ML20128D769
| ML20128D769 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 11/20/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20128D744 | List: |
| References | |
| NUDOCS 9212070377 | |
| Download: ML20128D769 (4) | |
Text
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SAFETY EVALVATION BY THE OFFICE OF_ NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 72 TO FACILITY OPERATING LICENSE NO. NPF-18 COMMONWEALTH EDISON COMPANY MSALLE COUNTY STATION. UNIT 2 DOCKET NO. 50-374
1.0 INTRODUCTION
By letter dated November 2, 1992, Commonwealth Edison Company (CECO, the licensee) requested an amendment to the LaSalle County Station, Unit 2, technical specifications (TS).
The request proposed to amend TS Table 3.6.3-1 to add a footnote that would temporarily waive the requirement for isolation valve 2G33-F040 on the reactor water cleanup (RWCV) return line to have a-valid Type C test until the next refuelir.g outage or until the unit goes to cold shutdown for a minimum of 2 weeks, whichever is sooner.
The TS change is required due to the discovery that the licensee's method for performing a Type C test on the 2G33-F040 containment isolation valve was invalid.
As a result, the valve was declared inoperable by the licensee and the Action Statement for TS Section 3.6.3 was entered.
Action Statement 3.6.3.a.1 requires the licensee to isolate the line with the inoperable valve within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Due to the fact that the other isolation valves in the line are check valves, the licensee is unable to isolate the line.
This placed them in Action Statement 3.6.3.a.2 which requires a shutdnwn.
An emergency TS amendment is required because insufficient time exists for the Commission's-usual 30-day notice to prevent an unnecessary plant shutdown.
2.0 DISCUSSION for LaSalle, automatic isolation for the main feedwater and the RWCV return lines is accomplished by two check valves (2B21-F010 and 2821-F032) in series on the main feedwater line, Long-term leakage protection is provided by remote manual isolation valves 2B21-F065 for the feedwater and 2G33-F040 for the RWCV return line. The RWCU return line to the feedwater system connects to the main feedwater piping between the outboard check valve 2821-F032 and the remote manual isolation valve 2B21-F065.
The configuration of the feedwater and RWCV systems for LaSalle County Station is shown in Figure 1 of the licensee's November 2, 1992, amendment request.
The RWCV return line also has a check valve (2G33-F039) which is located upstream of the 2G33-F040 valve.
The check valve is located between the 2G33-F040 valve and the vent path used in deterrining its leak rate during Type C testing.
Because of this configuration, the licensee was, actually testing the combination of the 2G33-F040 and the 2G33-F039 valves rather than 9212070377 921120 DR ADOCK 05000374 PDR.
testing the 2G33-f040 valve by itself.
1he leak rate for the 2G33-f040 valve by itself is unknown.
TS Table 3.6.3-1 contains the list of containment isolation valves 'or the licensee.
The licensee has requested an emergency T. change whien would add the following foo; ite to valve 2G33-f 040 in TS Table 3.0.3-1:
For the remainder of Cycle 5, or until the first outage in which the unit is in Cold Shutdown for two weeks or greater duration, the Type C test is not required to be current for the 2G33-f040 valve and its leakage is not required to be includeo in the total Type B t. C leakage specified by Specification 3.6.1.2.b.
This would allow Unit 2 to continue operation until the earliest opportunity to perform a valid Type C test on the 2G33-f040 valve.
In their November 2, 1992, submittal, the licensee presents three reasons for justifying this emergency TS amendment and allowing continued 9peration in their current condition, first, the licensee notes that the first isolation barrier is feedwater check valves 2B21-f010 and 2821-f032 which were accept d!y leak rate tested 1:,t refueling outage.
These valves also provide the automatic isolation function for both the main feedwater and the RWCU return lines.
Dual check valves installed on the line allow the containment leakage criteria of 10 CFR Part 50, Appendix J, to be met in the event of a single failure.
Second, the leak rate for the combination of the RWCU isolation
've (2G33-f040) and the upstream check valve (2G33-G039) have been riemonst rat
'o be in allowable limits for the RWCV line.
1he licensee has committed iot performing any maintenance or surveillance work on the check valve 2G33. 39 without additional testing to ensure that 2G33-f040 is
- operable, finally, the licensee indicated that since this valve does not isolate automatically, no credit is taken for the Type A test.
Thus, the leakage for valve 2C33-f040 not a factor in the acceptability of the Containment Integrated Leak note Test (CILRT).
3.0 EALUATIM lhe staff has reviewed the licensee's request and has found that temporarily operating ihe plant with an invalid Type C test for the EG33-f040 valve does not:
(1) provide a significant reduction in safety margin, (2) increase the probability or consequences of an accident previously evaluated, or (3) create the possibility of a new or different kind of accident from any accident prnicusly evaluated.
The staff finding is based on the fact that we automatic isolation function provided by the feedwater check valves 2821-f010 and 2B21-f032 is not degraded by the lack of a valid Type C test on the 2G33-f040 valve and that these valves were demonstrated to be acceptably leaktight during the last refueling outage. Also, the long-term isolation function of the RWCU return line for the 2C33-f040 valve can still be acceptably provided by the combination of that valve with the 2G33-F039 check
- valve, in addition, since no credit is taken for the 2G33-f 040 valve in the CILRT, the invalid Type C test does not affect the acceptabilitv
5e
3-containment integrity.
Based on the above, the staff finds the licensee's proposed TS amendment to be acceptable.
4.0 EMERGENCY ClR(MSTANCES 1his 15 amendment 15 being treated as an emergency 15 amendment because the licensee would have to unnecessarily shut down the plant without the amendment.
The licensee does not believe that they could have avoided this emergency situation because the validity of their method for Ty)e C testing the 2G33-f0'40 valve was only called into question recently by tie resident inspector.
The licensee stated that the configur3 tion being used to test the 2G33-f040 valve was believed to be acceptable because it was thought check valve 2G33-f039 would not completely seal, thus providing a vent path for a valid Appendix J Type C test, furthermore, based on the fact the staff had not questioned the validity of the test during previous Appendix J inspections, CECO believed the test method was acceptable.
Thus, the staff concludes as required by 10 CFR Part 50.91(a)(5) that the licensee could not have avoided this emergency situation.
Accordingly, the Commission has determined that there are emergency circumstances warranting prompt approval by the Commission.
5.0 ElMLEp_ SIGN 1f_1 CANT HA7ARDS "pNS10ERol10ft DE1ERMIMllpj lho Commission has provided standards for determining whether a significant hazards consideration exists (10 CFR 50.92(c)). A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed vendment 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 an accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
The staff has reviewed the licensee's submittal and found that the probability of an accident previously evaluated is not increased because the accident initiators for the feedwater or RWCU return line breaks discussed in the U) dated final Safety Analysis Report are not affected by potential lea (age through the 2G33-f040.
In addition, the i
consequences of an accident previously evaluated is not significantly increased because the feedwater line isolation check valves still provide automatic isolation and form the leakage barrier which is the boundary for the CILRT (Type A test), Also, the RWCU return line forms a tested leakage barrier for a long-term leakage control.
Therefore,.
operation of the facility in accordance with the proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The staff has also found that the use of the 2G33-f040 as a long-term isolation boundary following a RWCU return line break was previously evaluated and the nonconservative Type C test method does not create a new or different accident because the RWCU line forms the long-term isolation boundary utilizing both the 2G33-f040 and the 2G33-F039 check-L
i valve. The licensee's O pe C test results showed the leak rate for the combination of the 2G33-f040 and the 2G33-f039 to be acce) table.
Therefore, operation of the facility in accordance with tie proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.
In addition, the staff has found that operation of the facility in accordance with the proposed amendment does not involve a significant reduction in the margin of safety since the combined leakage of the 2G33-f040 and the 2G33-f039 check valve are within allowable limits for the RWCU return line. The feedwater isolation check valve leakages are within limits for the feedwater lines and fulfill the automatic isolation function for the feedwater containment senetrations.
Therefore, there is no significant reduction in t1e margin of safety.
Based on the foregoing, the Commission has concluded that the standards of 10 CFR 50.92 are satisfied.
Therefore, the Commission has made a final determination that the proposed amenon. vat involves no significant hazards considerations.
6.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois State official was notified of the proposed issuance of this amendment.
The State official had no comments.
7.0 ENVIRONMENTAL CONSIDERATION
This amendment changes 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.
The NRC staff has determined that this amendment involves no significant increase in the amounis, 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 made a final no significant hazards consideration finding with respect to this amendment. Accordingly, this amendment meets the eligibil:ty 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.
8.0 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 this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor Robert B. Elliott Date:
November 20, 1992
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