ML19221A717
| ML19221A717 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 05/18/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19221A715 | List: |
| References | |
| SER-790518, NUDOCS 7907030147 | |
| Download: ML19221A717 (3) | |
Text
__
O g
UNITED STATES b
NUCLEAR REGULATORY COMMISSION 3
3 1
h WASHINGTON, D. C. 20556 j
s
,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION CALVERT CLIFFS UNITS 1 and E BALTIM0RE GAS AND ELECTRIC C0t1PANY DOCKET NOS. 50-317/50-318 Backoround In February 1979, Baltimore Gas & Electric Company determined that the small break LOCA analysis used to support operation of Calvert Cliffs Units 1 and 2 at 2700 Mwt had been perfomed assuming one charging pump was supplying flow in addition to a high pressure injection pump. This assumption has not been approved by the staff for LOCA calculations for Calvert Cliffs. Calvert Cliffs reduced power to 2560 Mwt until Combustion Engineering completed a preliminary evaluation, provided in Reference 1, to support a return to 2700 Mwt operation. They also committed to provide a full reanalysis of the worst case small break LOCA, which was submitted by Reference 2 on March 13, 1979.
Method of Analysis The submittal presented the smal~l break LOCA ECCS perfomance for the 0.1 f t2 cold leg break in the pump discharge, which was identified in Reference 3 as the worst small break. A reactor power level of 2754 Mwt (102*,' of 2700 Mwt) and a peak linear heat generation rate (PLHGR) of 16.0 kw/ft were assumed for the reanalysis.
The evaluation was performed using Combustion Engineering's small break evaluation model, which is described in Reference 3.
Method of Evaluation
.}7}
7}
The CE small break evaluation model used in this analysis has been previously accepted by the staff for ECCS performance evaluation.
In Reference 3, the break size analyzed was shown to be limiting, without charging pump flow, and is considered to be acceptable. No credit is t#en 'o r injaction flow from the charging pumps in the reanalysis.
The PLHGR considered was 16.0 kw/ft, which bounds the Calver t Cliffs Unit 1 PLHGR of 14.2 kw/ft as well as the Calvert Cliffs Unit 2 PLHGR of 15.5 i
kw/ft. The fuel specific parameters f acluded in this analysis are representative of the limiting parameters for Calvert Cliffs 1 Cycle 4 and Calvert Cliffs 2 Cycle 2.
Therefore, the evaluation method is con-sidered acceptable.
O j
7907030 /9 7
/
i t
. Results 2 small break resulted in a peak clad temperature The analysis of the 0.1 ft of 1940 F and peak zirconium oxidation percentage of 7.967..
These values are substantially below the acceptance limits of 2200"F and 17%, respectively.
Conclusion The staff has reviewed the reanalysis of the Calvert Cliffs small break LOCA without charging pump injection. The analytical models are approved for ECCS performance evaluation and the results satisfy the ECCS Acceptance Criteria (10 CFR 50.46). Therefore, we conclude that this analysis provides a basis for continued operation at 2700 Hwt for Calvert Cliffs Units 1 and 2.
Dated-May 18, 1979 I
. References 1.
Baltimore Gas and Electric Company letter dated February 16, 1979, A. Lundvall, Jr., to R. W. Reid.
2.
Baltimore Gas and Electric Company letter dated March 13, 1979, J. W. Gore to R. W. Reid.
1 3.
CENPD-137, " Calculative Methods for the CE Small Break LOCA 3
Evaluation flodel," Supplement 1, January 1977 (Proprietary).
273 175
.