ML20084F659
| ML20084F659 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/17/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20084F640 | List: |
| References | |
| NUDOCS 9506020282 | |
| Download: ML20084F659 (5) | |
Text
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UNITED STATES g
E NUCLEAR REGULATORY COMMISSION If WASHINGTON, D.C. 20666-0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.119I0 FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO. 108TO FACILITY OPERATING LICENSE NO. NPF-15 4
SOUTHERN CALIFORNIA EDISON COMPANY l
SAN DIEGO GAS AND ELECTRIC COMPAM THE CITY OF RIVERSIDE. CALIFORNIA THE CITY OF ANAHEIM. CALIFORNIA SAN ONOFRE NUCLEAR GENERATING STATION. UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362
1.0 INTRODUCTION
By letter dated November 3,1993, Southern California Edison Company, et al.
(SCE or the licensee), submitted a request for changes to the Technical Specifications (TS) for San Onofre Nuclear Generating Station, Unit Nos. 2 and 3.
The proposed changes would revise TS 3/4.6.3, " Containment Isolation Valves," TS Table 3.6-1, " Containment Isolation valves," and the associated Bases, 3/4.6.3, to ensure that the containment isolation valves in Section D of the table are maintained functional. The proposed TS (1) require that these valves be in an ACTION statement when secured in their engineered safety feature actuation signal (ESFAS) actuated position and (2) limit the amount of time that these valves may be secured in their ESFAS position.
Prior to these amendments, a footnote in TS 3/4.6.3 considered these valves operable as long as they were secured in their ESFAS actuated position, even though they were incapable of performing their containment isolation function.
2.0 EVALUATION The function of the containment isolation valves is to isolate the containment atmosphere from the outside environment in the event of a postulated accident.
TS 3/4.6.3 ensures this function by (1) requiring the valves listed in Sections A, B, C, and D of Table 3.6-1 to be operable in Modes 1 through 4, (2) specifying surveillance requirements (SRs) to verify operability of these valves, and (3) providing the actions to be taken when the operability requirements are not met.
Table 3.6-1 is currently divided into four sections.
Section A, " Automatic Containment Isolation," contains containment isolation valves that are 9506020282 950517 PDR ADOCK 05000361 P
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. actuated by a containment isolation actuation signal and check valves inside containment that are considered to be automatic containment isolation valves in accordance with 10 CFR Part 50 general design criteria.
Section B,
" Containment Purge," contains containment purge isolation valves that are actuated by the containment purge isolation signal.
Section C, " Manual,"
contains manual valves that are assumed to be closed post-accident, but can, under administrative control, be opened during normal operation.
Section D, "Other," contains valves whose normal safe post-accident position is open, check valves, valves with a closed ESFAS actuated position, and valves with dual ESFAS functions (open/close).
l Existing TS consider valves in Section D of Table 3.6-1 operable when secured l
in their ESFAS actuated position. However, when secured, these valves may not be able to perform their containment isolation function.
Additionally,.
existing TS do not limit the amount of time that these valves can be secured in their ESFAS actuated position.
A footnote which allows securing check valves and valves with dual ESFAS positions in their ESFAS actuation positions is also inappropriately applied to some Section D valves.
Therefore, the licensee proposes to reorganize the existing Section D valves into three l
sections (D1, D2 and E).
In addition, the licensee proposes appropriate ACTION statements and allowable outage times (A0Ts) for each of these sections.
l The proposed reorganization of Section D was based on risk evaluations assessing the duration that these valves can be secured in the open position i
without significantly contributing to the risk of a significant offsite release.
The acceptance criteria for the risk evaluations are as follows:
(1) the risk of continued operation with the valves secured in their ESFAS actuated position shall be less than the risk of shutdown (core damage risk i
per shutdown is 5.0E-7), and (2) the increase in risk of core damage frequency and significant offsite release frequency with the valves secured in their ESFAS actuated position shall be less than 1 percent of current individual plant examination (IPE) values (1 percent of IPE values corresponds to less than 3.lE-7 per year for core damage and less than 4.9E-8 per year for significant offsite release).
The proposed Section D1 contains high-pressure safety injection (HPSI) and low-pressure safety injection (LPSI) valves that have been found to have an acceptable A0T of 90 days.
Risk evaluations performed by the licensee for this section of valves found (1) that there is a bigger risk associated with l
shutdown than there is with continued operation with these valves secured in their ESFAS actuation positions and (2) that there is a less than 1 percent increase in current IPE core damage or significant offsite release frequencies l
associated with securing these valves in their ESFAS actuated positions for l
90 days. An ACTION statement requiring inoperable valves to be secured in l
their ESFAS actuated position within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and restored to operable status I
during the next cold shutdown or 30 days, whichever is shorter, is provided I
for this category.
If these requirements are not met, the plant is required l
to be in at least hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
Although the 90-day A0T resulted in acceptable risk l
s.
o a
. values, the licensee chose 30 days to provide additional conservatism for this group of containment isolation valves.
The proposed Section D2 contains valves that were found to have an acceptable indefinite A0T.
Risk evaluations for this section of valves found (1) that there is a bigger risk associated with shutdown than with continued operation with these valves secured in their ESFAS actuation positions and (2) that there is a less than 1 percent increase in the updated IPE core damage or j
significant offsite release frequencies associated with securing these valves in their ESFAS actuated positions indefinitely or until the next cold shutdown.
Inoperable valves in this category will be required to be secured in their ESFAS actuated position within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and operable prior to entry into Mode 4 from the next cold shutdown. Otherwise, the plant is required to be in at least hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
The proposed Section E contains valves that should not be secured open.
These valves will be added to existing Action 1 of TS 3.6.3 and will, therefore, be treated like the valves of Sections A, B, and C.
Action 1 requires that either the inoperable valve (s) be restored to OPERABLE status or the affected penetration be isolated within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
If this action is not satisfied, the plant is required to be in at least hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
Based on the above discussion the staff finds acceptable the licensee's request to (1) reorganize existing Section D in Table 3.6-1 into Sections Dl,
" Safety Injection," D2, "Other," and E, "Other," as explained above; (2) add "E" to existing ACTION Statement 1 to require that the valves of new Section E be bounded by ACTION 1 of TS 3/4.6.3; (3) replace existing ACTION 2 with "With one or more of the valves specified in Section D1 of Table 3.6-1 inoperable, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> secure the inoperable valve (s) in its ESFAS actuated position, and restore the inoperable valve (s) to OPERABLE status during the next cold shutdown or 30 days, whichever is shorter; otherwise be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />"; and (4) add ACTION 3 stating "With one or more of the valves specified in Section D2 of Table 3.6-1 inoperable, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> secure the inoperable valve (s) in its ESFAS actuated position, and restore the inoperable valve (s) to OPERABLE status during the next cold shutdown; otherwise be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."
The licensee also proposes to relocate ACTION 1.d, "The provisions of Specification 3.0.4 are not applicable," as ACTION 4.
Thus, Specification 3.0.4 would not apply to any of the ACTION statements of this limiting condition for operation.
This would allow the plant to continue operation, including mode changes, with containment isolation valves secured in their ESFAS actuated positions as long as the remaining Action statements are satisfied.
The remaining ACTION statements limit the amount of time that these valves can be inoperable. As discussed earlier, these time constraints were conservatively derived from analyses of shutdown risk and core damage and i
a
. significant offsite release frequencies resulting from securing the valves in their ESFAS actuated positions. Therefore, the staff finds the licensee's request to relocate ACTION 1.d as ACTION 4 acceptable.
The last sentence in SR 4.6.3.1 currently reads " Valves secured ** in their actuated position are considered OPERABLE pursuant to this specification."
After verbal discussions between the staff and the licensee, it was agreed that changing the word " actuated" to " isolated" would more clearly indicate to the operators that the valves would have to be in their closed position in order for the valves to be considered OPERABLE pursuant to this TS. The licensee requested that its submitted TS change request be amended to reflect this change.
In addition, the licensee proposes to (1) relocate SR 4.6.3.1 to the next page due to text overflow; (2) add "E" to SRs 4.6.3.1 and 4.6.3.2; (3) replace "D" with "Dl" and "D2" in SR 4.6.3.5; (4) replace the last sentence of SR 4.6.3.5, l
" Valves secured ** in the ESFAS actuated position are considered OPERABLE pursuant to this specification," with " Specification 4.0.5 is not applicable when the valves are secured open"; (5) delete or relocate footnotes in Table 3.6-1, as appropriate, based on the proposed reorganization of the existing Section D valves; and (6) revise the existing Bases to reflect the above changes.
These changes were reviewed by the staff and found necessary l
to maintain consistency within the TS and provide appropriate SRs for the newly formed sections. Therefore, the staff finds these changes acceptable.
3.0 STATE CONSVITATION In accordance with the Commission's regulations, the California State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.
The NRC staff has determined that the amendments involve 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 amendments involve no significant hazards considera-tion, and there has been no public comment on such finding (59 FR 7699)
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.
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5.0 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, and (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.
Principal Contributor: Mohammed Shuaibi Date:
May 17,1995 1
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