ML19351F457
| ML19351F457 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 12/17/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Matlock R WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| References | |
| NUDOCS 8101130110 | |
| Download: ML19351F457 (1) | |
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UNITED STATdS NUCLEAR REGULATORY COMMISSION
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j REGION V 1990 N. CALIFORNIA BOULEVAMD 0,
%,4e,,*,o*g SUITE 202 WALNUT CREEK PLAZA WALNUT CREEK. CALIFORNIA 94506 December 17, 1980 Docket tio. 50-397 Washington Public Power Supply System P. O. Box 968 i
3000 George Washington Way Richland, Washington 99352 Attention: Mr. R. G. Matlock Program Director, Wi4P-2 Gentlemen:
The enclosed Information tiotice provides early notification of an event that may have safety significance. Accordingly, you should review the Information tiotice for possible applicability to your facility.
tio specific action or response is requested at this time; however, con-tingent upon the results of further staff evaluation, a Bulletin or a Circular recommending or requesting specific licensee actions may be issued.
If you have any question regarding this matter, please contact me.
Sincerely,
}l
%..L k R. H. E'gelken n
Director
Enclosures:
1.
IE Information tiotice flo. 80-45 2.
Recently Issued IE Information flotices cc w/ enclosures:
M. E. Witherspoon, WPPSS W. C. Bibb G. Sorensen, WPPSS hglO 3 33 0//O g
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SSINS No.: 6835 Accession No.:
801216002 IN 80-45 UtilTED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT n
WASHINGTON, D.C.
20555 y
December 17, 1980 IE Information Notice No. 80-45:
POTENTIAL FAILURE OF BWR BACKUP MANUAL SCRAM CAPABILITY The primary purpose of this Notice is to advise BWR licensees that a mechanism exists which could defeat one of the backup manual scram (reactor trip) features normally available to the reactor operator.
In some GE-designed reactors, placing the Mode Selector Switch (MSS) in " Shutdown" should actuate a scram.
This feature is used at some facilities as part of a normal reactor shutdown, and for certain plant situations the Technical Specifications require placing the MSS in the " Shutdown" position as a means of attaining immediate shutdown.
As described below, a situation may arise that blocks this scram.
The Pilgrim Nuclear Power Station has reported that following the loss of power from a vital M-G set and manual transfer to the alternate power source, the annunciator " Shutdown Scram Reset Pernissive" came on and stayed on.
Since such an annunciator may not be provided for all BWRs, some facilities may not be able to detect this condition.
Subsequent investigation revealed that when one RPS bus power supply is lost and the MSS.is.in the "Run".smode, relay K-17_ _
is immediately deenergized and af ter two seconds one of two series bypass contacts in the MSS scram circuit is closed. Upon restoration of RPS bus power, it is possible for relay K-16 to be energized before K-17 (i.e., a relay race).
If this occurs, the following conditions will result: (1) the normally open K-16 contact in the MSS scram bypass circuit is closed, thereby bypassing the MSS in
" Shutdown" Scram; and (2) relay K-17 will be kept deenergized.
I Even with this condition (i.e., the bypass circuit made up and the MSS in "Run")
a Scram should occur if the MSS is turned in a deliberate manner to " Shutdown" with a pause in either the "Startup" or " Refuel" mode; however, if the MSS is.
turned to " Shutdown" quickly such that relay K-17 is not energized, a Scram due to MSS manipulation may not occur.
l We understand that General Electric has been infonned of this potential for J
bypassing the MSS and that General Electric is preparing a Service Information l
Letter (SIL) containing reconnendations for preventing such bypassing.
This Information Notice is provided as an early notification of a possibly significant matter that is still under review by the NRC staff. Recipients should review the information for possible applicability to their facilities.
No specific action or response is requested at this time; however, if NRC evaluations so indicate, further licensee actions may be requested or required.
If you have any question regarding this matter, please contact the director of 1..:.:.:_ S i l
the appropriate NRC Regional Office.._
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l IN 80-45 December 17, 1980 1
RECENTLY ISSUED IE INFORMATION NOTICES D cnr,)D c3)D hfhlh o Juu2U.\\lfUm i
A Ju Information Date of Notice No.
Subject Issue Issued to 80-44 Actuation of ECCS in the 12/16/80 All PWR facilities Recirculation Mode While with an OL or CP in Hot Shutdown 4
80-43 Failures of the Continuous 12/5/80 All power reactor Water Level Monitor for facilities. with O!
I the Scram Discharge Volume or CP at Dresden Unit No. 2 s
80-42 Effect of Radiation on 11/24/80 All power reactor Hydraulic Snubber Fluid facilities with OL or CP 80-41 Failure of Swing Check 11/10/80 All power reactor Valve in the Decay Heat facilities with an OL
{
Removal System at Davis-or CP j
Besse Unit No.1 j
80-40 Excessive Nitrogen Supply 11/10/80 All power reacter l
Pressure Actuates Safety-facilities with Pelief Valve Operation to OL or CP Cause Reactor Depressur-ization
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80-39 Malfunctions of Solenoid 10/31/80 All light water reactor Valves Manufactured By facilities with Valcor Engineering Corporation OLs or cps i
80-38 Cracking in Charging Pump 10/30/80 All PUR facilities l
Casing Cladding with an OL or CP i
80-37 Containment Cooler' Leaks 10/24/80
' All power. reactor and Reactor Cavity facilities with l
Flooding at Indian Point
~0Ls or cps Unit 2 80-36 Failure of Steam 10/10/80 All power reactor Generator Support Bolting facilities with OLs or cps 80-35 Leaking and Dislodged 10/10/80 All categories G and Iodine-124 Implant Seeds G1 medical licensees OL = Operating Licenses
' CP = Construction Permits
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