ML20247K269
| ML20247K269 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/23/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247K267 | List: |
| References | |
| NUDOCS 8906010259 | |
| Download: ML20247K269 (3) | |
Text
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. SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION -
RELATED TO AMENDMENT NO. 64'TO FACILITY OPERATING LICENSE NPF-35 '
AND AMENDMENT NO. 58 TO FACILITY OPERATING LICENSE NPF-52 DUKE POWER COMPANY. ET AL.
CATAWDA NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-413 AND 50-414
1.0 INTRODUCTION
.By letter dated Ap(ril 6 '1989',)and supplemented April 21, 1989, Duke Power Compa ry, et al.,
the licensee proposed changes to the Catawba Units 1 and 2 ecifications (TSs) to identify special Rod Cluster Control Technical' Sp(RCCAs) which will be inserted in the Unit 2 core-prior to Cycle 3 Assed11es operation. Three new assemblies will be used as part of a proposed demonstration program.
The objective of the program is to demonstrate the interface compatibility and successful operating. experience with control rods having a specialized clad coating or plating and to compare the wear characteristics of wear resistant RCCA coating with conventional RCCA clad materials.
The TS changes are necessary to identify the insertion of the demonstration assemblies in the
. Catawba Unit 2 core for the duration of. the program. These changes would involve changing the description of the Control Rod Assemblies in Section 5.3.2 of the TSs for Catawba Unit 2 only. Unit 1 is included because the TSs for both units are combined in one document.
The April 21, 1989, letter clarifieo certain aspects of the request. Therefore, the substance of tt>e changes noticed in the Federal Registnr'and tht proposed no significant hazards consideration determination'n were not affected.
2.0 E_ VALUATION The Catewba units presently have RCCAs supplied by Westinghouse which have a conventional 304 stainless steel cladding material. The licensee is pursuing the possible use of Babcock and Wilcox Fuel Company (BWFC) designed 17x17 hybrid boron-carbide (B4C) control rod assemblies which have coatings or i
platings with special wear resistant characteristics. The initial phase of the demonstration program will involve the insertion of three specialized RCC assemblies in the Unit 2 core starting with reload Cycle 3.
Two of the assed lies will have Armaloy plated 304 stainless steel cladding on the rods and the third will have a chromium carbide coated Inconel 625 cladding. The basic Westinghouse RCCA design features are maintained to make the prinry interface features similar.
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e The B4C absorber pellet diameter and stack length are the same in the demonstration assemblies and the base Westinghouse RCCAs..The lower 12 inches of the Ag-In-Cd absorber stack has a 0.007-inch reduction in absorbar diameter which has a potential impact on shutdown margin. The licensee has stated that the net impact on shutdown margin assuming a full core of BWFC designed rods would be less than 0.004 percent change in reactivity.
For only three assenblies, the effect would be negligible. The new assemblies are lighter in weight by one to three pounds...This results in a slight decrease in scrim drop time.
However,-
the new rods are subject to the same testing program pr;or to startup to ensure-the TS requirements on scram time are met. The staff finds this acceptable.
The remaining RCCA physical characteristics other than coating or plating thickness are unchanged from the original assenblies. The BWFC RCCAs will be placed in shutdown bank locations through the duration of the demonstration program. The specific locations have been identified as coordinates J-03, G-03 and J-13 on the loadina'). pattern diagram (Figure 4.3.2-5A in the Catawba Final Safety Analysis Report The operating elevation of the shutdown bank RCCAs is l
essentially constant during operation. Under these conditions, there is no overlap between the coated region and the fuel assenbly guide tube except i
during startup and shutdown operations. Since sufficient shutdown margin and rod worth is maintained by equivalent absorber material, the reactivity concern is minimized..
The TS changes proposed for Catawba Unit 2 would identify the use of the specially-clad RCCAs and would correctly describe the design features relevant to the control-rod assemblies.
Based on its review, the staff concludes that the insertion of three demonstration RCCAs in Catawba Unit 2 has no adverse impact on safety and does not pose an undue risk to the public health and safety, and is, therefore, acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes to the installation 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, i
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 exposure. The NRC staff has made a determination that the amendments involve no significant hazards consideration, and there has been no public criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9)gibility comment on such finding. Accordingly, the amendments meet the eli l
Pursuant l'
to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
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4.0 CONCLUSION
The Commission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register 1
- s,
. (54 FR 15827) on April 19,'1989. The Commission consulted with the state of South Carolina.
No public coninents were received, and the state of South Carolina did not have any co;nments.
{
d We have concluded, based on the considerations discussed above, that:
(1) l there is reasonable assurance that the health and safety of the public will
- i 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 these amendments will not be inimical to the connon defense and.
security. or to the health and safety of the public.
Principal Contributor:
K. Jabbour PDII-3/DRP-I/II M. McCoy, SRXB/ DEST Dated: lidy 23,1989 l
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