ML20127P225

Safety Evaluation Accepting Response to SBO Rule

ML20127P225
Person / Time
Site:	Oyster Creek
Issue date:	11/23/1992
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20127P222	List: ML20127P218 ML20127P225
References
NUDOCS 9212020141
Download: ML20127P225 (2)

Text

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M21[ MENTAL SAFETY EYALVATION BY THE OFFICE OF NQCLEAILREACTOR REGULATION

}TATION BLACK 0VT RULE (19 CFR 50.63)

GPU NVCLEAR CORPORATION OYSTER CREEK NUCLEAR GENERATING STATIM DEELHO,_M_R12

1.0 INTRODUCTION

in the Supplemental Safety Evaluation (SSE) (dated February 12, 1992) regarding the licensee's compliance with the Station Blackout Rule, 10 CFR 50.63, the staff stated its positions that the licensee should establish an administrative procedure to ensure that during normal operation, the control room temperature does not exceed the initial control room temperature used in the heat-up cs1culation and should include a provision in their station blackout procedures, in accordance with NUMARC 87-00, to open the control room cabinet doors within 30 minutes following the onset of a Station Blackout (SBO) ,ent. By letter dated October 22, 1992, GPU Nuclear Corporation, the licensee, provided responses to the above staff positions. The staff's evaluation of the licensee's responses is provided below.

2.0 EVALVATION The licenseo performed a sensitivity study to demonstrate the effect of initial room temperatures used in the heat-uo analysis on the calculated peak temperatures. In the analysis, the licensee used five different initial control room temperatures which varied between 75'F (normal control room temperature setting) and 95 F, at 5*F intervals. For each of these initial temperatures, basis) and 106}F (maximum recorded temperature).he outdoor The t rounding room temperatures were ass temperatures for all cases varied between 104'F and 120'F. In addition, normal control room heat loads which would be reduced significantly during an SB0 event were assumed in the analysis. The sensitivity study indicates that at the end of the first hour (as reported in the safety evaluation, dated July 29, 1991, AAC for the equipment required to cope with an SB0 will be available within I hour during an SB0 event at the Oyster Creek plant) into an SB0 event, with an initial control room temperai ce of 95'F and an outdoor temperature of 106*F, the temperature in the control room would be 112*F.

Consequently, the licensee concluded that there is no need t' open control

'com cabinet doors during an SB0 event at the Oyster Creek plant or to procedurally ensure that the control room temperature does not exceed 75'F during normal operation.

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3.0 CONCLUSION

The staff found that there is sufficient conservatism in the above analysis and that with an assumed initiai room temperature of 95'F, the calculated peak temperature of 112*F for the control room is acceptable. Therefore, the staff concludes that there is no need for the licensee to procedurally maintain the control room temperature below 75'F during normal operation. In addition, during a site visit at the Oyster Creek plant, the staff found that the SB0 required control room cabinets utilize an o)en design. The instruments /

coniponents in the cabir.ets are exposed to tie control room atmosphere during normal operation and during an SB0 event. Therefore, the staff agrees with the licensee's conclusion that there is no need to open the control room cabinet doors during an SB0 event.

Overall, the staff considers the above cited SSE issue regarding the effects of loss of ventilation in the control room during an SB0 event at the Oyster Creek plant resolved.

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