05000247/LER-1981-011, Forwards LER 81-011/01T-0

Forwards LER 81-011/01T-0

ML093620882
Person / Time
Site:	Indian Point
Issue date:	05/22/1981
From:	O'Toole J Consolidated Edison Co of New York
To:	Grier B NRC/OE, NRC/OI/RGN-I/FO
Shared Package
ML093620883	List: 05000247/LER-1981-011, Forwards LER 81-011/01T-0 05000247/LER-1981-011-01, /01T-0:on 810508,pits Observed on Exterior Surface of Svc Water Pump Discharge Piping.Caused by External Corrosion,Resulting in Local Areas Below Min Wall Thickness. Areas Sand Blasted,Patch Welded & Repainted
References
NUDOCS 8106180250
Download: ML093620882 (3)

LER-1981-011, Forwards LER 81-011/01T-0

Event date:
Report date:
2471981011R00 - NRC Website

text

John 0. 0'1oole Vlck. Pr eh;Icjl Consolidated Edison Company of New York, Inc.

4 Irving Place. Now York. NY 10003 "elephone (212) 460-2533 I<

I May 22, 1981 Re:

Indian Point Unit No. 2 Docket No. 50-247 LE R-8 1- 011/l" 0 OJT Mr. Boyce H. Grier, Director Office of Inspection and Enforcement Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pa 19406

Dear Mr. Grier:

01l The attached Licensee Event Report LER-8-0ll/Q-3, -0 is hereby sub mitted in accordance with the requirements of Technical Specification 6.9.1.7.

This event is of the type described in Technical Specification 6.9.1.7.1.i.

Three copies of this letter and the attachment are enclosed as required.

Ve truly yours,

/77 attach.

cc:

Mr. Victor Stello, Jr., Director (30 copies)

Office of Inspection and Enforcement c/o Distribution Services Branch, DDC, ADM Washington, D. C. 20555 Mr. William G. McDonald, Director (3 copies)

Office of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Mr. T. Rebelowski, Resident Inspector U. S. Nuclear Regulatory Commission P. 0. Box 38 Buchanan, N. Y.

10511 AoO'~

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LICLNSLE LVLN I HLKPUH I CONTROL BLOCK:

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SEPORT L 1J@ I 0 51 0 l0o o 12 I 4I 71 1o I 5 I 01 8 ! 1@ 1 o 1 51 212 1Il 110 7

8 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES 0

O 2 I During inspection of service water pump discharge pipinapits were

• 6-3 I observed on the exterior surface.

Non-destructive examinat-ion nf the O 4 I pits indicated that the pipe wall thickness under four small plif wasi O 5 less than the minimum wall thickness required to meet seismic design [O6 J criteria, (0.135 inches).

Possible consequences could nave been the O

I eventual development of small pinhole leaks with no degradation in the 081 operability of the service water system.

7 8 9 80 SYSTEM

CAUSE

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VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE 9]

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10 11 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION LE R/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

17 REPORT 18 11 L-J Lu I 11111 L ji LT Li LOi NUMBER 226 28

29.

30......

231 32 ACTION FUTURE EFFECT SHUTDOWN f'

ATTACHMENT NPRD-4 PRIME COMP.

COMPCNENT TAKEN ACTION ON PLANT METHOD HOURS ( 22 SUBMITTED FORM SUB.

SUPRLIER MANUFACTURER I

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I External corrosicn caused four pits to be formed in the service water W

I pumps discharge piping which resulted in local areas below minimum walli 2I thickness.

The areas were sand blasted, a patch was welded over each 1 3 pitted area and the entire surfaces of the pipes repainted to prevent I

'- 4 I further corrosion.

7 8 9 80 FACILITY METHOD OF 80 STATUS

%POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION @

LJ I ol 0 o101 N/A 1 LcUI Special test of depth of pits I

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9 10 12 13 44 45 46 80 ACTIVITY CONTENT_

RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE @

16 LI 51LII N/A

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8 9

10 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE

DESCRIPTION

17Z, L olD N/A

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11 12 13 80 PERSONNEL INJURIES NUMBER

DESCRIPTION

7 8

9 11 1

80 LOSS OF OR DAMAGE TO FACILITY IYPE DE SCRI PTION

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8 9 10 80 PUBLICITY NRC USE ONLY ISSUED DESCRIPTION @

10 68 69 80; NAME OF PREPARER PHONE:

ATTACHMENT I Docket No. 05000247 Consolidated Edison Company LER 81-01.1/03L-0 of New York, Inc.

Indian Point Unit No. 2 While in cold shutdown the service water piping in the pump pit was sand blasted to remove surface corrosion. Visual inspection of the cleaned pipe showed a total of seven (7) pits had formed on three of six service water pump discharge lines.

The depth of the pits and surrounding wall thickness were measured using a pipe pit gage and an ultrasonic meter respectively.

The remain ing wall thickness under each pit was then calculated using the measured values.

Using an allowable wall thickness of 0.135 inches, which was based on seismic considerations, it was found that there were four pits which were below the value. These wall thicknesses were:

Line No. 23, 0.060 inches; Line No. 24, 0.060, 0.105 and 0.125 inches.

The cause of the pitting is believed to have been external

._corrosion resulting-from thedamnpconditions found-in the pump pit. A patch was welded over each pitted area and the entire surfaces of the pipes repainted to prevent further corrosion.

The size and small number of pits did not reduce the ability of the piping to withstand a design basis seismic event. Had one or more pits developed into through holes, the result would have been "pinhole" leaks which would not have significantly degraded the operability of the system.