ML20117E554

Safety Evaluation Supporting Amends 115 & 113 to Licenses DPR-80 & DPR-82,respectively

ML20117E554
Person / Time
Site:	Diablo Canyon
Issue date:	08/19/1996
From:	NRC (Affiliation Not Assigned)
To:
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ML20117E550	List: ML20117E554
References
NUDOCS 9608300059
Download: ML20117E554 (5)

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90 Cte j~.

UNITED STATES 3

,j-NUCLEAR REGULATORY COMMISSION o

'2 horilNGTON, D.C. 20666 4001 Ug

' SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 115 TO FACILITY OPERATING LICENSE NO. DPR-80 AND AMENDMENT NO.

113 TO FACILITY' OPERATING LICENSE NO. DPR-82 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON NUCLEAR POWER PLANT. UNIT NOS. 1 AND 2 DOCKET NOS. 50-275 AND 50-323

1.0 INTRODUCTION

By application dated November 14, 1994, as supplemented by letters dated December 7, 1995, February 2, 1996, May 28, 1996, and July 30, 1996, Pacific

' Gas and Electric Company (or the licensee), as the lead plant, requested changes to the Technical Specifications (Appendix A to Facility Operating License Nos. DPR-80 and DPR-82) for the Diablo Canyon Nuclear Power Plant, Units 1 and 2 (DCPP).

The proposed changes, based on generic Westinghouse' Owners Group (WOG) topical reports, would revised the slave' relay test frequency from quarterly'(Q) to refueling (R). Currently at DCPP and other Westinghouse plants, slave relays for the engineered safety features actuation system (ESFAS)'are tested quarterly with the exception of some relays which' were previously approved by the NRC to be tested every 18 months. The proposed changes to the TS would extend the test interval for all Potter and-

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Brumfield MDR slave relays in Westinghouse plant ESFAS to 18 months.

In order to justify these changes, PG&E provided generic Westinghouse Topical Reports, WCAP-13878, Rev. O, " Reliability & Assessment of Potter and Brumfield MDR Series Relays," dated June 1994, (proprietary version) (Ref. 1), WCAP-14117, i

Rev. O, dated June 1994, (non-proprietary version), (Ref. 2) and WCAP-13900, Rev. O, " Extension of Slave Relay Surveillance Test Intervals," dated April 1994 (Ref. 3).

Following review of the above topical ~ reports, the staff, by letter dated April 25,1995 (Ref. 4) requested additional information and PG&E responded by letters dated December 7, 1995 and February 2, 1996 (Refs. 5 and 6).

In addition, by letter dated April 12, 1996, the Westinghouse Owners j

Group submitted Revision 1 to WCAP-13878 and WCAP-14117 (Ref. 7).

By. letter dated May 31, 1996, the staff accepted and issued a Safety Evaluation Report (SER) to the WOG approving the above Topical Reports. The revision also removed table notation 4 from Table 4.3-2 and revised the appropriate associated. Bases.

The December 7, '1995, February 2,1996, May 28,1996, July 30,1996, supplemental-letters provided additional clarifying information and did not change the initial no significant hazards consideration noticed in the Federal Register on December 6, 1995 (60 FR 62495).

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2.0 BACKGROUND

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The NRC staff formed a Task Group in August'1983 to investigate problems i

concerning surveillance testing required by TS and to recommend improvements.

i The results of the study were published in November 1983 (Ref. 8) in NUREG-1024,-" Technical Specifications - Enhancing the Safety Impact." NUREG-1024 recommended that the staff review the bases for TS test frequencies; ensure i

that the TS required tests promote safety and do not degrade equipment; and review surveillance tests.to ensure that they do not unnecessarily burden personnel.

l The Technical Specifications Improvement Program (TSIP) was established in December 1984 to provide the framework for addressing the NUREG-1024 i

recommendations, and for rewriting and improving the TS. As an element of the l

TSIP, TS surveillance requirements were comprehensively examined as recommended in NUREG-1024. The results of the TSIP effort are presented in NUREG-1366, " Improvements to Technical Specifications Surveillance i

Requirements".(Ref. 9). The study concluded that, while some testing at power is essential, safety can be improved, equipment degradation decreased, and unnecessary personnel burden prevented by reducing the amount of testing at power. These three conclusions formed the basis for the four criteria that justify changes to surveillance intervals as follows:

Criterion 1 - The surveillance could lead to a plant transient, Criterion 2 - The surveillance results in unnecessary wear to equipment, i

Criterion 3 - The surveillance results in radiation exposure to plant personnel that-is not justified by the safety significance of the surveillance, Criterion 4 - The surveillance places an unnecessary burden on plant personnel because the time required is not justified by the safety significance of the surveillance.

3.0 EVALUATION In the SER for the above Westinghouse Topical Reports, the staff requested each licensee to address the following concerns:

-1.

Confirm the applicability of the WCAP-13878, Rev. I analyses for their plant.

2.

Ensure that their procurement program for P&B MDR relays is adequate for i

detecting the types of failures that are discussed in References 10, 11, 12 and 13.

I 3.

Ensure that all pre-1992 P&B MDR relays which are used in either normally energized or a 20 percent duty cycle have been removed from ESFAS applications.

. 4.

Ensure that a contact loading analysis for P&B MDR relays has been perfomed to determine the acceptability of these relays.

The DCPP licensee in its submittal dated December 7,1995, addressed each of the above issues. The licensee's response to these issues is discussed below:

1.

Slave relays used at DCPP are P&B MDR Model 4102 (latching) and 4103 (non-latching) type. Although WCAP-13878 analyzed P&B MDR model 4121-1 (latching) and 4103 (non-latching) type relays, the DCPP relays are similar in design to those analyzed in the WCAP, and therefore, the analysis adequately covers the DCPP relays. The staff concurs with the licensee's statement on the similarity of relays.

2.

Based on Report S93-06 from the NRC Office for Analysis and Evaluation of Operational Data (AE00) (Ref. 10), Information Notice (IN) 90-57 and Supplement 1-to IN 90-57 (Refs. 11 and 12), and a 10 CFR Part 21 notification from San Onofre Nuclear Generating Station (Ref.

13), PG&E has put in place an enhanced commercial grade dedication

. program to prevent substandard or refurbished relays from being installed in the plant. All existing relays in the warehouse will be re-inspected based on the enhanced dedication criteria. Only three relays procured as commercial grade were installed at DCPP and they have been verified to have passed sufficient dedication criteria and testing to assure.their acceptability.

Based on this, the staff finds that PG&E has an adequate commercial grade dedication program for P&B MDR relays for detecting potential failures.

3.

IN 92-04 (Ref.14) and AE00 Report S93-06. identified failures of normally energized or 20 percent duty cycle P&B MDR relays. At DCPP, there are 40 P&B MDR relays installed in each of the solid state protection system (SSPS) bays. Of these 40 relays, only 2 relays are normally energized at power, and neither relay performs a function covered by TS. Also at DCPP, none of the slave relays required by TS

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are energized during an outage since the SSPS is removed from service at that time. Therefore, the concern for removing normally energized or 20 percent duty cycle relays from ESFAS applications does not apply to DCPP.

4.

IN 92-19 (Ref.15) and AE00 Report S93-06 reported contact failures due l

to misapplication of P&B MDR relays. WCAP-13878, Rev. O, considered contact failures to be beyond the scope of the report. However, PG&E completed a loading study covering each contact on every DCPP SSPS P&B IOR slave relay for Unit 1 and found the relays acceptable. The DCPP Unit 2 design and contact loading is similar to Unit 1 and hence was not reviewed. The licensee's analysis satisfactorily resolves the' staff's concern in this area.

Based'on the review of WCAP-13878, Rev. 1, WCAP-14117, Rev. 1, and WCAP-13900, Rev. 0,' and the licensee's srbeittals referencing these topical reports, the staff concludes that the proposed test interval extension to every refueling outage for P&B MDR slave relays is justified for DCPP. However, consistent j

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that if two or more P&B MDR ESFAS subgroup. relays fail in a 12-month period, the licensee should reevaluate the adequacy of-the extended surveillance interval. The reevaluation should consider design, maintenance and testing of

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all P&B MDR ESFAS subgroup relays.

If the licensee determines that the surveillance interval is inadequate for detecting a single relay failure, the surveillance interval should be decreased. The revised surveillance interval should be such that the licensee can detect an ESFAS subgroup relay failure prior to the occurrence of a second failure.

By letter dated July 30, 1996, the licensee comitted to reevaluate the adequacy of the ' extended surveillance interval according to the criteria presented in the generic SER, 4.0-STATE CONSULTATION In accordance with the Commission's regulations, the California State official was notified of the proposed issuance of the amendments. The State official had no coments.

5.0 ENVIRONMENTAL CONSIDERATION

These amendments changes surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may. be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public coment on such finding (60 FR 62495). Accordingly, the amendments meet the eligibility criteria for i

categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.

6.0 CONCLUSION

-The Commission has concluded, based.on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered Ly operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, j

and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

7.0 REFERENCES

1.

Westinghouse Topical Report WCAP-13878, " Reliability Assessment of Potter &'Brumfield MDR Series Relays," (proprietary version) dated June

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1994, transmitted to NRC by Gregory M. Rueger (Pacific Gas and Electric Company for Diablo Canyon) letter DCL-94-254, dated November 14, 1994, i

2.

Westinghouse Topical Report WCAP-14117, " Reliability' Assessment of Potter & Brumfield MDR Service Relays," (non-proprietary version). dated

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June 1994, transmitted to NRC by Gregory M. Rueger (Pacific Gas and i

Electric Company for Diablo Canyon) letter DCL-94-254, November 14, 1994.

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Westinghouse Topical Report WCAP-13900, " Extension of Slave Rclay i

Surveillance Test Intervals," dated April 1994, transmitted to NRC by

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Gregory M. Rueger (Pacific Gas and Electric Company for Diablo Canyon)

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letter DCL-94-254, dated November 14, 1994.

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Melanie A. Miller (NRC) letter to Gregory M. Rueger (PG&E), dated i

April 27, 1995, " Request for Additional Information on Slave Relay Test j

Frequency Extension for Diablo Canyon Nuclear Power Plant, Units 1 and 2."

5.

Gregory M. Rueger (PG&E) letter (DCL-95-268) to USNRC, dated December 7, 1995, " Response to NRC Request for Additional Information on Slave Relay Test Frequency Relaxation Amendment."

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Warren H. Fujimoto (PG&E) letter (DCL-96034) to USNRC, dated February 2, 1996, " Respond to NRC Request on Slavo Relay Test Frequency Relaxation Amendment."

7.

Lee Bush ~(WOG) letter (WOG-SRT-96-005) to USNRC, dated April 12, 1996,

" Transmittal of Page Revisions to WCAP-13878 (proprietary), to address j

NRC review issues.

8.

NUREG-1024, " Technical Specifications - Enhancing the Safety Impact,"

dated November 1983.

9.

NUREG-1366, " Improvements to Technical Specifications Surveillance 4

Requirements," dated December 1992.

l 10.

Office for Analysis and Evaluation of Operational Data Special Study

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Report AE0D/S93-06, " Potter & Brumfield Model MDR Rotary Relay Failures," dated December 1993.

Il' 11..

NRC Information Notice 90-57, " Substandard, Refurbished Potter &'

Brumfield Relays Misrepresented as New," dated September 5, 1990.

1 12.

NRC Information Notice 90-57, Supplement 1, " Substandard, Refurbished 3

Potter & Brumfield Relays Represented as New," dated November 27, 1991.

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10 CFR Part 21 Notification dated July 21, 1995 from San Onofre Nuclear Generating U.ation (SONGS) concerning relays,that were returned to SONGS with bent contact arms following PLB rework.

14.

NRC Information Notice 92-04, "Misapplications of Potter & Brumfield MDR Model MDR Rotary Relay Failures," dated January 6,1992.

15.

NRC Information Notice 92-19, "Misapplications of Potter & Brumfield MDR Rotary Relays," dated March 2, 1992, Principal Contributor:

H. Garg l

Date: August'19, 1996

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