ML13316A703
| ML13316A703 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/15/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML13316A700 | List: |
| References | |
| TAC-55407, NUDOCS 8410170276 | |
| Download: ML13316A703 (5) | |
Text
0-UNITED STATES g
NUCLEAR REGULATORY COMMISSION
- J WASHtNGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 81 TO PROVISIONAL OPERATING LICENSE NO. DPR-13 SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 1 DOCKET NO. 50-206 APPENDIX A TECHNICAL SPECIFICATIONS
1.0 INTRODUCTION
By letter dated July 23, 1984, Southern California Edison Company (the licensee) proposed changes to the Technical Specifications for San Onofre Nuclear Generating Station, Unit No. 1. These changes would modify the Appendix A Technical Specifications relating to snubbers. A press release, published in local newspapers August 14, 1984, was used to provide notice of intent to issue this action.
No comments were received on the proposed determination that the requested amendment involves no significant hazards consideration.
2.0 DISCUSSION AND EVALUATION
2.1 Background
A seismic reanalysis program has been in progress for some time at San Onofre Unit 1. As part of this activity, changes in the number, size and type of snubber have been made. In addition, many hydraulic snubbersare being replaced by mechanical snubbers. The existing lists of snubbers in the San Onofre 1 Technical Specifications (TS) therefore would have to be revised to correspond to these plant changes.
The NRC issued generic letter 84-13 on May 3, 1984 regarding TS for snubbers.
Although originally directed to all licensees except SEP plant licensees, this letter, is also applicable to San Onofre 1 (see 7/31/84 letter from D. Crutchfield to SEP licensees). The generic letter permits the licensee to request a modification to the TS to remove the explicit lists from the TS provided the limiting condition for operation (LCO) for snubbers was appropriately modified. The licensee elected to follow the generic letter guidance rather than to include a modified list of snubbers in the TS. In addition, some changes to the snubber surveillance requirements were proposed.
8410170276 841015 PDR ADOCK 05000206 P
-2 2.2 Discussion The licensee has requested that the LCO in TS 3.13 be modified to require that all snubbers be operable except for those installed on nm safety related systems and then only if their failure or failure of the system on which they are installed would have no adverse effect on any safety related system. This definition is consistent with the basis of the explicit lists that had been included and also with the generic letter guidance.
Recordkeeping requirements concerning service life and installation date of snubbers have not changed. Any changes in snubber quantities, types or locations would be a change to the facility and would thus be subject to the provisions of 10 CFR 50.59. In particular, the licensee must maintain records of such changes including a written safety evaluation. The licensee must submit a report annually describing all facility changes made under.
10 CFR 50.59. Therefore, records of snubber modifications must be retained and are available for NRC review. Based on this, the staff finds the proposed change to the LCO is acceptable.
The existing TS provide that snubbers of rated capacity of greater than 50,000 pounds are exempt from testing. This TS was provided because of the impracticality of testing large snubbers. This TS was intended to apply specifically to the snubbers on the steam generators which are rated at 400,000 pounds. At the time those TS were implemented the steam generator snubbers were the only ones rated above 50,000 pounds.
As a result of the seismic modifications, new snubbers which are rated above 50,000 pounds but below 120,000 pounds have been installed. These snubbers can be tested with existing equipment. Therefore the proposed change would modify the TS to raise the limit to 120,000 pounds.
The large (400,000 pound) snubbers were originally exempted from testing because instruments were not available for them. Such technology now exists and the licensee is procuring the necessary equipment to test the steam generator snubbers as discussed in the licensee's August 30, 1984 letter. For the interim until suitable test equipment is obtained, the staff finds the proposed TS change acceptable. However, following procurement of the test instrument, appropriate TS changes should be proposed to delete this exemption.
The licensee has proposed that a paragraph in the surveillance requirements relating to seal materials which have not been demonstrated to be compatible with their operating environment be deleted since such materials are not used at San Onofre Unit 1. This change is editorial since it deletes an obsolete section and is therefore acceptable.
-3 It is proposed that paragraph C of TS 4.14 relating to Functional Tests be revised to state that for each snubber in the representative sample that does not meet the acceptance criteria, an additional 10% of that type of snubber shall be tested until no more failures are found or until all snubbers of that type have been functionally tested. The phrase beginning "until no more failures" would be added to reflect that if a failure is found in the second sample, testing should continue; the existing TS is not clear as to the course of action once the second sample was taken.
This change is considered to be a clarification of the TS and is therefore acceptable.
The next proposed change would modify the visual inspection acceptance*
criteria to remove the requirement to induce snubber movement if it can be done without disconnecting the snubber. Manually displacing the pipe to check snubber movement could result in damage to the piping. Snubber freedom of movement is verified during performance of the functional tests required by the TS. There is no acceptable method for manually checking snubber freedom of movement without disconnecting the snubber; therefore, the staff concludes that deletion of this part of the criteria is acceptable.
The last proposed change would change the functional test criteria for mechanical snubbers to require that the test verify (1) that the force required to initiate or maintain motion of the snubber is within the specified range in both directions of travel, (2) that restraining action is achieved within the specified range of velocity or acceleration in both tension and compression, and (3) that the release rate, where required, is within the specified range in compression or tension. The existing TS require only that freedom of movement over the range of stroke be verified.
The proposed criteria address the staff's requirements for snubber functional testing, i.e., that important response parameters fall within specified ranges and that correct motion in both directions be verified. Therefore, the proposed changes are acceptable.
2.3 No Significant Hazards Consideration Determination The Commission's regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant hazards considerations if operation of the facility in accordance with the amendment would not:
(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.
-4 The information in this SE provides the basis for evaluating this license amendment against these criteria. The change in the LCO does not affect the requirements that all safety-related snubbers are operable and therefore this change does not involve a significant increase in the probability or consequences of an accident previously evaluated nor does it create the possibility of a new or different kind of.accident. The proposed change affects only requirements for maintaining accountability of snubbers and not the requirements themselves, therefore, the change does not involve a significant reduction in any margin of safey. The proposed changes to the surveillance requirements add additional requirements and make administrative changes; therefore operation of the facility in accordance with this amendment does not affect theprobability or consequences of an accident previously evaluated nor does it create the possibility of a new or different kind of accident. Since the proposed snubber test criteria are more specific and restrictive, there is no decrease in the safety margin.
Accordingly the staff concludes that this amendment involves no significant hazards consideration.
2.4 State Consultation In accordance with the Commision's regulations, consultation was held with the State of California by telephone. The State expressed no comments on the proposed no significant hazards consideration determination.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area as defined by 10 CFR Part 20 and changes in the surveillance requirements. The staff has determined that the amendment 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 this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets 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 this amendment.
-5
4.0 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 will not be endangered by operation in the proposed manner; and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
5.0 ACKNOWLEDGEMENT H. Shaw and E. McKenna contributed to this evaluation.
Dated: October 15, 1984