ML20040A698
| ML20040A698 | |
| Person / Time | |
|---|---|
| Site: | 05000561 |
| Issue date: | 09/06/1977 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 770926, NUDOCS 8201210431 | |
| Download: ML20040A698 (3) | |
Text
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4 UNITED STATES h
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NUCLEAR REGULATORY COMMISSION y
W ASHINGTON, D. C. 20$56
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ggp 6 577-Docket No. 50-561 MEMORANDUM FOR:
D. B. Vassallo, Assistant Director for LWRs, DPM FROM:
T. M. Novak, Chief, Reactor Systems Branch, DSS
SUBJECT:
B-SAR-205 OPEN ITEMS Plant Name: B-SAR-205 Docket No.: 50-561 Licensing Stage: PDA LWR-3; T. Cox Responsible Branch & Project Manager:
Systems Safety Branch Involved: Reactor Systems Branch Description of Review: Post-ACRS Review Status: Incomplete The enclosed questions are necessary to complete the review of four open items as described in the July 1977 report to the Advisory Committee on Reactor Safeguards for the Babcock & Wilcox Standardized Plant, B-SAR-205. All items have been discussed with Babcock & Wilcox
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in previous phone conversations.
mas M. Novak, Chief Reactor Systems Branch Division of Systems Safety r
Enclosure:
Questions cc:
S. Hanauer R. Mattson D. Ross O. Parr T. Cox l
T. Novak I
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. Newbe Contact NRR:S. Newberry 1
Ext. 27911 i
I 8201210431 810403 PDR FOIA MADDEN 80-515 PDR
'I 211 -1
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m 211.0 REACTOR SYSTEMS BRANCH, SECTION A 211.1 Your analysis for_a high pressure injection line break (6.3) assumes no operator action until 20 minutes after the first indication of the break. Provide assurance that the HPI pump (s) would be available after this time considering the potential. for runout flows.
211.2 Sufficient assurance does not exist that the submitted (15.1.4) analyses properly bound the potential boron dilution events.
Evaluate the consequences of such an event occurring during conditions other than power operation or a refueling outage.
Discuss any other potential sources of dilution and address the design aspects which preclude or minimize.the potential for a dilution event.
211.3 The July 21, 1977 letter from J. Taylor to R. S. Boyd (5.2.2)
"B-SAR-205 - Outstanding Issues" states:
"During shutdown plant operations with one decay heat removal. train in operation, all four decay heat removal suction valves (two on each train)
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will remain open. This requirement will be included as an interface requirement in B-SAR-205 and in the final technical specifications. This V
resolves the staff concern that a single failure (spurious closure) of one of the valves during an overpressure transient could defeat the over-pressure protection provided b'y the decay heat removal system relief valves.
The staff does not believe that this requirement will completely eliminate all potential events and single failures. A postulated event could be the following:
The plant is operating in the shutdown cooling mode with one decay heat removal train operating and all four suction valves open as required by technical specifications. A loss of decay heat removal cooling would be initiated upon inadvertent closure of the suction valve in the operating train.
Assuming an additional single active component failure in the second train; i.e., inadvertent closure of one suction valve, no automatic protection. is available to prevent primary system pressure from exceeding the Appendix G limit due to the loss of decay heat removal.
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211-2 S.
211.3 Provide a discussion of the probability of the above (cont'd) scenario.
Discuss how the operator might prevent reactor coolant system pressure from exceeding the Appendix G limit for this loss of decay heat system cooling event.
211.4 Provide additional analyses to show that for moderate (15.0) frequency events, non-safety grade equipment action is not necessary to meet the applicable limits for primary and secondary system pressure and fuel damage. The analyses must include as a minimum those transients in Table 15.1-4 in B-SAR-205 which take credit for non-safety grade systems. A complete justification of assumptions and inputs must be included.
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