ML20082J713
| ML20082J713 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 08/22/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20082J704 | List: |
| References | |
| NUDOCS 9108280239 | |
| Download: ML20082J713 (3) | |
Text
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P UNITED STATES i
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I NUCLEAR REGULATORY COMMISSION WASHINGTON, D C. 20M4
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I SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACT 0r, REGULATION i
RELATED TO AMENDMENT NO. 38 TO FACILITY OPERATING LICENSE NO. NPF 58 LHECLEVELANDELECTRICILLUMINATINGCOMPANY,ETAL, PERRY NUCLEAR POWER. PLANT, UNIT NO. 1 DOCKET 00. 50 440
1.0 INTRODUCTION
By letter dated December 14, 1989, the Cleveland Electric Illuminating Company (CEI) requested a change to the Technical Specifications (TS$) for the Perry Nuclear Power Plant Unit 1.
The proposed change would revise the surveillance frequency specified in TS 4.3.8.2 for the turbine control valves from weekly to monthly.
The licensee's basis for the change is that the probability of generating a turbine missile at Perry would remain unchanged from that previously analyzed and approved by the NRC staff, while a benefit to safety would be realized by limiting the power changes necessary
-to conduct testing of the turbine valves.
In addition, minor word changes were proposed to clarify the intent of the specification.
2.0 EVALUATION According to Section 10.2.2.3 of the Perry Updated Safety Analysis Report (USAR), the turbine overspeed protection system is not safety-rclated and, as such, has no direct function in the safe shutdown of the reactor.
- However,'a reliable, redundant f ail. safe turbine overspeed system was incorporated into the plant's design for the protection of plant personnel and equipment..The turbine overspeed protection. system greatly reduces the probability of turbine missile generation in the event of damage to the turbine cr associated components, and consequently the probability of damage to systems necessary for safe shutdown is-also reduced.
Additionally, the potential for a breach of the primary coolant boundary, and the resultant release of radioactivity to the environment, is minimized.
The purpose of the surveillances performed on the turbine overspeed protection system and the-turbine steam valves that it controls valves, intercest valves and intermediate stop valves (stop valves, control
) is to ensure a high degree of relia)ility of those components, such that the probability of a missile-generating turbine failure is kept acceptably low. Table 3.1 of Supplement 3 to the Perry Safety Evaluation Report (NUREG-0887) specifies the staff's acceptance' criteria for the-probability of turbine missile generation, which for Perry is 1.0E-5 per year.
In a safety evaluation dated. August 23, 1989, the staff accepted the licensee's calculated turbine missile generation probability of 6.2E-6 per year, which met the specified i
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2 criteria.
The licensee's calculation was performed in accordance with a staff approved General Electric methodology, for the calculation, a monthly test frequency for the turbine control valves was conservatively assumed; therefore, the proposal to change the TS surveillance frequency from weekly to monthly will not impact the previously approved analysis.
The failure of a turbine control valve is bounded by the scenarios analyzed in the Perry USAR that result in a turbine trip.
Extending the surveillance interval for the turbine control valves from weekly to monthly may actually reduce the probability of test-related valve failures although failures may not be detected as promptly.
However, both of these II,ctors are likely to have only a slight impact on the reliability of the valves.
Therefore, the proposed change would not affect the existing accident analysis, in the submittal of December 14, 1989, the licensee indicated that a reduction in the control valve test frequency could improve operational safety by reducing perturbations to reactor operating conditions and by reducing the period of time that the reactor would be more vulnerable to an inadvertent scram during testing.
Current testing of the control valves requires a reduction to 90t power, while testing of the other turbine steam valves could possibly be conducted at power levels above 951 A smaller change in power level to conduct testing would have a reduced impact on other operating parameters including feedwater flow and reactor pressure, thus reducing the likelihood of transients. Also, the current testing causes a 1/2 scram signal to be initiated as the control valves are cycled, thus a reduction in test frequency would result in a slightly lower probability for an inadvertent scram.
The staff agrees that a reduction in test frequency of these valves could result in an improvement to plant safety.
The licensee has also proposed an editorul char.ge to the format of Surveil-lance Requirement 4.3.8.2.
This change ren.sv0s the references to the turbine overspeed protection subsystems and specifies the monthly surveillance frequency for the turbine control valves separately from the weekly frequency for the other turbine valves. This change does not modify any current test requirements (other than the control valve test frequency discussed previously) and more closely conforms to the format of the Standard Technical Specifications.
Based on the above evaluation, the staff finds the proposed changes to Section 4.3.8.2 of the Perry Unit 1 Technical Specifications to be acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Ohio State official was notified of the proposed issuance of the amendment.
The State official 1
had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a requirement with respect to the instal-lation or use of a facility component located within the restricted area as
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j defined in 10 CFR fort 20 or a change to a surveillance requirement. The staff has determined that tht amendment involve'4 no significant increase in the amounts, and no significant ch6cge in th9 types, of any effluents that may be released offsite and that there 1: nn significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards i
considerationandtherehasbeennopubliccommentonsuchfinding(55FR4282).
Accordingly, this amendment meets the eligibility criteria for categorical exclusionsetforthin10CFR51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statenent or environmental assessment need be prepared in connection with the issuance of this 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 4
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 this amendment will not be_ inimical to the common defense and security or to the health and safety of the public.
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Principal Contributor: Janes R. Hall, NRR Date:
Auoust 22, 1901 l
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