ML19249B657
| ML19249B657 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 08/20/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7909040643 | |
| Download: ML19249B657 (1) | |
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NUCLEAR REGULATORY COMMISSION
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WA1.NU T CH E E K. CA LIF ORNI A 9459G August 20, 1979 Docket ilo. 50-133 Pacific Gas and Electric Ccmpany 77 Beale Street San Francisco, California 94106 Attention: Mr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
Enclosed is IE Bulletin ilo. 79-02, Revision 1, Supplement flo.1, which clarifies ilRC positions on actions requested with regard to your power reactor facility (ies) with an operating license.
Should you have any questions regarding this Bulletin or the actions required by you, please contact this office.
Sincerely, d
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Enclosure:
IE Bulletin ilo. 79-02 Revision fio. 1 (Supplementilo,i) cc w/enclosurn:
W. Barr, PG&E W. Raymond, PG&E E. Weeks, PG&E, Humboldt Bay
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7908150164 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF If4SPECTION AND ENFORCEMEilT WASHINGTON, D.C.
20555 August 20, 1979 IE Bulletin No. 79-02 Revision fio. 1 (Supplement flo.1)
PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSI0ft ANCHOR BOLTS Description of Circumstances:
The supplement to IE Bulletin No. 79-02 is intended to establish criteria for the evaluation of interim acceptability of plant operation with less than the design factors of safety for piping supports due to as-built problems, under design, base plate flexibility, or anchor bolt deficiencies.
In the reviews for system operability of the Duane Arnold and Crystal River fdcilities, criteria have been developed by the NRC staff that defines pipe support operability.
The criteria have been applied in lieu of other analysis or evalua-tion.
Specifically, the licensees identified problems with pipe supports in which the original design factors of safety were not met but some lesser margin was available.
The design margins of four or five are intended to be final design and installation objectives but systems may be classed as operable on an interim basis with some lesser margin providing a progran of restoration to at least the Bulletin factors of safety has been developed.
Facilities which fall outside the operability criteria are considered to probably require a Technical Specifica-tion exception and will require review on a case by case basis.
Action to be Taken by Licensees:
For the following two cases, plant operation may continue or may begin:
a.
For the support as a unit, the factor of safety compared to ulti-mate strengths is less than the original design but equal to or greater than two.
b.
For the anchor bolts the factor of safety is equal to cr greater than two and for the support steel the original design factor of safety com-pared to ulitmate strengths is met.
The above criteria may be applied provided that the affected systems are up-graded to design margins of safety expeditiously for normally accessibile supports and by the next refueling for nonaccessible supports.
Accessibility is as de-fined in Bulletin No. 79-14 where "nornally accessible" refers to those areas of the plant which can be entered during reactor operation.
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IE Bulletin l'o. 79-02, Revision No.1 Page 2 of 2 Supplenent l'o.1 August 20, 1979 1.
Any support not satistying the criteria should be classed as inoperable and the Technical Specification action statement net unless ii. can be shown that the systen can function in a design basis seismic event without the support.
2.
Repairs to supports should result in return to the design factor of safety.
3.
Operations nay be continued while repairs to upgrade the system from a factor of safety equal to or greater than two with respect to design loads are perforred.
Consideration nust be given to the effect of the repair process on support function and system operability.
In other words the time the support is not functional should be limited to T.S. action statement times or the support must be determined not to cause the systen to be unable to perforn its function in a seismic event. The licensee should also exercise care not to take several supports on a given system out of service at the sare time or cause both trains of one safeguards systen to be made inoper-able at the sana time. Control over worknen on safety related systens during plant operation requires a hich degree of control by the licensee.
4 There are no special reporting requirements for this supplement to the Bulletin; however, the reporting requirenents as set forth in the regula-tions and licenses nust be net.
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