ML20206Q257

Sser Supporting 860607 & 0813 Proposed Limited Deferrel of Div II Emergency Diesel Generator Design/Quality Review Insps,Based on Favorable Implementation of Insp Program Outlined in Proposal

ML20206Q257
Person / Time
Site:	Grand Gulf
Issue date:	08/29/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20206Q255	List: ML20206Q251 ML20206Q257
References
TAC-61781, NUDOCS 8609040285
Download: ML20206Q257 (2)

Text

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g( UNITED STATES g g NUCLEAR REGULATORY COMMISSION

j WASHINGTON. D. C. 20655 SUPPLEMENTAL SAFETY EVALUATION REPORT REGARDING THE INSPECTION OF EMERGENCY DIESEL GENERATORS MANUFACTORED BY TRANSAMERICA DELAVAL, INC.

MISSISSIPPI POWER LIGHT C0. (MP&L)

GRAND GULF NUCLEAR STATION, UNIT 1 (GGNS)

DOCKET NO. 50-416

1.0 INTRODUCTION

By MP&L letter dated November 28, 1984, the GGNS Design Review / Quality Revalidation (DR/QR) report prepared by the TDI Owners Group was submitted. This report recommends, among other things, DR/QR inspections of both Division I and Division II Transamerica Delaval, Inc. (TDI)

3. emergency diesel generators (EDGs). MP&L plans to complete DR/QR inspections on the Division II EDG during the first refueling outage scheduled to begin in September 1986. The licensee proposes a limited inspection on the Division II EDG during the first refueling outage. The remaining inspections on the Division II EDG would be deferred until the next refueling outage. The limited inspection program is estimated by the licensee to result in a critical path savings of nine days for the first refueling outage.

2.0 EVALUATION By letter dated June 7, 1986, MP&L outlined its proposal regarding the limited deferral of DR/QR inspections for the Division II EDG. The TDI EDG's at Grand Gulf are V-16 type engines. The proposed plan involves the removal and inspection of cylinders No. 5 through No. 8 (left and right bank). MP&L indicated that by disassembling this section of the engine, the most highly stressed components would be inspected (i.e., main journal saddles and main journal oil holes).

Also, in its June 7,1986, submittal, MP&L concluded that the request for staff approval of a limited deferral of GGNS Division II EDG DR/QR inspection from the initial to the second refueling outage is fully justified based on the following considerations:

o Both GGNS TDI EDGs have favorable inspection histories.

o The "as-manufactured" comparable quality to Division I EDG refer(oftoDivision II EDG Grand Gulf is SSER No.6).

8609040285 860829 PDR ADOCK 05000416 G PDR

o The overall inspection history for nuclear application of the GGNS type TDI EDG has been favorable. Also, the Grand Gulf engines are over-designed such that the engine will continue to to be operated at reduced load (i.e. 82% design load).

o Both GGNS TDI EDG's have high start reliabilities, (i.e., Division I is 97.2% and Division II is 100%).

o The TDI Diesel Generator Owners Group has concurred with the limited deferral of DR/QR inspections.

Generally, the staff concurs with MP&L assessment. However, the above considerations did not adequately address the unique aspect of the GGNS TDI EDGs. Specifically, in relation to the connecting rods, Grand Gulf TDI engines utilize 1-7/8 inch connecting rod bolts in its design. As discussed in the staff's generic SER regarding TDI reliability at nuclear plants, TDI connecting rods with 1-7/8 inch bolts warrant special maintenance and surveillance requirements. The licensee was informed of the concern over the lack of inspection regarding connecting rods for cylinders No. 1 through No. 4.

Subsequently, MP&L and its consultants met with the staff on August 6, 1986.

As a result of this meeting, MP&L submitted supplemental information by letter dated August 13, 1986. As specified in the licensee's August 13, 1986, submittal, "high priority" inspections for the four assembled connecting rods (i.e., cylinders No. I through No. 4) will be performed in the initial refueling outage and the remaining inspection would be deferred until the second refueling outage. The staff concurs with this approach. Also, MP&L has comitted to perform hardness and material comparator tests on the Division II EDG connecting rods to address material concerns regarding these components which were recently identified at another nuclear facility.

3.0 CONCLUSION

S The staff finds that the licensee has provided sufficient justification for approval of the proposed limited deferral of the Division II EDG DR/QR inspections. This finding is based on the favorable implementation of the inspection program outlined in the MP&L submittals dated June 7 and August 13, 1986. MP&L recognizes that if these inspections identify components exhibiting an abnormal condition, ar appropriate evaluation will be made and the scope of the proposed inspection program may be expanded.

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