ML20206U433
| ML20206U433 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 02/09/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206U421 | List: |
| References | |
| NUDOCS 9902160026 | |
| Download: ML20206U433 (3) | |
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4 UNITED STATES E
NUCLEAR REGULATORY COMMISSION I
f WASHINGTON, D.c. 20565 @ 01 h..... p5 SAFEW EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 242 TO FACILITY OPERATING LICENSE NO-DPR-77 AND AMENDMENT NO. 232 TO FACILITY OPERATING LICENSE NO. DPR-79 TENNESSEE VALLEY AUTHORlW SEQUOYAH NUCLEAR PLANT. UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328
1.0 INTRODUCTION
The Tennessee Valley Authority (TVA, the licensee) requested amendments to Operating Licenses DPR-77 and DPR-79 for Sequoyah Nuclear Plant (SQN), Units 1 and 2, respectively, in a letter dated November 16,1998. The amendments would revise the SON Units 1 and 2 Technical Specifications (TSs) for the emergency diesel generators (EDGs) by adding a note to Surveillance Requirement (SRs) 4.8.1.1.2.d.10 and deleting SR 4.8.1.1.2.d.11. Specifically, the change would (1) allow performance nf SR 4.8.1.1.2.d.10 to be performed in Modes 1,2, 3 or 4, if the associated components are already out-of-service for testing or maintenance, and /2) remove the SR (4.8.1.1.2.d.11) that verifies certain lockout features that prevent EDG from starting.
2.0 BACKGROUND
TVA proposes to allow the surveillance testing that verifies that the automatic load sequencer timers are within 15 percent of their design setpoints to be performed at any operational mode if coupled with existing testing or maintenance. This change allows testing, currently required to be performed during plant outages, to be moved to periods with lighter, less complex maintenance schedules and therefnre make more efficient use of existing limiting condition for operation (LCO) allowed outage time.
The change to delete SR 4.8.1.1.2.d.11 from TSs is consistent with NUREG-1431, " Standard Technical Specifications for Westinghouse Plants." This proposal would remove items that are inconsistent with NUREG-1431 content in order to simplify TSs.
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i 3.0 EVALUATION SR 4.8.1.1.2.d.10 - Add a note that allows the SR to to perfctmed in Modes 1,2,3 or 4, if the associated equipment is out-of-service for maintenance or testing.
The EDGs serve as the plant emergency standby alternating current power source. They are designed, installed, and tested to requirements necessary to assure their availability. The EDGs consist of four estf-contained, water-cooled, automatic-starting, diesel engine driven, and 9 % 2160026 990209 PDR ADOCK 05000327 P
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2 stationary electric generators. Two EDGs in the same train are required to mitigate a design basis event in one unit; redundancy for single failure is provided by maintaining four EDGs in ready condition for automatic start. The EDGs are designed for automatic connection to the 6.9-kV shutdown boards with automatic load sequencer timers adding large loads to the boards in the appropriate sequence so that the EDGs do not overload during the process.
J Calibration of the time delay relays associated with automatic load sequence timers may defeat certain functions in the downstream equipment energized by the timer. This may require entry into LCOs associated with the function. However, the time required to perform the calibration is typically a small fraction of the LCO period. Maintenance and testing functions typically require periodic entry into these same LCOs. Coupling the calibrations with existing maintenance or testing LCO allowed outage time does not increase the unavailability of the equipment. It does allow the calibrations to be done at a time when the maintenance schedule is less complex and less harried, inherently reducing the potential for human error and more efficient use of LCO allowed outage time. This is consistent with NRC Generic Letter 91-04, which states, "The Staff concludes that the TS need not restrict surveillances as only being performed during shutdown.
Nevertheless, safety dictates that when refueling interval surveillances are being performed during power operation licensees give proper regard for their effect on safe operation of the j
plant." Standard TSs recognize this issue and allow plant-specific removal of mode restrictions based on meeting three criteria that performance of the SR will not:
Render any safety system or component inoperable. This criteria is met by doing the work coupled with existing out-of-service conditions.
l Cause perturbations to any of the electrical distribution sys.tems that could result in a challenge to steady state operation or to plant safety systems. Calibration of the time delay relays, associated with the load sequence timers, only affects downstream equipment, which will already be out-of-service for testing or maintenance activities. Therefore, there will be no challenge to steady state operation or to plant safety systems.
Cause or result in an anticipated operational occurrence with attendant challenge to plant safety systems. The work will be coupled with existing out-of-service conditions so it will not cause or result ir.) an anticipated operational occurrence.
The EDGs have various protective devices installed to shut down an EDG automatically to prevent heavy damage in the event of a system malfunction. As described in Final Safety Analysis Report (FSAR) Section 8.3.1.1, these devices are operative only during the exercise mode of operation, with the exception of the generator differential relay and the engine overspeed switch.
Removal of the requirement for verifying certain EDG lockout features that prevent EDG starting oniy when required is consistent with standard TSs (NUREG-1431). The surveillances implementing this SR verify that the EDG will not start if one or more of the emergency trips are active. This SR verifies an equipment protection function. The function is nonsafety related.
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Therefore, it does not meet the test for inclusion in TSs in accordance with 10 CFR 50.36 criteria. The equipment affected is not:
Used to detect or indicate a significant abnormal degradation of the reactor coolant system boundary.
A process variable, design feature or operating restriction that is an initial condition to a design basis accident (DBA).
A structure, system or component that is part of the primary success path and which functions or actuates to mitigate a DBA.
A structure, system or component, which operating experience or probabilistic safety assessment has shown to be significant to the public health and safety.
This SR was removed from TSs in the development of the Standard TSs (NUREG-1431). It was removed because the function was only for equipment protection and the requirement was not contained in the TSs of other recently licensed plants at that time. The functions will remain as described in FSAR Section 8.3.1.1. For the reasons discussed above, the U.S. Nuclear Regulatory Commission (NRC) staff finds the proposed changes to be acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Tennessee State official was notified of
- the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The 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 amendmen.t involves 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 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 66603, dated December 2,1998). 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.
6.0 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. end (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.
4 Principal Contributor: Ronald W. Heman j
Dated. February 9, 1999 i
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