ML20076N091
| ML20076N091 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 11/03/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20076N088 | List: |
| References | |
| NUDOCS 9411090187 | |
| Download: ML20076N091 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION k..s I\\h WASHINGTON, D.C. 20555 4001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 94 TO FACIl_ITY OPERATING LICENSE NO. NPF-62 ILLIN0IS POWER COMPANY. ET AL.
CLINTON POWER STATION. UNIT N0. 1 DOCKET NO. 50-461
1.0 INTRODUCTION
By letter dated August 12, 1994, Illinois Power Company the (the licensee) requested an amendment to Facility Operating License No. NPF-62 to revise Technical Specifications (TS) 3/4.3.1, " Reactor Protection System Instrumentation," TS 3/4.3.2, " Containment and Reactor Vessel Isolation Control System," TS 3/4.3.3, " Emergency Core Cooling System Actuation Instrumentation," TS 3/4.3.4.2, "End-of-Cycle Recirculation Pump Trip System Instrumentation," TS 3/4.3.5, " Reactor Core Isolation Cooling System Actuation Instrumentation," TS 3/4.4.2.1, " Safety / Relief Valves," and TS 3/4.4.2.2,
" Safety / Relief Valves Low-Low Set Function." The above referenced TS contain requirements to perform manual testing of the associated solid state logic at least once every four fuel cycles on a staggered basis. These tests are in addition to the automatic testing performed by the self-test system. The proposed TS change removes the requirement to perform manual testing of the solid state logic when the automatic testing is already performed.
2.0 EVALUATION The Clinton Power Station solid state logic design includes a computer-based self-test system (STS). The STS is a testing and surveillance system that is designed to continuously monitor system logic for the reactor protection, nuclear steam supply shutoff, automatic depressurization, high pressure core spray, low pressure core spray, residual heat removal and low pressure core injection, shutdown cooling, reactor core isolation cooling, end-of-cycle recirculation pump trip, and the relief and low-low set modes of the safety / relief valves.
The STS is a testing and surveillance subsystem that has the ability to continuously perform automatic testing of the nuclear safety protection system (NSPS) panel circuitry. The STS provides failure information such that failures can be traced to the module or circuit board level.
The tests performed by the STS include logic system functional tests (LSFTs) and response time testing (RTT). The STS is also used to augment conventional testing methods when performing channel checks, functional tests and calibrations. The scope of the STS functional and RTT capability for the nuclear system protection system logic extends from the analog trip module to the actuated device load driver.
9411090187 941103 PDR ADOCK 05000461 P
. A combination of conventional tests and the STS tests are necessary to perform complete end-to-end testing of the NSPS. The present TS requires that parts of the NSPS be tested independent of the STS to verify the operability of the 51S and confirm STS test results. The additional manual testing independent of the STS requires temporary system reconfiguration, and reduces system availability and component reliability.
The licensee stated that this additional manual testing also results in increased potential for unintended equipment actuation during manual testing. The removal of the manual testing requirement will reduce the potential for unwanted actuation and is supported by successful performance of the self-test system during the plant pre-operational testing and the last four refueling outages. The licensee stated that the proposed change will result in a net increase in overall safety.
A review of STS operational history by the licensee shows that the pre-operational test program confirmed that no functional failures existed which should have been detected by the STS. A review by the licensee of the manual testing of the NSPS logic during each of the past four refueling outages, including all the NSPS logic automatically tested by the STS, confirmed that no functional failures were identified by manual testing that were not detected by the STS.
Based on the above, the licensee proposes to revise the TS to remove manual testing of the NSPS logic independent of the STS.
The requirement to perform an LSFT every 18 months will not be revised.
With the absence of manual testing of the NSPS that verifies the operability of the STS, the importance of STS configuration management (both hardware and software) increases.
The licensee should verify that the STS configuration plan makes provisions for software control, storage of hardware and software (including verification of marking or labeling) and the implementation of system changes or enhancements (including interface control).
The licensee indicated that the STS is bounded by plant procedures that ensure continued configuration control of the STS. The staff finds this acceptable.
Based on the operating history test results, LSFT testing at 18-month intervals, the reduced potential for unwanted protection system actuation, the l
staff finds the proposed TS revision to remove the manual testing requirement i
of the STS to be acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment changes 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 changes surveillance requirements.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no
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. 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 amendment involves no significant hazards consideration and there has been no public comment on such finding (59 FR 49428). Accordingly, the amendment meets 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 amendment.
5.0 CONCLUSION
The staff 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:
Cliff Doudt Date: November 3, 1994 l