ML20072R390
| ML20072R390 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/15/1991 |
| From: | Gates W OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20072R393 | List: |
| References | |
| LIC-91-084I, LIC-91-84I, NUDOCS 9103250345 | |
| Download: ML20072R390 (2) | |
Text
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Omaha Public Power District 444 South 16th Street Mali Omaha, Nebraska 68102-2247 402/636 2000 March 15, 1991 LIC-91 0841 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station Pl-137 Washington, DC 20555
References:
1.
Docket No. '0-285 2.
Letter from NRC (S. J. Collins) to 0 PPD (W. G. Gates) dated December 12, 1990 3.
Letter from OPPD (W. G. Gates) to NRC (Document Ccntrol Desk) dateu February 28, 1991 (LIC-91-080R)
Gentlemen:
SUBJECT:
Supplement to January-June 1990 Semiannual Radioactive Effluent Release Report in response to Omaha Public Power District's (OPPDs) commitment to supplement any semiannual radioactive effluent release report containing erroneous dose results, attached is revised " Quarterly Cumulative Dose Contributions-From Radioactive Effluents" data (pages 1-3 and I-4) for the January-June 1990 period.
OPPD has determined that the January-June 1990 semiannual radioactive efflue.it release report alone contained erroneous data which nonconservatively stated dose results for radioactive liquid effluents fec:: Lim Monitor / Hotel Tank.
This commitment arose from a discrepancy between NRC and OPPD dose results during confirmatory calculations of offsite doses from radioactive liquid waste effluents as documented in Inspection Report 90-41, Open Item 285/9041 03 (Reference 2). The snurce of the errors was traced to modifications made in March of 1990 to the computer sof tware radionuclide data input table.
Output from this software is utilized in the preparation of the semiannual report. As a result of the modifications, instructions in the software code (which uees an indexing method to locate isotope data) did not read the correct isotope dai:
into the dose calculation formulas.
Corrections to the software occurred in October 1990 and the July-December 1990 semiannual radioactive effluent release report (Reference 3) was prepared using l/
the corrected code.
Calculations verified that the software code utilized I
prior to March of 1990 produced results in compliance with the Offsite Dose Calculation Manual.
To prevent the recurrence of indexing errors, the sof tware l
code is being rewritten so that it will locate isotope data by name tiefore I
input into the dose calculation formulas.
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U. S. Nuclear Reguletory Commission LIC-91-0841 Pag'e 2 Technical Specification requirements were maintained during the period of March 0ctober 1990 when the incorrect software modification was utilized.
If you should have any questions, please contact me.
Sincerely, 4V. 5 5&
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W. G. Gates Division Manager Nuclear Opeiations i
WGG/sel Attachment c:
LeBoeuf, Lamb, Leiby & MacRae R. D. Martin, NRC Regional Administrator, Region IV W. C. Walker, NRC Project Manager R. P. Mullikin, NRC Senior Resident inspector
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