ML17215A788
| ML17215A788 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/05/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17215A787 | List: |
| References | |
| NUDOCS 8503200505 | |
| Download: ML17215A788 (4) | |
Text
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+**y4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FLORIDA POWER AND LIGHT COMPANY, ET AL.
ST.
LUCIE PLANT, UNIT NO.
2 DOCKET NO. 50-389 LICENSE CONDITION ON AXIAL GROWTH The St. Lucie 2 license condition on axial growth states that:
"Prior to startup following the first refueling outage, the licensee shall provide an analysis and/or make hardware modifications to assure that shoulder gap clearance between fuel rods and fuel assembly end fittings is adequate".
The 'licensee has made hardware modifications on 16 Batch B and all Batch C
irradiated fuel assemblies to increase the available shoulder gap.
In addition, the new Batch D fuel assemblies were manufactured with a larger shoulder gap.
The staff approved such modifications (letter from J. Miller to J.
W.
Williams, Jr.,
November 9, 1984) as a means to correct the shoulder gap problem that occurred in AN0-2.
By a letter dated November 8, 1984 from J.
W. Williams, Jr. to D.
G. Eisenhut, the licensee provided an analysis to address the adequacy of shoulder gap for those unmodified Batch B fuel assemblies during Cycle 2 operation.
The licensee presented an axial growth analytical model and compared results between predic-tion and measurement.
The analytical model was based on an EPRI fuel rod axial growth correlation (Ref. I) and a guide tube growth correlation from the version 10 of MATPRO (TREE-NUREG 1180).
Although the EPRI fuel rod axial growth correlation contained two sets of data, Combustion Engineering and Westinghouse, the licensee stated that this correlation is the best available source for CE fuel rods except CENPD-198.
The staff questions on the adequacy of CENPD-198 led to the license condition.
Although the model used by the licensee depends on data that came from fuel assemblies that differ from those in St. Lucie 2, the results obtained by the licensee showed a large margin between the predicted gap and the gap actually measured by the licensee on Cycle 1 fuel.
8503200505 850305 PDR ADDCK 05000389 P
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Having demonstrated that the model was conservative, the licensee showed in its submittal that adequate margins remain for shoulder gap clearance at the end of Cycle 2.
The licensee included consideration of measurement uncertainty in the analysis.
Jnasmuch as the licensee demonstrated that the model used to predict gap size was conservative with respect to measured data on St. Lucie 2 fuel assemblies and then showed that adequate gap remains for Cycle 2 operation, the staff finds that the license condition has been satisfied.
However, since the licensee's analysis was for Cycle 2 and was based on a
model using data from different fuel assemblies, the licensee should perform measurements during the next outage in order to confirm that adequate shoulder gap remains for operation after Cycle 2 and to provide further confirmation of the licensee's model.
pate.
March 5, 1985 Principal Contributors:
S. L.
Wu D.
E. Sells
REFERENCE 1.
D.
G. Franklin, "Zircaloy-4 Cladding Deformation During Power Reactor Irradiation," Fifth ASTM Symposium on Zirconium in Nuclear Applications, August 4-7, 1980.
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