ML20207H927
| ML20207H927 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/24/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20207H923 | List: |
| References | |
| NUDOCS 8808300118 | |
| Download: ML20207H927 (3) | |
Text
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%,e....j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 117 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLEDO EDISON COMPANY M
THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-346
1.0 INTRODUCTION
By application dated March 4,1988 (Serial No.1487) and supplemented by letter dated May 4, 1980 (Serial No. 1520), the Toledo Edison Company and the Cleveland Electric Illuminating Company requested that the Davis-Besse Nuclear Power Station, Unit No.1 Operating License, Appendix A, Technical Specifications be revised. The proposed changes involve Technical Specifications (TS) Section 3/4.7.1.1. Turbine Cycle-Safety Valves; Table 3.7-1, Maximum Allowable High t
i Flux Trip Setpoint With Inoperable Steam Line Safety Valves; Table 4.7-1. Steam Line Safety Valves Per Steam Generator; and Bases Section 3/4.7.1.1. Turbine Cycle-Safety Valves.
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2.0 BACKGROUND
The proposed changes would allow the main steam safety valve (MP 1) setpoints and minimum number of valves to be more clearly stated consistent with the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section III,1971 Edition. The proposed changes 1
would also incorporate into the Limiting Condition for Operation a redefinition of the relationship between the total operable main steam safety valve relieving capability per steam generator and the reduced Reactor Protection System High
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Flux Trip setpoint. This redefinition would allow the High Flux Trip setpoint reduction due to an inoperable safety valve (s) to directly reflect the actual i
loss of steam relieving capability, versus the conservative relationship 1
(resulting in an increased reactor power penalty) presently employed in the Technical Specifications.
The requested changes to the High Flux Trip setpoint and required MSSV capacity will be evaluated in a later safety evaluation (SE).
Therefore, this SE will address only the acceptability of the proposed Technical Specification for MSSV setpoints.
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. 3.0 EVALUATION The proposed changes will require that at least one MSSV be set at no greater than system design pressure of 1050 psig (+1%). This is consistent with the 2
ASME Code requirements and is therefore acceptable. With the proposed changes the maximum analyzed system pressure due to limiting design basis events will remain below 110 percent of design pressure.
This is also consistent with the ASME Code and is acceptable. The values of the proposed MSSV setpoints are:
No. of MSSV's per Steam Genera to_r lift Setting (+1%)
2 1050 psig 7
1100 psig The licensee also proposes to eliminate Table 4.7-1 of the TS.
This would allow the licensee to change the setpoints of some of the MSSV's without requiring a change to the TS. The licensee states that the proposed changes will provide greater flexibility in valve set pressure and replacement while maintaining required overpressure protection for the steam generators.
In order to comply with the ASME Code, the +1% tolerance must be placed on each MSSV setpoint. The staff has determined that Table 4.7-1 may not neces-sarily be the only means to assure proper MSSV setpoints; however, there must be adequate control of the MSSV setpoints to assure adequate overpressure protection and system response. Therefore, future changes to the MSSV pressure setpoints would be acceptable providing the requirements of 10 CFR 50.59 are met.
For the interim period until the staff reviews the proposed High Flux Trip setpoint changes, the licensee has agreed to leave the current High Flux Trip setpoint in TS Table 3.7-1 as is.
It has been determined that leaving the
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TS for the High Flux Trips as they presently are is conservative in combination with the proposed revisions to the MSSV setpoints since the two smaller capacity valves are proposed to have the lower setpoints.
Therefore, this is acceptable for the interim period.
Until such time as the portion of the proposed amendment related to the MSSV steam relief capacity and the high flux trip setpoint is reviewed by the staff TS Table 4.7-1 and the reference to it in TS Section 4.7.1.1 must be retained with the modified setpoints shown above.
Therefore, the proposed revision to the Technical Specifications concerning MSSV setpoints is approved with the above stated provisions for the interim period until the staff completes the review of the High Flux Trip setpoints and the required MSSV relieving capacity.
4.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CFR 51.21, 51.32, and 51.35 an environmental assessment and finding of no significant impact has been prepared and published in the Federal Register on July 26, 1988 (53 FR 28081).
Accordingly, based upon the environmental assessment, the Comission has determined that the issuance of this amendment will not have a significant effect on the quality of the human environment.
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5.0 CONCLUSION
7 The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposet manner, and (2) public such activities will be conducted in compliance with the Commission's regulations, and the issuance of this amendment will not be inimical to the common defense and security cr to the health and safety of the public, r
i Principal Contributor:
C. Gary Hammer Dated:
August 24, 1988 f
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