ML19345F411

Forwards LER 81-001/03L-0.Detailed Event Analysis Submitted

ML19345F411
Person / Time
Site:	Cooper
Issue date:	01/30/1981
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19345F412	List: ML19345F411 ML19345F416
References
CNSS810062, NUDOCS 8102170430
Download: ML19345F411 (2)

Text

. - - _. . . _ _ _ . _

COOPER NUCLEAR STATION

.\'; "

i "" * * "se"E 2RM;U,"..",^5*^"

] Nebraska Public Power District l

l CNSS810062 January 30, 1981 Mr. K. V. Seyfrit, Director U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Sectioe 6.7.2.B.2 of the Technical Specifications for Cooper Nuclear Station snd discusses a reportable occurrence that was discovered on January ?, 1981. A li-censee event report form is also enclosed.

Report No.: 50-298-81-01

Report Date

January 30, 1981 Occurrence Date: January 2, 1981 Facility: Cooper Nuclear Station Brownville, Nebraska -68321 l Identification of Occurrence:

1 A condition which rceulted in operation in a degraded mode per-a mitted by a limiting condition for operation established in Section 3.6.H.3 of the Technical Specifications.

Conditions Prior to Occurrence:

Reactor power was at approximately 99% of rated thermal power.

Description of Occurrence:

During routine inspection, station personnel discovered hydraulic shock suppressor RF-S4 with the reservoir oil level equal to or slightly less than the discharge tube connection causing the shock suppressor to be inoperable.

1 Designation of Apparent Cause of Occurrence:

The apparent cause of this occurrence has been attributed to in-proper installation of the shock suppressor during the 1980 re-

~ fueling outage. The shock suppressor was installed with the reservoir connecting pipe at the higher end of the reservoir )<> C) k instead of at the lower end thus allowing the oil inlet port to the f g

discharge tube to become uncevered when the reservoir was approx-imately 50% full of fluid.

II k

8102370 @ S

i Mr. K. V. Seyfrit January 30, 1981 Page 2.

Analysis of Occurrence:

{

RF-S4 is a hydraulic shock suppressor installed to allow thermal growth of the HPCI feedwater piping during normal operation and to provide a restraint to pipe movement during a seismic event. This snubber does not provide a pipe suppcrt function during normal operation. There were no recorded naismic events prior to dis-

, covery of this occurrence.

RF-S4 is mounted at approximately a 10 degree angle above the horizontal position. It is believed that pipe movement during HPCI ,

j operation caused the fluid to be lost cut the reservoir vent plug. l j This shock suppressor was inspected on November 18, 1980 and the reservoir level was observed to be at 75* full and the oil inlet

port to the discharge tube was submerged.

The ADS and RCIC systems were operable during this period. This j

occurrence had no adverse effect on the public health and safety.

i Corrective Action:

The shock suppressor was correctly oriented and stroked to insure cylinder operability. This is a repetitive occurrence (reference LER 80-45). All other shock suppressors installed during the 1980 refueling outage were checked and proper installation verified.

These occurrences have been reviewed with appropriate station personnel.

Sincerely, j  %

L. C. Lessor Station Superintendent Cooper Nuclear Station LCL:cg Attach.

i-I t

y v e. ,-- ..--~ ~,.y, .,,,-..,y..,7,,~.--e,,.,,,.m....w+~. , . - . ,,~.-w. ,-.,,_,,,.,wrvr..-,,-y-, ~ , . , - ,-- .,-m,.7,-.w,2,.,, , - . 4 - - , - ----,.-c,. . - - , , - - .