ML19261E272
| ML19261E272 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/27/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7907050492 | |
| Download: ML19261E272 (1) | |
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NUCLEAR REGULATORY COMMISSION
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SUITE 202, WALNUT CREEK PLAZA o
WALNUT CREEK, CALIFORNIA 94596 June 27,1979 Docket tios. 50-275 50-323 oacific Gas and Electric Company 77 Beale Street
%n Francisco, California 94106 Attention: Mr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
The enclosed IE Circular fio. 79-il, is forwarded to you for information.
No written response to this Circular is required.
If you require additional information regarding this subject, please contact this office.
Sincerely,
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R. H. Engelken Director
Enclosures:
1.
IE Circular fio. 79-11 2.
List of IE Circulars Issued in the Last 12 Months cc w/encls:
W. A. Raymond, PG&E R. Ramsey, PG&E J. D. Worthington, PG&E 79 123 790705cygg
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 June 27, 1979 IE Circular No. 79-11 D: SIGN /CJNSTRUCTION INTERFACE PROBLEM Description of Circumstances:
Apparent inadequate comrunication between nuclear steam supply system (NSSS),
architect / engineer (A/E) W constructors have resulted in several cases where reactor vessels or the supports have been misoriented. lhe misoriemu tion problems appear to occur at sites wnere dual reactor units are being m^-"m cad cnd r2 ;..i...:ry :q str in nt M = m4re-imga of ihe other.
In 1975 TVA reported a aisorientation problem with the Sequoyah Unit 2 reactor vessel. Westinghouse was the flSSS supplier end TVA provided their own A/E service.
In 1977 the Southern California Edison Company reported a reactor vessel misorientation at San Onofre Unit 2.
Combustion Engineering was the NSSS supplier and Bechtel provided the A/E service.
In 1979 the Texas Utilities Generating Company reported a -eactor vessel support systen misorientation at Comanche Peak Unit 2.
Westinghouse supplied the USSS, Gibbs and Hill was the plant engineer and Brown and Root was the constructor.
Even though there appears to be minimal safety implications associated with the particular misorientation problens mentioned, repetition of the same type of errors suggests breakdowns in the design / construction interface relation-ships that could in turn lead to more significant safety problems.
Corrective preventive action is recomended for the following reasons:
If the interface control system between the USSS/AE/ Construction is narginal or ineffective as evidenced by the nisorientation of reactor vessels and their supports, it is possible that other safety related equipment may also be misoriented and/or mislocated.
In sone cases the errors may not be as obvious as a misoriented reactor vessel.
This type of error can and has resulted in hardware modifications and could cause functional and/or structural changes that affect design and operating parameters.
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