ML17223A994
| ML17223A994 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 11/09/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17223A993 | List: |
| References | |
| NUDOCS 9011160187 | |
| Download: ML17223A994 (4) | |
Text
~p,is REC41, P0 sn0
- spsp*dc+
t UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, O. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
TO FACILITY OPERATING LICENSE NO. DPR-67 FLORIDA POMER
& LIGHT COMPANY ST.
LUCIE PLANT UNIT NO.
1 DOCKET NO. 50-335
1.0 INTRODUCTION
By letter dated March 9, 1990, as supplemented September 24,.1990, Florida Power and Light Company (FPL) submitted proposed modifications to the St. Lucie Unit I Technical Specifications.
Specifically, the proposed changes would modify the Local Power Density (LPD) Limiting Safety System Setpoints (LSSS) in Technical Specification Figure 2.2-2, the LPD Limiting Condition for Operation (LCO) in Technical Specification Figure 3.2-2, and the Departure from Nucleate Boiling (DNB) LCO in Technical Specification Figure 3.2-4.
The September 24, 1990 letter provided supplemental information which did not alter the staff's initial determination of no significant hazards consideration as noticed in the Federal
~Re ister on April 4, 1990 (55 FR 12591).
2.0 EVALUATION To achieve greater operational flexibilityat lower power, FPL has proposed to expand the LPD LSSS Axial Shape Index (ASI) limits for power levels below 66 percent Rated Thermal Power (RTP) from a 0.4 to a 0.6 and for 100 percent power level from - 0.145 to - 0.2.
The changes would also expand the ASI limits of the LPD LCO for power levels below 45 percent RTP (but above 40 percent RTP) and the ASI limits of the DNB LCO for powers below 65 percent RTP (but above 40 percent RTP) from a 0.3 to+ 0.5.
In addition, changes are proposed to ASI limits of the LPD LCO at 85 percent RTP from 0.02 to - 0.08.
Design basis events initiated from intermediate power levels are bounded by either the full power or zero power results and, therefore, they are not typically analyzed at intermediate power levels.
Therefore, to justify the proposed changes to the Technical Specification LCO and LSSS ASI limits, a reevaluation of only those full power or zero power events which might be adversely affected was made by the licensee.
The proposed changes to the LPD LSSS ASI limits could affect the previously licensed analyses for events initiated at full power.
For example, the LPD.
LSSS trip ensures that the peak local power density in the fuel remains below 90iiib0187 90ii05'DR AGOCK 05000335 P
PDC'
that corresponding to fuel centerline melting as a consequence of axial power shape maldistributions.
However, this trip is not the primary trip in the safety analysis of any design basis event and, therefore, no full power events previously analyzed for St. Lucie Unit I are adversely affected.
The zero power events potentially affected by the proposed expansion of the ASI limits are the boron dilution, control element assembly (CEA) withdrawal, excess
- load, steam line break and CEA ejection, which were originally analyzed by Combustion Engineering (CE using deterministic methods.
A reevaluation of these events by Advanced Nuclear Fuels Corporation (ANF), the present St. Lucie Unit I fuel vendor, using NRC-approved statistical setpoint methodology, has added additional safety margin which allows the Technical Specification ASI limits to be expanded at lower power levels while still resulting in acceptable consequences for these low power events.
3.0 TECHNICAL FINDINGS The staff has reviewed the proposed modifications to the ASI limits for St. Lucie Unit 1.
Specifically, the proposed wider ASI bands have been reviewed for their impact upon the plant safety analysis.
The staff concludes. that the most recent safety analysis justifies the expanded ASI limits and, therefore, the 'proposed modifications are acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
We have determined that this 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 Comnission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
5.0 CONCLUSION
Me have concluded, based on the considerations discussed above, that,(l) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
November 9, 1990 Princi al Contributor:
~
Kopp
J