ML20085K398

Safety Evaluation Supporting Amends 100 & 89 to Licenses NPF-10 & NPF-15,respectively

ML20085K398
Person / Time
Site:	San Onofre
Issue date:	10/09/1991
From:	Office of Nuclear Reactor Regulation
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ML20085K396	List: ML20085K398
References
NUDOCS 9110310061
Download: ML20085K398 (3)

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3, 7 (e,i NUCLEAR REGULATORY COMMISSION UNITED STATES n -{' og ,a, wAsmNoTON, o.C. 385 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.100TO FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO.89 TO FACILITY OPERATING LICENSE WO. NPF-15 t SOUT;lERN CALIFORNIA EDISON COMPANY-SAN DIEGO GAS AND ELECTRIC COMPANY THE CITY OF RIVERSIDE, CALIFORNIA THE CITY OF ANA4EIM, CALIFORNIA SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NOS. 2 AND 3 DOCKET NOS. 50-361 AND 50-362 L 1.0 -INTRODUCTION By letter dated August 16, 1991, Southern California Edison Company, et al. (SCE or the licensee) submitted a request for changes to the Technical Specifications (TS) for San Onofre Nuclear Gecerating Station, Unit Nos. 2 and 3 The proposed changes would delete reference. to the moveable-in-core i detector system (MICDS) from TS 3.3.3.2, "In-Core Detectors," ar.d TS 3/4.8.4, " Electrical Equipment Protection Devices" (Table 3.8-1 " Containment Penetration'Cor,ductor.0vercurrent Protective Devices")., These changes will not revise the associated Bases. The licensee proposes to rely solely on the fixed in-core detector system (FICDS), dispensing with an alternate moveable in-core detector system for mapping neutron flux in the reactor cere. These changes to the TS will essentially preclude the use of the MICDS at San Onofre Nuclear L j Generating Station, Unit Nos. 2 and 3. 2.0 EVALUATION - Currently, the San Onofre Units 2 and 3 TS require an operable in-core detection system with at least 75% of all in-core detector locations'and a minimum of two quadrant symmetric in-core detector locations per core quadrant. An operable 'in-core detector location consists of a fuel asserr61y containing a fixed detector string with a minimum of four operable rhodium detectors or an operaole moveable in-core detector capable of mapping the location. The in-core detection system is used for monitoring azimuthal power tilt, radial peaking factors, local power density, and departure trom nucleate boiling margin. With the in-core detection system inoperable, the TS will not allow use of the system-for these monitoring or calibration functions. 9110310061 911009 l PDR ADOCK 05000361 i P PDR

ms- -2 The MICDS consists of two drive machines, two rotary transfer assemblies, two drive cables with detectors, and interconnecting Each drive machine has the capability of accessing half (28) guide tubes. of the in-core instrumentation calibration tubes; the moveable flux detectors were designed to be inserted into any of the 56 calibration tubes. The MICDS was designed to accept reactor coolant system leakage from the in-core monitoring system. Additionally, containment cable penetration overcurrent protection was provided. The licensee has decided to remove the MICDS and rely on the FICDS exclusively. The licensee lists several advantages in removing the MICDS. First the licensee intends to remove all MICDS equipment and install pressure, caps and room temperature vulcanizing plugs on the in-core instrumentation calibration tubes, eliminating 56 possible reactor coolant systems leakage paths and enhancing reactor pressure vessel integrity. Second, MICDS removal will reduce radiological exposures and critical path time involved in maintenance activities around the reactor pressure vessel head during routine refueling outages. Third, MICDS removal will provide for a safer work environment by reducing the number of ccmponents in the reactor pressure vessel head lift area. Fourth, all MICDS power sources will be disconnected, precluding any overcurrent events. The licensee states that the TS does not require MICDS to be operable if the FICDS is operable-for monitoring purposes. Operators et San Onofre Units 2 and 3 have not relied on the MICDS, but have used the FICDS only. In fact, the licensee has already precluded the use of the MICDS by disconnectin guide tubes (and plans to remove the equipment during upcoming outages)g the The I changes to the TS will ensure that the TS match the as-built plant configuration. The staff agrees with the licensee that the MICDS should be removed from the TS l to reflect current operating practice and plant design. The staff agrees that the removal of the MICDS will not affect the ability of the in-core detection system to perform its monitoring functions, though it will preclude the use of the MICDS and require exclusive reliance on the FICDS. The staff notes that the capping of 56 additional reactor coolant system leakage paths is a net safety benefit. Therefore, based upon the information provided in the licensee's August 16, 1991, submittal, the staff finds the proposed changes to the Technical Specifications for San Onofre Nuclear Generating Station, Unit Hos. 2 and 3, to be acceptable.

3.0 STATE CONSULTATION

In accordance with the Commission's regulations, the California State official was notified of the proposed issuance of the amendment. The State official had no comments.

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4.0 ENVIRONMENTAL CONSIDERATION

The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 1.1 CFR Part 20. 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 ray be released offsite, and that there is e,o significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a prcposed finding that the amendments involve no significant hazards consideration, and there has been no public connent on such finding (56 FR 43813). 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, 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: Lawrence E. Kokajko Date: October 9, 1991 ..}}