ML20246K267
| ML20246K267 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/23/1989 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | |
| Shared Package | |
| ML20246K252 | List: |
| References | |
| 1702, NUDOCS 8909050421 | |
| Download: ML20246K267 (5) | |
Text
._
. Dockat Numb:r 50-346
' Licensa Nunb r NPF-3
- S:ric1 Number 1702 Enclosure Page 1 APPLICATION FOR AMENDMENT TO FACILITY OPERATING LICENSE NUMBER NPF-3 DAVIS-BESSE NUCLEAR POVER STATION UNIT NUMBER 1 Attached are requested changes to the Davis-Besse Nuclear Power Station, Unit Number 1 Facility Operating License Number NPF-3. Also included are the Technical Description and Significant Hazards Consideration.
The proposed changes (submitted under cover letter Serial Letter 1702) concern:
Section 3/4.0, Limiting Condition for Operations and Surveillance Requirements
- Applicability, Surveillance Requirement 4.0.2.
For: D. C. Shelton Vice President Nuclear By:
T. J. er , Technical Services Director 292
$8 Sworn and subscribed before me this 23rd day of August, 1989.
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nu 4Q o m Yath Y Notary Pu6lic, State of Ohio L
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$fa EVELYNL DRESS J C, STATE OF 040 NOTARY PU3' MyComWr.r,a : AV 2,134
. Dockat Nurbar 50-346-
" ~
Liernse'Numbtr NPF-3:
-Serial Number'1702 Enclosure.
Page-2 The following information is provided to support. issuance of the requested changes to the Davis-Besse Nuclear' Power Station, Unit Number 1 Operating License Number NPF-3, Appendix A, Technical Specification, Section 3/4.0.
A. Time Required to Implement: This change is to be implemented by 1 November. 13, 1989.
'B. Reason for Change (License Amendment Request Number 88-0004):
Surveillance Requirement 4.0.2 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'of 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 4.0.2 further limits the 25 percent allowance for extending surveillance intervals by' requiring-that the combined time interval for any three consecutive surveillance not exceed 3.25 times the specified surveillance interval. This request proposes the removal of the 3.25 limit required by SR 4.0.2b.
C. Technical
Description:
See attached Technical Description (Attachment 1).
D. Significant Hazards Consideration: See attached Significant Hazards Consideration (Attachment 2).
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l 1
.~ Docket Number 50-346
. , Licpnse Number NPF-3 Serial Number 1702
' Attachment 1 Page 1 TECHNICAL DESCRIPTION Description of Proposed Technical Specification Change The purpose of'this technical description is to review a proposed change to the Davis-Besse Nuclear Power Station (DBNPS) Technical Specifications (TS) 3/4.0 (Limiting conditions for Operations and Surveillance Requirements -
Applicability), Surveillance Requirement (SR) 4.0.2. SR 4.0.2 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 of 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 4.0.2 further limits the 25 percent allowance for extending surveillance intervals by requiring that the combined time interval for any three consecutive surveillance not exceed 3.25 times the specified surveillance interval. This request proposes the removal of the 3.25. limit required by SR 4.0.2b. This request is similar to the License Amendments issued by the NRC on July 19, 1989, that deleted SR 4.0.2b from the Operating Licenses Technical Specifications for LaSalle County Station, Units 1 and 2.
Systems Affected No hardware changes vould be required for implementation of this proposed change.
Effects on Safety Many surveillance have a specified surveillance interval of 18 months.
Generally, an 18-month surveillance interval is intended to allow the surveillance.to be performed when the unit i; shut down during a refueling outage. Therefore, the actual time interval for the perfornence 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, thereby 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 shutdown to perform these surveillance is generally the only alternative short of a license amendment that defers the performance of these surveillance until the end of the fuel cycle.
Usually,thIlengthofafuelcyclewouldnotexceed18monthsbymorethan 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 NRC Staff has routinely approved one-time amendment requests to vaive the performance of 18-month surveillance until the end of the fuel cycle when they wou?d exceed the 3.25 limitation on consecutive surveillance yet vould not exceed the 25 percent allowance for extending the ?8-senth surveillance interval. A forced shutdown to perform m
. Docket Number 50-346-
~ .- license Number NPF-3
' Serial Number 1702 Attachment 1 Page 2 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 generally 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 s
' 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. Based on routine safety system instrumentation channel functional testing which adjusts any out of tolerance conditions (except for sensors), instrument drift, due to increased period between calibrations, will not be a concern.
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 activities, safety may be enhanced by the use of the allowance that permits a surveillance interval to be extended. In such cases, the safety benefit of extending a surveillance interval up to 25 percent would exceed the risk reduction derived by conforming to the 3.25 limitation. Furthermore, there is a large administrative and logistical burden on licensees that is associated with tracking the use of and exceptions to the 25 percent allowance for prior surveillance intervals >to ensure compliance with the 3.25 limit. This results in a diversion of resources and attention from more safety significant activities.
Based on the above discussion, it is concluded that the removal of the 3.25 limit for all surveillance is justified. In addition, the Bases of this specification is proposed to be 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 allovable extension limit.
Unreviewed Safety Questions / Evaluation The proposed changes vould not increase the probability of occurrence of an accident previously evaluated in the USAR because the accident conditions and assumptions are not affected since no hardware changes are being made nor is testing being degraded. Surveillance intervals vill continue to be constrained by the maximum 25 percent interval extension criterion of TS 4.0.2a.
The proposed changes vould not increase the consequences of an accident previously evaluated in the USAR because the accident conditions and j assumptions are not affected since no hardware changes are being made.
The proposed changes vould not increase the probability of a malfunction of equipment important to safety previously evaluated in the USAR because the changes do not involve a test or experiment and no station equipment is being modified. The proposed changes will not prevent any system from functioning as assumed in the USAR. Also, surveillance intervals vill centinue to be constrained by the maximum 25 percent interval extension criterion of TS 4.0.2a.
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. Docket Number 50-346
. License Number NPF-3 Serial Number 1702 l Attachment 1 Page 3 The proposed changes vould not increase the consequences of a malfunction of equipment important to safety previously evaluated in the USAR because these proposed changes do not involve a modification to equipment or change the operation of a system. The proposed changes vill not prevent any system from functioning as assumed in the USAR.
The proposed changes vould not create the possibility for an accident of a different type than any evaluated previously in the USAR because the proposed changes do not add or modify any existing equipment. Surveillance intervals vill continue to be constrained by the maximum 25 percent interval extension criterion of TS 4.0.2a.
The proposed changes would not create the possibility for a malfunction of equipment important to safety of a different type than any evaluated previously in the USAR because the changes do not involve a test or experiment and no station equipment is being modified.
The proposed changes vould not reduce the margin of safety as defined in the basis for any Technical Specification since surveillance intervals vill continue to be constrained by the maximum 25 percent interval extension criterion of TS 4.0.2a.
Conclusion Based on the above, it is concluded that the proposed Technical Specification and Bases changes do not constitute an unreviewed safety question.