ML20247L129
| ML20247L129 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 07/19/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247L117 | List: |
| References | |
| NUDOCS 8908010149 | |
| Download: ML20247L129 (3) | |
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UNITED STATES g
g NUCLEAR REGULATORY COMMISSION W
- j WASHINGTON, D. C. 20555 S
i e.....f SAFETY.EVALUAT10!l BY THE.0FFICE.0F NUCLEAR REACTOR. REGULATION
!~
SUPPORTING ANENDMENT NO. 68.70 FACILITY;0PERATING. LICENSE.N0..NPF-11 AND AMENDMENT NO. 50.TO. FACILITY.0PERATING. LICENSE.NO. NPF.18 COMMONWEALTH. EDISON. COMPANY LASALLE. COUNTY. STATION,. UNITS.I.AND 2 DOCKET N05. 50-373.AND 50-374 1.0 IldTRODUCTION By letter cated December 4, 1937 supplemented March 10, 1989 Commonwealth Ecison Company (the licensee) proposed changes to the Technical Specifications.
(TS) for LaSalle County Station, Units 1 ano 2.
The proposed changes would exempt surveillance specified with an 18-month surveillance interval from the provision of Specification 4.0.2 that limits the combined time interval for three consecutive surveillance to 3.25 times the 18-month surveillance interval. This is a lead-plant proposal for an improvement in TS that is a part of the NRC Technical Specification Improvement Program. This Safety Evaluation Report addresses the acceptability of the proposeo change to the TS
.for the LaSalle license. During the staff's review of the change as prcposed, it was concluded that a greater benefit to safety could be obtained by ccmpletely removing the 3.25 limit and thus all surveillance would be exempt from this limitation on extending surveillance intervals. The licensee concurred with this adjustment to the original proposal.
2.0 BACKGROUND
Specification 4.02 includes a provision that allows surveillance intervals to be extended by 25 percent of the specified time interval. This provides flexibility for scheduling the performance of surveillance and to permit consideration of plant operating conditions that may not be suitable for conducting a surveillance at its specified time interval. Such conditions include transient plant operation or safety systems that may be out-of-service due to maintenance or other ongoing surveillance activities. Specification 4.02 further limits the 25 percent allowance for extending surveillance intervals by requiring that the combined time interyc1 for any three consecutive surveillences not exceen 3.25 tines the specified surveillance interval. This assures that the provision for extending surveillance is not used repeatedly to provide an overall increase in the surveillance interval.
3.0 EVALUATION Many surveillance have a specified surveillance interval of 18 months.
Generally, an 18-month surveillance interval is intended to ellow the surveillance to be performed when the unit is shut down during a refueling 8900010149 090719 II ADOCK0500y{3 DR
outage. Therefore, the actual time interval for the performance of these surveillance is dependent on the length of a fuel cycle, but it cannot exceed 18 months plus the 25 percent allowance. The safety benefit of performing these surveillance during a plant shutdown is that systems do not have to be removed from service at a time that they are required to be operable. This minimizes the amount of time which systems are unavailable during power operation due to surveillance requirements, theret'y minimizing the impact on safety.
In a few instances, the TS specifically require some surveillance to be performed during a plant shutdown. When a limit is reached on extending an 18-month interval, a forced plant shutdowa to perform these surveillance is generally the only alternative short cf a license amendment that defers the performance of these surveillance until the end of the fuel cycle.
Usually, the length of a fuel cycle would not exceed 18 months by more than the 25 percent allowance, i.e., 4-1/2 months. A more common situation has been to encounter the 3.25 limit on the combined time interval for three consecutive surveillance intervals. The staff has routinely approved one-time amendment requests to waive the performance of 18-month surveillance until the end of the fuel cycle when they would exceed the 3.25 limitation on consecutive surveillance yet would not exceed the 25 percent allowance for extending the 18-month surveillance interval. A forced shutdown to perform these surveillance is not justified from a risk standpoint to avoid exceeding the 3.25 limit when extending these surveillance is within the 25 percent allowance. Because the 18-month surveillance are performed during a refueling outage when the plant is in a desirable condition for conducting these surveillance, the risk of the alternative to perform some of these surveillance during plant operation is greater than the impact on safety of exceeding the 3.25 limit and using the 25 percent allowance to extend these surveillance.
In addition to its application to refueling outage surveillance, the use of the 25 percent allowance for extending surveillance intervals can have a safety benefit when it is used during plant operation. When plant conditions are not suitable for the conduct of surveillance due to safety systems being out-of-service for maintenance or due to other ongoing surveillance 1
activities, safety is enhanced by the use of.the allowance that permits a j
surveillance interval to be extended.
In such cases, the safety benefit d extending a surveillance interval up to 25 percent would exceed the risk reduction derived by conforming to the 3.25 limitation.
Furthermore, there is l
a large administrative and logistical burden on licensees that is associated j
with tracking the use of the 25 percent allowance for prior surveillance i
intervals to er.sure compliance with the 3.25 limit. This recults in a diversion of re.ources and attention from more safety significant activities.
In view of these findings, the staff concludes that the removal of the 3.25 limit for all surveillance is justified because overall it will have l
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w a greater benefit to safety. The following modification of the proposed change to Specification 4.02 was discussed with the licensee and was found to be acceptable:
"4.0.2 Each Surveillance Requirement shall be performed within the specified surveillance interval with a maximum allowable extension not to exceed 25 percent of the specified surveillance interval."
In addition, the Bases of this specification was updated to reflect this change and noted that it is not the intent of the allowance for extending surveillance intervals that it be used as a convenience to repeatedly schedule the performance of surveillance at the allowable extension limit.
On the bases of its review-of this matter, the staff concludes that the above change to the TS for LaSalle County Station, Units 1 and 2 are acceptable.
4.0 ENVIRONt1 ENTAL CONSIDERATION The Commission has prepared and published in the Federal Register (54 FR 30295)
July 19, 1989 an Environmental Assessment related to the action and has concluded that an environmental impact statement is not warranted because there will be no environmental impact attributable to the action beyond that which has been predicted and described in the Commission's Final Environmental Statement related to the Operation of LaSalle County Station, Units 1 and 2 dated November 1978.
5.0 CONCLUSION
On the basis of the considerations discussed above,.the staff concludes 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 j
issuance of these emendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Thomas G. Dunning OTSB/00EA Paul C. Shemanski, NRR/DRSP Dated: July 19, 1989 i
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