ML19291C050
| ML19291C050 | |
| Person / Time | |
|---|---|
| Issue date: | 09/11/1979 |
| From: | Igne E Advisory Committee on Reactor Safeguards |
| To: | Sicss C Advisory Committee on Reactor Safeguards |
| References | |
| REF-GTECI-B-06, REF-GTECI-PI, REF-GTECI-RV, TASK-B-06, TASK-B-6, TASK-OR NUDOCS 8001110181 | |
| Download: ML19291C050 (3) | |
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UNITED STATES
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NUCLE AR REGUL ATOR.' COMMISSION
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ADVISORY COMMITTEE ON REACTOR SAFEGUARDS W ASHINGTON, D. C. 20555 o,
- j j September 11, 1979 T0:
C. Siess, Chairman of the Subcommittee on the Combination of Dynamic Loads FROM:
E. Igne, Staff Engineer hecu k
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SUBJECT:
SUBCOMMITTEE ON THE COMBINATION OF DYNAMIC LOADS I have prepared the attached proposed meeting summary for your review.
Copies are being distributed to the other ACRS members for their information and comment. Corrections and additions will be included in the minutes of the meeting.
Attachment:
As stated cc: ACRS Members ACRS Technical Staff k
}94 E. Case, NRR R. Baer, NRR J. Knight, DSS R. Mattu, DSS S. Hanauer, DSS V R. Bosnak, DSS R. Gamble, DSS 8001110 /8[
i PROPOSED
SUMMARY
OF THE AUGUST 22, 1979 MEETING 0F THE SUBCOMMITTEE ON COMBINATION OF DYNAMIC LOADS The purpose of the meeting was to review the topic of combination PURPOSE:
of dynamic loads on structures, components, and systems.
ATTENDEES:
Participants:
ACRS NRC STAFF M. Bender, Chairman P. Shewmon J. Knight H. Etherington R. Mattu M. Plesset S. Hanauer W. Gall, ACRS Consultant R. Bosnak T. Pickel, ACRS Consultant R. Gamble I. Catton, ACRS Consultant E. Igne, ACRS Staff INDUSTRY S. Bernsen, AIF R. Brandon, Westinghouse Natan, Combustion Engineering Kiss, General Electric MEETING HIGHLIGHTS, AGREEMENTS, AND REQUESTS:
The thurst of the meeting was the discussion of methods for the combination 1.
of dynamic responses as applied to structures, components, and systems.
A correct way of combining dyanmic responses due to dynamic loads input 2.
requires a time history analysis of the response of the structure and its response magnitudes added algebraically at each time increment for Since this method is time consuming and expensive, all dyanmic load input.
another acceptable method must be found.
It was a common practice in the nuclear industry to combine combination of dynamic responses using the algebraic summation method, although the absolute summation methods were also employed during this period.
In an effort to resolve the issue of combination of dynamic responses, 4.
the NRC Staff described its program TAP B-6 on Load, Load Combination and Stress Limits.
Currently, the Staff accepts only the absolute summation method for the 5.
Mark II and III containments but will soon accept the square root of the sum of the squares (SRSS) methods (Kennedy-Newmark criteria).
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Several bases have been given by the industry to justify the use of the 6.
SRSS method.
The Staff stated that if the dynamic responte functions have the following 7.
characteristics, zero mean, stationary, and non-correlated, then the SRSS technique is an exact method. The safety margin of this method depends on the deviation of the response function from the above characteristics.
The Staff reported that analysis based on fracture mechanics approach of 8.
the Duane Arnold type flaws and piping configuration indicate that the crack will be stable even if the internal pressure transient increases from a normal, operating pressure of 1000 to 3000 psi.
9.
A model demonstration of pipe crack stability was shown by Dr. Paris of the University of Washington during the meeting.
Westinghouse (W) position on the combination of seismic and LOCA loads 10.
They stated that if a combination of LOCA and SSE loads was discussed.
are deemed necessary, SRSS is an appropriate method of combination for application to the primary system and supports.
A ctudy by h[ concluded that the simultaneous occurrence of an earthquake 11.
and LOCA can be deleted from the set of events and event combination evaluated for h[ PWRs without undue risk to the health and safety of the public.
The Subcommittee heard a prepared statement by the AIF on issues concerning 12.
load combinations.
Cox.bination of dynamic loads have been discussed only for primary systcms.
13.
Secondary systems need to be addressed.
FUTURE MEETINGS:
The Subcommittee stated that it wishes to be kept informed on the status of TAP B-6 on a yearly basis.
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