ML20237A134
| ML20237A134 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/07/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20237A113 | List: |
| References | |
| NUDOCS 9808130119 | |
| Download: ML20237A134 (3) | |
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UNITED STATES p
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,j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066-0001 i
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.163 TO FACILITY OPERATING LICENSE NO. DPR-25 COMMONWEALTH EDISON COMPANY l
DRESDEN NUCLEAR POWER STATION. UNIT 3 DOCKET NO. 50-249 1
1.0 INTRODUCTION
By letter dated May 6,1998, Commonwealth Edison Company (Comed, the licensee) submitted a request for a one-time change to the Dresden Nuclear Power Station, Unit 3, Technical Specifications (TS) for the plant main steam safety valves (MSSVs). Specifically, the licensee requested that TS Surveillance Requirement (SR) 4.6.E.2 be revised such that the surveillance interval be extended from 40 months to 60 months for Unit 3, Cycle 15 only, and that the provisions of TS 4.0.B not be applicable to the 60-month interval. TS 4.0.B states that each surveillance interval shall be performed within the specified surveillance interval with a maximum allowable extension not to exceed 25 percent of the surveillance intewal.
2.0 BACKGROUND
Dresden, Unit 3, has eight MSSVs (spring actuated) and one Target Rock (pilot actuated) safety and relief valve (SRV). The licensee complies with both tha TS and the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) OM-1-1981 testing requirements by testing at least one-half (four of eight) of the MSSVs, or replacing them with valves which have been tested, every 18 months. The Target Rock SRV is categorized in its own ASME valve group and is tested every 18 months. The reason for the proposed one-time TS change is that MSSVs 3-203-4A, B, C, and D, currently in service at Dresden, Unit 3, were installed on June 13,1994, and the TS 40-month surveillance interval, including the 25 percent extension per TS 4.0.B expires on August 13,1998. Therefore, the licensee proposes a one-time oxtension of the TS SR 4.6.E.2 surveillance interval from 40 months to 60 months (with no exter.sion), to allow plant operation until the fifteenth refueling outage, scheduled for the end of Jant,ary 1999.
3.0 BASIS FOR TECHNICAL SPECIFICATION CHANGE in order to meet the above TS SR for the MSSVs, the plant must be shut down to Mode 4 to perform the necessary MSSV surveillance. Without performing the required MSSV surveillance and upon expiration of the surveillance interval, the plant would be required to enter TS 3.6.E, Action 1, since valves 3 203-4A, B, C, c.nd 13 would be declared inoperable for failure to perform the surveillance within the required inteival it was possible for the licensee to have performed the necessary surveillance on these four MSSVs during a recently planned outage for replacing
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certain electrical equipment which began on May 2,1998. However, the licensee stated that this l
would have resulted in additional dsks and hardships, without a corresponding benefit to quality or safety. The licensee stated that the surveillance would have resulted in additional risk and 9908130119 990007 PDR ADOCK 05000249 P
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. i radiation dose to personnel performing the valve replacement. The licensee also stated that the Reactor Water Cleanup System would be out-of-service during this outage, and that the Main Steam Line Drains could not be used as an altemative drain path for the reactor coolant if the MSSVs were being removed. The licensee also stated that the replacement of MSSVs would result in an approximately 4-day extension to the outage and an associated loss of plant power generacon.
In support of the proposed longer surveillance interval for the MSSVs, the licensee submitted setpoint te,t data for recent refueling outages at both Units 2 and 3. The data indicate that the last as-found data for valves 3-203-4A, B, C, and D, which are scheduled for replacement at the next refueling outage, were within the +/-1 percent TS tolerance limits (with one exception, which was only 3 p91 above the +1 percent limit). Also, for valves 3-203-4E, F, G and H, which were installed for 65 months and then tested in May 1997, the as-found setpoints were within the
+/-1 percent TS tolerance limits (with one exception, which was only 4 psi below the -1 percent limit). The licensee stated that all of these valves are subjected to the same maintenance procedures. Therefore, the licensee is confident that valves 3-203-4A, B, C, and D will have acceptable setpoint results after subsequent as-found testing.
l 4.0 EVALUATION The staff has reviewed the licensee's proposed one-time TS change and agrees with the licensee that the current requirement to test the four MSSVs 3-203-3A, B, C, and D by
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August 13,1998, would result in additional hardship and risk without a corresponding increase in quality or safety. Further, the staff agrees that, based on the as-found setpoint test data for the plant MSSVs, there is adequate assurance that the valves will perform adequately until the next refueling outage. Therefore, the staff finds the proposed one-time change to TS SR 4.6.E.2, which would allow the surveillance interval to be increased to 60 months with the provisions of TS 4.0.B not applicable, to be acceptable.
5.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Illinois State officialwas notified of the proposed issuance of the amendment. The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a surveillance requirement. The NRC staff has determined that the amendment involves ne 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 (63 FR 30263). Accordingly, the amendment meets the eligibility criteria for categorical exc;usion set fosth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmentti impact statement or environmental assessment need be prepared in connection with the issuance of the amendment, i
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7.0 CONCLUSION
i Based on the above evaluation, the staff cencludes that the licensee has demonstrated the adequacy of the proposed one-time change to the Dresden, Unit 3, TS. The proposed change provides for increasing the MSSV surveillance interval from 40 months to 60 months with the
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provisions of TS 4.0.6 not applicable. Therefore, the proposed changes to TS SR 4.6.E.2 for i
Dresden, Unit 3, are acceptable.
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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 maner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: G. Hammer Date: August 7, 1998 t
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