ML20153F369

Interim Deficiency Rept 86-02 Re Rejectable Indications in Weld Seams of Loop 1 Steam Generator & Pressurizer.Initially Reported on 860115.Fracture Mechanics Analysis Performed. Final Rept Will Be Submitted Upon Resolution of Issue

ML20153F369
Person / Time
Site:	Braidwood
Issue date:	02/11/1986
From:	Miosi A COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
1299K, 86-02, 86-2, NUDOCS 8602250505
Download: ML20153F369 (2)

Text

E , . - -

J< 'S' N Commonwealth Edison -

) one First Nitional Pizza. Chicago, tilinois f

g  ? '] Address Reply to: Post Office Box 767 (j Chicago, Illinois 60690 February 11, 1986 Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL. 60137

Subject:

Braidwood Station Unit 1 10 CFR50.55(e) Report No. 86-02 Rejectable Indications During Preservice Inspection on Loop 1 Steam Generator and the Pressurizer NRC Docket No. 50-456

Dear Mr. Keppler:

On January 15, 1986, the Commonwealth Edison Company Nuclear Licensing Department notified Mr. W.S. Little of your office of a potential deficiency reportable pursuant to 10 CFR50.55(e) regarding two (2) rejectable weld indications during Unit 1 preservice inspection at Braidwood Station. This letter fulfills the thirty (30) day reporting requirement and is considered to be an interim report. For tracking purposes, this potential deficiency was assigned number 86-02.

Description of Nonconformance Preservice inspection examinations under ASME Section XI 1977 Edition with addenda through the Summer, 1978 Addenda has resulted in two (2) rejectable ultrasonic indications in weld seams of the Loop 1 steam generator and the pressurizer at Braidwood Unit

1. One indication is in the upper shell to transition cone circumferential weld of the Loop 1 steam generator. The second indication is in the upper middle shell-to-lower middle shell circumferential weld of the pressurizer.

Analysis of Safety Implications Stresses due to system pressure and repeated heat-ups and cooldowns have the potential for causing Code rejectable weld indications to propagate into through-wall cracks. There is'a possibility that such propagation might occur before it could be detected by nondestructive testing during the first inservice inspection interval.

8602250505 860211 PDR ADOCK 05000456 S PDR FEB 14 III tea 7

.e ','

i For the indications in the Pressurizer, a through-wall crack would result in Reactor Coolant-System (RCS) leakage. In such an event, the loss of RCS inventory is expected to be small and I would be detected by the various available Reactor Coolant Inventory '

Monitoring Systems. ,

1 For the indications in the steam Generators, a through-wall crack would result in a secondary system steam leak. If such a leak 4 occurred, the leak would be expected to be small and it would be j detected by a change in the containment environmental parameters as I well as a change in the containment sump inventory, i l

In both cases of weld indication propagation, the resultant q 1eaks are expected to be promptly detected in order to prevent any '

adverse safety consequences.

l Corrective Action The two (2) rejectable indications have been characterized i as very small innocuous slag inclusions based on the Braidwood i preservice examination data and experience with similar indications in the components at Byron Station. Since the small slag inclusions have little or no effect on vessel weld integrity, the present condition of the components will not reduce the level of plant safety. The integrity of the vessels can be best preserved by not removing the indications. Fracture mechanics analysis have been performed which accepts the indications of the vessels for the forty (40) year plant life. This analysis will be submitted to NRR for concurrence.

A Final Report will be sent when resolution of this issue is reached with NRR.

Please address any questions that you or your staff may have concerning this matter to this office.

Very truly yours, (M'

Anthony D. Miosi Nuclear Licensing Administrator

/klj cc: NRC Resident Inspector Braidwood Director of Inspection & Enforcement U.S. Nuclear Regulatory Commission Washington, DC. 20555 1299K

.