ML20128F110

Forwards Safety Evaluation Re Leak on Core Spray in-vessel Annulus Piping & Concludes That Plant Can Be Safely Operated for One Fuel Cycle W/O Repairing Leak at Listed 1/4-inch Fillet Weld

ML20128F110
Person / Time
Site:	Oyster Creek
Issue date:	02/05/1993
From:	Dromerick A Office of Nuclear Reactor Regulation
To:	J. J. Barton GENERAL PUBLIC UTILITIES CORP.
Shared Package
ML20128F115	List: ML20128F110 ML20128F136
References
TAC-M85484, TAC-M85711, NUDOCS 9302110247
Download: ML20128F110 (4)

Text

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February 5, 1993 Docket No. 50-219 Mr. John J. Barton Vice President i.d Director GPU Neclear Corporation Oyster Creek Nuclear Generating Station Post Office Box 388 forked River, New Jersey 08731

SUBJECT:

OYSTER CREEK NUCLEAR GENERATING STAT 10N - NRC REVIEWS RELATED TO STARTUP FROM 14R REFUELING OUTAGE (TAC N05. M85484 AND M85711)

Pursuant to License Condition 2.C(5) and Technical Specification 6.9.3.e in full-Term Operating License DPR-16, GPU Nuclear submitted the results of core spray sparger and repair assembly inspections performed during the Oyster Creek 14R refueling outage.

This information was transmitted by letters dated January 15 and January 19, 1993.

The license condition requires GPU Nuclear to oMain authorization from the staff before the plant is restarted from each ref ueling outage.

During the 14R inspection of the core spray system in-vessel annulus piping, a leak was discovered on a 1/4-inch fillet weld (L-3a).

The information provided to the staff regarding these inspections included GPU Nuclear's evaluation of the safety implications of this leak.

The enclosed Safety Evaluation documents the staff's review of the information provided by GPU Nuclear.

The staff concluded that Oyster Creek can be safely oper..ted with this leak for at least another fuel cycle because the intended fu..ation of the core spray system would be maintained under the worst design basis condition even if the subject weld is-assumed to completely fail.

Oyster Creek Technical Specification 4.3.1 requires an inservice inspection program for evidence of intergranular stress corrosion cracking (IGSCC) in certain alping systems identified in NRC Generic _ Letter 88-01.

By letter dated fearuary 2,1993, GPU Nuclear submitted flaw evaluations for flaws in two Recirculation System welds (NG-D-18) and NG-D-?3) iden'ified during the 14R IGSCC inspection.

GPU Nuclear concluded that these flaw indications are small and do not require any repair.

The' staff has reviewed these evaluations and has concluded that the GPU Nuclear evaluation is acceptable. However, these welds should be inspected during the next refueling outage to ensure there is no unacceptable growth in the flaws.

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inch and about 18% through wall in depth, was previously dispositioned as a root geometry ir. 1986.

The Itcensee performed a crack growth calculation for this flaw without considering the benefit of stress improvement.

The results of the calculation showed that the final flaw size at the end of the next fuel cycle is well within the ASME Code allowable.

The licensee also reported that there was no change in the flaw size of an axial indication which was.

previously identified after stress improvement.

The licensee is required to submit detailed crack growth calculations within 60 days after plant start-up.

i Weld NG-D-23 is a discharge nozzle to safe-end weld on a recirculation "D" loop. An axially oriented indication with minor circumferential components l

was found at the safe-end about 1.9 inch from the weld during this outage.

Initially, this indication with a length of 0.9 inch and about 45% through wall in depth was reported to be connected to the inside surface.

However, after performing additional examinations and further evaluation of the ultrasonic data, including evaluation by experts from EPRI, the licensee had determined that the subject indications were geometric reflectors associated with a weld repair and were not connected to the inside surface.- As shown on the construction records, a weld repair was performed at about the same location where a boat sample was removed from the inside surface of the safe-end prior to initial start-up.

The licensee performed _a fatigue crack ' growth calculation assuming the indications as a connected subsurface flaw.

The cyclic load considered in the cal (.ulation was-a pressurization to 1250 psi and-back to zero pressure. Assuming 100 such events per fuel cycle, the corresponding fatigue crack growth was reported to be 0.001 inch, which'is very small. The licensee's evaluation also showed that the size of the reported indication is well within the ASME Code allowable in IWB-3640.

Based on our review, the staff concludes that the licensee's evaluation of the reported indications on Welds NG-D-18 and NG-D-23 is acceptable, and that Oyster Creek can be safely operated with the subject welds in the at-1s-condition for at least-another fuel cycle. However, welds NG-D-18 and NG-D-23 should be inspected during the next refueling-outage to ensure there is no unacceptable flaw growth.

Regarding the two issues discussed above, GPU Huclear has the-staff's authorization to restart from the 14R refueling outage.

Thelicensee$shouldsubmittheinformationrequestedintheSafetyEvaluation and the infomation for-lGSCC no later than 60 days after plant restart.

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Mr. John J. Barton This requirement affects nine or fewer respondents and therefore is not subject to Office-of Management and Budget review under P.L.90-511 Sincerely, Original signed by Alexander W. Dromerick, Sr. Project Manager-Project Directorate 1-4 Division of Reactor Projects 1/11

-Office of Nuclear Reactor Regulation

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Safety Evaluation cc w/ enclosure:

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OfflCIAL-RECORD COPY:

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Mr. John J. Barton Oyster Creek Nuclear GPU Nuclear Corporation Generating Station t

CCt Ernest L. Blake, Jr.. Esquire.

Resident inspector Shaw, Pittman, Potts & Trowbridge c/o U.S. Nuclear Regulatory Commission 2300 N Street, NW.

Post Office Box 445 Washington, DC 20037 forked River, New Jersey 08731 Regional Administrator, Region i Kent Tosch, Chief U.S. Nuclear Regulatory Commission New Jersey Department of 475 Allendale Road Environmental Protection King of Prussia, Pennsylvania 19406 Dureau of Nuclear Engineering CN 415 BWR Licensing Manager Trenton, New Jersey 08625 GPU Nuclear Corporation 1 Upper Pond Road Parsippany, New Jersey 07054 1

Mayor

'I Lacey Township 818 West Lacey Road forked River, New Jersey 08731 Licensing Manager Oyster Creek Nuclear Generating Station Mail Stop:

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Post Office Box 388 forked River, New Jersey 08731 9

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