ML20217B540

Safety Evaluation Supporting Amend 193 to License DPR-40

ML20217B540
Person / Time
Site:	Fort Calhoun
Issue date:	10/06/1999
From:	NRC (Affiliation Not Assigned)
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Shared Package
ML20217B517	List: ML20217B511 ML20217B520 ML20217B540
References
NUDOCS 9910120286
Download: ML20217B540 (2)

Text

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{ NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30e06 0001 i

'k*****,d SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULAIJQN l

RELATED TO AMENDMENT NO.193 TO FACILITY OPERATING LICENSE NO. DPR-40 l OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION. UNIT NO.1 DOCKET NO. 50-285

1.0 INTRODUCTION

By application dated March 31,1999, Omaha Public Power District (OPPD) requested changes to the Technical Specifications (Appendix A to Facility Operating License No. DPR-40) for the ,

Fort Calhoun Station, U'11t No.1 (FCS).' The requested changes would increase the minimum n3 quired reactor coolant system (RCS) flow rate and change the surveillance requirements for RCS flow rate.. The changes would increase the RCS minimum flow rate for departure from nucleate boiling ratio (DNBR) margin during power operation above 15 percent of rated power from 197,000 gallons per minute (gpm) to 206,000 gpm, as noted in Section 2.10.4 c'the Technical Specifications. In addition, the surveillance frequency would be changed from monthly to refueling, or at least every 18 months, as defined in Table 3-3 in Section 3.0.2 of the Technical Specifications. Revisions would also be made to Basis Sections 2.10.4 and 3.1 in support of the above technical specifications changes.

2.0 EVALUATION in 1998, OPPD performed a steam generator orifice plate removal (modification MR-FC 005) which resulted in an increase in RCS flow rate to an estimated value of 207,500 gpm.

Subsequent measurements confirmed the flow rate to be higher than the estimated value.

The calculation of the RCS flow rate by a precision calorimetric heat balance is recommended in NUREG-1432, "The improved Technical Specifications for Combustion Engineering Plants,"

due to improved accuracy in the determination of the flow rate. The proposed minimum RCS flow rate of 206,000 gpm indicated flow provides increased margin over the previously approved indicated flow rate of 202,500 gpm. Margin to DNB and margin to peak cladding temperature will thus be maintained with the proposed change in allowable flow rate. In addition, flow rate measurements through January 1999 indicate an average flow rate of 208,800 gpm,1 per cent higher than the proposed limit.

The existing required flow rate measurement interval is monthly. The proposed change to measure the flow rate following each refueling outage, or at 18 month intervals, whichever is more frequent, and within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the reactor power level exceeds 95 percent is also consistent with the surveillance frequency required in NUREG-1432, provided the precision heat balance methodology is employed.

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' The proposed increase in minimum RCS flow rate to an indicated value of 206,000 gpm from the previously approved value of 202,500 gpm is acceptable. Determination of the RCS flow rate by precision calorimetric balance is acceptable since it provides a more accurate

' determination of the flow rate than the older methods used during the licensing of the plant.

Measurement of the RCS flow rate within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of exceeding 95 percent reactor power following refueling, or at 18 month intervals, is acceptable.

The above changes to the Fort Calhoun Station Unit 1 Technical Specifications are consistent with NUREG-1432.

. 3.0 ' STATE CONSULTATION in sceordance with the Commission's regulations, the Nebraska State official was notified of the

. proposed issuance of the amendment. The State official had no comments.

4.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to instaMation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no rignificant hazards consideration and there has been no public

' comment on such finding (64 FR 27322). Accordingly, the amendment meets the eligibility ,

criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) I no environmental impact statement or environmental assessment need be prepared in  !

connection with the issuance of the amendment.

5.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manrer, (2) such activities will be conducted in compliance with the Comtnission's regulations, and (3' the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: R. Landry Date: October 6, 1999 L _