ML20207H425
| ML20207H425 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/22/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20207H424 | List: |
| References | |
| NUDOCS 8607240311 | |
| Download: ML20207H425 (4) | |
Text
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,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO FACILITY OPERATING LICENSE N0. NPF-6 ARKANSAS POWER AND LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT 2 DOCKET N0. 50-3E8
1.0 INTRODUCTION
Arkansas Power and Light Company (APL), by letter from T. Gene Campbell (APL) to George W. Knighton (NRC), dated June 9, 1986, has requested a revision to Arkansas Nuclear One-Unit 2 (AN0-2) Technical Specification 3.10.1, "Special Test Exceptions-Shutdown Margin." This specification presently allows shutdown margin to be reduced to less than the normal operating shutdown margin requirements during low power physics testing provided that certain conditions are met. One of these conditions (Surveillance Requirement 4.10.1.2) requires that all CEAs not fully inserted in the core be shown to be capable of full insertion when tripped from at least the 50% withdrawn position within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to reducing shutdown margin to less than the normal operating requirements.
The requested revision would allow this surveillance to be performed within the past 7 days prior to margin reduction instead of within the prior 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
This request has been made in order to enable low power physics tests to be accomplished without an additional trip to verify CEA insertability. The startup test program includes a CEA trip test before criticality in order to measure CEA drop times and demonstrate CEA insertability. Criticality is then achieved and low power physics tests are performed. Measurements of CEA worths are made later and may involve the reduction of shutdown margin as permitted by Technical Specification 3.10.1.
Since these CEA worth measurements are performed several days after the CEA insertability tests were performed, the reactor would have to be tripped again to demonstrate CEA insertion capability and satisfy the current 24-hour criterion.
The requested revision would, therefore, eliminate the necessity for an additional trip during physics tests by requiring CEA insertability to be verified within 7 days prior to reducing shutdown margin instead of within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
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2.0 SAFETY EVALUATION The primary concern in extending the surveillance time period for verifyir.g CEA insertability is whether or not there could be an increase in the prob-ability of a stuck CEA over a 7-day period of time as compared to the present 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time period.
Consideration of the configuration of the components that are used in CEA insertion indicate that there is nothing which could cause a significant increase in the probability of a CEA to become untrippable since there is no significant change in the geometry of these components over the 7-day period of low power physics testing.
The components considered include the fuel assembly (including) foreign material buildup in the gap between the CEA and the guide tube, the CEA, the CEA extensior, shaft, the control element drive mechanism, and the upper guide structure. Also, since the CEAs will insert by gravity upon loss of power, the probability of a stuck CEA is not increased due to an electrical malfunction, if one were to occur during physics testing.
The staff concludes that the proposed change continues to provide assurance that all CEAs are trippable during low power physics testing and does not affect the amount by which shutdown margin may be reduced during this period.
It is therefore, acceptable.
3.0 EVALUATION
SUMMARY
The staff has reviewed the proposed surveillance requirement change to the AN0-2 Technical Specification associated with the shutdown margin special test exception. This change would allow a time duration of 7 days following verification of CEA trippability during which time shutdown margin may be reduced to accommodate physics testing.
The staff concludes that the proposed change is acceptable since it continues to provide assurance that all CEAs are trippable during low power physics testing and does not affect the amount by which shutdown margin may be reduced during the testing period.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
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 published a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, the amendment meets the eli for categorical exclusion set forth in 10 CFR 651.22(c)(9)gibility criteria Pursuant to 10 CFR 951.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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5.0 CONCLUSION
We have 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, and (2) such activities will be conducted in compliance with the Commission's regulations, and 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 to this SE was L. Kopp.
Dated:
July 22, 1986
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ISSUANCE OF AMENDMENT NO. 76 TO FACILITY OPERATING LICENSE NPF ARKANSA5 NUCLEAR ONE, UNIT NO. 2 DISTRIBUTION ket File 50-368 NRC PDR Local PDR PBD7 Reading FMiraglia JLee (. 5)
RSlee Attorney, ELD LHarmon EJordan BGrimes JPartlow TBarnhart(4)
WJones WRegan LKopp ACRS (10)
OPA LFMB EButcher NThompson