ML16138A706
| ML16138A706 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/25/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16138A705 | List: |
| References | |
| NUDOCS 9005140140 | |
| Download: ML16138A706 (3) | |
Text
Rjk REGUZ UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 183TO FACILITY OPERATING LICENSE DPR-38 AMENDMENT NO. 183TO FACILITY OPERATING LICENSE DPR-47 AMENDMENT NO. 180TO FACILITY OPERATING LICENSE DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS 1, 2 AND 3 DOCKETS NOS. 50-269, 50-270 AND 50-287
1.0 INTRODUCTION
By letter dated August 14, 1987, and supplemdntal correspondence dated April 22, 1988, and January 23, 1990, Duke Power Company (the licensee) proposed amendments to the operating licenses for Oconee Nuclear Station (ONS), Units 1, 2 and 3, which would revise Technical Specification (TS) 3.4.4.
The TS revision would change the minimum indicated level required to be available in the upper surge tanks from 5 feet to 6 feet. The change was required to account for instrument error and to ensure adequate Emergency Feedwater (EFW) supply availability while switching to an alternate source. Some changes were also proposed to the Bases of TS 3.4. The changes are applicable to all three units.
2.0 EVALUATION The EFW system for the ONS, Units 1, 2 and 3, is designed to supply sufficient feedwater following a reactor trip at power to enable the Reactor Coolant System to cool down to conditions at which the Decay Heat Removal System may be operated. The system utilizes two upper surge tanks (UST) on each unit to provide the primary source of water for the EFW pumps. The two upper surge tanks are cross-connected and supply sufficient inventory to provide the required minimum EFW flow for maintaining hot shutdown for at least 67 minutes under conservative conditions. This inventory corresponds to a tank volume of 30,000 gallons, equivalent to a UST level of 5 feet. The UST level of 5 feet is based on tank geometry only and does not consider the effects of possible instrument error.
Duke Power Company performed an analysis to determine the adequacy of the UST level of 5 feet. As a result of this analysis, it was determined that a maximum UST level instrumentation error of 9 inches could be expected. The licensee's evaluation showed that an indicated UST level of 6 feet was required to ensure that an actual UST volume of 30,000 gallons was present.
This one foot increase included the allowance for instrument error plus an 9005140140 900425.
PDR ADOCK 05000269P P
-2 allowance for depletion of EFW inventory while switching to an alternate water source. The licensee's analysis indicates that the allowance of 9 inches conservatively bounds the uncertainty associated with each of the various UST level indications.
Duke Power Company requested changes to ONS TS 3.4.4 to reflect this change in UST level.
Additionally, changes to the table of EFW flow demand in the Bases of TS 3.4.4 were included to reflect revised calculations used to determine the decay heat, reactor coolant pump heat, and required EFW flow following a reactor trip from 102 percent power.
The changes in the decay heat calculations incorporate a realistic assumption of 440 effective full power days per cycle instead of the previously assumed infinite operation, actual reactor coolant pump heat input instead of nameplate power and conservative assumptions of delayed neutron power.
The revised values bound any Oconee core decay heat level and do not affect the capability to achieve and maintain hot shutdown under the most conservative conditions with only the EFW pumps operating.
Based on its review of the licensee's request, the NRC staff agrees with the licensee's conclusions that the changes have no adverse impact on the design or operation of the station and would not pose an undue risk to public health and safety.
The requirement to maintain a higher minimum indicated UST level will provide improvement in the availability and reliability of the water sources for EFW operation for decay heat removal.
Therefore, the changes are acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes in requirements with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendments involve 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 these amendments involve no significant hazards consideration, and there has been no public comment on such finding.
Accordingly, the amendments meet 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 these amendments.
4.0 CONCLUSION
The Commission's proposed determination that the amendments involve no significant hazards consideration was published in the Federal Register (54 FR 31105) on July 26, 1989.
Subsequent clarifying information submitted by the licensee on January 23, 1990, did not change our proposed finding. The Commission consulted with the State of South Carolina.
No public comments were received, and the State of South Carolina did not have any comments.
-3 We have 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 manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
L. Wiens, PDII-3/DRP-I/II L. Wert, Resident Inspector, Oconee Dated:
April 25, 1990