ML19031B953

Reactor Vessel - Incore Instrument Tubing 10CFR50.55(E) Significant Deficiency.

ML19031B953
Person / Time
Site:	Salem
Issue date:	08/09/1978
From:	Martin T Public Service Electric & Gas Co
To:	Grier B NRC/IE, NRC Region 1
References
Download: ML19031B953 (2)

Text

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Thomas J. Martin Public Service Electric and Gas Company 80 Park Place Newark, N.J. 07101 201/430-8316 Vice President Engineering and Construction August 9, 1978 Mr. Boyce H. Grier, Director "3 ff U. s. Nuclear Regulatory Commission Office of Inspection and Enforcemen~

Region 1 631 Park A:venue King of ~russia, P~nnsylvania 19406

Dear Mr. Grier:

REACTOR VESSEL - INCORE INSTRUMENT TUBING 10CFR50.55(e) 11 SIGNIFICANT DEFICIEHCY" HO. 2 UNIT SALE!,~ NUCLEAR GENERATING ST.ATION .

On July 19, *1978 a verbal report was made to Region 1, Office of Inspection and Enforcement represeptative Mr. R. Gallo, advising that in the course of performing Presei~ice Mechanized examinations of the Salem No. 2 Unit Reactor Vessel on Sat~rday, July 15, Southwest Research Institute apparently swept ~ltrasonic calibr~~ion block //5-CSCL-42SAM into. the vessel while manipulating their auto-mated inspection device above the reactor flange.

The following information is hereby sub~itted pursuant to our initial report and in accordance with the requirements of 10CFR50.55(~):

1. Description of the Deficiency The calibration block fell from* the vessel flange hitting the core support ledge putting a shallow *dent in the cladding at the o0 location, then proceeded to fall into 12 ft. of water. Before coming to rest at the bottom of the vessel, the.block apparently hit. bottom mount~d instrumentation tube

1. 28 causing this tube to bend outwards approximately four (4) degrees, and caused two nicks in the cladding on the bottom of the vessel. While examining all bottom mounted instrumen-tation tubes by the rod and ball method, tube #47 was found to be slightly bowed. ~owever, this tube apparently was not struck by the calibration block due to its location.

2. Corrective Action . '

PSE&G has e~aluated the damage found in the vessel and the following minor repairs are anticipated:

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Mr. Boyce H. Grier 8/9/78 (1) Cosmetic blending of the.dent on core support ledge.

(2) Cosmetic blending of the nicks in cladd~ng on the bottom of the vessel.

(3) Straightening of tubes #28 and #47, if they are determined*

by Westinghouse *to be out of tolerance.

T~ese repairs will be performed using approved procedures developed by Westinghouse in September 1978.

Southwest Research Institute has-investigated the circumstances leading up to the calibration block being swept iinto the vessel and -is in *the piocess of issu~ng a report to PSE&G; Preliminary information from Southwest Research indicates that steps during Preservice Inspection, such as physically securing calibratio~ blocks and requiring a technician to be stati~ned in the ~essel fling~ area while manipulating the mechanized inspection device are being considered.

The ~ossibility of this type of incident occuring during Inservice Inspection has been'iev~ewed and considered virtually non-existent since calibration is. performed completely remote of the vessel flange.

Very truly yours, CC: Mr. Leif J. Norrholm Resident Reactor Inspector U. S. Nuclear Regulatory Commission Drawer :r Hancocks Bridge, New Jersey 08033