ML19353A084
| ML19353A084 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 12/16/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| References | |
| NUDOCS 8101070095 | |
| Download: ML19353A084 (1) | |
Text
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UNITED STATES l'
NUCLEAR REGULATORY COMMISSION o
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j' GLEN ELLYN,lLUNOIS 60m l
December 16, 1980 i
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Those on Attached List:
4 The enclosed IE Information Notice No. 80-44 provides early notification of an event that may have safety significance. Accordingly, you should review the Information Notice for possible applicability to your facility.
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No specific action or response is requested at this time; however, contingent upon the results of further staff evaluation, a Bulletin or Circular recom-1 mending or requesting specific licensee actions may be issued.
If you have any questions regarding this matter, please contact this office.
i Sincerely, i
i N.
s ames G. Keppler' Director
Enclosure:
IE Information 4
i Notice No. 80-44 i
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f;132 Docket No. 50-266 u,.o
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gjy Docket No. 50-301 Rjg gy Wisconsin Electric Power Company J
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Mr. Sol Burstein Executive Vice President Power Plants 231 West Michigan Milwaukee, WI 53201 cc w/ encl:
G. A. Ree1, Plant Manager Central Files AD/ Licensing AD/ Operating Reactors T. Colburn, ORB /NRR AEOD Resident Inspector, RIII PDR Local PDR John J. Duffy, Chief Boiler Inspector Peter Anderson, Wisconsin's Environmental Decade e
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SSINS No..
6835 d
Accession No.
3 8012160001 IN 80-44 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 December 15, 1980 IE INFORMATION NOTICE N0. 80-44:
ACTUATION OF ECCS IN THE RECIRCULATION MODE WHILE IN HOT SHUTDOWN PURPOSE:
The intent of this Information Notice is to alert PWR licensees and holders of construction permits of a potentially generic problem involving inadvertent actuation of the emergency core cooling system (ECCS) in the " Recirculation Mode".
Such an event occurred at the Davis-Besse Nuclear Power Station (Docket No. 50-346) on December 5, 1980.
The plant was in a hot shutdown mode of opera-tion at the time of the event a1d was undergoing certain maintenance activities as described below.
DISCUSSION:
Just prior to the inadvertent actuation of the ECCS, the licensee was attempt-ing to isolate electrical shorts and/or grounds in the Safety features Actua-tion System (SFAS).
Towards this end, A-C power had been removed from Channel 3 o' the SFAS.
Upon reenergizing Channel 3 it was noted that an indicating lamp l
was out; therefore, an attempt was made to replace the failed lamp with a spare unit.
While removing a lamp from a spare output slot in a Channel 3 chassis, an arc was drawn between the lamp and the module chassis.
This arcing was apparent-ly due to a combination of shorts or grounds in the SFAS, which coupled with the " common" connection between Channel 1 and 3 resulted in the loss of a power supply in Channel 1.
Since all the bistable trips in Channel 3 had not been completely reset, and since a power supply to Channel 1 was lost, SFAS Levels 1, 2, 3 and 5 were actuated by the two-out-of four actuation logic.
Since SFAS Level 5 indicates that the Borated Water Storage Tank (BWST) is at a low level, the ECCS was placed in a recirculation mode (i.e., the ECCS suction was aligned to the emergency containment sump.)
In order to place the ECCS system in the recirculation mode, the supply valves
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leading to the Decay Heat Removal (DHR) pumps from the BWST start closing l
after those in the ECCS line and from the containment emergency sump fully open.
Thus, during this valve transition period, a flow path existed to the reactor coolant system (RCS) via the BWST and the ECCS pumping system (i.e., the DHR pumps); however, since the RCS pressure was higher than that of the pumping system (2100 vs. 1600 psig) no BWST water was pumped into the RCS.
- Rather, during the valve transition time of about 1-1/2 minutes, approximately 15,000 gallons of borated water was drained from the BWST to the containment emergency sump.
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