ML20198S417
| ML20198S417 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/21/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198S411 | List: |
| References | |
| NUDOCS 9711140039 | |
| Download: ML20198S417 (3) | |
Text
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Jt UNITE) STATES 0j
,j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. - m1
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.131AND123TO FACILITY OPERATING LICENSE NOS. DPR 42 AND DPR-60 NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT. UNIT NOS.1 AND 2 DOCKET NOS. 50 282 AND 50 30s
1.0 INTRODUCTION
By letter dated November 6,1996, as supplemented April 10 and October 1,1997, the Northern States Power Company (NSP or the licensee) requested amendments to the Technical Specifications (TS) appended to Facility Operating License Nos. DPR 42 and DPR-60 for the Prairie Island Nuclear Generating Plant, Unit Nos.1 and 2. The proposed amendments involve use of the swing motor-driven safeguards cooling water pump, the testing frequency of cooling water isolation valve actuation circuits, revision of site descriptive information, and removal of certain requirements contained in the Site and Engineered Safety Features sections of the TS. This evaluation pertains only to the proposed requirements 'or the swing motor-driven safeguards cooling water pump and the testing frequency of cooling water isolation valve actuation circuits. More information is needed prior to staff approval of the changes requested by the licensee to TS 5.1 and the remainder of TS 5.4. These changes will be addret. sed in a separate licensing action.
The April 10 and October 1,1997, letters provided clarifying information within the scope of the original application and did not change the staff's initial proposed no significant hazards considerations determination.
2.0 EVALUATION 2.1 Swino Coolina Water Pumo Section 3.3.D.1.a of the existing Prairie l= land TS require that four of five cooling water pumps be operable and states requirements for aligning the motor-driven (swing) safeguards cooling water pump if one of the two diesel-driven safeguards cooling water pumps become inoperable. However, Section 3.3.D.2.a of the Prairie Island TS allows two of the three safeguards cooling water pumps to be inoperable for up to 7 days provided that certain conditions are met. The licensee proposes to change Section 3.3.D.1.a to include an option to enter TS Section 3.3.D.2.a (i.e.,7-day action requirement) in lieu of aligning the motor-driven safeguards cooling water pump as currently required by TS 3.3.D.1.a.
9711140039 971021 PDR ADOCK 05000282 P
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2 The licensee originally upgraded the motor-driven safeguards cooling water pump and established the requirement stated in TS 3.3.D.1.a (submittal dated March 20,1992) in order to increase the availability of the cooling water system and to provide additional operational capability during periods when one of the two diesel-driven safeguards cooling water pumps is inoperable. The licensee's proposed change to TS Section 3.3.D.1.a provides additional operational flexibility without diminishing the cooling water system performance and operationel capability below what is currently allowed by TS 3.3.D.2.a which states the allowed outage time requirements for the cooling water system pumps. Therefore, the proposed change to TS Section 3.3.D.1.a is acceptable.
2.2 Coolino Water Isolation Valves The existing Prairie Island TS 4.5.B.3.e requires that the actuation circuits for toe Cooling Water System valves that isolate non-essential equipment to be tested in accordance with Section 4.2 of the TS, which requires quarterly testing. TS 5.4 3 also describes the logic for the cooling water isolation valves. Currently, the turbine building cooling water loads are isolated if the header experiences high flow coincident with low pressure. Recent system essessment activities performed by the licensee determined that system performance could be improved if the valve actuation logic were modified to isolate on an SI [ safety injection) signal coincident with low header pressure. The licensee plans to install a modification that would impi; ment the above cooling water isolation valve logic during the next refueling outage. However, due to the Si circuit inputs into this logic, it can be tested only during outages. Therefore, the licensee has proposed the change to TS 4.5.B.3.e to require testing of the cooling water isolation valves circuitry during refueling outages. The licensee has also proposed the change to TS 5.4 3 which describes the isolation logic.
The licensee has determined that by changing the logic for the actuation circuitry for the cooling water isolation valves from high flow coincident with low header pressure to an SI signal coincident with low header pressure plant safety will be improved. In 1995 Prairie Island performed a self assessment Service Water System Operational Performance Inspection (SWSOPI) and determined that plant safety would be improved by making the turbine building cooling water isolation header directly responsive to an SI signal. Current inputs to the isolation logic are not positive indicators that an accident is in progress.
The original plant design isolated the turbine building cooling water header on an SI signal to assure that essentialloads were supplied with cooling water during an accident. However, the isolation logic was modified during plant construction due to concems with spurious Si signals. The earlier concems with spurious SI signals are addressed by retaining the low header pressure input. The low header pressure input will also be raised during the plant modification which will cause the isolation to occur sooner. These changes do not fall under the guidance for increased surveillance interval instrument drift contained in Generic Letter 91-04, " Changes to Technical Specification Surveillance Intervals to Accommodate a 24-Month Fuel Cycle," because the pressure switches within the circuitry will continue to be calibrated in accordance with their current surveillance schedules. These changes will assure that essentialloads are supplied with cooling water during an accident. Therefore, the proposed changes to TS 4.5 3 and TS 5.41 are acceptable.
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3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Minnesota State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATIOtj The amendments change 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 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 effluents that may be released offsite, and that there is no significant increaso 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 (62 FR 4338). 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) j 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 the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: J. Tatum B. Wetzel Date:
October 21, 1997
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