ML20137Y058

Requests facility-specific Info Re Requests for Exemption from GDC 4,concerning Protection Against Dynamic Loads Resulting from Postulated Breaks of Primary Main Loop Piping.Info Re Leakage Detection Sys Should Be Included

ML20137Y058
Person / Time
Site:	Davis Besse, Oconee, Arkansas Nuclear, Crystal River, Rancho Seco, Midland, Bellefonte, 05000000
Issue date:	02/18/1986
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Reinaldo Rodriguez SACRAMENTO MUNICIPAL UTILITY DISTRICT
Shared Package
ML20137Y062	List: ML20137Y058
References
NUDOCS 8603120110
Download: ML20137Y058 (3)

Text

_- ___ __ _ _ _ - _ - - _ _ _ _ _ ._ - - _ _ _ - _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ - _

F;bruary 18, 1986 '

Docket No. 50-312 Mr. Ronald J. Rodriguez Assistant General Manager, Nuclear Sacramento Municipal Utility District 6201 S Street P. O. Box 15830 Sacramento, California -9E813

SUBJECT:

SAFETY EVALUATION OF B&W OWNERS GROUP REPORTS DEALING WITH ELIMINATION OF POSTULATED PIPE BREAKS IN PWR PRIMARY MAIN LOOPS Re: Rancho Seco Nuclear Generating Station The NRC staff has reviewed the B&W Owners Group reports BAW-1847, Rev. 1, and BAW-1889P which apply " leak-before-break" technology as an alternative to

. designing against dynamic loads associated with postulated ruptures of primary coolant loop piping. As discussed in the enclosed letter to the B&W Ow.1ers Group, we have concluded that an acceptable technical basis has been prc/ided to eliminate, as a design basis, the dynamic effects of large ruptures in the main loop piping of those R&W Owners Group facilities listed in the enclosure.- Authorization by the NRC to not provide protection against the dynamic loads resulting from postulated breaks of primary main loop piping will require an exemption from General Design Criterion 4 (GDC4).

Such exemptions must be justified on a facility specific basis. Each. request for an exc:nption should include a safety balance in accordance with the guidance provided in NRC. Generic letter 84-04, " Safety Evaluation of Westinghouse Topical Reports Dealing With Elimination of Postulated Pipe Breaks in PWR Primary Main Loops," February 1,1984. In addition, information for each facility should be submitted to denonstrate that leakage detection systems installed at the facility comply with Regulatory Guide 1.45.

Generic Letter 84-04 informed all operating PWR licensees, construction permit holders and applicants for construction permits of the staff's intent to proceed with rulemaking changes to GDC-4 to permit the use of analyses that demonstrate the probability of rupturing piping is extremely low under design basis conditions. On July 1,1985, the Comission published a proposed modification to GDC-4 which would permit the use of such analyses for PWR primary coolant loop piping. The NRC staff is currently in the 2

i Mr. Rodriguez process of final rulemaking. Promulgation of the final' rule will eliminat'e the need for exemption requests and perfomance of safety balances; however,

.the requested information on leakage detection systems should be submitted.

Sincerely, 7.ElG E SIGMi:D3r REE1. Rusge >

John F. Stolz, Director PWR Project Directorate #6 Division of PWR Licensing-B

Enclosure:

As Stated cc w/ enclosure:

See next page C.ISTRIB' JTION Ringram Qagket File) ACRS-10 NRC run Gray File L PDR- EBrach PBD-6 Rdg H0rnstein FMiraglia OELD EJordan BGrimes JPartlow SMiner GKalman WPaulson RWeller PBD-6p P p(\ PRD-6 k P D-6 daev PRD-6 6 Ringram WPhulson;cr SMine RWeller JS (

GKaJman BP W\\/86 7/l4/86 $/10/86 4/6 /86 4//3/86 .1

. _ _ _ _ _ _ _ _ _ _ - _ _ - _ _ _ _ - - _ _ _ _ _ _ _ - _ _ _ _ - - _ _ _ _ _ _ _ _ _ - - _ _ __s

e Mr. R. J. Rodriguez Rancho Seco Nuclear Generating Sacramento Municipal Utility District Station CC*

Mr. David S. Kaplan, Secretary Sacramento County and General Counsel Board of Supervisors Sacramento Municipal Utility 827 7th Street, Room 424 District Sacramento, California 95814 6201 S Street P. O. Box 15830 Ms. Helen Hubbard Sacramento, California 95813 P. O. Box 63 Sunol, California 94526 Thomas Baxter, Esq.

Shaw, Pittman, Potts & Trowbridge 1800 M Street, N.W.

Washington, D.C. 20036

, Mr. Robert B. Borsum *

! Babcock & Wilcox Nuclear Power Generation Division Suite 220, 7910 Woodmont Avenue Bethesda, Maryland 20814 Resident Inspector / Rancho Seco c/o U. S. N. R. C.

14410 Twin Cities Road Herald, California 95638

. Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Director Energy Facilities Siting Division Energy Resources Conservation &

Development Commiss!on 1516 - 9th Streat Sacramento, California 95814 Mr. Joseph 0. Ward, Chief Radiological Health Branch State Department of Health Services 714 P Street, Office Building #8 Sacramento, California 95814

.