ML19253C712
| ML19253C712 | |
| Person / Time | |
|---|---|
| Issue date: | 11/26/1979 |
| From: | Pappas H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wright G ILLINOIS, STATE OF |
| References | |
| NUDOCS 7912120004 | |
| Download: ML19253C712 (2) | |
Text
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GLEN ELLYN,ILLINols 60137 NOV 2 61979 State of Illinois Department of Public Health ATTN:
Mr. Gary N. Wright, Chief Division of Nuclear Safety 535 West Jefferson Street Springfield, IL 62761 Gentlemen:
The enclosed IE Information Notice No. 79-29 titled " Loss of Nonsafety-Related Reactor Coolant System Instrumentation During Operation" was sent to the following licensees on November 16, 1979:
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) 1534 288 7 D12120 cro 9
9 NOV 2 61979 I
State of Illinois
-2_
Iowa 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)
Ohio Edison Company Erie 1, 2 (50-580, 50-581)
Public Service of Indiana Marble Hill 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)
Sincerely, LA 7 I
elen as, Chief Administrative Branch
Enclosure:
IE Information Notice No 79-29 cc w/ encl:
Mr. D. W. Kane, Sargent & Lundy Central Files Reproduction Unit NRC 20b Local PDR NSIC TIC 1534 289
SSINS No.: 6300 Accession No.:
7910250490 UNITED STATES i
NUCLEAR REGULATORY COMMISSION OFFICEOFINSPECTIONANDENFQgMENT WASHINGTON, D. C.
2055Y November 16, 1979 IE Information Notice No. 79-29 LOSS OF NONSAFETY-RELATED REACTOR COOLANT SYSTEM INSTRUMENTATION DURING OPERATION This notice contains information regarding a loss of reactor coolant system instrumentation as a consequence of a failure of a static transfer switch to transfer to an alternate supply.
At 3:15 p.m. on November 10 with Unit 3 of the Oconee Station at 100 percent power, the main condensate pumps tripped, apparently as a result of a technician performing maintenance on the hotwell level control system.
This led to reduced feedwater flow to the steam generators, which resulted in a high reactor coolant system (RCS) pressure reactor trip and simultaneous turbine trip at 3:16:57 p.m.
At 3:17:15 p.m., the inverter power supply, nonsafety-related, feeding all power to the integrated control system (ICS) tripped and failed to automatically transfer its loads from the DC power source to the regulated AC power source.
The inverter had tripped due to blown fuses, resulting in loss of RCS indicators and recorders in the control room, except one wide range RCS pressure recorder.
This condition existed for approximately three minutes, until an operator could reach the equipment room and switch the inverter manually to the regulated AC source.
As a result of the power failure to the ICS, all valves controlled by the system assumed their respective fail positions.
This resulted in a cool down of the RCS to 1635 psi and 530 degrees F.
The operator, expecting this condition, started all makeup pumps and opened the associated high pressure injection valves to the RCS which limited the rate of RCS pressure reduction and associated reduction in pressurizer level.
At 3:20:42 p.m.,
power was restored to the ICS and RCS conditions were restored.
Although RCS cooldown limits were exceeded, the pressurizer and steam generators did not go dry, and at least 79 degrees F subcooling was maintained during this event.
No engineered safety features actuation setpoints were reached, and, except for the components discussed above, no component malfunc-tions occurred.
The licensee has installed a redundant electromechanical transfer switch between the loads and the regulated supply.
This switch will actuate and power the loads from the regulated supply should the original static switch fail to transfer.
Longer term resolution of the need or desirability to separate these instruments onto diverse electrical supplies or to provide redundant instrumentation display channels for operator use from essential power supplies are also under 1534 290
IE Information Notice No. 79-29 November 16, 1979 Page 2 of 2 consideration.
It is anticipated that further NRC evaluations will result in issuance of an IE Circular, Bulletin, or NRR Generic letter in the near future which will recommend or request specific applicant or licensee actions.
This Information Notice is provided to inform licensees of a possibly significant matter.
It is expected that recipients will disseminate the information to all operational personnel working at their licensed facilities.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
No written response to this Information Notice is required.
Enclosure:
Recently Issued IE Information Notices 1534 291
IE Information Notice No. 79-29 Enclosure November 16, 1979 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 79-28 Overloading of Structural 11/16/79 All power reactor facilities Elements Due to Pipe Support with an OL or CP Loads 79-27 Steam Generator Tube 11/16/79 All power reactor facilities Ruptures At Two PWR holding OLs and cps Facilities79-12A Attempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and power reactors with an OL or CP 79-26 Breach of Containment 11/5/79 All power reactor facilities Integrity holding OLs and cps 79-25 Reactor Trips At Turkey 10/1/79 All power facilities with Point Units 3 And 4 an OL or a CP 79-24 Overpressurization Of 10/1/79 All power reactor facilities Containment Of A PWR Plant with a CP After A Main Steam Line Break 79-23 Emergency Diesel Generator 9/26/79 All power reactor Lube Oil Coolers facilities holding OLs and cps 79-22 Qualification of Control 9/14/79 All power reactor Systems facilities with operating licenses and construction permits.
79-21 Transportation and Commercial 9/7/79 All power and research Burial of Radioactive Material reactors with OL's 79-20 NRC Enforcement Policy 9/7/79 All Holders of Reactor (Rev. 1)
HRC Licensed Individuals OLs and cps and Production Licensees with Licensed Operators 1534 292
.