ML20147H358
| ML20147H358 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 03/04/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20147H333 | List: |
| References | |
| NUDOCS 8803080460 | |
| Download: ML20147H358 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION n
- h\\.....)j WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 55 TO FACILITY OPERATING LICENSE NO. NPF-11 AND AMt!NDMENT NO. 36 TO FACILITY OPERATING LICENSE NO. NPF-18 COMMONWEALTH EDISON COMPANY LASALLE COUNTY STATION, UNITS 1 AND 2 DOCKET NOS. 50-373 AND 50-374
1.0 INTRODUCTION
By letter dated August 24, 1987, the Commonwealth Edison Company requested to amend Facility Operating License NPF-11 and NPF-18.
The proposed change of the Technical Specifications clarifies the conditions necessary to perform the jet pump operability surveillance and correct typographical errors.
2.0 OISCUSSION A decision was made to install a new impeller in the IB Reactor Recirculation (18 RR) pump; however, based on pump calculations, rated flow from the IB RR pump will be reduced by 2.5% due to the smaller size of the replacement impeller.
The use of this impeller has been evaluated by General Electric and has been found to be acceptable for use in the IB RR pump.
However, the reduction in flow provided by the smaller impeller could create a problem I
meeting the surveillance requirements of Technical Specification 4.4.1.2.1.
This specification calls for the same flow control valve position to be established to perfonn the jet pump surveillance. With equal flow control value positions, the flows in the two reactors recirculation loops will not be equal.
General Electric analysis shows that to balance the flows between the two RR loops, a 6% position difference between FCY position would be required.
8803000460 000304 DR ADOCK 050 3
2 Based on past operating experience, this flow mismatch, with the new impeller installed and valve positions equal, could prevent meeting the surveillance requirement 4.4.1.2.1.c.
This is due to the fact that the baseline jet pump curves are taken in the normal system mode (RR Flow Controllers in Auto) which balances drive flows between the Recirculation Loops.
The wording of Technical Specification 4.4.1.2.1 is based on the fact that given pumps of equal pumping capacity and identically calibrated control systems, equal indicated FCV positions should produce equal drive loop flows. Therefore, Commonwealth Edison believes the intent of the specification is to balance loop drive flows before performing the jet pump operability surveillance. This interpretation is consistent with the requirements of Technical Specification 3.4.1.3, which limits drive flow mismatch to less than 5% (with core flow greater than 70% of rated core flow), and intends to enforce balanced loop flows. Using specification 3.4.1.3 as a guide, the criteria for balanced drive flows for performance of surveillance 4.4.1.2.1 shall be that the indicated drive flow difference be within 5% of rated recirculation flow.
In this manner, system differences or changes throughout plant life which affect the FCV position versus drive flow relationship will not impede the successful performance of the surveillance.
The staff nas concluded that the requested Technical Specifications revision to require balanced drive flow rather that the same flow control valve positions for jet pump operability surveillance is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes in the installation and use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The staff has determined that these 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 connent on such finding. Accordingly, these 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 Connission made a proposed detemination that these amendments involve no significant hazards consideration which was published in the Federal Register (52 FR 49220) on December 30, 1987, and consulted with the state of Illinois. No public connents were received, and the state of Illinois did not have any connents.
3 The staff 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 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.
REFERENCE Letter from Commonwealth Edison to NRC, "LaSaile County Station, Units 1 and 2 Proposed Amendment to Technical Specification for Facility Operating License NPF-11 and NPF-18 Jet Pump Operability" dated August 24, 1987.
Principal Contributor:
Paul Shemanski, NRR/P03-2 Dated: March 4, 1988
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