ML19350A559
| ML19350A559 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 03/02/1981 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| References | |
| NUDOCS 8103160488 | |
| Download: ML19350A559 (2) | |
Text
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,'o, UNITED STATES NUCLEAR REGULATORY COMMISSION
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GLEN ELLYN, ILLINOIS 60137 March 2, 1981 i
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Gentlemen:
The enclosed IE Circular No. 81-03 is forwarded for your information.
No written response to this circular is required.
If you have any questions l
1 related to this matter, please contact this office.
I Sincerely, f
[( hx,f,_ [NE h/JamesG.Keppler Director
Enclosure:
IE Circular l
No. 81-03 l
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.N Docket No. 50-358 Cincinnati Gas and Electric Company ATTN:
Mr. Earl A. Borgmann Senior Vice President Engineering Services and Electric Production 139 East 4th Street Cincinnati, 011 45201 cc w/ encl:
J. R. Schott, Plant Superintendent Central Files AD/ Licensing AD/ Operating Reactors
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AEOD t Inspector, RIII
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MAR 0 41981*
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liarold W. Kohn, Power 6 u.s. g,ym Siting Commission Citizens Against a Radioactive g
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SSINS No.: 6830 Accession No.:
8008220271 IEC 81-03 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 March 2, 1981 IE Circular No. 81-03: INOPERABLE SEISMIC MONITORING INSTRUMENTATION Description of Circumstances:
On November 8, 1980, an earthquake occurred off the coast near Eureka, California.
The earthquake was reported to have a magnitude of 7.0 on the Richter Scale at the epicenter, approximately 25 tc 75 miles from the Humboldt Bay Power Plant facility.
There were 12 separate seismic events above a magnitude of 3.5 that occurred within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the earthquake, the largest event measuring 5.2.
Reported damage to structures included several houses that were moved off supporting posts, various chimneys that were knocked down, one highway overpass that collapsed, and unspecified damage that occurred at two pulp' mills.
There were three potentially different sources of plant response data: three sets of magnetic tape triaxial accelograph recorders; three sets of triaxial film recorders (passive device); and one set of triaxial response spectrum recorders (passive device).
A review of the records from these instruments indicated the following: the magnetic tape triaxial recorders did not produce useful records due to a degraded low-voltage power supply in the recording system (previously scheduled for routine servicing one week after the earthquake);
a buildup of dirt and dust appeared to make inoperable six of the nine film recorders (the readings from the other three are considered highly unreliable and were not obtained from the same set of triaxial recorders); the triaxial response spectrum recorder was the only instrument believed to produce reliable data.
On January 24, 1980, an earthquake measuring 5.5 on the Richter Scale occurred about 10 miles north of Lawrence Livermore Laboratory (near San Francisco, California).
Numerous aftershocks also occurred with one measuring 5.2 on January 26.
The damage to civil structures was considered minor.
Rancho Seco Nuclear Plant, located approximately 45 miles northeast of the earth-quake area, reported no physical damage, although plant personnel felt slight building motiori.
Rancho'Seco was shutdown for refueling during these earthquakes.
During this period, the electrical seismic instrumentation system was inoperable because portions of the system were out for calibration.
For the other instruments, power was not being supplied due to electrical cable roblems. Whether the seismic instrumentation would have a U.S. Geological Survey equipment clo from a passive recorder showed peak DUPLICATE DOCUMENT Entire document previously 7
entered into system under:
xNOB6082.2077/
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