ML19350A558
| ML19350A558 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 03/02/1981 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Davidson D CLEVELAND ELECTRIC ILLUMINATING CO. |
| References | |
| NUDOCS 8103160487 | |
| Download: ML19350A558 (2) | |
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UNITED STATES 4
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~1 NUCLEAR REGULATORY COMMISSION 3
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GLEN ELLYN, ILLINOIS 60137 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,
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[#JamesG.Keppler l
Director
Enclosure:
IE Circular No. 81-03 i
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t-Docket No. 50-440 Docket No. 50-441 The Cleveland Electric Illuminating Company ATTN: !!r. Dalwyn R. Davidson Vice President - System Engineering and Construction Post Office Box 5000 Cleveland, OH 44101 cc w/ enc 1:
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/Sgf Siting Commission Daniel D. Wilt, Attorney llelen W. Evans, State of Ohio
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SSINS No.: 6830 Accession No.:
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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 1 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 seisnic 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 ine 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 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, power was not being supplied due to electrical cab roblems.
Whether the seismic instrumentation would have a U.S. Geological Survey equipment clo from a passive recoroer showed peak DUPLICATE DOCUMENT Entire document previously entered into system under:
xnO 86b82.20%7i No. of pages.
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