ML19353B018
| ML19353B018 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 12/01/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19353B011 | List: |
| References | |
| NUDOCS 8912110059 | |
| Download: ML19353B018 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 74 TO FACILITY OPERATING LICENSE NO. DPR-34 AND PROPOSED' REACTOR DEFUELING PUBLIC SERVICE COMPANY OF COLORADO FORT ST. VRAIN NUCLEAR GENERATING STATION DOCKET NO. 50-267
1.0 INTRODUCTION
By letter dated September 14, 1989 as revised October 13, 1989 Public Service:
~ Company of Colorado (the licensee) submitted proposed Technical Specifications (TS)relatedtodefuelingtheFortSt.VrainNuclearGeneratingUnt(FSV).
d FSV was permanently. shutdown on August 18, 1989 and defueling will be accomplished in preparation for decomissioning. The October 13, 1989 revision to the g
September 14, 1989 application clarified the sequence for unloading the fuel and does not change the staff's previous determiration of no significant l-hazards consideratior.
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The proposed amendment would allow the use of defueling elements containing no fuel but loaded with boron to replace the negative reactivity of the control rods. These.unfueled elements replace fueled elements as they are removed to maintain the structural integrity of the core until defueling is-complete. The present TS does not contain a description of these unfueled I
elements and the description must be incorporated into the TS to allow defueling.
2.0 EVALUATION l
The licensee has proposed the addition of a description of the defueling 1
elements to Section 6 of the TS. The defueling elements are made of graphite l
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.i. and have the' same outer dimensions as the fuel elements that they are replacing.
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Defueling elements have coolant channels that align with coolant channels of other elements and structures above and below. Since these elemen'ts are unfueled there will be no decay heat contribution from fission products.
In addition, 1
the staff has determined that adequate decay heat coolant provided to the i
I remaining core.will not be disrupted by the use of the refueling elements as coolant flow characteristics are the same as with fueled elements.
a Twelve blind holes in defueling elements are filed with boron carbide cylinders.
These cylinders replace the control rods in each element and provide the shutdown reactivity needed for defueling. The staff has reviewed the use of boron carbide in these unfueled elements and has determined that the boron carbide provides more negative reactivity in the element than the control rods it replaces.
1 As needed, new neutron. sources of Californium 252 will be placed in the reactor j
core as a supplement to existing sources to ensure that. sufficient count rate is maintained for reactivity monitoring during defueling. The staff has determined that an adequate count rate can be maintained during defueling with the use of I
these sources.
The NRC staff has reviewed the proposed use of these defueling elements and has determined that adequate structural integrity, cooling, shutdown margin, and reactivity menitoring will be maintained in the FSV reactor core during defueling. Therefore, the staff finds this proposed TS change acceptable and that the licensee may proceed with defueling.
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3.0 ENVIRONMENTAL CONSIDERATION
The 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 exposures.
The Comission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public I
coment on such finding. Accordingly, the amer.dment meets the. eligibility criteriaforcategoricalexclusionsetforthin10CFRSection51.22(c)(9).
Pursuantto10CFR51.22(b),noenvironmentalimpactstatementorenviron-mental assessment need be prepared in connection with the issuance of.the amendment.
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4.0 CONCLUSION
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The staff 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, and (2) such j
activities will be conducted in compliance with the Comission's regulations, and the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributors:
Kenneth L. Heitner, PDNP Laurence 1. Kopp, SRXB Peter B. Erickson, PONP/DRSP Dated:
December 1, 1989
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