ML19257B048
| ML19257B048 | |
| Person / Time | |
|---|---|
| Issue date: | 02/21/1979 |
| From: | Edison G NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Rosa F Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-30, REF-GTECI-EL, TASK-A-30, TASK-OR NUDOCS 8001150156 | |
| Download: ML19257B048 (2) | |
Text
.'
.e UNITED STA TES y'
NUCLEAR REGULATOHY COMMISslON n
WASHINGTON. O C. 20555
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February 21, 1979 MEMORANDUM FOR:
Faust Rosa, Chief, Power Systems Branch, Division of Systems Safety, NRR FROM:
Gordon E. Edison, Head, Systems Engineering Section, Probabilistic Analysis' Staff, RES
SUBJECT:
COMPLETED TASKS IN TAP A-30 The purpose of this memorandum is:
(1) to confirm our earlier agreement on a minimum acceptable D. C. power system for analysis in TAP A-30 (D.C. Power),
and (2) to document the basis for certain tasks in TAP A-30 being com-plete (these tasks were performed or managed by Power Systems Branch).
Your response indicating agreement on these items is requested.
If you know of additional bases in items (1) and (2), I would appreciate know-ing them.
Discussion follows.
1.
Minimum Acceptable D.C. Power Systems As indicated by PSB in late 1978, the D. C. power system in the Connecticut Yankee plant at Haddam Neck, Conn., is a minimum acceptable system which just meets present regulatory criteria; i.e. no commercial LWR's exist in the U.S. with a less accept-able D.C. system for licensing purposes.
The PAS analyses have been proceeding on this basis.
A " typical" minimum system (2-battery) was documented in a PSB memo from C. Liss to R. Fitzpatrick dated August 25, 1978
(" Proposed DC Basis and Augmented System Configuration"). The PAS need for additional detail prompted an analysis of the D.C.
Power Survey of 61 plants reported by D0R on August 18, 1977 (W. R. Butler to R. L. Tedesco, " Survey of D.C. Power Supplies at Operating Plants"). This analysis (not documented) was done by PSB and concluded that the Haddam Neck plant was the minimum system.
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. 2.
Basis for Completion of Tasks in TAP A-30, Rev. #1, dated May,1978.
Task 1 - Detailed Scoping of the Issue. This task is complete based on the discussion in NUREG-0305 and the scoping of the TAP itself.
Task 2 - Establish Data Base. This task is complete based on all existing D.C. Power and loss of offsite power LER's, NPRDS, IEEE data, EPRI data and the D.C. Power Survey currently being used. The D.C. Power Survey and some of the LER's were documented in the memorandum from W. R. Butler to R. L. Tedesco (referred above).
IEEE data from the Std. 500-1977 are given in a memorandum from C. Liss to R. Fitzpatrick dated August 25, 1978.
(Reliability Assessment of the D.C. Power System in a Typical Nuclear Power Plant). The EP7I data on trip frequency are given in EPRI NP-801 (ATWS: A Reappraisal).
Additional LER data and analyses have been compiled in our current effort and will be documented in the final report.
Task 3 - Establish Time Available for Manual Actions. This task is complete based on NUREG-0305 Appendix A supplemented by a memorandum from B. W. Sheron to R. Fitzpatrick dated January 25, 1978 (" Core Uncovery Times for Loss of AC/DC Power Accident").
Task 6 - Quantify Reliability of Present Minimum System. A portion of this task is complete. The minimum acceptable D.C.
system has been identified as noted earlier in this memorandum.
Remaining Tasks - The remaining tasks are being revised to form a new Task Action Plan, and are in various stages of completion.
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Gordon E. Edison, Head Systems Engineering Section Probabilistic Analysis Staff Office of Nuclear Regulatory Research cc: J.W. Pittman S.H. Hanaue R. G. Fitzpatrick G. C. Lainas P. W. Baranowsky 1750 079
.