ML20244D408

Notifies That Applicant Submittal Re Functional Capability of ASME Code Class 1 Auxiliary Piping Sys Technically Acceptable,Contingent Upon Exemption Request Concerning LOCA Dynamic Effects on Branch Lines.Input to Sser Encl

ML20244D408
Person / Time
Site:	Seabrook, 05000000
Issue date:	07/11/1985
From:	Bosnak R Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
Shared Package
ML20235T530	List: ML20235T528 ML20235T579 ML20235T663 ML20235T691 ML20235U003 ML20235U602 ML20235X083 ML20244B841 ML20244B906 ML20244C358 ML20244C416 ML20244D120 ML20244D121 ML20244D168 ML20244D171 ML20244D239 ML20244D261 ML20244D328 ML20244D408 ML20244D460 ML20244D746 ML20244D756 ML20244D811 ML20244D814 ML20244D823 ML20244D839 ML20244D840 ML20244D862 ML20244D876 ML20244D880 ML20244D951 ML20244D982 ML20244D989 ML20244D992 ML20244E001 ML20244E005 ML20244E016 ML20244E024 ML20244E031 ML20244E069 ML20244E099 ML20244E103 ML20244E155 ML20244E178 ML20244E229 ML20244E232 ML20244E238 ML20244E242 ML20244E344 ML20244E356 ... further results
References
FOIA-87-51 NUDOCS 8507190175
Download: ML20244D408 (3)

Text

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- Ono J14.111665 MEMORANDUM FOR: Thomas M. Novak, Assistant Director for Licensing Division Licensing FROM: Robert J. Bosnak, Acting Assistant Director for Ccmponents & Structures Engineering Division Engineering

SUBJECT:

INPUT FOR SER SUPPLEMENT - SEABROOK STATION DOCKET NO.

50 443 In the Seabrook SER, the staff identified an open issue regarding the functional capability of ASME Code Class 1 auxiliary piping systems. The applicant has provided the staff with additional, information to demonstrate the functional capability of piping. I.t should be noted that as part of the applicant's justification, the applicant is relying on the elimination of the LOCA dynamic loadings from the load combinations used for the evaluation of piping as a result of its reques't for partial exemption from GDC-4 which was submitted separately. From a technical standpoint, the staff finds the applicant's submittal addressing the functional capability issue to be acceptable. However, our acceptance is contingent upon the staff approval of the applicant's exemption request relating to the LOCA dynamic effects on branch lines connected to the reactor coolant loop.

l The attached SER input is being transmitted for inclusion in the next SER supplement.

Robert J. Bosnak, Acting Assistant Director for Components & Structures Engineering Division of Engineering l

Attachment:

As stated cc: J. Knight, DE E. Sullivan, DE G. Knighton, DL V. Nerses, DL F. Cherny, DE  ;-- ~

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OFFICIA'L RECORD COPY

f MECHANICAL ENGINEERING BRANCH INPUT TO SSER - SEABROOK STATION, DOCKET #50-443 3.9.3. ASME Code Class L L and 3_ Components, Component Supports, and Core Support structures In Section 3.9.3 of the SER (NUREG-0896 dated March 1983), the staff identified an open item regarding the functional capability of ASME Code Class 1 auxiliary piping systems. In letters from J. DeVincentis to G. Knighton dated August 21, 1984, February 1,1985 and July 1,1985 , the applicant has provided the staff with the basis used to ensure the functional capability of ASME Code Class 1 piping systems.

l Concurrently, in a letter from J. DeVincentis to G. Knighton dated August 9,1984, the applicant, requested a partial exemption from 10CFR50 Appendix A General Design Criterion 4 (GDC-4) requirements for postulating breaks in the reactor coolant loop (RCL) piping. The applicant performed its analysis for the functional capability of ASME Class 1 piping systems contingent upon the staff approval of the specific exemption request for eliminating the effects of dynamic loadings resulting from postulated breaks in the RCL on branch lines connected to the RCL. Thus, the functional capability issue for branch lines connected to the RCL was evaluated for seismic and other dynamic transient loadings excluding the LOCA dynamic loadings.

The applicant perfonned analyses for these essential Class 1 piping systems for which functionality is required for safe shutdown of the plant. The analyses included approximately 4300 locations in the piping systems. Of the 4300 points, only 6 points exceeded the Level C primary stress limit as provided in the ASME Code Section III Subsection NB (1980 Edition up to and including the Winter 1981 Addenda). Because the staff considers the Level C primary stress limit as revised in the Surtner 1981 Code Addenda to be an adequate basis to ensure the functionality of piping systems, the staff a focused primarily on the six points which exceeded the Level C primary stress l limit. However, no points exceeded the ASME Code Level D stress limit which l is required to ensure the piping structural integrity under LOCA conditions. i For the six points which exceeded the Level C stress limit, the appifcant has  !

dennonstrated that no mechanism exists which could result in collapse or )

instability of the piping system. Furthermore, the six points which exceeded i the Level C limit were located in five independent piping subsystems and were 4 either reducers or run pipe. Thus, the degree of ovalization of these piping I components will not cause a significant reduction in flow area even for relatively large piping deflections. Because the six points are distinctly separated and cannot interact, the potential for the fonnation of a plastic hinge or total collapse due to instability which could lead to a condition adversely affecting the functionality of the piping does not exist.

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2 Based on our review of the information provided by the applicant, the staff finds that the applicant has adequately demonstrated that by excluding the LOCA dynamic loads from the load combinations used for the evaluation of piping systems, the stresses remaining in the piping are sufficiently low to f ensure the functionality of the piping system. Thus, contingent upon the i !

acceptability and approval of the GDC-4 exemption request, the staff concludes from a technical standpoint that the open issue identified in the SER l regarding the functional capability of ASME Code Class 1 auxiliary piping systems is closed.

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