05000029/LER-1986-010, Forwards LER-86-010-00.One Day Extension Granted by D Havercamp for Submission of LER

Forwards LER-86-010-00.One Day Extension Granted by D Havercamp for Submission of LER

ML20212N895
Person / Time
Site:	Yankee Rowe
Issue date:	07/28/1986
From:	St Laurent N YANKEE ATOMIC ELECTRIC CO.
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 8609020025
Download: ML20212N895 (1)

LER-2086-010, Forwards LER-86-010-00.One Day Extension Granted by D Havercamp for Submission of LER

Event date:
Report date:
0292086010R00 - NRC Website

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YANKEE ATOMIC ELECTRIC COMPANY r.i.onon. ts,si s2<.82e,

m. Star Route, Rowe, Massachusetts 01367

.YAuxes .

July 28, 1986 U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention: Dr. Thomas E. Murley, Regional Administrator

Subject:

Licensee Event Report 50-29/86-10 Potential Loss of Shutdown Cooling

Dear Sir:

In accordance with 10 CFR 50.73(a)(2)(v), the attacheri Licensee Event ,

Report is hereby submitted. A one-day extension for the submission of this report was granted by Mr. Donald Havercamp of the NRC.

Very truly yours, hW ( W*

Normand N. St. Lau ent Plant Superintendent ELM /nm Enclosure cc: [3] 9 SARC Chairman (YAEC)

[1] Institute of Nuclear Power Operations (INPO) 8609020025 860728 PDR ADOCK 05000029 S PDR 3 ff : D

esRC Form 3ge U.S. NUCLEJM REOULATORY COeAMaessOse A3I APPROVED Oue eso.3190 -1104 LICENSEE EVENT REPORT (LER)

' ACeuf v haut "' Yankee Nuclear Power Station Rowe. Massachusetts o l5 l0 lo lol0l2l9 1 loFl 0 l 2 TITLEtop Potential Loss of Shutdown Cooling EVENT DATE 456 LER NUMSER to REPORT DATE(7) OTHER F ACILITIES INVOLVED tel F ACILITV NawES DOCKET NUMBERi$l MONTH DAY YEAR TEAR 58,$, ,8y,'

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On June 27, 1986, at 0137 hours0.00159 days <br />0.0381 hours <br />2.265212e-4 weeks <br />5.21285e-5 months <br />, during a maintenance outage with the plant in Mode 5, main coolant was inadvertently drained to the Low Pressure Surge Tank (LPST). This could have resulted in a loss of shutdown cooling. This event

! occurred while transferring to the alternate method of shutdown cooling par procedure OP-2162, Attachment C. Performance of this procedure was necessary because of the failure of the shutdown cooling pump's shaft seal. During the evolution, approximately 2000 gallons of water was drained from the pressurizer and main coolant pressure dropped from 100 psig to 10 psig. The pressurizer did l not empty. The Control Room Operator (CRO) immediately secured the LPST cooling

pump and the Primary Auxiliary Operator (PAO) isolated the flow path. The CR0 l

started all three charging pumps and restored pressurizer level and pressure.

The root cause of this accurrence has been attributed to personnel error. While

, conducting the alternate shutdown cooling valve Ifneup, CH-V-654 was not fully

! shut, which resulted in a main coolant system to LPST flow path. The PA0 l thought that the valve had completed its full travel when he operated the manual valve. This occurrence was reviewed with the appropriate plant personnel and the need for strict procedural compliance was emphasized.

l This is the first occurrence of this nature. There were no adverse effects to the public health or safety as the result of this occurrence.

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e send Felm 3eeA U.S. NUCLE AR [ECULATORY COMMIS$aON i

" 1 LICENIEE EVENT REPORT (LER) TEXT CONTIN'JATION ApenovEO oMe No. 3 iso-otc4 EXPtIES: S/31/85

.AC8LITY NAME (1) DOCKET NUMSElv (27 LER NUMBER (6) PAGE131 Yankee Nuclear Power Station vcan agg,a, ' 4=,p '

Rowe, Massachusetts  ;

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On June 27, 1986, at 0137 hours0.00159 days <br />0.0381 hours <br />2.265212e-4 weeks <br />5.21285e-5 months <br />, during a maintenance outage with the plant in Mode 5, main coolant was inadvertently drained to the Low Pressure Surge Tank (LP5T). This could have resulted in a loss of shutdcwn cooling. This occurred while transferring from normal shutdown cooling to the alternate method of ,

shutdown cooling using the LPST cooling pump and cooler per approsed procedure  !

OP-2162, Attachment C. Performance of this procedure was necessary because of the failure of the shutdown cooling pump's shaft seal. During this evolution

~

approximately 2000 gallons of water was drained from the pressurizer, the pressurizer level indication dropped quickly from 300 inches to an offscale low condition, and main coolant pressure dropped from 100 psig to 10 psig. The .

pressurizer did not empty. The Control Room Operator (CRO) iminediately secured

• the LPST cooling pump and the Primary Auxiliary Operator (PAO) isolated the flow path by shutting SC-V-614 and SC-V-661. The CR0 also started all three charging pumps and restored pressurizer level and pressure to 300 inches and 100 psig, respectively.

The root cause of this occurrence has been attributed to personnel error by the PA0. While conducting the alternate shutdown cooling valve lineup, CH-V-654 was not fully shut which resulted in a flow path from the main coolant system to the LPST. The PA0 thought that the valve had corpleted its full travel when he had operated the manual valve during his valve lineup.

This is the first occurrence of this nature at this facility. Without any operator action the valve lineup could have ellowed the main coolant loops to be drained and a loss of shutdown cooling could have resulted. For this to occur, however, the event would have had to continued completely unnoticed. The LPST would have filled and subsequently vented water through a 1" vent line to the gravity drain tank. High level alarms on the LPST and the gravity drain tank would have alerted the operators to this event. However, prompt action by the operators upon noticing the initial level decrease in the pressurizer

. resulted in a quick termination to this event. In no case, would the core have been uncovered. There were no adverse effects to the public health or safety as a result of this occurrence.

All members of the Operations Department involved in this event were instructed of its potential consequences and the need for strict procedural compliance in conjunction with the utilization of practical systems knowledge when performing plant evolutions. Plant personnel were made aware of this event and complete compliance with plant procedures and programs at all times was emphasized.

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