ML20213C990
| ML20213C990 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 05/24/1979 |
| From: | Bosnak R Office of Nuclear Reactor Regulation |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-0277, CON-WNP-277 NUDOCS 7907110055 | |
| Download: ML20213C990 (1) | |
Text
DISTRIBUTION:
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ltEMORAMOUM FOR:
S. A. Varga, Chief, Light Water Reactors Branch #4, DPM FROH:
R. J. Bosnak. Chief, Mechanical Engineering Cranch, DSS
SUBJECT:
WPPSS NUCt. EAR PROJECT NO. 2 DELAY IN SECOND ROUND QUESTIONS OF FSAR SUPFLEMENTAL FIRST riOUND QUESTION OF FSAR i
In preparation for the May 18, 1979, scheduled du! date for second round questions, tha !!echanical Engineering Branch perfomed a curaary review of Sections 3.5, 3.9, and 3.10 of the FSAR as amended through Amendnent 3 of March 23, 1979.
This review indicated that none of the MEB's first round questions had been addressed in the FSAR. The eesponses to these. questions fom :n integral, and essential, element of our next stage af review. Ccnsecuently, it is folt that a more detailed review, loading to second round questions, is not.justi-fled at this time.
To permit sufficient time for scheduling of the review and the revicw, itself, it is suggested that second round questions not be scheduled for at loest eight to twelve weeks after receipt'of an appreciable porcentaco
(>90%) of the responses to the first round questions.
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However..this review has indicated an additional area of concern which must be resolved before we can cogletokour review.
It is requested that the attached request for additional infomation be transmitted to the applicant as a supplemental first round qwistion rather than delaying to the second round which will be quite sor.e tino in the future.
Forwarding it at this time will maximize the applicant's tire for tesponse thereby decreasing the chance of it becoming an outstanding issue in the SEC.
j R. 1. Gosnak, Chief Pechanical Engincaring Cranch Division of Systees Safety
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l 110 MECHANICAL ENGINEERING 110.38 Section 3.7.3.6 (page 3.7-37)-refers to Section 3.7.2.6 (page 3.7-27)
(3.7.3.6) for a discussion of the method of c'ombining the three components of (RSP) earthquake motion. The second and third paragraphs of this section indicate that the loads are computed assuming simultaneous seismic input in one horizontal and the vertical directions. However, the method of combining these responses is not indicated.
It is the Staff's position that algebraic summation may lead to non-conservative results because of opposite signs tending to cancel each other when not justified on a time history basis. Therefore, the appropriate method should be to sum the absolute values of the responses when this method is used. Provide a commitment to meet this position or alternatively use the SRSS method for summing all three seismic spe.tial components as now provided for in Regulatory Guide 1.92.
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