05000278/LER-1980-016, Forwards LER 80-016/01T-0

Forwards LER 80-016/01T-0

ML19331B632
Person / Time
Site:	Peach Bottom
Issue date:	08/04/1980
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19331B633	List: 05000278/LER-1980-016, Forwards LER 80-016/01T-0 05000278/LER-1980-016-01, /01T-0:on 800717,reanalysis by Bechtel of as-built Piping Determined That Stresses on Snubber 3-10-GB-S-44 Exceeded Operability Criteria.Caused by Inadequate Design Due to as-built Condition & Seismic Analysis Info Variance
References
NUDOCS 8008120517
Download: ML19331B632 (2)

LER-1980-016, Forwards LER 80-016/01T-0

Event date:
Report date:
2781980016R00 - NRC Website

text

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 (21si e4 -4ooo August 4, 1980 Mr. B oy c e 11. 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:

SUBJECT:

Licensee Event Report Narrative Description The following occurrence was reported to Mr. Cowgill, U.S.

Nuclear Regulatory Commission, Region I, Office of Inspection and Enforcement, on July 17, 1980.

Reference:

Docket No. 50-278 Report No.:

LER 3-80-16/1T Report Date:

July 31, 1980 Occurrence Date:

July 17, 1980 Facility:

Peach Botton Atomic Power Station Unit 3

'RD #1, Delta, PA 17314 Technical Specification Reference:

Technical Specification 3.11.D.2 states in part that "From and after the time that a snubber is determined to be inoperable, continued reactor operation is permissible only during the succeeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> unless the snubber is sooner made op e ra ble or replaced".

Technical Specification 6.9.2.A.(9) requires reporting " performance of structures, systems or components that require remedial action or corrective measures to prevent operation in a manner less conservative than assumed in the accident analyses in the safety analysis report or technical specifications bases".

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Grier Page 2 August 4, 1980 LER 3-80-16/1T Description of the Event:

Re-analysis of as-built piping determined that stresses on pipe s_pport (snubber) 3-10-GB-5-44 exceeded the orerability criteria.

Bechtel reported this analysis to the licensee on July 17, 1980.

Consequences of Event:

Although the pipe support stresses exceed the operability criteria, the stresses in the associated piping, assuning support failure, were still within operability limito.

The safety significance is therefore ainimal.

Cause of Event

The seismic analysis used the original support design as input, rather than the actual as-built condition.

As a result, the pipe support design was inadequate.

Corrective Action

The hydraulic snubber was replaced by a mechanical snubber on J.ly 19, 1980, resulting in a safety factor of 2.85 for the support.

The snubber is therefore operable.

The concrete expansion bolt installation, that will enhance the safety factor to greater than 4.0, requires the "C" RHR loop out of service.

The NRC requested by telephone on 7/20/80 that the expansion bolt installation work be delayed until the next Unit 3 shutdown to avoid degraded operation with an RHR subsystem out of service.

Improvements to the support will be performed, as requested, during the next Unit 3 outage.

Bechtel is performing further analysis to ensure acceptable criteria for all snubbers.

Previous Similar Occurrences:

LER Nos. 2-79-33/IP, 2-79-35/IP, 2-79-43/IP, 2 44/IP, 3-79-19/IP, 3-79-23/IP, 3-79-25/IP, 3-79-26/IP, 3 30/IP.

Very truly yours, M. J. Cooney Superintendent Generation Division / Nuclear Attachment cc: Director, NRC - Office of Inspection and Enforcement Mr. Norman M.

Haller, NRC - Office of Management & Program Analysis w

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