ML20249A766
| ML20249A766 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/11/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20249A762 | List: |
| References | |
| NUDOCS 9806180202 | |
| Download: ML20249A766 (4) | |
Text
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i UNITED STATES s
j NUCLEAR REGULATORY COMMISSION 2
WASHINCTON, D.C. 306eH001 4,.....,o SAFETY EVALUATION BY THE OFFICC 0F NUCLEAR REACTOR REGULATION BELA_IED TO AMENDMENT N0. 222 TO FACILITY OPERATING LICENSE N0. NPF-3 TOLED0 EDISON COMPANY CENTERIOR SERVICE COMPANY AND THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION. UNIT NO. 1 DOCKET NO 0-346
1.0 INTRODUCTION
By letter dated August 26, 1997, Toledo Edison Company, Centerior Service Company, and The Cleve'and Electric Illuminating Company (the licensees),
submitted a request for changes to the Davis-Besse Nuclear Power Station, Unit No.1, Technical Specifications (TSs).
The proposed amendment would revise Technical Specification Section 3/4.2,
" Power Distribution Limits." The departure from nucleate boiling (DNB) parameters limiting condition for operation (LCO) action statement would be raodified due to in industry notification.
7.0 LICENSING BASIS The licensing basis for the systems affected by the proposed changes includes the Davis-Besse Updated Safety Analysis Report (USAR) Section 4, " Reactor."
Specifically, Section 4.4 discusses the thermal hydraulic aspects of system design.
3.0 BACKGROUND
On January 30, 1997, Framatome Cogema f uels (FCF) notified Davis-Besse that the action statement for TS 3.2.5, " Power Distribution Limits - DNB Parameters - Limiting Condition for Operation," was incomplete and non-conservative for degraded reactor coolant system (RCS) flow conditions. The licensees subsequently notified NRC of this concern in Licensee Event Report (LER)97-003 dated March 3, 1997. Revision 1 of this LER was submitted on August 19, 1997.
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' 4.0 EVALUATION On November 3, 1983, the NRC issued License Amendment No. 64 for Davis-Besse.
This amendment revised TS 3.2.5 to include the action statement which is the subject of this evaluation. This TS currently reads:
3.2.5 The following DNB related parameters shall be maintained within the limits shown on Table 3.2-2.
a.
Reactor Coolant Hot Leg Temperature b.
Reactor Coolant Pressure c.
Reactor Coolant Flow Rate APPLICABILITY:
MODE 1 ACTION:
If parameter a or b above exceeds its limit, restore the parameter to within its limit within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or reduce THERMAL POWER to less than 5%
of RATED THERMAL POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
If parameter c exceeds its limit, either:
1.
Restore the parameter to within its limit within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, or 2.
Limit THERMAL POWER at least 2% below RATED THERMAL POWER for each 1% parameter c is outside its limit for four pump operation within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, or limit THERMAL POWER at least 2% below 75% of RATED THERMAL POWER for each 1% parameter c is outside its limit for 3 pump operation within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Actions 1 and 2 were added in Amendment No. 64.
As discussed in LER 97-003, FCF detern.ined that the apparent cause of the inadequate TS action statement was that calculations performed by FCF in support of the licensees' application for Amendment '?a. 64 did not consider the need to adjust reactor protection system (RPS) trip setpoints. Upon notification by FCF, the licensees determined that the required flow rate has been maintained at the plant.
In addition, administrative procedures were put in place and remain in effect (pending approval of this amendment request) to i
take actions consistent with the requested change if TS 3.2.5 is entered due I
to degraded RCS flow conditions.
FCF reactor core thermal-hydraulic analyses determined that to preserve DNB margins with reduced RCS flow, the high flux and the flux / delta flux / flow RPS trip setpoints s!,ould be reduced.
In addition, the RPS variable low pressure trip setpoint should be adjusted. These actions are not currently specified in TS 3.2.5.
- l In lieu of performing analyses to determine the appropriate trip setpoints and including actions in the TSs to perform setpoint adjustments, the licensees propose to revise TS 3.2.5 by removing the allowance to reduce thermal power based on degraded RCS flow (actions 1 and 2 quoted above).
The TS would be modified to remove actions 1 and 2, and to include the flow rate LC0 in the remaining action. The proposed TS reads:
3.2.5 The following DNB relat d parameters shall be maintained within the limits shown on Table 3.2-2.
a.
Reactor Coolant Hot Leg Temperature b.
Reactor Coolant Pressure u.
Reactor Coolant Flow Rate APPLICABILITY: MODE 1 ACTION:
If any parameter above exceeds its limit, restore the parameter to within its limit within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or reduce THERMAL POWER to less than 5%
of RATED THERMAL POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
This would essentially restore the TS actions to the original wording at plant licensing.
The limits placed on DNB-related parameters ensure that these parameters will not be less conservative than were assumed in the applicable analyses and thereby provide assurance that the minimum DNB ratio will meet the required criteria for each analyzed transient.
RCS flow rate is not expected to vary during steady state 3 or 4 pump operation. Under the proposed TS change, if the flow rate is below the LC0 limit, the parameter must be restored to within acceptable limits within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or power must be reduced as stated within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
This power reduction ensures adequate DNB ratio margin and eliminates the potential for a violation of the accident analysis bounds.
The 2-hour completion time for restoration provides sufficient time to adjust plant parameters, determine the cause for the off normal condition, and take corrective actions as appropriate.
The time allotted is based on plant operating experience. The 6-hour completion time is reasonable, also based on plant operating experience, to reduce power in an orderly manner in conjunction with even control of steam generator heat removal.
The staff has determined that the proposed TS change adequately addresses the FCF concern discussed above.
In addition, the change is consistent with the 23 original safety analysis cond'cted for plant licensing, and is conservative compared to the existing TSs. Therefore, the proposed change is acceptable.
5.0 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.
6.0 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 1, the amounts, and no significant change in the types, of any effluent 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 (62 FR 52590). 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.
7.0 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) the 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:
A. Hansen F. Orr Date:
June 11, 1998
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