ML20214N953
| ML20214N953 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 09/11/1986 |
| From: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20214N955 | List: |
| References | |
| NUDOCS 8609170186 | |
| Download: ML20214N953 (2) | |
Text
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September 11,1986 i
s Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Virgil C. Summer Nuclear Station Docket No. 50/395 i
Operating License No. NPF-12 Deletion of Total Uranium Weight from Technical Specifications
Dear Mr. Denton:
South Carolina Electric & Gas Company (SCE&G) hereby requests a revision to the Virgil C. Summer Nuclear Station Technical Specifications. Design Features Section 5.3.1, " Fuel Assemblies," of the Technical Specifications identifies a maximum total fuel rod weight of 1766 grams of uranium. Recent improvements to the fuel design, including an as-built density increase and chamfered pellets with a reduced dish, have increased fuel weight slightly. These weight increases i
will cause the maximum fuel rod weight in subsequent fuel cycles to exceed the currently specified maximum value of 1766 grams. The proposed Technical l
Specification change will delete the maximum total weight limitation per fuel rod contained in the Design Features Section. Attachment I contains a copy of Technical Specification page 5-6 marked-up to reflect the proposed change.
i The Technical Specification value as stated in Section 5.3.1 was not intended to be descriptive or representative of all fuel loadings and has not been used as a direct input to safety analyses. The weight difference by which the rod uranium weight may in the future exceed the 'imit currently specified will not have a significant impact on the safety analyses. Other Technical Specification Sections cover other necessary fuel related parameters and therefore deletion of the fuel rod weight limit is not significant to the safe operation of the plant.
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The actual uranium weight has no bearing on the power limits, power operating level or decay heat rate. Technical Specifications on power and power distribution control the fission rate and, hence, the rate of decay heat production.
l The composition of the fuel is closely monitored to assure acceptable fuel performance for such things as thermal conductivity, swelling and densification.
i Fission product cleneration is not sensitive to the mass of fuel involved but to the power level. As' ong as the power gen'erated by the core is unaffected, there will be no significant impact on the radiological source terms.
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Mr. Harold R. Denton Page 2 September 11,1986 Uranium mass has no impact on Emergency Core Cooling System (ECCS) LOCA analyses. LOCA analyses are sensitive to parameters such as pellet diameter, ht shrinking factor and pellet density as they relate to pellet-clad gap, stack heig!umetric heat generation. Individuaifuel rod uranium pellet temperature and vo weight, as currently reported in the Technical Specifications, is not explicitly modeled in any non-LOCA event. Total uranium present in the core is input into the transient analyses, but is generated using a methodology independent of the value presented in the Technical Specifications.
The mass of uranium is accounted for in the standard fuel rod design through Van,ropriate modeling of the fuel pellet geometry and initial fuel density.
app ations in uranium mass associated with allowable as-built variations, but within the specification limits for the pellet dimensions and initial density, are accounted for in the reactor core o 's'gn analyses and therefore have no impact on margin to reactor core design critria. The fuel rod uranium weight currently found in the Technical Specifications is not a direct input to the analyses of either maximum seismic /LOCA fuel assembly dynamic response or the seismic response of the reactor vessei and internals.
Enclosed as Attachrn at ll is SCE&G's No Significant Hazards Determination.
This proposed change has been reviewed and approved by both the Plant Safety Review Committee and the Nuclear Safety Review Committee. Please find enclosed the application fee of $150 required by 10CFR170.
The statements and matters set forth in this submittal are true and correct to the best of my knowledge,information and belief.
If you should have any questions please advise.
er ruly ours, bNw
. A. N uman l
AMM: DAN /bh Enclosures pc:
O. W. Dixon, Jr/T. C. Nichols, Jr.
C. L. Ligon (NSRC)
E. H. Crews, J r.
R. M. Campbell, Jr.
I E. C. Roberts K. E. Nodland O. S. Bradham R. A. Stough D. R. Moore G. O. Percival J. G. Connelly, Jr.
R. L. Prevatte l
W. A. Williams, Jr.
J. B. Knotts, J r.
Group Managers H. G. Shealy W. R. Baeh r NPCF C. A. Price File l
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