ML19290F054
| ML19290F054 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 03/11/1980 |
| From: | Carroll D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8003180014 | |
| Download: ML19290F054 (3) | |
Text
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4 UNITED STATES s
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7, NUCLEAR REGULATORY COMMISSION b
E REGION lli 799 ROOSEVELT ROAD o,
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,o GLEN ELLYN. ILLINOIS 60137 g,;{t 11 MEMORANDUM FOR: Those on Attached List FROM:
Dorothy E. Carroll, Acting Chief, Administrative Branch
SUBJECT:
IE INFORMATION NOTICE NO. 80-10 The attached IE Information Notice No. 80-10 titled " Partial Loss of Non-Nuclear Instrument System Power Supply During Operation" was sent to the following licensees on March 10, 1980:
American Electric Power Service Corporation Indiana and Michigan Power Company D. C. Cook 1, 2 (50-315, 50-316)
Cincinnati Gas & Electric Company Zimmer (50-358)
Cleveland Electric Illuminating Company Perry 1, 2 (50-440, 50-441)
Commonwealth Edison Company Braidwood 1, 2 (50-456, 50-457)
Byron 1, 2 (50-454, 50-455)
Dresden 1, 2, 3 (50-10, 50-237, 50-249)
La Salle 1, 2 (50-373, 50-374)
Quad-Cities 1, 2 (50-254, 50-265)
Zion 1, 2 (50-295, 50-304)
Consumers Power Company Big Rock Point (50-155)
Midland 1, 2 (50-329, 50-330)
Palisades (50-255)
Dairyland Power Cooperative LACBWR (50-409)
Detroit Edison Company Fermi 2 (50-341)
Illinois Power Company Clinton 1, 2 (50-461, 50-462) 800a1800l9
Those on Attached List -
Ic"a Electric Light & Power Company Duane Arnold (50-331)
~
Northern Indiana Public Service Company Bailly (50-367)
Northern States Power Company Monticello (50-263)
Prairie Island 1, 2 (50-282, 50-306)
Publi-vice of Indiana Marble in11 1, 2 (50-546, 50-547)
Toledo Edison Company Davis-Besse 1,(50-346)
Union Electric Company Callaway 1, 2 (50-483, 50-486)
Wisconsin Electric Power Company Point Beach 1, 2 (50-266, 50-301)
Wisconsin Public Service Corporation Kewaunee (50-305) f / f L,c / G iis44 Dorothy E. Carroll, Acting Chief Administrative Branch
Enclosure:
IE Information Notice No. 80-10
Addressees - Memorandum dated March 10, 1980 IE Files MPA/DTS Centra' Files Reproduction Unit NRC 20b
SSINS No..
6870 UNITED STATES Accession No.
NUCLEAR REGULATORY COMMISSION 8002280640 0FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 March 7, 1980 IE Information Notice No. 80-10 PARTIAL LOSS OF NON-NUCLEAR INSTRUMENT SYSTEM POWER SUPPLY DURING OPERATION Description of Circumstances:
This notice contains information regarding Crystal River Unit-3 response to a loss of non-nuclear instrumentation (NNI) as a consequence of loss of the
+24 volt power supply to the NNI.
At 2:23 p.m. on February 26 with Crystal River Unit-3 at 100% power, the
+24 volt power supply to the NNI was lost, due to a short to ground.
This initiated a sequence of events (detailed in the enclosure) wherein the PORV opened and stayed open as a direct result of the NNI power supply loss.
HPI initiated as s result of depressurization through the open PORV, and with approximately 70% of NNI inoperable or inaccurate, the operator correctly decided that there was insufficient information available to justify terminating HPI.
Therefore, the pressurizer was pumped solid, one safety valve lifted, and flow through the safety valve was sufficient to rupture the RC Drain Tank rupture disk, spilling approximately forty-three thousand gallons of primary water into containment.
The Crystal River-3 event is closely related to the November 10, 1979 event at Oconee Unit-3 wherein the inverter supplying power to the Integrated Control System (ICS) and to parts of the NNI failed. That event was the subject of IE Information Notice 79-29 (November 16, 1979) which was followed by IE Bulletin 79-27 (November 30, 1979).
The CR-3 event involved loss of only part of the power available from an inverter, rather than the inverter itself, since the +24v supply is only one of several power supplies drawing power from one inverter.
The effects are very similar, however, in that the ICS lost part of its input signals in both events.
The +24 volt power supply short to ground has tentatively been identified by the licensee to have occurred between knife edge connectors of a Bailey Control Company Voltage Buffer Card. The voltage buffer card was misaligned in its receptacle, and adjacent connectors carrying +24v and " common" were bent such that they contacted one another.
This subsequent re-energizing of the power printed circuit card. Subsequent revi' DUPLICATE DOCUMENT voltage buffer card which was also mis The specific circuit cards which were '
Entire doctunent previously The connectors on these cards are slig entered into systeln under:
different angle than those found on si
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carry part numbers 6624608A1 or 6624J0,
7d10 more subject to misalignment.
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