ML13331A894
| ML13331A894 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/15/1986 |
| From: | SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML13331A893 | List: |
| References | |
| TAC-63317, NUDOCS 8611050295 | |
| Download: ML13331A894 (3) | |
Text
DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE NO. 163 TO THE TECHNICAL SPECIFICATIONS PROVISIONAL OPERATING LICENSE OPR-13 This is a request to revise Section 4.1.1, "Operational Safety Items" of the Appendix A Technical Specifications for San Onofre Nuclear Generating Station, Unit 1.
Description Included as part of Technical Specification 4.1.1 is Table 4.1.2, "Minimum Equipment Check and Sampling Frequency."
This table delineates requirements to "check" specified systems or components to verify proper functioning.
Included in Table 4.1.2 is a requirement to verify control rod drop times during each refueling outage. During a review of various refueling outage procedures, a discrepancy was identified between the technical specification acceptance criterion for this surveillance and the design basis for the San Onofre Unit 1 accident analyses as evaluated in the Final Safety Analysis (FSA).
The technical specification acceptance criterion of less than 2.7 seconds for the control rods to move from full out to full in exceeds that of the FSA design basis of 2.44 seconds.
For this reason, this proposed change requests to revise Technical Specification Table 4.1.2 to reduce the acceptance criterion for control rod drop time from 2.7 seconds to 2.44 seconds.
A review was conducted of all previous control rod drop time testing data.
This review determined that the majority of control rod drop times have been between 2.10 and 2.20 seconds.
At no time has a control rod drop time exceeded 2.44 seconds. Accordingly, San Onofre Unit 1 has at no previous time operated with control rod drop times greater than that assumed in the FSA accident analyses.
Existing Technical Specification The existing Technical Specification Table 4.1.2 Item 3 is as follows:
Check Frequency
- 3. Control Rod Drop
- a. Verify that all rods At each refueling move from full out to shutdown full in, in less than 2.7 seconds 83611050295 861015 PDR ADOCK 05000206 P
-2 Proposed Technical Specification The proposed Technical Specification Table 4.1.2 Item 3 is as follows:
Check Frequency
- 3. Control Rod Drop
- a. Verify that all rods At each refueling move from full out to shutdown full in, in less than 2.44 seconds Safety Evaluation The proposed change discussed above shall be deemed to constitute a significant hazards consideration if a positive finding is made in any of the following areas:
- 1. Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No This proposed change would revise the current technical specification acceptance criterion to conform with the design basis for the FSA accident analyses. The acceptance criterion for control rod drop time as used in the previously evaluated accident analyses in the FSA will not be impacted by this proposed change. Therefore, under no circumstances will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. Will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No Measurement of control rod drop time provides a mechanism for detection of potential deterioration of function.
This proposed change will not impact the ability or the method of performing this task.
This change will incorporate the appropriate acceptance criterion into the Technical Specifications, and in doing so, will provide consistent acceptance criterion with the FSA accident analyses. As a result, under no circumstances will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated.
7..*
-3
- 3.
Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?
Response: No The margin of safety for this Technical Specification is defined by the ability to insert negative reactivity into the reactor by control rod insertion in a timely manner. This change will reduce the maximum allowable time for control rod insertion in the technical specifications. In actuality, however, the proposed change will have no impact on the margin of safety since the reduced acceptance criterion will be consistent with the design basis for the FSA accident analyses.
Based on this consideration, the proposed specification will ensure the ability to insert negative reactivity into the reactor by control rod insertion in a timely manner. Therefore, it is concluded that under no circumstances will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety.
The Commission has provided guidance concerning the application of the standards for determining whether a significant hazards consideration exists by providing certain examples (48 FR 14870) of amendments that are considered not likely to involve significant hazards considerations.
This proposed change to the specifications is most similar to example (1i) related to a change that constitutes a more stringent surveillance requirement.
Safety and Significant Hazards Determination Based on the safety evaluation, it is concluded that: (1) the proposed change does not involve a significant hazards consideration as defined by 10 CFR 50.92; and (2) there is reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment as described in the NRC Environmental Statement.
MJT:6597F