ML20149F454
| ML20149F454 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 08/02/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20149F452 | List: |
| References | |
| NUDOCS 9408100257 | |
| Download: ML20149F454 (3) | |
Text
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I4UCLEAR REGULATORY COMMISSION
't WASHINGTON D.C. 2055MW1
,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 146 TO FACILITY OPERATING LICENSE NPF-9 AND AMENDMENT N0.128 TO FACILITY OPERATING LICENSE NPF-17 Qt)KE POWER COMPANY MCGUIRE NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS. 50-369 AND 50-370 INTRODUCTION By letter dated dated May 5, 1954, as supplemented June 13, 1994, Duke Power Company (the licensee) submitted a request for changes to the McGuire Nuclear Station, Units 1 and 2 Technical Specifications (TS). The requested changes i
would increase the pressurizer safety valve (PSV) and main steam safety valve 1
(MSSV) lift tolerance ranges. The licensee made a similar proposal in an application dated June 26, 1991. The staff did not complete its review of this item in the amendments for McGuire Units 1 and 2 numbered 128 and 110 in i
response to that application.
The staff has considered the restated proposal i
on this issue in the May 5,1994 submittal, as supplemented on June 13, 1994, to supercede and replace in its entirety the earlier version of the request and has reviewed it accordingly.
The specific changes include TS Sections 3/4.4.2 and 3/4.7.1 to reflect an increased PSV setpoint tolerance of + 3%, - 2% and an increased MSSV setpoint tolerance of f 3%.
Specifically, the licensee proposes thitt during normal surveillance, if the valves are found to be within the proposed tolerances, i
they will be within the bases of the accident analyses; however, the valves will be reset to i 1% to prevent the accumulation of setpoint dritt outside the allowable tolerance.
At McGuire 1 and 2, there are a total of three PSVs set at 2485 psig.
The four main steam lines have a total of 20 MSSVs (i.e., five per main steam line), each set at increments which range from 1170 psig to 1225 psig.
The licensee is proposing to revise the McGuire Units 1 and 2, TS to allow a relaxation in setpoint tolerance for the as-found test condition from i 1% to
+ 3%, - 2% for the PSVs and from i 1% to i 3% for the MSSVs. The amount by which the PSV setpoint is allowed to drift downward is restricted to 2% of nominal in order to ensure the PSVs do not open before a reactor trip on high pressure. The licensee is proposing to reset the PSVs and MSSVs to i 1% prior to declaring the valves operable if the as-found lift settings exceed i 1%.
Further, the licensee states that these proposed changes will reduce the amount of work performed in a radiological or otherwise dangerous environment.
No$o$69 PDR
. EVALUATION The licensee is proposing to relax the as-found setpoint tolerances for the PSVs and MSSVs from i 1% to i 3%. This relaxation is applicable for PSV and MSSV drift which occurs during the operating cycle. The licensee's submittals include the results of the Unit 1 Cycle 8 reload analysis (which is also applicable to Unit 2.) This reload analysis examined the effects of relaxing the PSV and MSSV setpoint tolerance on the plant safety analysis including the effects on the maximum primary and secondary system pressures.
This analysis was reviewed and approved by the NRC staff in a letter to the licensee dated November 27, 1991.
The licensee's reload analysis considered the necessary changes in the analysis parameters for the relaxed PSV and MSSV setpoint tolerance. An increased PSV or MSSV setpoint affects the peak primary or secondary system pressure. The licensee evaluated the limiting events which cause primary and secondary system overpressure conditions including the feedline break, locked rotor, rod ejection, turbine trip, MSIV closure, and uncontrolled bank withdrawal events and determined that the peak system pressures do not exceed 110% of the system design pressures.
The minimum allowable PSV pre w re is restricted to - 2% of the nominal setpoint to ensure that the PSVs do not open before a reactor trip on high pressure. The licensee has also determined that decreasing the MSSV setpoint to - 3% of the nominal setpoint tu the potential to affect the steam generator tube rupture accident; however, the existing licensing basis analysis remains bounding.
The licensee has determined that the proposed TS changes do not result in a significant reduction in the margin of safety. The limiting transient in each accident category has been analyzed to determine the effect of the change in the setpoint tolerances. The licensee determined that the results of these analyses meet all acceptance criteria and demonstrate that the peak pressures in the primary and secondary systems do not exceed 110% of the system design pressures in accordance with the ASME code.
Further, in order to prevent the setpoints from drifting outside the i 3% range, the licensee will continue to require both PSV and MSSV setpoint tolerances to be restored to i 1% when the as-found lift setting exceeds i 1% prior to declaring the PSVs and MSSVs operable.
This will prevent excessive setpoint drift which would cause the peak system pressures to exceed the allowable limits.
Based on the above evaluation, the staff agrees that the analysis which the licensee has provided demonstrates the acceptability of the proposed TS changes. The proposed increase in the setpoint tolerances of the PSVs and the MSSVs has been shown to be acceptable for meeting the plant design basis.
Also, for those occurrences where the as-found setpoints of PSVs or MSSVs are in excess of i 1%, resetting to within i 1% of the nominal setpoint will be required prior to declaring them operable.
Therefore, these proposed TS changes have no significant safety impact to the operation of McGuire, Units 1 and 2 and are acceptable.
. i 3.0 STA1E CONSULTATION i
In accordance with the Commission's regulations, the North Carolina State official was notified of the proposed issuance of the amendments.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in 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 amendments involve no significant hazards consideration, and there has been no public comment on such finding (59 FR 32029 dated June 21, 1994). Accordingly, the 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 the amendments.
5.0 CONCLUSION
The Commission 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,
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and (3) the issuance of the amendments will not be inimical. to the common defense and security or to the health and safety of the public.
Principal Contributor:
C. Hammer Date:
August 2, 1994 I
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