ML20070C797
| ML20070C797 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/28/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20070C775 | List: |
| References | |
| NUDOCS 9407070024 | |
| Download: ML20070C797 (3) | |
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t UNITED STATES NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 20566-0001
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SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
188 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLED0 EDIS0N COMPANY CENTERIOR SERVICE COMPANY MQ THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION. UNIT NO. 1 DOCKET NO. 50-346 1.0 MITRQQVCTION By letter dated January 31, 1994, Toledo Edison Company (the licensee) requested a revision to the Technical Specifications (TS) for Davis-Besse Nuclear Power Station.
The proposed amendment revises TS 3/4.1.1.2,
" Reactivity Control Systems-Boron Dilution," and its Bases.
The change would permit the addition of water of lower boron concentration than the reactor coolant system (RCS) in Mode 5 (cold shutdown), provided that the boron concentration of the water to be added is equal to or greater than the boron coxentration associated with the shutdown margin requirement specified in 3.1.1.1.
The amendment is related to Amendment No. 176, which was issued by the NRC on December 8, 1992, and incorporated a similar revision for Mode 6 operation.
2.0 EVALVATI0B Technical Specification 3.1.1.2 requires that the flow rate of reactor coolant through the RCS be greater than or equal to 2800 gpm whenever a reduction in RCS boron concentration is being made.
This minimum flow rate provides adequate mixing, prevents stratification, and ensures that reactivity changes will be gradual in the RCS, Maintenance activities during plant outages may require that the RCS level be reduced below the level of the reactor vessel flange.
One such example would involve the installation of steam generator nozzle dams which necessitates that the RCS be drained down to about 18 inches above the RCS hot leg centerline. When this occurs, procedural limits are placed on the maximum decay heat removal (DHR) flow rate to prevent vortexing and pump cavitation.
The proposed change to TS 3/4.1.1.2 would result in less burden to the operators and greater flexibility in the choice of water addition sources with the DHR flow rate procedurally restricted to less than 2800 gpm. Without the proposed change, the boric acid addition tank is used to raise RCS level until 9407070024 940628 ADOCK0500g6 i DR
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^ t it is high enough such that the DHR flow rate can be increased above 2800 gpm and then the desired water sources (e.g., borated water storage tank or a clean waste receiver tank) can be used for~any necessary water addition.
The proposed change eliminates the step of having to increase the RCS level using the boric acid addition tank.
Technical Specification 3.1.1.1 requires that the shutdown margin shall be equal to or greater than 1% delta k/k.
The associated action statement for Technical Specification 3.1,1.1 states: With the SHUTDOWN MARGIN less than 1%
delta k/k, immediately initiate and continue boration at equal to or greater than 18 gpm of 7875 ppm boron or its equivalent, until the required SHUTOOWN MARGIN is restored.
Thus, if the RCS meets these reactivity requirements, and water is added to the RCS that also meets these reactivity requirements, then the RCS is assured to remain in compliance with the reactivity condition requirements.
Therefore, the possibility that the added water may be of lower boron concentration than the RCS is of no adverse consequence to safety.
The NRC staff has reviewed the licensee's application and on the basis of the above information finds that the proposed change to the water addition boron concentration requirements is acceptable. Therefore, this amendment is approved.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Ohio State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement.
The 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 significant hazards consideration and there has been no public comment on such finding (59 FR 12369).
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), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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5.0 CONCLUSION
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, (2) such activities will be conducted in compliance with the Comission's regulations, and (3) the issuance of this amendment will not be ic.imical to the common defense and security or to the health and safety of ti,.* public.
Principal Contributor:
G. West, Jr.
Date: June 28, 1994 A
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