ML20247N181

Safety Evaluation Supporting Plant Inservice Testing Program & Request for Relief

ML20247N181
Person / Time
Site:	Wolf Creek
Issue date:	09/20/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20247N171	List: ML20247N167 ML20247N181
References
NUDOCS 8909260168
Download: ML20247N181 (21)

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. .,k UNITED STATES p  ?> NUCLEAR REGULATORY COMMISSION 5 :j WASHINGTON, DI C. 20555 k ,[

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE, TESTING PROGRAM AND REQUEST FOR RELIEF WOLF CREEK NUCLEAR OPERATING CORPORATION WOLF CREEK GENERATING STATION DOCKET N0. 50-482 INTRODUCTION The Code of Federal Regulations, 10 CFR 50.55a(g), requires that inservice testing (IST) of ASME Code Class'1, 2, and 3 pumps and valves be performed '

in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda, except where specific written relief has been re-quested by the licensee and granted by the Commission. In requesting relief under 10 CFR 50.55(a)(3)(1) or (g)(6)(1), the licensee must demonstrate that:

(1) the proposed alternatives provide an acceptable level of quality and safety or (2) conformance with certain requirements of the applicable Code edition and addenda is impractical for its facility.

The Regulation,10 CFR 50.55(a)(3)(1), and (g)(6)(i) authorizes the Comission to grant relief from requirements upon making the necessary findings. The NRC staff's findings with respect to granting or not granting the relief request as part of the licensee's IST program are contained in the Safety Evaluation (SE) issued on the licensee's program.

The Wolf Creek Generating Station (WCGS) First Ten Year IST Program, Revision 1, was found acceptable for implementation with certain conditions in a safety evaluation (SE) report dated January 15, 1988. Subsequently, Wolf Creek Nuclear Operating Corporation, the licensee, by letter dated April 14, 1988, submitted a response to the staff's SE. In addition the licensee submitted letters dated June 29, 1988, September 1, 1988, and October 20, 1988, in response to the staff's request for additional information. The licensee's submittals describe the changes to the IST program in response to the 19 anomalies identified in Appendix C of the Technical Evaluation Report (TER) attached to the NRC SE.

The major changes involved the addition, revision, and deletion of 12 relief requests and minor changes that involved reclassifying 16 valves from passive to active and clarifying a cold shutdown justification. The program for the first ten year interval is based on the requirement of the 1980 Edition through the Winter of 1981 Addenda and these requirements remain in effect through the first 120 month interval of commercial operation.

EVALUATION The staff, with the assistance of its contractor, EG&G, has reviewed the licensee's submittal containing revised relief requests from the ASME Code (the Code),Section XI, Subsections IWP and IWV. The letter report provided as Attachment 1 is EG&G's evaluation of the licensea's response to Items 4, 5, 6,

'9, 11, and 12 in Appendix C of the TER. The staff has reviewed the EG&G letter 8909260168 890920 PDR ADOCK 05000482 PDC

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, "k report and concurs in, and adopts its findings. In addition, the staff has

' evaluated the'. licensee's responses to the remainder of Appendix C items dealing with relief requests and a cold shutdown testing justification. The evaluation is_ provided below. ' A suunary of the staff and EG&G relief requests determinations is presented in Table 1.

1.0 -PUMPS 1.0.1 . Bearing Temperature Measurements 1.0.1.1 Relief Request ~(Item 19 of Appendix C)

The licensee has requa ted relief from the Section XI, Paragraph IWP-3300 requirement to measure bearing temperature annually on auxiliary feedwater.

pumps PAL 01 A & B,'and PALO2, boric acid transfer pumps PBG02 A & B (inboard bearing._only), centrifugal charging pumps PBG05 A & B, fuel pool. cooling pumps PEC01.A & B, essential service water pumps PEF 01 A & B, component cooling water pumps PEG 01 A, B, C, & D, residual heat removal puups PEJ01_A & B, safety injection pumps PEM01A and B, (inboard bearing only), containment spray pumps PEN 01A.and B, and emergency fuel oil transfer pumps PJE01A and B. The licensee has proposed no alternative testing.

1.0.1.2 Licensee's Basis for Relief

1) "The bearings of certain pumps addressed in this Relief Request are cccled by their respective process fluid. Thus, bearing temperature measurements would be highly dependent en the temperature of the cooling medium."

2) "The bearing temperature taken at one-year intervals provide little data toward determining the incremental degradation of a bearing cr providing

=any meaningfully trend information."

3) "The pumps addressed by this Relief Request, except for the Emergency Fuel Oil _ Transfer Pumps, are subjected to vibration measurements on

a. quarterly basis in accordance with Subsection IWP-4500. Vibration measurements are a significantly more reliable indication of pump bearing degradation than are temperature measurements."

4) "The pumps addressed by this Relief request have no permanently installed temperature monitoring devices or access for measurement with a portable temperature measuring device. The only exceptions are the outboard bearing of the CCPs and SI Pumps which have installed local temperature measuring devices in the oil return line from the bearing."

"In sumary, other measurable parameters are more indicative of pump performance and in.some instances the measured temperature does not represent the actual j bearing temperature. Therefore, pump bearing temperature will nct be measured j with the exceptions noted in Item 4 auove."

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1.0.1.3 Evaluation The bearings on the Emergency Fuel Oil Transfer Pumps PJE01A and B are in the main flow path of the fluid being pumped. Therefore, temperature measurement, as outlined in Section XI, paragraph IWP-4300, is not required and no relief I

is necessary.

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for all other pumps in the Relief Request, the imposition of the Code requirements would result in a significant burden on the licensee due to the modifications that would be required. Although the 11cer.see did not propose an alternate testing condition, all pumps addressed by this relief request except the Emergency Fuel Oil Transfer Pumps are subject to the Code requirement of quarterly vibration monitoring. The monitoring of vibration is a more reliable indication of pump degradation than annual temperature measurements.

Based on the impracticality of complying with the Code requirements and consid-ering the burden on the licensee if the Code requirements were imposed and the vibration measurements that will be taken to determine pump mechanical con-dition, relief may be granted from the Section XI requirement to measure bearing temperature annually on all the pumps in this relief request.

1.0.2 Allowable Ranges of Test Quantities 1.0.2.1 Relief Request (Item 18 of Appendix C)

The licensee has requested relief from the allowable ranges of test quantities requirements of Section XI, Table IWP 3100-2, for pump differential pressure and flow for the Fuel Pool Coolant Pumps PEC01A and B. The licensee has pro-posed that the required action range (HIGH) be above a value equal to 108 per-cent of the reference value for the test quantities of flow rate and differen-tial pressure. The Alert-range (HIGH) will be above a value equal to 105 per-cent of the reference value flow rate and differential pressure.

1. r, . 2. 2 Licensee's Basis for Requesting Relief "Tht requirement to declare a pump inoperative when a Test Parameter exceeds the reference value by 3 percent is not technically justified, sound engineering judgement, nor acceptable plant operating practices for the following reasons:

- Indiscriminately declaring safety system pumps inoperable results in excessive and unneeded testing of other plant Safeguard Systems and Componer.ts. Such testing could ultimately detract from the overall reliability of the Plant Safety Systems. In addition, unwarranted testing unnecessarily adds to the burden of the Operations Force and dilutes efforts focused on the performance of their primary duties. Also, Operators are subjected to additional and unnecessary radiation exposure.

- The case where a Test Parameter exceeds the reference value is not necessarily indicative of pump degradation. It may merely signify that the reference value is probably at the lower side of the statistical scatter of the test data and

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, 4 the specific test in question is on the upper side. Note that the reference values are subject to the same elements of statistical error associated with any other individual test.

- The 3 percent limitation is overly restrictive when compared to the accuracy of the instrumentation used to gather the test data. Analysis has shown that in order to consistently remain below the 3 percent limit, l instrument loop accuracies in the range 0.5 to 0.75 percent would be re- )

quired. This presents a significantly more restrictive requirement than that established by Paragraph IWP-4110 ( 2 percent).

- Power Plant Operating Systems are not configured in a manner that provides '

the laboratory-type conditions demanded to meet the repeatability implied by the 3 percent restriction. Several of the tests require throttling with large Gate or Butterfly Valves using remote manual control. Thus, non-quantifiable System Flow conditions are created that are certain to affect measured test quantities.

- To ensure the reference values do not reflect operations at the lower end of the performance spectrum and, thus, ultimately be reflected in frequently exceeding the upper performance limits as a result of instrument drift, all related instrumentation is calibrated on a frequent basis.

- This requirement provides no additional measure of reliability to the equipment.

- When the upper limits tre exceeded, the only reasonable way of correcting the inoperative condition is to conduct an analysis to ensure that the pump is indeed operable and capable of meeting its intended function. When this is done, in accordance with Subarticle IWP-3230(c), a new reference value must be established. Due to the test conditions and methods of testing at WCGS, any change in the reference point eliminates the correlation of future test results with past pop performance. Because the usefulness of any past data in determining a trend for pump performance is essentially eliminated, a primary goal ar.a basis for the Inservice Testing Program could be jeopardized.

- The h sign minimum flow for worst case conditions in the spent fuel pool is 3,250 gpm. This flow rate correlates to the actual test flow. The system design feature used to compensate for pump degradation is the pump discharge valve. This valve is presently throttled approximately 2/5 open. As pump l flow and differential pressure degrade with wear, the valve will be adjusted i to maintain the minimum flow.

- The pump vendor (Gould) stated that only the following two plausible )

situations would result in a dramatic drop in pump head: j i

1 The loss in suction pressure causing the pump to go into " full '

cavitation".

2 The improper setting of the impeller clearance after pump maintenance.  !

On this model of pump, the suction clearance is crucial to pump l performance.

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i Both of these situations are unaffected by " time in service" or pump wear.

The vendor has no information, either experience based or from test data, to indicate that catastrophic failure in pump performance is likely after degradation of approximately 10 percent."

1.0.2.3 Evaluation Section XI, Paragraph IWP-3210 states that if the ranges of Table IWP-3100-2 cannot be met, the owner shall specify in the records of tests the reduced range limits to allow the pump to fulfill its function. In addition, with these reduced limits, a licensee should be able to demonstrate that signi-ficant degradation would be detected. With the limits in Table IWP-3100-2, ,

these safety-related pumps were being declared inoperable when they were known j to be in good operating condition. Therefore, the licensee has specified new '

range limits for these pumps as provided for in the Code. The licensee has proposed to use a required action range (HIGH) that would be above a value equal to 108 percent of the reference value for the test quantities of flow j rate and differential pressure. The Alert range (HIGH) would be above a value i equal to 105 percent of the reference value flow rate and differential pressure.  !

By letter dated October 20, 1988, the licensee provided additional information in two areas: (1) the current ASME Code,Section XI, vibration amplitude levels versu; ANSI /ASME OM-6, levels; and (2) the possibility of a failure mechanism thaf would be characterized by a 10 to 20 percent degradation in hydraulic performance without an associated rise in component vibration identifying the developing failure. In the letter, the licensee indicated that the vibration amplitude for the fuel cooling pumps measured per IWP-4500 was approximately 1 0.2 mil. For these pumps, the ASME Code,Section XI, Table IWP-3100-2 (High Value) would be 1.0 mil and the Required Action Range (High Value) would be 1.5 mil. In comparing the Section XI, Alert and Required Action Range values with those in the more recent ANSI /ASME OM-6 Standard, the licensee noted that for the fuel pool cooling pumps the Section XI values were more conservative ,

and that the measured values are well within the limits allowed by Section XI. I In addition, the licensee's letter dated October 20, 1988, provided conclusions i from their discussions with the pump vendor. The conclusions were: (1) degra-dation in hydraulic performance would indicate significant wear to the pump impeller and wear rings with an associated imbalance induced vibration and (2) the vendor expects that the consequent increase in vibration readings would exeed the alert limit of 1 mil for the fuel pool cooling pumps.

Based on: (1) the impracticality of meeting the Code requirements; (2) the  !

licensee's letter dated October 20, 1988, providing a comparison between ASME ,

Code,Section XI and ANSI /ASME, OM6, with regards to vibration, and detailing  !

discussions between the licensee and pump vendor on pump degradation; (3) the fact that the licensee has not been able to consistently meet the Code specified ,

flowrate and differential pressure high limit for these safety related pumps even though the pumps have been in good working condition; and (4) the proposed less restrictive limits authorized by the Code, the staff recommends that i relief be granted from the Code requirements as requested. The licensee shall I l

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, follow the corrective action requirements of IWP-3230(a) when the measured pump differential pressure or flow rate is greater than 1.05 of the reference value and follow the corrective actions specified in IWP-3230(b) when the measured pump differential pressure or flow rate is greater than 1.08 of the reference value.

l 1.0.3 Relief Request (Item 18 of Appendix C) l l

The licensee has requested relief from the allowable range of test quantities of requirements of Section XI, Table IWP-3100-2, for pump differential pressure for Emergency Fuel Oil Transfer Pumps PJE01A and B. As an alternate thE licensee will use an acceptance criteria of 1.5 psig of the reference value and the pumps will be tested quarterly.

1.0.3.1 Licensee's Bases for Requesting Relief "The Emergency Fuel Oil Transfer pumps are small submersible pumps. Their nominal differential pressure is only 12 to 13 psid. This means the maximum allowable high tange is less than 0.4 psi above the reference value.

By using a more~ accurate discharge pressure gauge the maximum instrument error is limited to 0.0 psi.

The data scatter nver the last two years of surveillance testing has been greater than eight percent (1.0 psi). This variation in data appears to be the result of short run time of the pumps (approximately 2 minutes) during the surveillance test and the configuration of the system piping. The variation in data does not appear to be the result of instrumentation inaccuracies.

Additionally, the capability exists to cross-connect the two trains of the Emergency Fuel Oil System (see figure 9.5.4-1 of the USAR)."

1.0.3.2 Evaluation Flow measuring instrumentation was installed and calibrsted on the emergency fuel oil transfer pumps in November 1988. This instrumentation w s installed in order to measure flow rates as required in Section XI paragrapl. IWP-4600 (See PR-8).

The nominal differential pressure across these pumps is generally 12-13 psig. The code requires verification of a reference value differential pressure that is accurate to within +3% or -10%. Considering the small differential pressure of the pumps, the code acceptance criteria would require

. verification of a reference value differential pressure to fall within approximately +0.4 psig and -1.3 psig.

Testing performed by the licensee with the recently installed flow instrumentation indicates that the acceptance criteria established by the code cannot be met.

The test run time is limited by the size of the day tank and the conditions do not accommodate stabilizing the pump prior to taking data. The licensee's proposed acceptance criteria should be adequate for detecting significant pump I

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. degradation. Further assurance of pump operability is provided in the monthly diesel generator operability test when the emergency fuel oil transfer pumps must operate to support diesel operation. While the monthly diesel generator tests do not verify differential pressures across the transfer pumps, functional operability is demonstrated. In addition, there are cross connect capabilities to permit the two Emergency Fuel Oil Transfer Pumps to supply fuel oil to either day tank. In view of the difficulty of measuring differential pressure and the considerations noted above, the licensee's proposed acceptance criteria of 21.5 psig is reasonable.

Based on the impra;ticality of complying with the code requirements of measuring differentnl pressure across these pumps and considering the burden of declaring the transfer pumps and ultimately the diesel generators inoperable if the code requirements are met, relief may be granted from the Section XI requirements and the licensee's proposed alternative acceptance criteria of 1.5 psig is considered acceptable.

2.0 VALVES 2.0.1 Relief Request (Item 10 of Appendix C)

The licensee has requested relief from the exercising requirements of Section XI, Paragraph IWV-3520, for EN-V003, V004, V009, and V010 the of containment spray pump suction from the refueling water storage tank and discharge check valves, and has proposed to partial-stroke exercise these valves quarterly and to disassemble, inspect, and manually exercise the valve disks or a sam-ling basis during refueling outages.

2.0.1.1 Licensee's Bases for Requesting Relief The flow path that would provide sufficient flow to fully open these valves cannot be utilized since it could result in spraying containment.

2.0.1.2. Evaluation Testing these valves can be accomplished by either establishing spray flow through the containment spray rings or by minimum flow path recirculation back to tne refueling water storage tank. The recirculation back to the refueling water storage tank is not a full-flow path and using it would only result in a partial-stroke exercise of these valves. The only full-flow path is through the containment spray nozzles which would result in spraying water inside containment. Therefore, it is impractical to full-stroke these valves with flow either quarterly during power operations or during cold shutdowns. These valves will be partial-stroke exercised using the test flow path quarterly and they will be exercised during a valve disassembly and inspection with a nianual full-stroke of the valve disk on a sampling basis during refueling outages.

Based on the impracticality of complying with the Code required testing frequency and the licensee's proposed alternative testing frequency, relief from the Code requirements may be granted as requested provided the licensee follows the staff's position on testing check valves by disassembly as stated below:

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

2. 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.

3. Where the licensee demonstrates 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. 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.

A different valve of each group is required to be disassembled, inspected, and manually full-stroke exercised at each refueling outage, until the entire group has been tested. If the disassembled valve's full-stroke capability is in question, the remaining valves in that group must also be disassembled, inspected and manually full-stroke exercised during the same outage.

Based upon the above evaluation the staff has determined that it is impractical to full-stroke valves EN-V003, V004, V003 and V010 with full flow either quarterly during power operations or during colo shutdowns because the only full flow spray path would result in spraying water inside the containment. Accordingly the staff concludes that it is acceptable tu partial-stroke exercise these valves quarterly using the test flow path and to manually full stroke these valves disks on a sampling basis during refueling outages.

i 2.0.2 Relief Request (Item 8 of Appendix C) l The licensee has requested relief from the power operated valve stroke time trending requirements of Section XI, Paragraph IWV-3417(a), for all rapid-acting, power operated values whose function is safety related and has l proposed to apply a maximum stroke time limit of 2 seconds to all rapid acting, power operated valves; i.e., those valves with normal stroke times less than two seconds. Yalves exceeding the 2 second limit will be corrected in accord-ante with IWV-3417(b).

2.0.2.1 Licensee's Bases for Requesting Relief It is impractical to apply the strict requirements of Paragraph IWV-3417(a) in any meaningful way without installing sophisticated timing devices. Operator reaction time could easily vary by 0.5 seconds thereby adding considerable error to test results of quick-acting valves. Therefore, the 50% increased-test-frequency criteria will not be app'.ied when maximum valve stroke times are 2 seconds.

2.D.2.2 Evaluation The licensee has demonstrated that it is not practical to obtain accurate

. measurements of stroke time for pcwer operated valves that operate in two seconds or less. Variability of stroke times of rapio acting power operated valves is primarily a function of timing methods and is not a reliable indicator of valve degradation. Based on the design of these valves the staff has con-cluded that assi5ning a maximum strcke time of two seconds is a reasonable alternative to the Code requirements for these valves. The licensee has coriraitted to declare these valves inoperable if the maximum stroke time is exceeded and to implement corrective action in accordance with IWV-3417(b).

Therefore, since the licensea's proposal is a reasonable alternative to the Code requirements for providing csaraia.e of valve operability, relief may be granted as requested.  ;

3.0.1 VALVES TTSTED DURING COLD SHUTDOWNS (Item 15 of Appendix C)

The following paragrapt. 4:u.tiiies cmgry E valves in the containment spray system that come under the excccising requirements of the ASME Code,Section XI ano are not full-stroke exercised every three months during plant operation. These valves are specifically identified L3 the cwner in accordance with Paragraphs IWV-3412 and -3522 and are full-stroke exercised during cold shutdowns and refueling outages.

The valves in this Section have been reviewed and the staff agrees with the licensee that full stroke testing of these valves during power operations is not practical due to the valve type, location, or system design.

EN-HV-1 and 7, the isolation valves in the containment spray pumps suction from the containment sump, cannot be exercised during power operations because opening these valves could allow water to leak into the containment sump frota the pump suction line and air to get into the suction piping which could bind and damage the containment spray pumps. Current procedures isolate and drain the suction header prior to stroking these valves and then fill and vent the header prior to placing the system back in service. It is impractical to perform this testing during power operations. Thesc valves will be exercised and have their stroke times measured during cold shutdowns and refueling cutages.

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4.0 CONCLUSION

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Based on the foregoing evaluation, the staff has determined that, pursuant to 10CFR50.55a(g)(6)(i),therequirementsoftheCodeareimpracticaland pursuantto10CFR50.55a(a)(3)(i),thealternativestoCoderequirementswill

-provide an acceptable level of quality and safety. The relief is granted, based upon the alternative testing imposed, is authorized by law and will not endanger lift ci property cr the comon defense and security and is otherwise in the public interest giving due consideration to the burden placed upon the licensee if the requirements were imposed on the facility.

Principal Contributors: T. McLellan E. Sullivan H.'Shaw D. Pickett Dated:

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4 o WOLF CREEK GENERATING STATION SE TABLE 1

SUMMARY

OF RELIEF REQUESTS RELIEF SECTION XI ALTERNATE REQUEST .TER/SER' REQUIREMENT EQUIPMENT METHOD OF ACTION NUMBER SECTION & SUBJECT IDENTIFICATION TESTING BY NRC Pump SE Relief 1.0.1.1 IWP-3300 Measure Pumps-PAL 01A&B No Alternate Granted Request Pump Bearing PALO2, Testing- (g)(6)(i)

PR-1 Temperature PBG02A&B, Proposed and Relief PBG05A&B, Not Required PEC01A&B, for PJE01A&B PEF 01A&B, FEG01A,B,C&D PEJ01A&B, PEM01A&B, PEN 01A&B, and PJE01A&B Pump SE _IWP-3200-2 Fuel Pool Alert Relief Relief 1.0.2.1 Alert and Coolant Pumps Range Granted Request Required PEC01A&B Increased (g)(6)(i)

PR-11 Action Range to 105%

(high) and Action Limits Range (high)

Limits Increased to 108%

Pump SE IWP-3200-2 Emergency Fuel Acceptance Relief Relief 1.0.3 Alert and Oil Transfer Criteria Granted Request Required Pumps PJE01A&B of 1.5 psig (g)(6)(1)

PR-13 Action Range From the l (highandLow) Reference 3' months Value I

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4 WOLF CREEK GENERATING STATION SE TABLE 1

SUMMARY

OF RELIEF REQUESTS RELIEF SECTION XI ALTERNATE REQUEST TER/SER- REQUIREMENT EQUIPMENT METHOD OF ACTION NUMBER SECTION & SUBJECT IDENTIFICATION TESTING BY NRC Valve TER IWV-3522 Valves BB-V118, 10 CFR 50 Relief Relief 1.1 Check Valves -V148, -V178, Appendix J Granted Request Shall be -V208, BG-8381, Type C Lea k (a)(3)(i)

VR-3 Exercised -V204,KA-V204, Tests (AT-1 at least once -V648, -649, or by IWV-3 months -V-650, -V651, 3420 EM-V006, and EP-V046 Valve TER IWV-3521 BB-8948A,B, Full-Stroke Relief Relief. 1.2 Test Frequency C and D Exercise Granted Request During (g)(6)(i)

VR-9 Refueling Outage Valve' TER IWV-3521 EP-8956A,B, Full-Stroke Relief Relief 1.4 Test Frequency C and D Exercise ' Granted Request During (g)(6)(i)

VR-14 Refueling Outage Valve TER IWV-3520 EC-V001, -V024, Partial- Relief Relief 1.4 Quarterly -V002 and -V025 Stroke Open Granted Request Exercising Quarterly, (g)(6)(1)

VR-16 Full-Stroke Provided Open During Compliance l

Cold Shut- with NRC i downs, Staff I-I Disassembly Position and Inspec-tion for Closure Capability at Refueling l

WOLF CREEK GENERATING STATION SE TABLE 1

SUMMARY

-0F RELIEF REQUESTS RELIEF SECTION XI. ALTERNATE REQUEST TER/SER REQUIREMENT EQUIPMENT METHOD OF ACTION NUMBER SECTION & SUBJECT IDENTIFICATION TESTING BY NRC Valve ' SE- IWV-3520 EN-V003, -V004, Partial- Relief Relief 2.0.1 Quarterly -V009 and -V010 Stroke Granted Request Exercising Quarterly, (g)(6)(i)

VR-17 and Dis- Provided assemble compliance and In. with NRC spection staff at a re- position fueling outage Frequency Valve SE IWV-3417(a) All Power Take Correc- Relief.

Relief 2.0.2 Corrective Operated tive Action Granted Request Action Valves if Stroke (a)(3)(1) ,

VR-23 Requirements Time Exceeds Fixed Reference Value of 2 sec Cold SE EN-HV-1, Full Stroke Agree Shutdown 3.0.1 and during Cold Justifi- EN-HV-7 Shutdowns cation and Refueling Outages

ATTACHMENT 1

. LETTER REPORT, TECHNICAL EVALUATION OF SE RESPONSE FOR VALVE RELIEF REQUESTS VR-3, VR-9, VR-14, AND VR-16 FOR THE PUMP AND VALVE INSERVICE TESTING PROGRAM, WOLF CREEK GENERATING STATION

1. RELIEF REQUEST EVALUATIONS

' 1.1 Relief Reouest VR-3 The licensee has requested relief from exercising safety injection accumulator water supply check valve EM-V006, safety injection accumulator nitrogen supply check valve EP-V046, and auxiliary feedwater _and main steam control accumulators nitrogen supply check valves KA-V648, KA-V649, KA-V650, and KA-V651 in accordance with the requirements of Section XI, Paragraph IWV-3522 and has proposed to verify valve closure, their safety position, during 10 CFR 50, Appendix J, Type C valve leak rate testing which is performed at least once per 2 years or by IWV3420 Leak Test which is performed at least once per 2 years.

1.1.1 Licensee's Basis for Reouestino Relief. "When these valves are in operation there is no practical means to test valve closure. Valve closure cannot be verified due to system design. To perform a closure verification constitutes a Leak Test which presents a significant hardship during Cold Shutdown. Leak Testing requires an extended period of time which causes extended outages of securing Seal Water Injection to RCP Seals, NORMAL Charging, Component Cooling Water, Instrument Air to Containment, water and nitrogen to the Emergency Accumulators, and nitrogen to the entire Power Block."

Verification of valve closure will be done either in conjunction with the 10 CFR 50 Appendix J Type C Leak Tests (AT-1) conducted at least once per 2 years or in conjunction with IWV3420 Leak Test (AT-3) conducted at least once per 2 years."

1.1.2 Evaluation. Valves EM-V006, EP-V046, KA-V648, KA-V649, KA-V650, and KA-V651 cannot be closure verified during power operation or cold shutdown as the only method available to verify valve closure is 1

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v'alve leak testing. These valves are not equipped with valve position indication and some of the required test connections are located inside containment. Compliance with the Code required testing frequency is '

impractical since this would require quarterly plant shutdown, cooldown, and containment entry. Procedures required for leak rate testing during

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cold shutdown could delay plant startup. Based on the impracticality of j complying with the Code required testing frequency and the licensee's ]

proposed alternative testing, relief from the Code requirements may be granted as requested.

1.2 Relief Reauest VR-9 l I

l The licensee has requested relief from exercising safety injection J pumps, accumulators, and residual heat removal pumps discharge to reactor coolant system (RCS) cold legs check valves BB-8948A, BB-8948B, BB-8948C, and BB-8948D according to Section XI, Paragraph IWV-3521 and has proposed verifying valve operability by full-stroke exercising these valves on a refueling outage frequency.

1.2.1 Licensee's Basis for Reauestino Relief. " Full Stroke or Partial Stroke Exercising during NORMAL Operations cannot be accomplished since System Pressure required to perform the test is not enough to overcome RCS pressure. Full Stroke Exercising during Cold Shutdowns cannot be accomplished since the Flow Rate required to Full Stroke the valves would require injection into the RCS, which could cause cold over-pressurization of the RCS."

"These valves will be Full Stroke Exercised during Refueling Outages.

Verification of Check Valve operability will be demonstrated in accordance with the methodology used in the Pre-Operational Testing Program. The differential pressure across the entire System (between Accumulator and the RCS) will be approximately the same as that used in the Pre-Operational Test. Accumulator Pressure vs. time and Accumulator Level vs. time will be measured to calculate System resistance. Demonstrating acceptable System resistance verifies the Accumulators are capable of operating adequately and indicates that the Check Valves are not CLOSED or partially CLOSED."

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1.2.2 Evaluation. Valves BB-8948A, BB-89488, BB-8948C, and BB-8948D 11 cannot be exercised during power operation since the safety injection and residual heat removal pumps and accumulators cannot overcome RCS pressure. I 1

These valves cannot be exercised during cold shutdown because the necessary '

exercising flow would cause an RCS low temperature overpressurization.

Utilizing preoperational testing methodology to verify these check valves' full-stroke capability during refueling outages should provide an

' acceptable level of quality and safety, however, the licensee should evaluate test data and establish test ecceptance criteria that demonstrates that these valves are being full-stroke exercised.

Compliance with the Code required testing frequency would be impractical since this would require quarterly plant shutdown, cooldown, and reactor head removal. Based on the impracticality of complying with the Code required testing frequency and the licensee's proposed alternative testing frequency, relief from the Code requirements may be granted, provided that the licensce evaluates test data to ensure that these valves are being full-stroke exercised.

1.3 Relief Reouest VR-14 The licensee has requested relief from exercising accumulators discharge to RCS cold legs check valves BB-8956A, BB-8956B, BB-8956C, and BB-8956D according to Section XI, Paragraph IWV-3521 and has proposed verifying valve operability by full-stroke exercising these valves on a refueling outage frequency.

1.3.1 Licensee's Basis for Reouestina Relief. " Full Stroke or Partial Stroke Exercising during NORMAL Operations cannot be accomplished since System Pressure required to perform the test is not enough to overcome RCS pressure. Full Stroke Exercising during Cold Shutdowns requires injection into the RCS which could result in cold over-pressurization of the RCS." ,

l "These valves will be Full Stroke Exercised during Refueling Outages.

Verification of Check Valve operability will be demonstrated in accordance

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l L .. with the methodology used in the Pre-Operational Testing Program. The differential pressure across the entire System (between Accumulator and the RCS) will be approximately the same as that used in the Pre-Operational Test. Accumulator Pressure vs. time and Accumulator Level vs. time will be measured to calculate System resistance. Demonstrating acceptable System resistance verifies the Accumulators are carable of operating adequately and indicates that the Check Valves are r.ot CLOSED or partially CLOSED."

1.3.2 Evaluation. Valves BB-8956A, BB-8956B, BB-8956C, and BB-8956D i cannot be exercised during power operation since the accumulators cannot overcome RCS pressure. These valves cannot be exercised during cold shutdown as the necessary exercising flow would cause an RCS low temperature overpressurization. Utilizing preoperational testing methodology to verify these check valves' full-stroke capability during refueling outages should provide an acceptable level of quality and safety, however, the licensee should evaluate test data and establish test acceptance criteria that demonstrates that these valves are being full-stroke exercised.

Compliance with the Code required testing frequency would be impractical since this would require quarterly plant shutdown, cooldown, and reactor head removal. Based on the impracticality of complying with the Code required testing frequency and the licensee's proposed alternative testing frequency, relief from the Code requirements may be granted, provided that the licensee evaluates test data to ensure that these valves are being full-stroke exercised.

1.4 Relief Reouest VR-16 The licensee has requested relief from the exercising requirements of Section XI, Paragraph IWV-3520, for FC-V001, V002, V024, and V025, the check valves in the main steam supply to the auxiliary faedwater turbine, and proposed to partial-stroke exercise these valves open quarterly during power operations, full-stroke them open during cold shutdowns, and to verify the reverse flow closure of these check valves by disassembling, inspecting, and manually exercising the valve disks during refueling outages on a sampling basis.

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l.4.1 Licensee's Basis for Reouestino Relief--FC-V001 and V024 are in

. series in one of the Main Steam Supply Lines to the AFWP Turbine. FC-V002 and V025 are located in the opposite Main Steam Supply Line. A closed check valve test cannot be performed on each valve due to there not being drain or test lines located between either pair of check valves.

A different valve in this group will be disassembled, inspected, and manually full stroked at each refueling. If the full stroke capability of the disassembled valve is in question, the remainder of the valves in this group will be disassembled also, inspected, and manually full stroked at the same outage.

In Note 16 of their IST program the licensee stated that full stroke exercising these valves requires full flow from the turbine driven auxiliary feedwater pump. Obtaining full flow with this pump during normal operations would cause thermal shocking of the steam generator feedwater l nozzles due to the injection of cold water. This is highly undesirable.

The valves will be partial stroked quarterly and full stroked during cold shutdowns.

1.4.2 Evaluation--To draw enough steam through valves FC-V001, V002, V024, and V025 to verify a full-stroke exercise with flow would require establishing essentially full turbine driven auxiliary feedwater pump flow. The recirculation flow path used during the monthly turbine driven auxiliary feedwater pump tests is not a full-flow path, therefore, insufficient steam flow passes through the steam check valves to assure that they full-stroke open. The only flow path that allows full auxiliary feedwater flow is when the pump is lined-up to discharge into the steam generators. Auxiliary feedwater flow should not be directed into the steam generators for testing during power operations because this would inject relatively cold water into the feedwater piping and nozzles which could thermal shock these components and result in their premature failure.

These valves will be partial-stroke exercised open quarterly during the l pump test when recirculation flow is established and full-stroke exercised open by feeding the steam generators during cold shutdowns when the temperature differeratialt are reduced.

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. The reverse flow closure of these valves cannot be determined during power operations or during cold shutdowns because there are no test )

connections that allow these valves to be individually verified closed. '

f Therefore, these valves cannot be exercised closed quarterly during power i

operations unless extensive system modifications, such as installing test taps, are made to permit this testing. It would be burdensome for the licensee to make such modifications because of the cost involved.

' Additionally, reduced system reliability could result from failures associated with the additional system penetrations. The closure capabiliy of these valves will be verified by valve disassembly, inspection, and manual stroking during refeeling outages on a sampling basis.

The NRC Staff position is that valve disassembly and inspection can be used to meet the exercising requirements of IWV-3520 for check valves which cannot be full-stroke exercised by other means. Where it is burdensome to disassemble and inspect all applicable valves each refueling outage, a sample disassemb'y and inspection plan for groups of identical valves in similar applications may be employed.

The sample disassembly and inspection program involves grouping similar valves and testing one valve in each group during each refueling cutage. 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 (process fluids, chemistry, temperature, differential pressure, flows, and testing).

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).

A different valve of each group is required to be disassembled, inspected, and manually full-stroke exercised at each refueling outage, until the entire group has been tested. If the disassembled valve's full-stroke capability is in question, the remaining valves in that group must also be disassembled, inspected, and mannally full-stroke exercised during the same outage 6

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. . . Based ~on the: impracticality'of. complying with the Code' requirements,

,: the burden to the licensee if the Code requirements were imposed, and considering ~ the licensee's croposed ' alternate. testing of verifying valve 1

.e . closure. capability by disassembly, inspection,L and manually exercising the '

valve disks during reactor' refueling ' outages, relief may. be granted from the Code' requirements'as requested.

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