping"); water-hammer prevention practices; the 
environmental qualification of the MOVs and other nearby equipment; 
radiological consequences both on and off the plant site that could result 
from a pipe leak or break; and probabilistic risk considerations.  Where 
applicable, BWR licensees should include in their plant-specific safety 
assessments MOVs used for containment isolation in lines to the isolation 
condensers.  If a BWR licensee believes that there are MOVs with potential 
deficiencies at its facility that have greater safety significance than the 
HPCI, RCIC and RWCU MOVs (and the MOVs in the isolation condenser lines) 
described herein, the licensee should justify as part of its plant-specific 
safety assessment the prioritization of its effort to identify and correct 
MOV deficiencies. 

BWR licensees should consider the implementation of short-term corrective 
actions.  For example, BWR licensees should evaluate the feasibility of 
increasing torque switch settings where the motor, actuator, and valve are 
designed to accommodate such an increase.  BWR licensees should develop 
procedures and provide training for plant personnel to respond to a pipe 
leak or break in a line containing a deficient MOV, particularly if the 
deficiency cannot be corrected in the short term.

BWR licensees may accomplish these recommendations as part of an accelerated 
response to Generic Letter 89-10 for the applicable MOVs.  For example, BWR 
licensees could complete the design-basis reviews for those MOVs and could 
establish torque switch settings as described in Recommended Actions a and b 
of the generic letter, respectively.  Recommended Action c of the generic 
letter requests that the MOVs be tested in situ under design-basis 
differential pressure and flow conditions, where practicable.  For those 
instances where design-basis testing in situ is not practicable and an 
alternative to such testing cannot be justified at this time, the staff 
recommends that the BWR licensee use the "two-stage" approach discussed in 
Generic Letter 89-10 and Supplement 1.  Following that approach, the BWR 
licensee would determine the operating requirements of the MOV using the 
best data currently available and then obtain applicable data as soon as 
possible. 

While the reporting requirements below are addressed to BWR licensees, all 
licensees and construction permit holders should consider the applicability 
of the information obtained from the MOV tests and the staff evaluation of 
the 
.

                                    - 4 -                 October 25, 1990 

test results to other MOVs within the scope of Generic Letter 89-10.  In 
addition, all licensees and permit holders should consider this information 
in the development of priorities for implementing the generic letter 
program.

REPORTING REQUIREMENTS

In order for the NRC to determine whether any BWR operating licenses should 
be modified, suspended or revoked, BWR licensees shall provide written 
information, signed under oath or affirmation pursuant to Section 182 of the 
Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f), as follows:

1.   Within 30 days of the receipt of this letter, BWR licensees shall 
     notify the NRC staff that a plant-specific safety assessment report 
     addressing, as a minimum, the factors described herein, is available on 
     site for staff review.  BWR licensees shall also notify the NRC staff 
     whether they believe that there are MOVs with deficiencies of greater 
     safety significance than the MOVs used to provide containment isolation 
     in the steam supply lines of the HPCI and RCIC systems, in the supply 
     line of the RWCU system, and in the line to the isolation condenser.

2.   Within 120 days of the receipt of this letter, BWR licensees shall 
     provide to the NRC staff the following:

     a. Criteria, reflecting operating experience and the latest test data,
        that were applied in determining whether deficiencies exist in the
        HPCI, RCIC and RWCU MOVs described herein, in the MOVs in isolation
        condenser lines, and in any MOVs considered to be more safety
        significant, as applicable;

     b. The identification of any MOVs found to have deficiencies; and

     c. A schedule for any necessary corrective action.

3.   Subsequent to the determination of necessary corrective actions or the
     establishment of the schedule for completion of those actions, BWR
     licensees shall inform the NRC staff of any changes to the planned 
     actions or schedule.

As noted above, based on the generic safety assessments prepared by the NRC 
staff and the BWR Owners' Group, the staff believes that justification 
exists for individual plants to which those safety assessments are 
applicable to take 18 months or to the end of the first refueling outage, 
following issuance of this generic letter supplement, whichever is later, to 
resolve any deficiencies in the HPCI, RCIC and RWCU MOVs described herein.  
However, if a BWR licensee determines that a more limited time is mandated 
by its plant-specific safety assessment, the licensee should utilize the 
more restrictive time.  If additional time is needed to complete the 
corrective actions, BWR licensees should submit the plant-specific safety 
assessment and obtain staff approval for the corrective action schedule.
.

                                    - 5 -                 October 25, 1990 

BACKFIT DISCUSSION

Based on operating experience and research results, the staff determined 
several years ago that MOV tests beyond those previously acceptable are 
necessary to satisfy the NRC regulations.  As that determination constituted 
a backfit, the staff prepared Generic Letter 89-10 in accordance with NRC 
procedures for the issuance of staff guidance containing backfit provisions.  
Supplement 3 represents a further backfit in that the staff is requesting 
BWR licensees to advance the schedule for Generic Letter 89-10 with respect 
to specific MOVs at BWR plants.  This limited advancement of the Generic 
Letter 89-10 schedule is the result of the information obtained from 
NRC-sponsored MOV tests indicating that deficiencies might exist in certain 
MOVs installed to perform containment isolation functions at BWR plants.  
The staff has determined that the issuance of Supplement 3 to Generic Letter 
89-10 is necessary to provide confidence that BWR facilities are in 
compliance with their safety analyses and NRC regulations such as described 
in 10 CFR Part 50, Appendix A, Criteria 54 and 55.  More specifically, 
because deficiencies might exist in the MOVs described herein, the staff 
does not have adequate confidence that (1) as required by Criterion 54, the 
applicable piping systems which penetrate containment have been provided 
with leak detection, isolation, and containment capabilities having 
redundancy, reliability, and performance capabilities which reflect the 
importance to safety of isolating these piping systems, or have been 
designed with the capability to test periodically the operability of the 
isolation valves and associated apparatus or (2) as required by Criterion 
55, appropriate requirements, such as higher quality in design, fabrication, 
and testing, to minimize the probability or consequences of an accidental 
rupture of lines which are part of the reactor coolant pressure boundary and 
penetrate reactor containment have been provided as necessary to assure 
adequate safety.  Therefore, the staff has determined that the backfit 
provisions of this generic letter supplement are justified under 10 CFR 
50.109 (a)(4)(i).  Based on its safety assessment, the staff determined that 
no immediate corrective actions are needed and that BWR licensees may 
proceed to resolve any deficiencies in the MOVs described herein as 
recommended in this letter.

This request is covered by Office of Management and Budget Clearance Number 
3150-0011, which expires December 31, 1991.  The estimated average burden 
hours are 150 person-hours per licensee response, including assessment of 
the new recommendations, searching data sources, gathering and analyzing the 
data, performing data evaluations, and preparing the required letters.  
(These estimated average burden hours pertain only to the identified 
response-related matters and do not include the time for actual 
implementation of the requested action.)  Send comments regarding this 
burden estimate or any other aspect of this collection of information, 
including suggestions for reducing 
.

                                    - 6 -                 October 25, 1990 

this burden, to the Information and Records Management Branch, Division of 
Information Support Services, Office of Information Management, U.S. Nuclear 
Regulatory Commission, Washington, D.C., 20555; and to the Paperwork 
Reduction Project (3150-0011), Office of Management and Budget, Washington, 
D.C.  20503.




                                    James G. Partlow
                                    Associate Director for Projects
                                    Office of Nuclear Reactor Regulation

Enclosures:  As stated

TECHNICAL CONTACT:
Thomas G. Scarbrough  (301) 492-0794

LEAD PROJECT MANAGER:
Anthony T. Gody, Jr.  (301) 492-1387
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