ML20215E618
| ML20215E618 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 12/11/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215E612 | List: |
| References | |
| NUDOCS 8612230031 | |
| Download: ML20215E618 (3) | |
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UNITED STATES
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WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO FACILITY OPERATING LICENSE N0. NPF-6 l
ARKANSAS POWER AND LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT 2 DOCKET NO. 50-368 1.0 INTRCDUCTION By letter dated April 25, 1986, Arkansas Power and Light Company (AP&L) submitted a request to amend Facility (ANO-2).
Operating License No. NPF-6 for the Arkansas h'uclear One, Unit No. 2 The request was for proposed changes to the Technical Specifications involving an increase in the refueling water tank (RWT) maximum solution temperature, an incruse in the required shutdown margin for Modes 1 through 4, the verification of moderator temperature coefficient (MTC) and a more I
negative MTC. This Safety Evaluation (SE) addresses the first three of the above stated changes. The proposed change involving a more negative MTC was addressed in an SE associated with Amendment No. 80 issued September 10, 1986.
2.0 EVALUATION The proposed change to Technical Specifications 3.1.2.8.b and 3.5.4 will increase the required maximum solution temperature for the borated water in the RWT from 100*F to 110*F. The maximum solution temperature is
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specified to assure that the maximum borated water injection temperature assun.ed in the ANO-2 Final Safety Analysis Report (FSAR) emergency core cooling systems (ECCS) evaluation is not exceeded. The RWT maximun solution temperature assumed in the ANO-2 FSAR is 120'F. Under the current Technical Specifications, whenever the RWT solution temperature approaches @'F due to direct solar heating, the RWT is cooled using a containmefft spray pump and shutdown cooling heat exchanger. The proposed change is expected to reduce frequent use of ECCS system required to ' cool the RWT during the sunner months. We have reviewed the proposed change and found it acceptable based on the fact that the proposed change is bounded by the existing accident analysis results in Chapter 15 of the ANO-2 FSAR since the proposed maximum solution temperature is within the assumptions of the FSAR accidents analysis and i
that there still would be sufficient margin between the proposed maximum solution temperature and that assumed in the FSAR accident analysis and ECCS functional analysis.
8612230031 861211 ADOCK0500g8 PDR P
' The proposed change to Technical Specification 3.1.1.1 will increase the required minimum shutdown margin for Modes 1 through 4 from 5.0% delta k/k to 5.5% delta k/k. The purpose of the proposed change is to assure that future operating cycles comply with the accident analysis limits i
specified in Chapter 15 of the ANO-2 FSAR. For the current operating cycle, Cycle 6, the proposed change will provide additional shutdown margin and thus, will not reduce the reactivity control system's capability for contrciling the reactivity transients associated with postulated accident conditions within acceptable limits. Further 'the proposed change will not reduce the systems capability for making the reactor subcritical from all operating conditions and for maintaining the reactor sufficiently subcritical to preclude inadvertent criticality in the shutdown condition.
Based on the foregoing discussion, we have found the proposed change acceptable.
The proposed change to Technical Specification Surveillance Requirement 4.1.1.4.2 pertains to the periodic verification of MTC values. MTC can be described as the change in reactivity that results from a change in the temperature of the water in the core. The MTC limit is an input parameter in various transients and accident analysis.
.o ensure that the assumptions used in the transient and accident analysis remain valid throughout each fuel cycle since MTC changes slowly due principally to the reduction in reactor coolant system boron concentration associated with fuel t1rnup, the MTC measurements are required by Surveillance Requirement 4.1.1.4.2.
Under the proposed change, MTC measurement frequencies will be reviseo from within 7 EFPD after reaching a RATED THERMAL POWER equilibrium boron concentration of 800 ppm and 300 ppm to a frequency of prior to and within 14 EFFD after reaching a RATED THERMAL POWER equilibrium boron concentration of 800 ppm and 300 ppm respectively. The purpose of the proposed change is to allow greater operational flexibility in the perfonnance of MTC measuremer.ts. We have reviewed the proposed change and found it accepteble based on the fact that the proposed change will not reduce the number of required MTC measurements but it will merely expand the periods during which MTC measurements have to be performed and that it will not sign-ificaGtly affect the confidence in the MTC measurements since the MTC changGs slowly.
2.0 EVALU TION
SUMMARY
Based:on the staff evaluation described above, the proposed changes to ANO-2; Technical Specifications 3.1.2.8.b. 3.5.4, 3.1.1.1 and 4.1.1.4.2 are a ceptable.
ENVIRjNMENTALCONSIDERATION
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3.0 This amendment involves a change in tRe installation or use of a facility component located within the restrictfd area as defined in 10 CFR Part 20.
The steff has determined that the amehdment involves no significant increase in the arrounts, and no significant change in the types, of any effluents that tnay le released offsite, and that there is no significant increase I
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. 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 551.22(c)(9)gibility criteria Pursuant to 10 CFR 651.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
4.0 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 activitics 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 contributors to this SE was L. Kopp and R. Lee.
Dated: December 11, 1986 i
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