ML20057E953
| ML20057E953 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 10/04/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057E950 | List: |
| References | |
| NUDOCS 9310130410 | |
| Download: ML20057E953 (4) | |
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E UNITED STATES (1(
=j NUCLEAR REGULATORY COMMISSION wAswiucTon. o.c. 20sss-coos v
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
RELATED TO AMENDMENT N0.123T0 FACILITY OPERATING LICENSE NO. DPR-75
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i PUBLIC SERVICE ELECTRIC & GAS COMPANY l
l PHILADELPHIA ELECTRIC COMPANY l
DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY l
SALEM NUCLEAR GENERATING STATION. UNIT NO. 2 DOCKET NO. 50-311
1.0 INTRODUCTION
By letter dated August 4, 1993, as supplemented August 24, 1993, the Public Service Electric & Gas Company (the licensee) submitted a request for changes to the Salem Nuclear Generating Station, Unit 2, Technical Specifications (TS).
The requested changes would modify the TS for the A.C. power sources, on a one-time basis, during the Unit 1 lith refueling (IR11) outage, to allow switchyard modifications.
2.0 EVALUATION This amendment application requests, on a one-time basis during the upcoming 1R11 outage, that footnotes be added to the SGS Unit 2 TS 3.8.1.1 (limiting condition for operation [LC0]) Action Statements a and b.
The amendment will extend the allowed outage time (A0T) from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> for one
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inoperable offsite power circuit and reduce the number of diesel starts that would be required by the present action statements for one inoperable offsite j
power circuit.
PSE&G is planning an extensive switchyard modification during the IR11 outage to increase the operational flexibility and overall reliability of offsite power.
The switchyard modification would install 500 kV and 13 kV buses to q
allow the future connection of the new 500/13.8 kV station power transformers I
(SPT) T3 and T4. The work scope also includes the addition of 13 kV
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disconnect switches and a new key interlock system.
The existing 500/13.8 kV 4
SPTs T1 and T2 must be deenergized to allow installation of the T3 and T4 buses. The SPTs T1 and T2 will be deenergized one at a time to modify their respective buses T3 and T4 so that one offsite power source is always available during this outage. According to the installation schedule, each SPT is expected to be deenergized for 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> during the IRll outage.
9310130410 931004 PDR ADOCK 05000311 P
. When an existing 500/13.8 kV SPT (Tl or T2) is deenergized, one of the offsite power circuits required by TS 3.8.1.1 becomes inoperable (applicable in MODES 1, 2, 3, and 4). Therefore, this modification will force operators to enter the TS action statements, unless both units are in cold shutdown or refueling modes. TS 3.8.1.1, Action "a" requires unit shutdown if one offsite power circuit is inoperable for more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Presently, Action "a" also requires repetitive testing of each of the three emergency diesel generators (EDG) every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> until the action statement is exited.
Action "b" applies to a condition where one offsite power circuit and one EDG are inoperable, and allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from the time of initial loss to restore both offsite power circuits and all three EDGs to operable status.
Chance 1:
Add the following footnote to the SGS Unit 2 TS 3.8.1.1, Action a:
Perform Surveillance Requirement 4.8.1.1.2.a.2 within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to each entry into Action Statement 3.8.1.1.a during the Unit 1 11th refueling outage for the installation of bus connections for 500/13.8 kV Station Power Transformers (SPT's). Repeat Surveillance Requirement 4.8.1.1.2.a.2 for each diesel within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of the diesel's last successful test, unless the affected 500/13.8 kV SPT has been restored to OPERABLE status. No additional diesel testing is required during entry into Action a for installation of the 500/13.8 kV bus connections.
The present action statement for one inoperable offsite power circuit would require each of the three Unit 2 diesels to be started within one hour and once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter.
PSE&G, in its submittal of August 4, 1993, proposed to eliminate the requirement for repetitive diesel starts and claimed that the action is consistent with the NRC's position as given in the new Westinghouse Standard Technical Specifications (NUREG-1431). However, NRC staff pointed out that the referenced section of NUREG-1431 is only applicable to an A0T of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
PSE&G agreed to revise their proposal to test each Unit 2 EDG within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before deenergizing the SPT and within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after the previous test unless the action statement has been exited. The requested amendment would still reduce the Unit 2 EDGS from several (approximately 50) starts. The switchyard configuration for the transformer connections will not introduce a common failure mode for the EDGs or 4.16 kV vital buses. On the basis of the adequate demonstration of EDG operability and no common failure mode, the staff finds this change acceptable.
Chance 2:
Add the following footnotes to SGS Unit 2 TS 3.8.1.1, Action a:
One offsite power circuit may be inoperable for 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> for installation of bus connections for 500/13.8 kV SPT T3 and T4 during the Unit 1 lith refueling outage.
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] Action "a" of TS 3.8.1.1 requires unit shutdown if one of the offsite power
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circuits is inoperable for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. During the switchyard modification one of two 500/13.8 kV SPT (Tl or T2) will be inoperable.
According to the PSE&G installation schedule, each SPT is expected to be deenergized for 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> during the IR11 outage. Since 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> is very close to the allowed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of A0T, PSE&G proposed increasing the A0T to 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> so that a forced shutdown could be avoided if the installation time exceeds j
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
In response to the staff's question as to why specifically i
120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> was chosen in lieu of a smaller interval as the proposed A0T, PSE&G l
stated that its Nuclear Department administrative procedure for work control states that planned entries into action statements should be limited in 4
duration not to exceed 2/3 of the A0T. Extending the A0T from 72 to 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> for this activity would make the scheduled action statement entry equal to approximately 57 percent of the A0T.
1 PSE&G also submitted the Salem probabilistic risk assessment (PRA) model that was used to estimate the effect of the A0T extension on the core damage i
probability. The PRA results support the conclusion that extending the A0T in the action statement from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> poses less risk to the operating unit than manually shutting down the unit when the allowable 72-hour A0T is exceeded. The PRA results also support the conclusion that the total increase in core damage probability associated with the proposed A0T increase j
is very low.
The staff finds this change to be acceptable because 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> for the A0T is consistent with PSE&G's existing administrative procedure. Also the PRA results support the conclusion that extension of the A0T poses less risk than 1
manually shutting down the unit and an insignificant increase in core damage i
probability.
l Chance 3:
Add the following footnote to SGS Unit 2 TS 3.8.1.1, Action b:
120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> if this Action Statement is entered during installation of bus connections for 500/13.8 kV SPT T3 or T4 during the Unit I lith refueling outage.
Currently the action statement "b" of TS 3.8.1.1 with one offsite circuit and one EDG inoperable, allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from the time of initial loss to restore all three EDGs and both the offsite power circuits to operable status. The proposed change would allow 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> from the time the SPT is inoperable during the IRll outage, which is consistent with the request of the A0T for action statement "a", addressed in " Change 2" previously. The current action statement also requires at least one of the two inoperable sources to be operable within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or to 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 followina 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Similarly, if one of the three EDGs should not start during the 72-hour required surveillance tests and one of the SPTs is still deenergized during the IRll outage, PSE&G is required to restore one of the sources within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to operate the plant.
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- This change is consistent with the 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> requested A0T for the SPT in
" Change 2," and is acceptable.
The proposed changes in the TS are for use during the IRll outage only and will not change the design, function, or method of operation of any equipment at SGS. Two entries into the revised Action Statement will be required during the IRll outage to connect the two new transformers. The staff concludes that the proposed TS changes are consistent with other provisions of the existing TS, and their technical bases.
3.0 STATE CONSULTATION
In accordance with the Comission's regulations, the New Jersey State official was notified of the proposed issi'ance of the amendment. The State official had no coments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a require,nent with respect to installation or use cf a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC 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 i
significant incresce in individual or cumulative occupational radiation exposure. The Cc mission has previously issued a proposed finding that the
=mendment involves no significant hazards consideration, and there has been no
,.ublic comment on such finding (58 FR 46250). Accordingly, the amendment
'reets 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 amendment.
5.0 CONCLUSION
The Comission 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 Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
i Principal Contributor:
S. K. Mitra Date:
October 4. 1993 L
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