ML19350A569
| ML19350A569 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point, Palisades File:Consumers Energy icon.png |
| Issue date: | 03/02/1981 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Dewitt R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8103160508 | |
| Download: ML19350A569 (2) | |
Text
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'o UNITED STATES 8 3,
'g NUCLEAR REGULATORY COMMISSION
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a REGION ill e
799 ROOSEVELT ROAD g
GLEN ELLYN. ILLINOIS 6o137 March 2, 1981 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 related to this matter, please contact this office.
Sincerely,
(( hA,f sw
[#JamesG.Keppler Director l
Enclosure:
IE Circular No. 81-03 l
'8.103 2 e o 5@
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.,1' Docket No. 50-155 Docket No. 50-255 Consumers-Power Company ATIN:
Mr. R. B. DeWitt Vice President
~ Nuclear Operations 212 West Michigan Avenue Jackson, MI 49201 cc w/ encl:
D. P. Hof fman, Nuclear y
Licensing Administrator C. J. Hartman, Plant
((./g Superintendent R. V. Montross, Manager
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ad Local PDR NSIC TIC Ronald Callen, Michigan i
Public Service Co= mission Myron M. Cherry l
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SSINS No.
6830 Accession No..
8008220271 IEC 81-03
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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 to 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 largsst 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 se.
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);
l a buildup of dirt and dust appeared to make inoperable six of the nins film 1
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 i
data.
On January 24, 1980, an earthquake measuring 5.5 on the Richter Scale occurred about 10 miles 1 orth of Lawrence Livormore 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 motion.
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, I
power was not being supplied due to electrical cable problems. Whether the seismic instrurcentation would have a U.S. Geological Survey equipment clo
l from a passive recorder showed peak 7
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4 xNo Boo 82.20F7/
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