ML20012C917
| ML20012C917 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 03/21/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20012C915 | List: |
| References | |
| NUDOCS 9003260111 | |
| Download: ML20012C917 (2) | |
Text
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UNITED STATES b
b NUCLEAR REGULATORY COMMISSION ng W ASHINGTON,0. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULAT10N 0
RELATED TO AMENDMENT NO. 71 TO FACILITY OPERATING LICENSE NPF-35 AND AMENDMENT NO. 65 TO FACILITY OPERATING LICENSE NPF-52 DUKE POWER COPFANY. ET AL.
CATAWBA NUCLEAR STATION, UNITS 1 AND' 2
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DOCKET NOS. 50-413 A2 50-414 1.0 iffTRCDUCTION By lette d&ted ibytaber IU,1089, Nke Power Company, et al. (the licensee),
proposed amendnentt +,o Cathwba Nuclear Station, Units 1 and 2, Technitt.1 Sreecificbtion (15) 3,1.3.5, " Shutdown Rod Insertion Limit,' and figure 3.1-1,
" led Bank insertion Limits versus Thermal Peter Focr Loop Operation." Specifi-l:
cally, the definition of " fully withdrawn" is changed from *228 steps withdrawn" to "et least 225 steps wMhdrtwn." Additionally, TS Basis 3/4.1.3 is revised to provide justification for the 15 change.
2.0 TVALUATION The licensee proposed the above TS revision to minimize localized rod cluster control assently (RCCA) wear and to extend its life.
Unusually high wear rates have been reported in 17x17 RCCAs at several domestic and foreign Westinghouse plants.
The observed wear is the result of flow induced vibratory contact between RCCA rodlets and upper internals guide cards when the RCCAs are parked in the fully withdrawn position.
The proposed TS revision permits axici repositioning within the range of "225 steps fully withdrawn" to "230 steps fully withdrawn" (the nechanical withdrawal limit for the control rod drives).
As a result, alrea@ worn rodlet cladding surfaces can be shifted l
eway from the guide cards.
1 The licensee's analysis of the proposed TS change indicates that its irpact on key safety parameters is negligible and bounded by the Final Safety Analysis Report (FSAR) accident analyses.
The slight increase in rod drop time (0.018 availabic n.argin (1.8 seconds)y withdrawnAlso, sufficient excess shutdown margin seconds) at the "230 step full position is accomnodated by the to conpensete for the approximately 30 pcm decrease et the "225 steps fully l
withdrawn" position.
The maximum positive reactivity insertion rate resulting from an uncontrolled RCCA bank withdrawal from a subcritical or low power startup condition, as well as at power, is negligibly changed by the proposed TS revision and remains bounded by the accider.t analyses.
RCCA ejection accidents at the "225 step or greater fully withdrawn" position are also bounded by existing analyses.
In addition, the revised axial power distri-bution resulting from the proposed change is accomodated by the available 9003260111 900321 h
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e, i i peaking factor margin and remains within the established TS limits. At the "225 steps fully withdrawn" position, a raximum decrease of 50 pcm in trip reactivity worth results from the proposed change. To compensate for this slight decrease, the licensee has stated that a 75 pcm penalty will be l
considered in all trip reactivity calculations.
Based on its review, the NRC staff finds that the proposed change would have a negligible impact on safety and would not pose an undue risk to the public health and and safety. Therefore, the change is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes in requirements with respect to the installa-tion or use of facility components located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released off site and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Comission has previously istved a proposesi finding that the 3mendments involve ao significant hazards consideration, and there has been no public i
criteria for categorical exclusion set forth ir.10 CFR 51.22(c)(9)gibility comer;t on such finding. Accordingly, tht. amersdments w et the eli Pursuant to 10 CFR 51.22(b), no environmental i matt statement or environrentti assess-ment need be prepared in connection with the issuance of these amendraents.
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4.0 CCNCLUSION i
The Comission's proposed determination that the smendments involve no I
significant hazards consideration was published in the Federal Register (55FR4264)on February 7, 1990. The Comission consulted with the State of South Carolina. No public comments were received, and the State of South Carolina did not have any coments.
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 Comission's regulations, and the issuance of these amendments will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
K. Jabbour PDII-3/DRP-1/II H. Abelson, SRXB/ DST Dated: March 21, 1990 c.
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