ML20101M900

Forwards Rev to Relief Request 40-VRR-2 for Plant First Ten Yr Interval Pump & Value IST Program

ML20101M900
Person / Time
Site:	Limerick
Issue date:	04/01/1996
From:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9604080141
Download: ML20101M900 (6)

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& 10CFR50.55a(g)(5)(iii) v PECO NUCLEAR ncma c - ev Nuclear Group Headquarters A lJMr or PECO fvecy 965 Chesterbrook Boulevard Wayne, PA 19087-5691 i

l April 1,1996 Docket Nos. 50-352 50-353 Ucense Nos. NPF-39 NPF-85 U.S. Nuclear Regulatory Commission .

Attn: Document Control Desk l Washington, DC 20555

Subject:

Limerick Genemting Station, Units 1 and 2 l Revision to Relief Request for the First Ten Year j interval Pump and Valve inservice Testing Program l Gentlemen Attached is a revision to Relief Request No. 41-VRR-2 (i.e., Revision 3) for the Limenck Generating Station (LGS), Units 1 and 2, First Ten Year Interval Pump and Valve Inservice Testing (IST) Program. This revision to Relief Request No. 41 VRR-2 is necessary in order to  :

support the implementation of a Technical Specifications (TS) Change Request (i.e., TS Change Request No. 96-01-0) for LGS, Units 1 and 2, submitted to the NRC under separate correspondence dated March 29,1996. Relief Request No. 41-VRR-2 requests relief from the requirements of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and {

Pressure Vessel (B&PV) Code concerning the testing of Automatic Depressurization System '

(ADS) valves.

Relief Request No. 41-VRR-2 was initially submitted as pan of the original IST Program submitted to the NRC for review and approval by letter dated November 23,1988. By letter dated March '

1 5,1991, the NRC issued its Safety Evaluation Raport (SER) and supporting Technical Evaluation Report (TER) for the LGS, Units 1 and 2, First Ten Year Interval IST Program. As documented in its SER and TER, the NRC indicated that the Relief Request No. 41 VRR-2 was approved provided it be revised to include criteria for valve stroke time testing. Relief Request No.

41-VRR-2 was revised to address the NRC's concem rega'r ding stroke time testing of the ADS valves, and was resubmitted to the NRC by letter dated May 1,1992.

In a letter dated February 17,1993, the NRC indicated that it had reviewed the revision (i.e.,

Revision 1) to Relief Request No. 41-VRR-2; however, the revision did not include a maximum limiting stroke time value. The NRC requested that a maximum limiting stroke time value be assignef for the ADS valves, and incorporated into this Relief Request. Relief Request No.

41-VRR-2 was subsequently revised (i.e., Revision 2) to include a maximum limiting stroke time as requested by the NRC.

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l As a result of processing proposed TS Change Request No. 96-01-0 for LGS, Units 1 and 2, we  !

l determined that it was necessary to revise Relief Request No. 41-VRR-2. Therefore, we are I l submitting Revision 3 to Relief Request No. 41-VRR-2 in order to support the implementation of '

TS Change Request No. 9641-0. The details and justification for relief are provided in the l l

l attached Relief Request. We would appreciate the NRC's expeditious review of this revision to l Relief Request No. 41-VRR-2, and request that the NRC prant the relief by May 12,1996, in order I to support a mini-outage scheduled for LGS, Unit 2.

l If you have any questions or require additional informatkr, please do not hesitate to contact us.

Very truly yours, l

h f, ,

G. A. Hunger, Jr.

Director - Licensing i

Attachment i I

cc: T. T. Martin, Adm!mstrator, USNRC, Region I (w/ attachment)

N. S. Perry, USNRC Senior Resident inspector, LGS (w/ attachment) l l

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ATTACHMENT Umorick Generating Station Units 1 and 2 First Ten-Year Interval inservice Testing Program REUEF REQUEST NO. 41-VRR-2, Revision 3 l

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IAs. Units 1 and 2 Docket sos. 50-352/353 IST Prosram Belief Bequest Pese 1 of 3 REI.IEF REQUEST NO. 41-VRR-2, REVISION 3 system Nuclear Boiler Valve (s): PSV-041-lF013E, H, K, M, S PSV-041-2F013E, H, K, M, S Category: B, C Function: Depressurization of the RCS to allow for low pressure coolant injection.

Testing Requirement (s):

Exercise quarterly and stroke time.

Basis for Relief:

Revision 3 of this relief request requests relief from quarterly exercise test and stroke time test performed in accordance with ASME Section XI Subsection IWV-3412 and IWV-3413 respectively. The ASME Section XI exercise and stroke time test requirements were satisfied as described in Revision 2 of this relief request, by in-situ actuation at reduced system pressure on a refuel outage frequency.

This relief request contends that in-situ testing imposes an unnecessary challenge on the subject valves and has been linked to SRV degradation (e.g., pilot and/or valve leakage). Pilot degradation, while not a concern with respect to the ADS safety function, could, if severe enough, lead to SRV set-point drift, spurious SRV actuation and/or failure to properly reseat. Such events have occurred at Limerick and other BWRs with similar ADS /SRV valves. If any of these valves fail to re-close after testing, the plant would be placed in a LOCA condition requiring plant shutdown in accordance with Technical Specifications (TS) 3.4.2.b. In addition, a recent study (i.e., BWR owner's Group Evaluation of NUREG-0737, Item II.K.3.16, Reduction of Challenges and Failures of Relief Valves) recommends that the number of ADS openings be raduced as much as possible. This evaluation further contends that adequate demonstration of ADS /SRV operability is still provided through the remaining existing tests and inspections. Overall, this change should reduce SRV leakage and improve ADS /SRV reliability by reducing the potential for spurious SRV l actuation.

Adecuacy of Testina The in-situ test of the ADS /SRVs is not necessary because the remaining ADS surveillance tests and SRV tests provide comparable assurance of ADS valve operability. These remaining tests and the ADS /SRV performance requirement verified by each are described below:

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I 145. units 1 and 2 Docket see. 50-352/353 l Ist Program Belief Bagnost Pese 2 of 3 I A. Division 1&3 ADS Loale System Functional Test This test, performed each refuel, verifies the ECCS logic which actuaten ADS on low reactor water level - Level 1, and high drywell pressura, Verification of ADS from the start of the automatic initiation logic to, but not including, instrument gas / accumulator solenoids is demonstrated. Note that the basis references do not require actual stroking of the ADS /SRV.

Reference:

TS Sections 3.3.3, 4.5.1.d.2.a, UFSAR Sections 6.3.4.2 and 7.3.1.1.1.2.9.

B. MSRV Cvelic Test This test, performed each refuel and each time maintenance is performed on the SRV, verifies proper operation of the ADS solenoid valves, air operator and pilot assembly. This test will serve as the new alternate IST exercise test as described in the Alternate Testing section of this relief request.

References TS Section 4.0.5, LGS Environmental Qualification (EQ) Report, and General Electric Co. SIL 196, Supplement 11.

C. ADS Leak Test This test, performed each refuel and each time maintenance is performed on the ADS valve, verifies that ADS instrument gas / accumulator leakage is low l enough to ensure that there will be sufficient pneumatic pressure for design basis ADS /SRV operation. The ADS design basis calls for two ADS /SRV l actuations over a period of 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to depressurize the RPV down to the RHR shutdown cooling operating pressure range.

Reference UFSAR Sections 5.2.2.10 and 5.2.2.4.1.

D. SRV Setooint/Leakaae Testina These functional tests and inspections, performed on at least 50% of the SRV pilot stages each refuel outage, verify that the pilot valve and setpoint spring assembly open and close at the required set-pressure, and that leakage is within strict specified criteria.

Reference:

TS Section 4.4.2.2.

E. Main Disc Exercise Test (New Reauirement)

The Limerick SRV Preventive Maintenance (PM) Program, performed on at least two (2) SRVs each refuel outage, ensures that the main discs can freely open and that all 14 SRVs per unit are verified within seven (7) operating cycles.

These combined tests (A through E) described above verify all required ADS critical component performance requirements. This relief request will only change the frequency of verification that pilot disc opening directly results in opening of the main disc. However, this ADS /SRV sub-component function is considered to be extremely reliable based on the simplicity of this aspect of the SRV design and is supported by Limerick and industry ADS /SRV valve performance history.

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IAE, Unita 1 and 2 O

Docket sos. 50-352/353 IST Program Relief Request l Pese 3 of 3 The elimination of the in-situ functional test during start-up also removes the current method of stroke time testing of the ADS valves. Stroke time testing is currently provided by indirect means through the detection of steam flow by acoustic l monitoring. For fast acting valves such as the ADS /SRVs, the current practice of measuring stroke times is of limited or no value as a degradation detection method.

ADS /SRV degradation is more reliably detected by the test and inspections described in items A through E. As an alternative, the response time of the pilot valve l assembly will be measured in conjunction with SRV Setpoint/ Leakage Terting and the l MSRV Cyclic Test, performed after reinstallation, will ensure that the controls have

! been properly connected.

Alternate Testing Perform exercise and stroke time testing utilizing the testing methods and at the frequencies specified in items A through E, above.

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