ML19350A562
| ML19350A562 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Byron, Braidwood, Quad Cities, Zion, LaSalle  |
| Issue date: | 03/02/1981 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Reed C COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8103160494 | |
| Download: ML19350A562 (2) | |
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'o UNITED STATES
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l' NUCLEAR REGULATORY COMMISSION y,
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799 ROOSEVELT ROAD e*
GLEN ELLYN ILLINOIS 60137
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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,
[( h.L,5 tw
[#JamesG.Keppler Director
Enclosure:
IE Circular No. 81-03 l
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Docket Nos. 50-10, 50-237, 50-249; 50-254, 50-265; 50-295, 50-304; 50-373, 50-374; 50-454, 50-455; 50-456, 50-457 Commonwealth Edison Company ATTN:
Mr. Cordell Reed Vice President N
Post Office Box 767 Chicago, IL 60690 4
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\\J J. S. Able, Director of Nuclear Licensing C
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D. J. Scott, Stat. ion
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'S Superintendent y
N. Kalivianakis, Plant ro Superintendent
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K. L. Graesser, Station Superintendent L. J. Burke, Site Construction Superintendent T. E. Quaka, Quality Assurance Supervisor R. II. llolyoak, Station Superintendent B. B. Stephens,on, Project Manager V. I. Schlosser, Project Manager R. E. Querio, Station Superintendent Gunner Sorensen, Site Project Superintendent R. Cosaro, Project Superintendent J. F. Gudac, Station Superintendent Central Files AD/ Licensing AD/ Operating Reactors AEOD R
nt Inspectors, RIII Local PDR NSIC TIC Dean liansell, Office of Assistant Attorney General Myron M. Cherry
SSINS No.
6830 Accession No.:
8008220271 IEC 81-03 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
205;5 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 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 !cw-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 dcmage, 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 cable roblems.
Whether the seismic instrumentation would have a U.S. Geological Survey equipment clo
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