ML20005C118
| ML20005C118 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/12/1981 |
| From: | Carroll J JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-05.A, TASK-3-5.A, TASK-RR NUDOCS 8111180417 | |
| Download: ML20005C118 (3) | |
Text
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50- 919 q
OYSTER CREEK NUCLEAR GENERATING STATION d
g (609)693-6000 P O BOX 388
- FORKED RIVER
- 08731 Novemberl2, 1981
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Mr. Dennis M. Crutchfield, Chief e-
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Operating Reactors Branch No. 5 i
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Division of Licensing E$*' er 8 U.S. Nuclear Regulatory Commission Washington, D. C.
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Subject:
Oyster Creek - SEP Topic III-5. A, " Effects of g li>
Pipe Break on Structures, Systems and Compo-nents Inside Containment" References :
(a)
Letter from the Nuclear Regulatory Commission (D. Crutchficid) to Jersey Central Power and Light Company (I. Finfrock), dated June 10, 1981, "0yster Creek - SEP Topic III-5.A, Effects of Pipe Break on Structures, Systems, and Components Inside Containment" (b)
Report dated July 30, 1979, "SEP Topic III-5.A, liigh Energy Piping Systems Inside Containment, Effects of Postulated Breaks"
Dear Mr. Crutchficid:
This letter is in response to Reference (a), which identified certain areas of SEP Topic III-5. A where additional evaluations are considered required, and requested a schedule for completing the evaluations.
It is planned to complete the additional evaluations by December 30, 1981. These evaluations will, in summary, cover tne following information:
1.
Dynamic Effects of' Pipe Whip Interaction evaluations were originally performed for 141 postulated break locations to identify components and structures which could be contacted by either a whipping pipe or a jet. These evaluations will be reviewed to cnsure that they are conservative. This could include, for exampic I
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- showing as suggested in Reference (a) that (1) the pipe geometry is simple so that the direction of pipe motion and jets originally assumed is clearly reasonable, or (2) vulnerable targets are not contacted regardless of the direction of pipe whip or jets.
It is noted that Reference (a) also requested further information _with regard to the cascading effects of pipe
- whip, i.e., instances where a whipping pipe could contact another secondary pipe, which in turn might cause subsequent unacceptable contacts.
In Reference (b), it was shown that pipe breaks in any of the secondary. pipes which could be ~ contacted as a result of the postulated primary pipe breaks would not result in contact with a j
i vulnerable target needed to-achieve safe shutdown.
In particular, all interactions due to one pipe whipping into a second nearby system involved pipe lines which individually had been evaluated as part of the primary pipe l
i whip study and were found not to contact any vulnerable-targets. Accordingly, concurrent breaks in two or more lines have the same effect, i.e., there is no contact with targets needed for safe shutdown. As a result, we consider that we have addressed your concern in Reference (b), and we do not plan additional review of this area. Clearly, if our review of the original interaction evaluations
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described above shows a line or lines which can contact components or systems required for safe shutdown, the effects on the original cascading piping evaluations will also be assessed.
2.
Containment Wall Penetration The original evaluation of the effects of pipe whip on the containment wall was based on the test results contained in Reference (b).
In particular,_these results show that there will be no damage to the containment wall if wall deflection is limited to less than about 3.25 inches by 3
contact with the outer concrete shield wall, and the load contact area is greater than the area equivalent to a 14-inch diameter circle. Additional-justification will be provided that (1) impact of the wall by pipes of 14-inch diameter or greater would result in sufficient contact area and (2) the gap between the containment wall and concrete j
shield wall does not exceed about 3.25 inches.
In this regard, the nominal gap size is 2.75 inches in the cold condition.
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\\< Reference (a) also requested justification that the test, which was performed under essentially static conditions, is applicabic to dynamic loading conditions.
This question was addressed specifically on Page IV-6 of Reference (b). Accordingly, further clarification of the NRC question is requested. We do not currently plan additional work in this area.
Sincerely, J. T. Carroll, J.
Acting Director Oyster Creek 1r i
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