ML19350A572
| ML19350A572 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 03/02/1981 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Linder F DAIRYLAND POWER COOPERATIVE |
| References | |
| NUDOCS 8103160511 | |
| Download: ML19350A572 (2) | |
Text
.
T f.'/1 4,9
'o,
UNITED STATES j#
,, ~j NUCLEAR REGULATORY COMMISSION g
- . r REGION lil e,
f 799 ROOSEVELT ROAD
,/
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,
(( /b-[>. [Ew-h/JamesG.Keppler Director
Enclosure:
IE Circular No. 81-03 81082805//
g
m.
s 4
Docket No. 50-409 Dairyland Power Cooperative ATTN:
Mr. F. W. Linder General Manager 2615 East Avenue - South La Crosse, WI 54601 cc w/ encl:
c)
D R. E. Shimshak, Plant
- A Superintendent O 'g% g Central Files
,g1 AD/ Licensing
~
AD/ Operating Reactors 6
$k
'S AEOD p
s Resident Inspector, RIII b
N PDR
\\\\
Local PDR John J. Duffy, Chief Boiler Inspector Stanley York, Chairman Public Service Commission f
3 e
SSlNS 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: IN0PERABLE 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 damar,e 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 aporoximately 45 miles northeast of the earth-quake area, reported no physical damage, although plant personnel felt slight building motion.
l Rancho'Seco was shutdown for refueling during these earthquakes.
During this l
period, the electrical seismic instruraentation system was inoperable because I
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 instrumentaticn would have a s
.w U.S. Geological Survey equipment clo from a passive recorder showed peak DUPLICATE DOCUMENT i
i j
Entire document previously 4
l entered into system under:
l
}
ANO l
No. of pages:
l a-l
~
,