ML20247L107
| ML20247L107 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 03/31/1989 |
| From: | Reeves E Office of Nuclear Reactor Regulation |
| To: | Mcdonald R ALABAMA POWER CO. |
| References | |
| TAC-71579, NUDOCS 8904050387 | |
| Download: ML20247L107 (16) | |
Text
_
March 31,1989 l
Distribution:
Docket No. 50-364 ! Docket M ie OGC-8 NRC PDR ACRS(10) l Local PDR ELJordan PD21 r/f EAReeves Mr. R. F. Mcdonald SAVarga ,
Senior Vice President GClainas Alabama Power Company PDAnderson ,
P. O. Box 2641 BLMozafari Birmingham, Alabama 35291-0400 JGPartlow TSullivan
Dear Mr. Mcdonald:
EMarsh
SUBJECT:
INTERIM APPROVAL OF THE INSERVICE INSPECTION PROGRAM AND THE INSERVICE TESTING PROGRAM FOR PUMPS AND VALVES - JOSEPH M. FARLEY i NUCLEAR PLANT, UNIT 2 (TAC NO. 71579)
The NRC staff and its consultant, EG&G Idaho, have performed an initial j review of the Joseph M. Farley Nuclear Plant, Unit 2, (Farley Unit 2) Pump and l I
Valve Inservice Testing (IST) program for the second ten year interval, which the licensee submitted by letter dated December 15, 1988. We conclude that the IST program is reasonably complete with respe,.t to all components required to be in the program.
The Unit 2 IST Program has been updated to the requirements of the ASME Code,Section XI, 1983 Edition through the Summer 1983 Addenda, which is also the j Code of record for Unit 1. Except for minor editorial and technical differences t l in design which are summarized in the December 15, 1988 submittal, the updated i Unit 2 IST Program is identical to the Unit 1 Second Ten-Year Interval IST .
Program submitted by letters dated September 30 and November 20, 1987 3 (Revision 0), March 29, 1988 (Revision 1) and September 9, 1988 (Revision 2). i The reliefs requested for the Unit 1 IST Program, Revisions 0 and I were granted by NRC letters dated December 10, 1987 and March 30, 1988, respectively. ] ;
The September 9,1988 letter contained Revision 2 of the Unit 1 IST Program which included one additioncl relief request.
At this time, we have identified no inconsistencies, except those identified in Enclosure 1. The provisions of Enclosure 1 must be followed in conducting d your programs. On this basis, we have determined that an interim period of l relief is appropriate until the staff can complete its safety evaluation of the program. Since this interim approval does not represent the results of the i final program review, the final Safety Evaluation (SE) could contain relief I request denials or identify components that should be added to the Farley l Unit 2 IST program. We expect to issue the final 5E in the near future.
By a separate letter dated December 16, 1988, you submitted the Inservice i l Inspection (ISI) program for the second ten year interval of Farley Unit 2. !
On February 8, 1989, you responded to our request for a list of relief requests i
required for the Unit 2 sixth refueling outage. An ISI program must be '
approved or interim approval granted so that an approved program is available for utilization during the current outage. However, the staff has not I completed the detailed evaluation of the revised program for the second ten year interval. Because of the need in the current refueling outage, pursuant 8904050387 890331 PDR ADOCK 05000364 - e P PDC
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Mr. R. P. Mcdonald i to 10 CFR 50.55a(g)(6)(1), pending completion of our detailed review, we grant interim relief for the requests listed below, from those ISI requirements of the ASME Code that you have requested..
Granted Interim Relief RR-1 RR-7 RR-16 RR-31 RR-2 RR-9 RR-17 RR-32 '
RR-4 RR-10 RR-18 RR-39 RR-5 RR-11 RR-28 RR-41 RR-6 RR-12 RR-29 RR-42 Therefore, you are authorized to implement your proposed program except where your Technical Specifications are more restrictive. From the date of this letter until we complete our detailed review of your revised submittal and issue our SE, you must comply with both your existing Technical Specifications and your proposed ISI program. In the event that conflicting requirements arise for any component, you must comply with the more restrictive requirements. Thus, the granting of this relief from the ASME Code should not be interpreted to give you relief from any of the requirements in your l
, existing Technical Specifications.
1 l When our de. tailed reviews of your December 15 and 16,1988 submittals are '
complete we will issue final approval of your programs M the form of SEs which may untain modifications resulting from the staff's review or which may grant relief from any ASME Code requirements that are determined to be impractical for your facility for the duration of the second ten year inspection interval.
Thestaffhasdeterminedthatpursuantto10CFR50.55a(g)(6)i,grantingthe revised interim approval for the reliefs, as discussed above, for the Farley Unit 2 IST and ISI programs for the second ten year interval is authorized by law and will not endanger life or property or the common defense and security.
The staff has also concluded that granting the approvals is otherwise in the public interest considering the burden that could result if the requirements were imposed on the facility. The interim reliefs will terminate upon issuance of our final SEs.
Sincerely, Edward A. Reeves, Acting Director Project Directorate 11-1 Division of Reactor Projects I/II Office of Nuclear Reactnr Regulation
Enclosures:
As stated ,
cc w/encls:
See next page (LTR.
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Mr. W. G. Hairston, III Alabama Power Company Joseph M. Farley Nuclear Plant cc: '
-Mr. R. P. Mcdonald Resident Inspector l Executive Vice President U.S. Nuclear Regulotory Commission ;
Alabama Power Company Post Office Box 24 - Route 2 Post Office Box 2641 Columbia, Alabama 36319 j Birmingham, Alabama 35291-0400 l Mr. Bill M. Guthrie D. Biard MacGuineas, Esquire Executive Vice President Volpe, Boskey and Lyons Alabama Power Company 918 16th Street, N.W.
Post Office Box 2641 Washington, D.C. 20006 Birmingham, Alabama 35291-0400 Mr. Louis B. Long, General Manager Charles R. Lowman Southern Company Services, Inc. Alabama Electric Corporation Post Office Box 2625 Post Office Box 550 i Birmingham, Alabama 35202 Andalusia, Alabama 35420 !
Chairman Regional Administrator, Region II Houston County Commission U.S. Nuclear Regulatory Commission Dothan, Alabama 36301 101 Marietta Street, Suite 2900 Atlanta, Georgia 30323 l Ernest L. Blake, Jr., Esquire i Shaw, Pittman, Potts and Trowbridge Claude Earl Fox, M.D.
2300 N Street, N.W. State Health Officer Washington, DC 20037 State Department of Public Health State Office Building Montgomery, Alabama 36130 Robert A. Buettner, Esquire l Balch, Bingham, Baker. Hawthorne, Mr. D. N. Morey l Williams and Ward General Manager - Farley Nuclear Plant l
Post Office Box 306 Post Office Box 470 i Birmingham, Alabama 35201 Ashford, Alabama 36312 i
ENCLOSURE 1 FARLEY UNIT 2 IST PROGRAM INCONSISTENCIES IDENTIFIED DURING THE REVIEW Inconsistencies in the licensee's programs noted during the course of this review are sumarized below.
- 1. Pump Relief Request PR-12 requests relief'from the IWP-4500 requirement that vibration be measured for the service water pumps at a pump housing..
. Relief can' be granted, as requested, provided that t1e motor bearing housing that contains the motor thrust' bearing is the motor housing where the vibration is proposed to be measured.
- 2. Valve Relief Request Q2E21-RV-12 requests relief from the IWV-3522 ;
requirement that the CVCS seal injection check valves to the RCPs be forward flow operability verified quarterly. As the proposed testing is not a. deviation from the Code requirements, relief is not necessary and has not been addressed in this report. .These relief requests should be
' deleted from the IST program for both units.
- 3. The following relief requests are concerned with check valve sample-disassembly / inspection:
Q2E11-RV-3 Q2E11-RV-4 Q2E11-RV-5 i Q2E11-RV-7 Q2E13-RV-1 Q2E13-RV-3 I Q2E21-RV-2 Q2E21-RV Q2E21-RV-6 j Q2E21-RV-10 Q2E21-RV-11 Q2E21-RV-13 Q2E21-RV-14 Q2N23-RV-1 Q2P16-RV-3 Q2P16-RV-4 Q2E13-RV-4 Relief can be granted for these requests, provided the licensee tests these check valves in accordance with Attachment 1 to this enclosure.
- 4. Since the plant Technical Specifications (TS) do not provide the minimum operability requirements for plaht start-up, general relief from the requirement to repair prior to start-up of the plant any valves that are declared inoperable due to Section XI testing performed during cold ,
shutdown, can not be granted for such valves in flow paths not covered by the plant TS. If relief is needed from IWV-3417(b) for any of these valves, the licensee should submit relief requests for specific valves.
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- 5. Pump Relief Request RP-15 requests relief from the IWP-3110 requirement ;
that differential pressure and flow rate measurements be readily i duplicated during subsequent inservice tests. The licensee proposed to !
utilized pump curves' for comparing differential pressure and flow rate for 1 component cooling water pumps P001A-B, P001B-AB, and P001C-A. Relief can be granted, as requested, provided the licensee applies table IWP-3100-2 acceptance criteria to measured values.
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- 6. Pump Relief Request PR-11 requests relief from the IWP-3100-2 flow rate high range limits for service water pumps P001A-A, P0018-A, P001C-AB, P0010-8 and P001E-B. The licensee proposed that these limits be raised because service water inservice pumps are to be tested in combination.
The licensee has not provided sufficient technical justification to be i
granted relief for this request, thus the relief is denied.
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m ATTACHMENT POTENTIAL GENERIC DEFICIENCIES RELATED TO IST PROGRAM 5 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 +otal flow through multiple parallel lines does not provide verification of flow rates through the individual valves and is not a valid full-stroke exercise.
l Full flow testing of a check valve as described above may be impractical to l 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,.
l 2. A description of the alternative technique used and a summary of l the procedures being followed,
, 3. A description of the method and results of the program to qualify I
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 inspecticr 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. Alternative to Full Flow Testing of Check Valves.
The most connon 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 coulo 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 3 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 kspected 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 graup 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.
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A different valve of each group is required-to be-disassembled, l 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 1 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 diassembly must be repeated ,
unless extension of the interval can be justified. J 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 i i group would be disassembled and inspected only once every 8 years. l 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 i 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 j or whether more valves from the_ group should be disassembled during every i 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 i
by actual in-plant data from previous testing. la order to support extension '
of the valve disassembly / inspection intervals to longer than once every 6 years, licensees should develop the following information:
I 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.
- 6. A review of industry experience, for example, as documented in NPRDS, l regarding the same type of valve used in similar service. j
- c. A review of the installation of each valve aduressing the "EPRI Appli-cations Guidelines for Check Valves in Nuclear Power Plants" for ;
problematic locations. J
- 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 func-l tion 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
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have a s acified 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 postive 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:
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- a. main feedwater header check valves
- b. : ump discharge check valves on parallel pumps
- c. (eep 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 i of the RCPB. P!Vs are within the reactor coolant pressure boundary '
(RCPB).
The following summary is based upon the staff's review of responses.to i Generic Letter 87-06, Periodic Verificnion of Leak Tight Integrity of i Pressure Isolation Yalves. 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 require- ;
ments and LCOs in the plant TS. Some pre-1979 plants have only Event i VPIVs(seebelow)intheplantTS. Some pre-1979 plants have no TS !
requirements regarding PIVs. I 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.
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- b. Event V PIVs Event Y 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 j this event in the WASH-1400 study. 1 l
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e e 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, I based on plant-specific NRC supplied lists of PIVs, and required i licensees to modify their TS accordingly. These orders are known as I the " Event Y 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 i to testing of PIVs. The staff has determined that in some cases the i procedures are inadequate to assure that these valves are individually {
1eak 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 i The Code intent with respect to measuring the full-stroke times of power
-operated valves is to verify operability and to detect' valve degradation. j 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 infonnation publicly available includes an INP0 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 Re;: air 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 l. Expansion of this bulletin in the form of a generic letter is being considered by the NRC.
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 Ifmits-and any limits identified for the relevant valves in the plant TS or safety analysis.
The purpose of the limitig value of full-stroke time is to establish a value for taking correctne action on a degraded valve before the valve reaches the point where there is a high probability of failure to perforni its safety function if called upon. The NRC has, therefore, established the guidelines described below regarding limiting values of full-stroke.
time for pok :r 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 i 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 I function.
When the TS or safety analysis limit for a valve 1-s less than the value established using the above guidelines, the_TS or safety analysis limit should be used as the limiting value of full-strokt 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 ti'me 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 follodng for powc oprated valves with stroke i times 10 seconds or less: (a Limiting values of full-stroke times shall be specified [IWV-3413(a)], ( ) Valve ~strue times shall be measured to (at least) the nearest second [IWV-3413(b)] cnd (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 previbus test ,
is an acceptable (and possibly better) alternative to the staff. However, since this is different from the Code requirewnt, this deviation should be documented in the IST program.
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l 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 requirmnt is to detect i 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. l 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: I 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 corrcctive acticn is taken. This I can result from a stroke time difference of 0.02 seconds, which is vsvally not indicetive 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 man mum limiting value of full-stroke time of 2 seconds to these valves and, u,'n exceeding this limit, declares the valve inoperable and takes correctivs actioninaccordancewithIWV-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. l
- 7. Testing Individtal Control Rod Scram Valves in Boiling Water Reactors (BWRs)
BWRs are equipped with bottom-entry hydraulically driven control rod drive I 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 scrammi @ 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.
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l The control rod drive system , ses 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 the.se 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
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! 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.
l Closure verification of the charging water header check valves requires that the control rod drive pumps be stopped to depressurize the charging i 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 outivt 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 L
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9 defined in the plant TS can be an acceptable alternate athod of detecting degradation of these valves. Also, trending the strol 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 Statments ASME Section XI, IWP-3220, states "All test data shall be analyzed within 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> 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 state-ment. These ACTION statements genert.!!y have a time period after which, if the equipment is still inoperable, the plant is required to undergo some specific action such as comence 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 l available, the shift individual (s) responsible for conducting the test {
(i.e., shift supervisor, reacter operator) should be able to make a timely 1 determination as to whether or not the data meets the requirements. 1 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 recalf-brate 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 sumary, 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 vlaves, the associated component must be declared inoperable and the TS ACTION time must be started. !
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- 9. Pump Testing us,ry 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 evaulated 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 .
I path that can be utilized for pump testing during any plant operating '
I 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 i
provided that pump differential pressure, flow rate, and bearing vibration measurements are taken during this testing and that quarterly testing i 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 l 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 supercede the thrust of this Bulletin. Licensees should ensure that if pumps are tested in the low flow condition, the i flow is sufficient to prevent damage to the pump. '
l l
- 10. Containment Isolation Valve Testing
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All containment isolation valves (CIVs) that are included in the Appendix J, program should be included in the IST 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 I requirementsofIWV-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 l position represents a deviation frcm 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 1 in their IST programs. Licensees should review their IST programs to l ensure adequate scope. Examples that are frequently erroneously omitted from IST programs are:
- b. control room chilled water system pumps and valves, i
- 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.
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