05000278/LER-1983-012, Forwards LER 83-012/-01T-0.Detailed Event Analysis Encl

Forwards LER 83-012/-01T-0.Detailed Event Analysis Encl

ML20076F161
Person / Time
Site:	Peach Bottom
Issue date:	05/09/1983
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Allan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20076F165	List: 05000278/LER-1983-012, Forwards LER 83-012/-01T-0.Detailed Event Analysis Encl
References
NUDOCS 8306010438
Download: ML20076F161 (3)

LER-2083-012, Forwards LER 83-012/-01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2782083012R00 - NRC Website

text

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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O BOX 8699 PHILADELPHIA. PA.19101 (215)8414000 May 9, 1983 Docket Nos. 50-278 Mr. J. M. Allan, Acting Administrator Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19046

SUBJECT:

Licensee Event Report Narrative Description i

Dear Mr. Allan:

The following occurrence was reported to Mr. A. R.

Blough of Region I, U.S. Nuclear Regulatory Commission, on April 25, 1983.

Reference:

Docket No. 50-278 Report Number: 3-83-12/IT-0 Report Date: May 9, 1983 Event Date: April 25, 1983 Facility: Peach Bottom Atomic Power Station RD 1, Delta, PA 17314 Technical Specification

Reference:

Technical Specification 3.6.G, Structural Integrity, states that "The structural integrity of the primary system boundary shall be maintained at the level required by the original acceptance standards throughout the. life of the station.

The reactor shall be maintained in a Cold Shutdown condition until each indication of a defect has been investigated and evaluated."

i B306010438 830509 I I PDR ADOCK 05000278 5 PDR g %b

Mr. J. M. Allan Paga 2 Description of the Event:

During the Unit 3 refueling outage, while performing non destructive. examinations following Induction Heating. Stress Improvement Treatment of Reactor Recirculation and RHR suction lines, indications have been found in the treated piping.

Indications found were detected and sized utilizing radiographic and/or ultrasonic examination methods. The indications have been found in the heat affected zone of 12 welds. Three of the welds are in the 20" non-isolatable section of the .Iuut suction line.

These welds are identified 10-0-5, 10-0-6, and 10-0-7. (For reference see letter to D. G. Eisenhut from S. L. Daltroff, dated  ;

Octiber 1, 1981, which presented piping layouts and weld '

identifications). The remaining 9 welds with indications are the vertical riser to elbow welds in nine of the ten 12" recirculation risers. These 9 welds are identified: in the A

-Loop, 2-AHK-2, 2-AHH-2, 2-AHJ-2, 2-AHG-2; in the B Loop, 2-BHE-2, 2-BHD-2, 2-BHC-2, 2-BHB-2, and 2-BHA-2.

axial.

The indications in the recirculation risers are all They are located in both the pipe and elbow side-of the weld. The maximum depth of the indications found in the risers is .48".

Each of the. riser welds with indications has at least 2 indications. The average number of indications is 4 per weld.

The maximum number of indications found in a single weld was 8, found in weld 2-BHD-2.

The indications in the RHR suction line are all circumferential. The approximate maximum depth is 0.5". Both welds 10-0-5 and 10-0-6 have intermittent indications around their entire circumference. The longest single indication length in wel 10-0-5 is approximately 9" long and in weld 10-0-6 the '

longest single indication length is approximately 13" long.  ;

Cause of the Event:

The preliminary analysis of the data shows a pattern t

typical of intergranular stress corrosion cracking.

l

, Immediate Corrective Action:

' The scope of the inspection of the remaining welds on both the RHR and recirculation piping is being increased to include 100% of the non-conforming circumferential piping welds.

, (NUREG-0313, Rev.1 defines non-conforming) . A fracture

! mechanics analysis was performed by the NSS vendor on the 12

' welds to aid in determining method of repair. Vendor has indicated that performing a thin clad weld overlay (1/4 thickness 5

d

Mr. J. M. Allan Page 3 to recirculation riser welds and 0.4 thickness to RHR suction welds) justifies continued operation for at least 18 more months on each of the twelve welds. Plans are being made to thin clad weld overlay these 12 welds as discussed with NRC staff in Bethesda, Maryland, on May 6, 1983. It has been estimated that there will be 280 man-rem of exposure used during the repair.

Philadelphia Electric Company's response to I.E.

Bulletin 83-02, to be submitted before resuming power operations, will provide all additional information on this subject.

Sincerely gy C c-, 7 , / A 7 8 /

M. J. Cooney Superintendent Nuclear Generation Division cc: Document Control Desk A. R. Blough Site Inspector P.O. Box 399 Delta, PA 17314-0399

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