ML20082E703
| ML20082E703 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 11/11/1983 |
| From: | Sherwood G GENERAL ELECTRIC CO. |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-83-047-000 MFN-207-83, PT21-83-047-000, PT21-83-47, NUDOCS 8311280285 | |
| Download: ML20082E703 (3) | |
Text
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GENERAL $ ELECTRIC NUCLEAR POWER SYSTEMS DMSION GENERAL ELECTRIC COMPANY e 175 CURTNER AVENUE e SAN JOSE, CAuf ORNIA 9 MC 682, (408) 925-5040
- /8 November 11, 1983 MFN # 207-83 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Washington, DC 20555 Attention:
Richard C. DeYoung
SUBJECT:
10CFR Part 21, P,EPORTABLE CONDITION HANFORD 2 ELECTRICAL SEPARATION This letter is to inform the NRC of a reportable defect per 10CFR Part 21, as reported to R. L. Baer of your office by G. B. Stramback, Manager of Safety Evaluation Programs on 11/11/83.
Inadequate electrical separation, use of aluminum switch enclosures, was identified in a few control panels at Hanford 2 site.
The utility was notified and corrective action has been completed.
The attached evaluation identifies all pertinent information required by 10CFR Part 21.
Very truly yours,
_^ T&
G enn G. Sherwood, Manager Nuclear Safety & Licensing Operation GGS:pc/L10035*
Attachment cc:
L. S. Gifford, GE Bethesda T. E. Murley, NRC Region I J. P. O'Reilly, NRC Region II J. G. Keppler, NRC Region III U. Potapovs, NRC Region IV J. B. Martin, NRC Region V
@ <qc1 AL CM 8311280285 831111 PDR ADOCK 05000397 PDR S
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1.
Name and address of the individual or individuals informing the commission.
Dr. G. G. Sherwood, Manager of Safety and Licensing Operations, General Electric Company, 75 Curtner Avenue, San Jose, CA 95125.
2.
Identificatien of the facility, the activity, or the basic components supplied for such facility or such activity within the United States which fails to comply or contains a defect.
Aluminum switch enclosures designed at the Hanford 2 Nuclear Power plant site.
3.
Identification of the firm constructing the facility or supplying the basic component which fails to comply or contains a defect.
N/A:
Covers were built and installed by site personnel.
4.
Nature of the defect or failure to comply and the safety hazard which is created or could be created by such defect or failure to comply.
The condition involves the use of thin (0.03" - 0.06") aluminum control switch enclosures intended to provide electrical separation between redundant divisions of Class 1E wiring.
The Hanford site personnel designed and installed two enclosures for NSSS panels (1 each in panels P642 and P601), and six for BOP panels.
The use of aluminum is questionable for this application because of its low melting point.
Under certain postulated conditions, an electrical arc might perforate such enclosures and thus penetrate the protective barrier between redundant divisions' circuits.
The probability of actually incurring damage sufficient to disable redundant circuits and cause a substantial safety hazard is considered low though not incredible.
It is this probability of a remote occurence that prompts the reporting of this condition, although the conclusion is that no pressing safety issue exists.
Wiring within the enclosures is limited to 14 AWG having fuse protection at 15 amp maximum.
A short-circuit arc would likely be of very short duration; just long enough to blow the fuse.
However, a wire might conceivably arc against the enclosure itself and cause a small perforation with sufficient heat to damage redundant divisional wires if they are in contact with the other side of the enclosure.
5.
The date of which the information of such defect or failure to comply was obtained.
November 11, 1983.
6.
In the case of a basic component which contains a defect or fails to comply, the number and location of all such components in use at, supplied for, or being supplied for one or more facilities or I
activities subject to the regulations in this part.
l RW5: pc/L10032*-1 11/10/83
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Since the eight enclosures at Hanford 2 were designed, built and installed locally at the site, the condition appears to be limited to Hanford 2.
However, to assure aluminum enclosures are not used as Class IE separation barriers in other GE BWRs, GE has taken corrective action as indicated below.
7.
The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complete the action.
Corrective action has been effectively taken at Hanford to replace all aluminum enclosures in Class IE panels ith steel ones.
The following Field Deviation Disposition Requests (FDDRs), and AE equivalent for B0P. effected the replacements:
FDDR (or AE)
Panel Equivalent No.
P601 KK1-795 Rev. 5 P642 KK1-785 Rev. 2 All B0P PED 218-CS-8409 8.
Any advice related to the defect or failure to comply about the facility, activity, or basic components that has been, is being, or will be given to purchasers or licensees.
In order to assure aluminum enclosures are not used as Class IE separation barriers in other GE BWRs, GE has issued Field Disposi-tion Instructions (FDIs) to all requisition plants.
If any more aluminum enclosures are discovered, they will be replaced with steel in accordance with GE manufacturing standards and the occurrence (s) will be reported to the NRC.
RWS:pc/L10032*-2 11/10/83
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