ML19257B889
| ML19257B889 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 01/01/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| TASK-03-11, TASK-3-11, TASK-RR NUDOCS 8001210157 | |
| Download: ML19257B889 (5) | |
Text
YI a na jo, UNITED STATES 8
{t NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D. C. 20555 g,
o January 1, 1980 Docket No. 50-155 Mr. David P. Hoffman Nuclear Licensing Administrator Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201
Dear Mr. Hoffman:
Recent seismic design evaluations conducted in the Systematic Evaluation Program (SEP) have indicated a potential safety concern relative to the anchorage and support of safety related electrical equipment.
It has also been observed that non-seismic Category I auxiliary items (dolleys, gas bottles, etc.) may be dislodged by an earthquake and damage safety related equipment. These issues were identified during site visits to Dresden 2, Haddam Neck, Ginna, Oyster Creek, Palisades and Millstone 1 by review teams consisting of NRC representatives and consultants. Since operability of the subject equipment may be essential during and af ter a seismic disturbance, we request that you assess the capability of all safety related electrical equipment (as well as non-seismic Category I auxiliary items) to resist seismic forces and iglement reriedial measures, as necessary, to increase safety margins. All operating licensees of nuclear power facilities are being notified of this issue by an I&E Information Notice (Enclosure 1).
Within 30 days, you are requested to develop an action plan for resolution of this issue cnd to submit it for our review. The following issues should be addressed:
1.
Does positive anchorage exist (load carrying mechanism other than friction);
2.
If positive anchorage exists, has the anchorage system been engineered with adequate capacity; and 3.
Was the anchorage fabricated to quality standards?
The results of your investigation of Item i should be submitted within 60 days of the date this letter is received.
It should describe any corrective action considered necessary. The overall issue, including any required modifications, should be resolved by September 1,1980.
1774 050 Bn1 21 o is 7
. Although the final seismic design basis for your facility has not been resolved, and other changes may be required, appropriate action on this matter should not be delayed.
If necessary, consideration should be given to pt oviding temporary supports with more pennanent supports being installed after all seismic questions have been resolved.
- incerely,
(~~
j
.f':l'eTl'G.' Eisenhut, feting Director llLt! ':ti,n k il f Darr Division of Operating Reactors Office of Nuclear Reactor Regulation
Enclosure:
As stated cc w/ enclosure:
See next page e
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. cc w/ enclosure:
Mr. Peul A. Perry, Secretary U. S. Environmental Protection Consumers Power Coupony Agency 212 West Nichigan Avenue Federal Activities Branch Jackson, Michigan 49201 Region V Office ATTN:
EIS COORDINATOR Jucd L. Bacun, Esquire 230 South Dearborn Street Consumer:. Power Coupany Chicago, Illinois 60604 212 dest Michigan Avenue Jackson, Michigan 49201 Herbert Grossuan, Esq., Chairman Atouic Safety and Licensing Board Hunton u Williams U. S. Nuclear Regulatory Commission George C. Freeman, Jr., Esqui, e Washington, D. C.
20555 P. O. Box lbh Ricni..ond, Virginia 23212 Dr. Oscar H. Paris Atomic Safety and Licensing Board Peter W. Steketee, Esquire U. S. Nuclear Regulatory Commission SOS Peoples buildin3 Washington, D. C.
20555 Grand nopius, nicriigari 49503 Mr. Frederick J. Shon
.anelcun. Horuun, doisuan and Weiss Atociic Safety and Licensing Board 17 d I Street, N.
W.
U. S. Nuclear Regulatory Comuission Suite bub Washington, D. C.
20555 Wdshinston, u. C.
20006 Big Rock Point Nuclear Plant hr. Junn v'heill, II ATTN: Mr. C. J. Hartman noute 2, bux 44 Plant Superintendent tiaple City, nichigan 49o64 Charlevoix, Michigan 49720 Charlevou Public Li~ rary u
10/ Clintun street Charlevoix, hici.isan
,9720 Cho i ri:ian
\\
Lounty ooard of Supervisors Litorlevoix Ccunty 9
Charlevoix, hicnigen 49720 uffice of the Governor (2) g Koou 1 - Lopitul t,uiluins Lansirig, iiicnigan 4o913 Director, Technical assessi..ent vivision Of fice of Raciation Pru3ral.is un-459; U. b. Envirunuental Protectiun A ency 9
Lrystal hall #2 Arlington, Virginia 20460 1774 052
UNITED STATES 1UCLEAR REGULATORY COMMISSION OFFIwE OF INSPECTION AND ENFORCEMENT WASHINbTON, D.C.
20b55 NOVEMBER
,1979 IE Information Notice No. 79-ANCHORAGE AND SUPPORT OF SAFETY RELATED ELECTRICAL EQUIPMENT Description of Circumstances Recent seismic design evaluations in connection with the NRC Systematic Evaluation Program (SEP) have indicated a potential safety deficiency relative to the anchorage ano support of safety related electrical equip-ment. This subject was highlighted for more in-cepth evaluation af ter site visits to several facilities. These reviews have inoicated that equipment is supported in a non-uniform manner. This may have resulted from the fact that earlier engineering design criteria did not require rigorous analyses.
Further evaluations are continuing for the SEP plant designs.
In some cases, design mooifications may be required to render acceptable seismic design ma rgi ns.
In general, a lack of engineered supports of safety related electrical equip-ment has been observeo at certain SEP plants. Typical components affected incluce:
-AC and DC motor control centers
-transformers
-switch gear
-inverters
-control room panels
-battery racks
-instrument panels
-cable trays Also, a related observ4 tion indicates that non-seismic Category I ancillary items (colleys, gas bottles, block anc tackle gear, ductwork, etc. ) are located such tnat they may dislodge, in' pact ano damage safety relatec equipment during an earthquake.
The types of anchorage systems utilized in these plants and their expected capacities vary widely. For example, high uncertainty exists relative to the capacity of non-engineered tack welds and attachments that rely on frictional clanping forces.
In some cases, equipment has been found free standing with no means of positive lateral support.
(Friction being the only lateral load carryng mechanism). Most of ten, heavier equipment is anchored using 1) tack welds to steel angles embeaded in concrete; 2) clips that rely on frictional resistance; 3) concrete embedded anchor bolts; or
- 4) external braced frames. Lighter equipment housed in cabinets or attached to panels.or racks has been anchored using 1) bolts; 2) sheet metal screws; 3) tack welds; and 4) braced racks.
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-2 The potential concern is that certain pieces of equipment may not have adequate levels of seismic resistance capability due to limited anchorage capacity. The potential problems relate to overturning and/or sliding of large equipment and gross movement or unacceptable forces on smaller attached equipment that may render it inoperable during an earthquake. For certain large battery racks, this judgement is supported by computations that predict unacceptable seismic behavior.
Section 3.10 of the Standard Review Plan provides acceptance criteria for the seismic qualification of Category I electrical equipment. These criteria include IEEE Std. 344, " Guide for Seismic Qualification of Class 1 Electrical Equipment for Nuclear Power Generating Stations", first issued in 1971.
Facili-ties designed before about 1971 without benefit of such design and testing criteria may have some anchorage deficiencies.
The NRC staff is continuing to evaluate this issue on the SEP plants as part of the seismic review in the SEP. Remedial action has been taken on one SEP plant to date.
This Information Notice is provided as an early notification of a possible significant matter.
It is expected that recipients will review the design criteria for anchorage and support of safety related electrical equipment including as-built installation details to assure adequate capability to resist seismic forces. No written response is required.
If you have any questions regarding this matter, please cont.act the Director of the appropriate NRC Regional Office.
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