ML19329D687
| ML19329D687 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 12/03/1975 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19329D686 | List: |
| References | |
| NUDOCS 8003160306 | |
| Download: ML19329D687 (2) | |
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-SUPPLEMEtiT TO THE DRAFT SAFETY EVALUATI0il (C0flTAIfWEiiT SYSTEMS)
CRYSTAL RIVER Uf1IT 3
- DOCKET f40.
50-302 ECCS Containment Pressure Evaluation _.
Appendix K to 10 CFR 50 of the Commission's regulations requires that the effect' of operation of all the installed pressure reducing systems and For the evaluation it is processes be included in the ECCS evaluation.
conservative to minimize the containment pressure since this will increase the resistance to steam flow in the reactor coolant loops and reduce the Following a loss-of-coolant accident, the reflood rate in the core.
pressure in the containment building will be increased by the addition of steam and water from the primary reactor system irto the containment atmosphere. After initial blowdown, heat flow from the core, primary metal structures, and steam generators to the ECCS water, will produce addi tional=- steam. This steam together with any ECCS water spilled froa the primary system will flow through the postulated break into the This energy will be released to the containment during totn containment.
the blowdown and later ECCS operation phases; i.e., reflood and post-reflood' phases.
Steam Ei.crg -removal occurs within the containment by several means.
condensation on the. containment walls and internal structures serves as
- a. passive energy _ heat sink that beccmes effective early in the blowdown Subsequently, the operation of the. centainment heat removal transient.
-systems such as containment sprays and fan coolers will remove energy froin the containment atmosphere. When the energy removal rate exceeds the rate of energy addition from the primary system, the containment j
pressure will decrease trem its maximum value.
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2 The ECCS containment pressure calculations for-Crystal River Unit 3 were done generically by B&W for reactors of this type as described in BAW-10103 "ECCS Evaluation of B&W's 177-FA Lowered Loop NSS." The NRC staff reviewed-B&W's ECCS evaluation model and published a Status Report on 4
October 15, 1974, which was amended November 13, 1974. He concluded that B&W's containment pressure model was acceptable for ECCS evaluation.
We required, however~, that justification of the plant-dependent input parameters used in the analysis be submitted for our review of each-i plant.
Justification for' the containment input data were submitted for Crystal River Unit 3 dated October 15, 1975.
This justification includes a cccpsrison
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of the actual containment parameters for Crystal River with those assumed by.B&W in BAW-10103.
Florida Power Corpcration has reevaluated tL contain-ment net-free volume, the passive heat sinks, and operation of the containment heat-removal systems with regard to the conservatism for the ECCS analysis.
This evaluation was based on as-built drawings.
The containment heat removal systens were 5ssumed to operate 'at their maximum capacities, and minimum
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operational values for the spray water and service water temperatures were assumed. The containment pressure analysis by B&W in BAW-10103 was demonstrated to be -conservative for Cry 3tal River Unit 3.
We have concluded that the plant-dependent information used for the ECCS containment pressure analysis for Crystal. River Unit 3 is reasonably conserva-tive, and therefore, the calculated containment pressures are in accordance with Appendix K to -10 CFR Part 50 of the-Commission's. regulations.
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