ML20029B550
| ML20029B550 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 01/28/1991 |
| From: | Gates W OMAHA PUBLIC POWER DISTRICT |
| To: | Collins S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| RTR-REGGD-01.109, RTR-REGGD-1.109 LIC-91-033R, LIC-91-33R, NUDOCS 9103120373 | |
| Download: ML20029B550 (3) | |
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.g ygg Omaha Public Power District 444 South 16th Street Mall Omaha. Nebraska 68102-2247 402/636-2000 January 28, 1991 LIC-91-033R Mr. Samuel J. Collins, Director Division of Reactor Projects V. S. Nuclear Regulatory Commission Rngion IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011
References:
1.
Docket No. 50-285 2.
Letter from NRC (S. J. Collins) to OPPD (W. G. Gates) dated December 12, 1990
Dear Mr. Collins:
SUBJECT:
NRC Inspection Report 90-41, Open Item 285/9041-04; Radiological Services Group Radioactive Effluent Dose Calculations As requested in Reference 2, this letter is to inform you of Omaha Public Power District's (OPPD's) findings and actions necessary to resolve NRC Inspection Report 90-41, Open item 285/9041-04.
This item concerns dose calculations prepared by OPPD's Radiological Services group from radioactive liquids, airborne iodine and particulate effluents which did not agree with NRC dose calculations.
In a telephone conversation between Mr. Phil Harrell of the NRC and Mr. Tom Therkildsen of my staff, OPPD requested and was granted an extensien to January 28, 1991 to submit its response.
Radioactive Liauid Doses in Jg In comparison to the NRC's PC-DOSE program, OPPD's LADTAP program calculated a g o.
conservatively high radioactive liquid doses.
Two factors caused this 58 discrepancy.
First, the dose factor library contained incorrect entries for
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some of the isotopes.
Secondly, a conversion error occurred during the inspection while formatting data presented by the NRC for input into OPPD's Q
LADTAP program.
o ct To resolve this situation, the dose factor library has been updated to conform M
with Regulatory Guide 1.109, Revision 1.
Dose calculations were repeated using Sg the updated dose factor library and corrected input values.
As a result, OPPD cu c and NRC dose calcu'ations now match. The updated dose factor library will be used to prepare the July to December 1990 Semi-Annual Radioactive Ef fluent Release Report.
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Mr. Samual J. Collins U..S. Nuclear Regulatory Commission LIC-91-033R Page 2 OPPD's routine method for preparation of the Semi-Annual Report prevents the type of error which occurred while converting NRC data into a format acceptable to LADTAP.
A review of previous Semi-Annual Reports since the implementation of the updated Radiological Effluent Technical Specifications (RETS) in the fourth quarter of 1985 was conducted.
Reanalysis of the report containing the highest dose in this period using the updated dose factor library determined that the Total Body and Critical Organ dose calculations were correct as submitted.
Dose calculations for radioactive airborne iodine and Darticulates from-incestion oathways includina cow meat, cow milk and vecetation The calculations for the cow meat, cow milk, and vegetation pathways for ingestion of airborne iodine and particulates are the onl/ calculations that remain in disagreement with NRC results.
These pathways nrovide a very small percentage of the total dose to the public from radioactive effluents generated by Fort Calhoun Station.
OPPD dose calculatinn differences if substantiated, are not sufficient to cause these doses to exceed regulatory limits.
OPPD is utilizing Regulatory Guide 1.109 Revision 1 to verify the pathways, constants and calculations used in the GASPAR program.
Currently, the verification process is app oximately 20% complete.
Attached is an Action Plan containing the status of the tasks neces:;&ry to resolve the differences between dose calculations-performed by ine NRC's program-(PC-DOSE) and OPPD's programs (LADTAP, GASPAR).
Unless unforeseen circumstances arise during the GASPAR verification process, OPPD ;hould be able to complete the actions.necessary to resolve Open Item 285/9041-C1 by July 31, 1991.
If you should have any questions, please contact me.
Sincerely, GV k Y W. G. Gates Division Manager Nuclear Operations 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
ACTION PLAN FOR RESOLVING OPPD & NRC DOSE COMPARISONS FOR LIQUID AND AIRBORNE EFFLVENTS STATUS Action Tasks
(% Comolete_)
1.
LADTAP 1 - Liquid Effluents A.
Compare pathways with Reg. Guide 1.109 100 8.
Compare calcu'ations and constants with Reg. Guide 1.109 100 C.
Compare OPPD LADTAP/NRC results 100 ___
D.
Update OPPD LADTAP Dose Library 100 E.
Calculate the liquid dose for the highest quarter with Reg. Guide 1.109 for Tech. Spec, compliance 100 f.
Document Actions for NRC Review 50 11.
GASPAR I - Airborne Effluents A.
Compare pathways with Reg. Guide 1.109 20 B.
Compare calculations and constants with 20 Reg. Guide 1.109 C.
Compare GASPAR/NRC /esults 20 D.
Revise GASPAR (if necessary) 0 E.
Document actions for NRC-review 20 f