ML20059F947
| ML20059F947 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 01/11/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20059F945 | List: |
| References | |
| NUDOCS 9401180038 | |
| Download: ML20059F947 (5) | |
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7-4 UNITED STATES j.. II.j NUCLEAR REGULATORY COMMISSION WASHINGTON, D C. 20565-0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO 167 TO FACILITY OPERATING LICENSE N0. DPR-71 AND AMENDMENT NO.- 198 TO FACILITY OPERATING LICENSE NO. DPR-62 CAROLINA POWER & LIGHT COMPAfil BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS 50-325 AND 50-324
1.0 INTRODUCTION
By letter dated October 19, 1993, Carolina Power & Light Company (the licensee) submitted a request for changes to the Brunswick Steam Electric Plant, Units 1 and 2 (BSEP), Technical Specifications (TS). The requested changes to the TS add a footnote to Surveillance Requirement 4.6.1.2.b to allow a one-time exemption from the accelerated Type A containment integrated leak rate test (CILRT) requirements.
Since the two previous Type A tests were classified as failures for each BSEP unit, the licensee is required to institute an accelerated Type A test frequency in accordance with TS Surveillance Requirement 4.6.1.2.b.
The change would allow both BSEP units to return to a normal testing frequency such that the next Unit 1 Type A test would then be performed during the Reload 9 outage, scheduled for March 1995, and the next Unit 2 test during the Reload 12 outage, scheduled for March 1997.
2.0 EVALUATION In its application, the licensee also requested a one-time exemption from the requirements of 10 CFR Part 50, Appendix J, Section III.A.6.(b), that would require accelerated Type A testing if two consecutive periodic Type A tests i
fail to meet the applicable acceptance criteria in Section III. A.5(b).
The i
failure to meet this acceptance criteria requires the performance of a Type A test at each plant shutdown for refueling or approximately every '8 months, whichever occurs first, until two consecutive Type A tests meet the acceptance criteria, after which time the normal retest schedule may be resumed.
The i
licensee failed to meet the total measured leakage rate acceptance criteria during the last two Type A tests performed on BSEP Unit 1, in 1987 and 1991 respectively, and during the last two tests on BSEP Unit 2, in 1991 and 1992.
respectively.
The licensee's bases for requesting the exemption are that the accelerated test schedule results in an extended outage and increases the outage cost without a significant safety benefit and that Type A testing causes drywell structural stress that would be minimized by a return to a normal test frequency. The exemption request will be covered in a separate evaluation issued by the staff.
9401100038 940111 PDR ADDCK 0500 4
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2 In its letter dated October 19, 1993, the licensee stated that each unit is currently in an accelerated testing condition due to as-found testing failures that were within L,t 0.75 Lleakage limits, except for the 1987 Unit 1 test, but exceeded the curren Appendix J to 10 CFR Part 55. leakage limit of Section III.A.5.(b)(2) of The litansee based its request on the fact that the as-left limit of 0.75 L,f the containment leak-tightness during thewas specif for possible deterioration o interval between Type A tests. The licensee states that this margin for deterf oration is no longer needed when the as-found Type A test is performed.
The licensee believes that it should be technically acceptable to use L, as the as-found Type A test acceptance criterion.
The as-found Type A condition is represented by 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 Tyr 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 that would interfere with the satisfactory completion of a periodic Tyne A test and such paths are isolated during the test, the Type B or Type C as % ind leakage rates measured on the isolated penetrations after the completion of the Type A test are added in to the Type A as-found leakage rate total. The w-left Type A condition is represented by the periodic Type A leakage rate after any required repairs and/or adjustments are made.
The staff has reviewed the history of the Type A tests conducted at BSEP and found that the last two Type A as-found test results have been failures as noted below:
Unit 1 Tvoe A Test History Date of As-Found Leak Rate As-Left Leak Rate 0.75 L, limit Test
(% wt. Der day)
(% wt. Der day)
(% wt. Der day) 1987 Greater than L,
.2150 0.375 1991
.4956
.3408 0.375 Unit 2 Tvoe A Test History Date of As-Found Leak Rate As-Left Leak Rate 0.75 L, Limit Test
(% wt. Der day)
(% wt. Der day)
(% wt. Der day) 1991
.4042
.3552 0.375 1992
.4420
.3511 0.375 The staff noted that the last two test results for each unit have exceeded the acceptance criterion of 0.75 L, that is required by Appendix J.
Except for the 1987 test on Unit 1, the test results did not exceed the maximum allowable rate of 1.0 L. The licensee indicated that the 1987 Unit I failure was caused by a c,ontainment penetration failure that was identified during the local leak rate testing. The licensee also stated that the primary reason for failing the as-found limits is considered to be the leakage savings additions from Type C testing of valves and the Type B testing of penetrations, where w.
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leakage rates of repaired or replaced components are added into the integrated Type A test results.
The licensee stated that the major contributors to the 1987 Unit I test failure were from (1) penetration X9A, Feedwater Loop A Injection, and (2) penetration X54E, Containment Monitor, CAC-AT-1262, Discharge. The licensee further stated that correcti"' actions were completed to repair several valves associated with these penetrations and that, if the leakage from these penetrations were not considered, the as-found leakage savings would have been 0.049 % wt. per day.
For the 1991 Unit 1 Type A test, the majors contributors were stated to be (1) penetration X98, Feedwater Loop B Injection, (2) penetration X14, Reactor Water Cleanup (RWCU) Suction Line, and (3) penetration X10, Reactor Core Isolation Cooling Turbine Steam Supply Line.
These penetrations were repaired by the repair or replacement of affected valves.
The licensee stated that the major contributors to the 1991 Unit 2 test failure were from (1) penetration X220, Torus Purge to Standby Gas, and (2) penetration X8, Main Steam Line Drain.
The major contributors to the 1992 Unit 2 failure were from (1) penetration X14, RWCU Suction, and (2) penetration X12, Residual Heat removal Shutdown Cooling Suction.
The licensee conducted repairs to several valves to correct the leakage through each of these penetrations.
The NRC staff has reviewed the licensee's request and finds that there is adequate assurance that there will not be any significant undetected degradation in the primary containment leakage during the next Type A test interval in that the primary contributors to potentially exozssive leakage l
paths will be measured during the required Type B and Type C tests. These-i latter tests will be conducted at least during each 18-month refueling outage, but on no case at intervals greater than 2 years (Sections III.D.2 and III.D.3 of Appendix J to 10 CFR Part 50). Any potentially excessive leakage paths will continue to be repaired and/or adjusted prior to restart and at intervals of 18 months, thereby continuing to ensure the integrity of the containment.
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Additionally, the allowable leak rate on Type A tests contains a 25 percent safety margin between the leak rate acceptance criterion and the leak rate assumed for the containment during a loss-of-coolant accident.
Based on these i
considerations, the staff issued a one-time exemption to Section III.A.6(b) of Appendix J to 10 CFR Part 50 in a letter to the licensee dated and concluded that the actions will ensure compliance with the maximum 1
permissible containment leakage rate specified in the BSEP-Technical Specifications.
Therefore, the staff finds that the proposed TS changes are acceptable.
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3.0 STATE CONSULTATION
In accordance tith the Commission's regulations, the State of North Carolina official was notified of the proposed issuance of the amendment.
The State official had no comments.
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4.0 ENVIRONMENTAL CONSIDERATION
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 significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (58 FR 59745). -Accordingly, the 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-the amendment.
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:
P. D. Milano Date:
January 11, 1994
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DISTRIBtJTION:
" Docket File ~
NRC/ Local PDRs PD 11-1 Reading File S. A.-Varga S. S. Bajwa P. D. Anderson P. D. Milano R. J. Barrett J. C. Pulsipher D. Hagan G. Hill (4)
C. Grimes ACRS (10)
OPA OC/LFDCB E. Hershoff, RII
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