ML20094J096
| ML20094J096 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/06/1992 |
| From: | Gates W OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20094J100 | List: |
| References | |
| LIC-92-086R, LIC-92-86R, NUDOCS 9203120069 | |
| Download: ML20094J096 (2) | |
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Omaha Public Power DL7trict 444 South 16th Street Mall Omaha, Nebraska 68102-2247 402/636-2000 Harch 6, 1992 LIC-92-086R U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Hail Stetion Pl-137 Washington, DC 20555
References:
1.
Docket No. 50-285 27(,1991 (LIC)-91-320A)(Document Control Desk)
W.G. Gates to NRC 2.
Letter from OPPD dated November Letter from OPPD (W.G. Gates)92-020R)(Document Con to NRC 3.
dated February 12, 1992 (LIC-Gentlemen:
Additional Information Concerning Fort Calhoun Station (FCS) Cycle
SUBJECT:
14 Reload Appiication On February 13, 1992, during the preparation of reactor physics analyses to support Cycle 14 startup operations, a member of the OPPD staff identified a discrepancy in a predicted fuel assembly k, value in a core location which will A subsequent review concluded that an contain hafnium flux suppression rods.
error did exist in the Batch N fuel assembly cross section data set containing hafnium rods which was developed by ABB Combustion Engineering. Since the cross section data set was used in the Cycle 14 core reload analysis (Reference 2), it l
was necessary to evaluate the impact on the safety analysis using the corrected I
cross sections.
The purpose of this letter is to document the impact of this error and provide the necessary changeout pages to the Cycle 14 reload application to support the NRC review.
The impact of the corrected cross sections en Reference 2 was a reduction in the This change resulted in a small Box No. 1 power (containing the hafnium rods).
increase (indicated in Table 1) in the integrated radial peaking factor of the limiting fuel assembly.
Other parameters input to the safety analysis also changed.
However, the changes were in the conservative direction or were incorporated into the safety analysis by reanalyzing the potentially non-conservative events. Table 1 summarizes the Reference 2 parameter values versus the corrected values for the Cycin 14 analysis.
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PAGE 2 i
Attachment I contains changeout pages for Reference 2 reflecting the effects on the safety analysis with the use of revised input parameters of Table 1.
The changes are noted by revision bars in the right-hand page margin. It shnuld also be noted that the clarifications identified in f'eference 3 have also been j
incorporated into the changeout pages.
The use of NEM biases / uncertainties is conservative for ute with the NEM based analyses.
In Attachment 2. justification for use of the leference 3 NEM-based j
biases / uncertainties for peaking factors is provided.
In summary, the effects of the cross section error are considered to be small with the slight increase in integrated radial peaking factor being the most i
significant change to Reference 2.
It is concluded that based on Attachment 1, acceptable resul{s continue to be obtained and that application of the Reference 3 NEM biases / uncertainties further minimizes the impact of the cross-section error.
1 The above information, together with telephone discussions with the NRC on February 21, 1992, should address the NRC's questions on this matter.
As discussed, this information has been submitted expeditiously in order to support l
the planned April 26, 1992 start-up of FCS.
l If you should have any questions, please contact me.
i Sincerely l
A [/b**
1 W. G. Gates Division Manager i
Nuclear Operations
+
WGG/sel c:
LeBoeuf, Lamb, Leiby & MacRae D. L. Wigginton, NRC Senior Project Manager S. D. Bloom, NRC Project Engineer R. D. Martin, NRC Regional Administrator, Region IV R. P. Hullikin, NRC Senior Resident Inspector 1
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