ML20073J085
| ML20073J085 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/29/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20073J079 | List: |
| References | |
| NUDOCS 9410060210 | |
| Download: ML20073J085 (3) | |
Text
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4 UNITED STATES B
NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 20566 0001 k..... j/
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.191 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLED0 EDISON COMPANY 8@
THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION. UNIT 1 DOCKET N0. 50-346
1.0 INTRODUCTION
By letter dated March 30, 1994, Centerior Energy requested an amendment to Operating License NPF-3, which would revise the Davis-Besse Nuclear Power Station Unit 1 Technical Specifications (TS).
Specifically, the proposed changes would increase the required boration flowrate from 18 gpm to 25 gpm in the event the required shutdown margin is not met, and increase the minimum boron concentration for the borated water storage tank (BWST) and the core flooding tanks (CFT) from 1800 ppm to 2100 ppm, and increase the minimum boric acid addition system (BAAS) volume from 600 gallons to 700 gallons.
The proposed changes would also revise the Action statements for an inoperable BWST or CFT, and the Surveillance Requirements relating to boron concentration sampling of the CFT and the chemistry testing of the trisodium phosphate (TSP) contained in baskets in the containment normal sump.
2.0 EVALUATION A proposed change to TS 3/4.1.1.1 would revise the Action statement to increase the required boration flowrate from 18 gpm to 25 gpm in the event the shutdown margin requirement is not met; boration must be initiated immediately and continued until the shutdown margin is within its limit.
Since it is imperative to raise the boron concentration of the reactor coolant system as quickly as possible, an increase in required baration flowrate is in the conservative direction and is, therefore, acceptable. The same change to the Action statements of TS 3/4.10.4 makes this special test exception consistent with TS 3/4.1.1.1.
Proposed changes to TS 3/4.1.2.8 wo; 1 increase the minimum required BAAS volume from 600 gallons to 700 gal'.
- and increase the minimum required BWST boron concentration from 1800 ppm to 2100 ppm during shutdown Modes 5 and 6 (below 200 F). The boron capability required below 200 *F must be sufficient to provide a shutdown margin of 1% after xenon decay and cooldown from 200 "F to 70 'F.
This requirement is met with either 700 gallons of 7875 ppm borated h006021094o929 P
ADOCM 05000346 PDR
. water from the BAAS or 3000 gallons of 2100 ppm borated water from the BWST.
The proposed changes are, therefore, acceptable.
Proposed changes to TS 3/4.1.2.9 and TS 3/4.5.'4, applicable during Modes 1, 2, 3, and 4, would revise TS Figure 3.1-1 and increase the minimum required BWST boron concentration from 1800 ppm to 2100 ppm.
The boration capability of the BWST and the BAAS must be sufficient to provide a shutdown margin from all operating conditions of 1% after xenon decay and cooldown to 200 'F.
The maximum boration capability requirement occurs from full power equilibrium xenon conditions and requires the equivalent of 9071 gallons of 7875 ppm borated water from the BAAS or 75,300 gallons of 2100 ppm borated water from the BWST. This requirement is met by the proposed changes and bounded by the proposed new Figure 3.1-1.
The proposed changes are, therefore, acceptable.
Proposed changes to the Action statements of TS 3/4.1.2.9 and TS 3/4.5.4 would increase the allowable outage time for restoring the BWST to operable status from I hour to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> in the event it is inoperable because of boron concentration or temperature not within limits. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> requirement will remain if the BWST is inoperable for any other reason.
This 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> limit was developed by considering the time required to change boron concentration or temperature and is consistent with NUREG-1430, " Revised Standard Technical Specifications for Babcock & Wilcox Pressurized Water Reactors." In addition, since the contents of the BWST would remain available for injection during the 8-hour time period, if necessary, there would be no adverse effect on pl~ ant safety. The proposed changes to the Action statements are, therefore, acceptable.
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A proposed change to TS 3/4.5.1 would increase the minimum required CFT boron concentration from 1800 ppm to 2100 ppm. This would ensure that the minimum boron concentration of the CFTs is the same as the proposed minimum boron concentration for the BWST, as assumed in the reload analysis for the post-LOCA borated water mixture concentration. As for the similar change approved previously for the BWST, the boron concentration increase is in the i
conservative direction and would have no adverse effect on plant safety. The proposed change is, therefore, acceptable.
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A proposed change to the Action statement of TS 3/4.5.1 would increase the allowable outage time for restoring a CFT to operable status, in the event, it is inoperable due to the boron concentration not being within limits, from I hour to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
If it is inoperable for any other reason, the 1-hour allowable outage time would remain in effect. With a reduced boron concentration, the ability to maintain subcriticality may be reduced, but the effects of reduced boron concentration on core subcriticality during post-LOCA reflood would be minor, because the initial voiding maintains the reactor subcritical.
In addition, the volume of the CFT would still be available for injection. Therefore, this change, which is consistent with NUREG-1430, is acceptable.
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. Another proposed change to the Action statements of TS 3/4.5.1 would change the actions that need to be taken in the event CFT operability cannot be restored. The Action statement would change from requiring the plant to go to hot shutdown (Mode 4) to hot standby (Mode 3) with RCS pressure less than 800 psig. TS 3/4.5.1 is applicable in Modes 1 and 2, and in Mode 3 with the RCS pressure greater than 800 psig. In Mode 3 with RCS pressure below 800 psig, the CFT motor-operated isolation valves are closed to isolate the CFTs from the RCS. Therefore, the proposed change would be consistent with the applicability Modes of the TS and is acceptable.
A proposed change to TS 3/4.5.1 would replace the current Action statement 3.5.1.b for a CFT inoperable due to the isolation valve being closed with a new Action statement which would allow one hour to restore the CFT to operable status for any reason other than the boron concentration not being within limits. The current TS Action requires either immediate opening of the isolation valve or proceeding with a controlled plant shutdown within I hour.
Due to the severity of the consequences should a LOCA occur in this condition, the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> completion time to open the valve, remove power to the valve, or restore the proper water volume or nitrogen cover pressure ensures that prompt action is taken and minimizes the time the plant is potentially exposed to a LOCA in this degraded condition.
If the CFT cannot be returned to operable status within I hour, the plant must be placed in a Mode in which the LC0 does not apply. As mentioned previously, this may be done by placing the plant in Mode 3 with RCS pressure less than 800 psig. The proposed change is acceptable and consistent with NUREG-1430.
A final proposed change to TS 3/4.5.1 would eliminate the Surveillance Requirement 4.5.1.b to sample the CFT boron concentration within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> of a solution volume increase of greater than 80 gallons, if the solution volume increase was the result of addition from the BWST. This proposed change is acceptable because the water contained in the BWST is within CFT boron concentration requirements and, therefore, the addition of BWST water would not result in the CFT boron concentration going out of limits.
The proposed changes to the TS Bases associated with the above proposed TS changes are consistent with the proposed changes and are acceptable.
Recently, both Three Mile Island, Unit I and Oconee have discovered control rods which dropped slower than TS requirements. A possible reason for the slower drop-times has been attributed to crud deposits in the control *od drive mechanisms. The crud is believed to originate throughout the RCS and is due, in part, to operation with relatively low pH levels, caused by longer fuel cycles using increased RCS boron concentrations without compensating increases in lithium concentrations.
In response to our request, the licensee stated that th1: problem does not exist at Davis-Besse since they do not have the older type of control rod mechanisms in use at Three Mile Island, Unit I and Oconee.
Since the problem has not been seen in the newer type of mechanism used at Davis-Besse, the staff agrees with the licensee's assessment.
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. The staff has-reviewed the proposed changes to the Davis-Besse TS described and evaluated above and finds them acceptable for the reasons stated in the above evaluation.
3.0 STATE CONSULATION In accordance with the Commission's regulation, 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 and changes a surveillance requirement. The staff has determined that
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the amendment involves no significant increase in the amounts, and no signif-icant 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 27067). 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 i
statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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 Commission's regulations, and (3) issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
L. Kopp K. Parczewski Date: September 29, 1994 l