ML20126F547

Safety Evaluation Supporting Amend 75 to License NPF-30

ML20126F547
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Site:	Callaway
Issue date:	12/16/1992
From:	Office of Nuclear Reactor Regulation
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NUDOCS 9212300377
Download: ML20126F547 (6)

Text

.%4 UNITED STATES o

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aE NUCLEAR REGULATORY COMMISSION

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WASHINGTON, D.C. 206Ei6 -

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SAFETY EVALUATION BY THE-0FFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 75 TO FACILITY OPERATING = LICENSE NO. NPF-30 UNION ELECTRIC COMPANY CALLAWAY PLANT. UNIT 1 DOCKET NO. 50-483

1.0 INTRODUCTION

a In a letter dated March 15, 1991, the Union Electric Company (the licensee) requested three exemptions from certain requirements in 10 CFR Part 50, Appendix J, Sections Ill.A.I.(a), III.A.S.(b) and III.D.l.(a). The licensee-also requested two revisions to the Callaway Technical Specifications (TSs),

3/4.6.1.1 and 3/4.6.1.2, one of which was dependent on the granting of the-exemption requests. -The exemptions were issued on:0ctober 22, 1991.

The-proposed TS revision that was dependent on the exemptions is TS 3/4.6.1.2, which revises the ACTION statement for'3.6.1.2 and' clarifies the Surveillance Requirements for 4.6.1.2.a, and 4.6.l.2.b.

Each of these-three items is-t considered separately in the following evaluation.

In a~ letter dated December 13, 1991, the licensee withdrew a portion of its original amendment request for Surveillance Requirement 4.6.1.2.a.

The. revision to-TS 3/4.6.1.1

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was made in Amendment No. 62 to the Callaway license, issued on September 11, 1991.

In letters-- dated September 16, 1992:and October 30, 1992,1the licensee-provided clarifying information and bases revisions associated with TS 3/4.6.1.2 that-did not change:the-initial proposed determination of no

'significant hazards consideration or affect the notice published September 4, 1991 (56 FR 43816);

2.0 EVALUATION r

2.-1 TS 3.6.1.2 The present ACTION statement in TS 3.6.1.2_is based on the acceptance _ criteria:

for the periodic masured overall integrated leakage rate-test'(ILRT which 'is also identified as a Type-A test) as well-as for the Types-B and C tests-as stated.in_ Sections III.A, III.B and III.C of Appendix J.

The present..TS acceptance criteria for _the periodic' Type A tests. requires that, if the-measured overall integrated containment leakage rate exceeds 75 percent-of the-3 maximum allowable leakage rate (L,)- at the calculated peak containment internal pressure -(P ) related to the design basis-accident (DBA), then the overall integrated leakage rate shall be restored to less-than 0.75 L

-to increasing the reactor coolant system (RCS)- temperature above 2001. prior i

921230037'7-921216 PDR ADOCK 0S000483 i

P PDR,

The licensee proposed that this requirement for the Type A tests be clarified and made more specific by establishing an "as found" condition and an 'as left" condition, each with its own acceptance criteria.

In that the present requirement cited above is in confomance with, and reflects the requirements of,Section III.A.5.(b)(2) of Appendix J, the licensee requested and the Commission granted an exemption from the specific Appendix J requirement as cited above.

The licensee proposes that the acceptable leakage rate for the "as found" Type A condition be the leakage rate calculated by adding the differences between the "as found" and "as left" measured local leakage rates from each Type B and Type C test to the leakage rate measured in the Type A test. These Type B and Type C tests are usually conducted prior to conducting the Type-A test.

In the event that potentially excessive leakage paths are identified which would interfere with the satisfactory completion of 3 periodic Type A test and such paths are isolated during the test, the Tyr>e B or Type C "as found" leakage rates measured on the isolated rr,et.ations after the comple-tion of the Type A test would be added to the Type A "as found" leakage rate total.

The "as left" condition is represented by the periodic Type A leakage rate after any required repairs and/or adjustments are made.

The licensee's specific proposal for the revised acceptance criteria in lieu of the present single criterion cited above (i.e., L*1,less than 0.75 L ) is that the "as found" allowable leakage rate should be and the "as left" allowable leakage rate should be less than 0.75 L,.

The licensee's basis for this proposal is that the acceptance criterion for L,,, was established in Appendix J as 0.75 L, in order to provide a margin of 2$ percent (i.e., 0.25 L ) to account for possible deterioration of the reactor primary containm,ent leak-tightness between the periodic Type A tests.

The licensee also states the value-of L is the leakage rate assumed in the accident analyses in Chapter 15 of tne Einal Safety Analysis ' Report (FSAR),

(Refer to Item 111.2.2 of Table 15A-1 of the Callaway FSAR.) The licensee-further states that there is no need for the 25 percent margin at the end of a Type A test interval to account for deterioration during this interval.

l The NRC staff finds that the licensee's proposal for the acceptance criterion for the "as found" maximum allowable leakage rate of L is acceptable on the basis that, throughout the prior Type A test interval,,the reactor primary i

containment leakage would have been at or below the value assumed in the Callaway accident analyses.

Furthermore, the licensee's proposal continues to maintain the requirement that the reactor primary containment leakage rate l

prior to restart of the plant (i.e., the "as left" condition)- be reestablished as less than 0.75 L,.

l The NRC staff further finds that there is added assurance that there will not be any significant undetected degradation in the reactor primary containment leakage during each Type A-test interval in that the primary contributors to potentially excessive leakage paths will be measured during the required Type B and Type C tests. These latter tests will be conducted at least during 1

each 18-month refueling outage but in no case at intervals greater than 2 years (Refer to Section III.D.2 and III.D.3 of Appendix J).

The principal contributors to any deterioration in the containment leakage rate would thereby be detected and corrected at least once during a 36-month Type A test interval.

The air locks will also continue to be tested at intervals of 6 months.

The staff finds that the proposed revision to the ACTION statement in TS 3.6.1.2 does not pose any undue risk to public health and safety in that the licensee will continue to demonstrate the containment overall integrated leak rate will be less than 0.75 L, prior to restart after a refueling outage.

In this regard, the margin to account for possible deterioration of the reactor primary containment leak-tightness between periodic Type A tests will be maintained.

Further, any potentially excessive leakage paths will continue to be repaired and/or adjusted prior to restart and at intervals no greater than 24 months, except for air locks tested at 6-month intervals, thereby continuing to ensure the integrity of the containment.

The licensee also proposes to expand the ACTION statement of TS 3.6.1.2 with regard to the acceptance criterion for the combined leakage rate for all penetrations subject to Type B and Type C tests.

The present criterion is that the combined leakage rate be less than 0.60 L, prior to increasing the RCS temperature above 200*F.

In its letter of March 15, 1991, the licensee proposes three alternative actions in the event that the combined leakage rate for all penetrations and valves subject to Type B and Type C tests exceed 0.60 L,.

These are:

(1) restore the combined leakage rate to less than 0.60 L, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; or (2) isolate each " failed" penetration within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; or (3) 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 />.

These proposed revisions to the ACTION statement of TS 3.6.1.2 are an

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improvement over the present TS requirements in that the three action items cited above now establish reasonable time intervals (i.e., either 4 or 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) to accomplish one of the three proposed alternatives. At present, the ACTION statement does not address the possibility that the LC0 might not be met during plant operations, even though Type B and C tests are sometimes conducted during plant operation (Modes 1 through 4). The staff considers this to be an inadequacy of current standard TS.

If the LC0 was not met, the licensee would be in TS 3.0.3 and required to initiate plant mode shut down within I hour.

Such precipitous action is unnecessary and it is inconsistent with the philosophy of response times generally expressed by the TS. These three proposed actions and their associated time constraints are consistent with the ACTION statement in TS 3.6.3, " Containment Isolation Valves."

Furthermore, the acceptance criteria for the combined leakage rate for all penetrations and valves subject to Type B and Type C tests remains unchanged at 0.60 L,.

l

On the basis that the proposed ACTION statement for TS 3.6.1.2 maintains the present Types A, B, and C test requirements for the leak-tightness of the reactor primary containment and establishes actions with prudent time-requirements in the event that the acceptance criteria for Types.B and C tests are not met, the staff finds that the proposed revision to TS 3.6.1.2 is acceptable.

2.2 TS 4.6.1.2.a The present surveillance requirements in TS 4.6.1.2.a establish two schedular requirements for the periodic Type A tests.

The first of these is that the Type A tests be conducted at 40 10-raonth intervals while the second schedular requirement is that the third test of each set of three Type A tests be conducted during the shutdown for the 10-year plant inservice inspection--

(ISI).

In that this latter requirement is in conformance with, and reflects the requirements of,Section III.D.I.(a) of Appendix J, the licensee requested and the Commission granted an exemption from this specific Appendix J requirement as cited above.

With respect to the coupling requirement that the third Type A test of each set of three be conducted when the plant is shutdown-for the 10-year plant ISI, the licensee states in its letter cated March 15, 1991, that it is performing the inservice volumetric, surface and visual examinations of components and system pressure tests in accordance_with 10 CFR 50.55a(g)(4) throughout the 10-year inspection intervals.

The major portion of this effort is presently being performed every 18 months during the refueling outages.

The staff finds that there is no benefit to be gained by the coupling requirement cited above in that elements of the Callaway ISI program are conducted throughout the 10-year cycles at the 18-month refueling outages rather than at the end of the 10-year cycles.

Consequently, the subject-coupling requirement offers the Callaway facility no benefit either to safety or to economical operation of the facility.

Moreover, each of these two surveillance tests (i.e., the Type A tests and the 10-year ISI program) is independent of the other and provic^es assurances of different plant characteristics. The. Type A tests assure ute required leak-tightness for the reactor primary containment to demonstrate compliance with the guidelines of 10 CFR Part 100. The-10-year ISI program provides assurance of the structural integrity of the plant's structures, systems, and components as well as verifying operational readiness of. pumps and valves in compliance with 10 CFR 50.55a. There is no safety-related concern necessitating their coupling in the same refueling outage. Accordingly, the staff-finds that the proposed revision to TS 4.6.1.2.a is acceptable.

With respect to the first schedular requirement for the periodic Type A tests in TS 4.6.1.2.a, the licensee proposed in its letter dated March 15, 1991, that the present prescriptive Type A test interval of 40 10 months be replaced with a nonprescriptive requirement that the Type A tests

"...be conducted during each 10-year service period at approximately equal e

I intervals..." This wording is compatible with the schedular requirement in Section III.D.I.(a) of Appendix J.

However, the Commission's present policy with respect to TS surveillances implementing Appendix J requirements is to establish specific numerical values for an acceptable range of time during which the Type A tests shall be performed (e.g., 40 10 months).

After discussing this issue with the staff, the licensee stated in its letter dateo December 13, 1991, that it was withdrawing its prior request to modify TS 4.6.1.2.a.

Its basis for this decision was that a forthcoming revision to Appendix J of 10 CFR Part 50 would permit it the flexibility to match its present 18-month refueling schedule with the schedular requirements for Type A tasts in the revised Appendix J.

The staff anticipates that the pending decision by the Commission regarding a revision to Appendix J will provide the relief needed by the licensee in that the pending revision to Appendix J, if adopted in its present form, will permit a significantly longer test interval.

Accordingly, tne staff has deferred its decision regarding the licensee's proposed deletion of the 40 10-month Type A test interval from TS 4.6.1.2.a, pending Commission approval of the proposed revision to Appendix J.

On this basis, the present schedular requirement in TS 4,6.1.2.a for a Type A test interval of 40 10 months will remain.

2.3 TS 4.6.1.2.b The present surveillance criteria in TS 4.6.1.2.b for a periodic Type A test has a single acceptable value for the maximum allowable leakage rate (i.e.,

0.75 L,).

In the event that a Type A test fails to satisfy this acceptance criterion, the test schedule for subsequent Type A tests must be reviewed and approved by the Commission.

If two consecutive Type A tests fail to meet the 0.75 L, acceptance criterion, the Type A tests must be conducted on an accelerated test schedule (i.e., at least every 18 months) until two consecutive Type A tests meet the acceptance criterion.

In order to provide a more rational approach to the acceptance criteria for the periodic Type A tests, the licensee proposes to establish an "as found" condition and an "as left" condition, each with its own acceptance criterion.

This proposal was discussed and found acceptable in Section 2.1 of this Safety Evaluation.

Since the exemption from certain requirements of Section III.A.5.(b)(2) of Appendix J was granted on October 22, 1991, and the staff has found the acceptance criteria for the "as found" and the "as left" conditions acceptable, the staff finds the proposed revision to TS 4.6.1.2.b acceptable.

3.0 STATE CONSULTATION

In= accordance with the Commission's regulations, the Missouri State official was notified of the proposed issuance of the amendment. The State official had no comments.

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4.0 ENVIRONMENTAL CONSIDERATION

This amendment involves a change to a requirement with respect to the instal-lation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or a change to a surveillance requirement. 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 (56 FR 43816).

Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to ~0 CFR 51.22(b), no 1

environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

5.0 CONCtVSION 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, (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:

M. D. Lynch Date:

December 16, 1992

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