ML20028H225
| ML20028H225 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/09/1990 |
| From: | Parker T NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9011190100 | |
| Download: ML20028H225 (2) | |
Text
,
Northam testes Power Company 414 Nicollet Mall Minneapoks, Minnesota $$4011927 Telephone (612) 330 6500 November 9, 1990 U.S. Nuclear ReEulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISIAND NUCLEAR GENERATING PIANT Docket Nos. 50 282 License Nos. DPR 42 50 306 DPR 60 Update on Plans for Increasing the Relinbility of the Chlorine Detection System
Reference:
letter from C E larson to W L Axcison dated October 5, 1989, titled:
" Plans for Increasing the Reliability of the Chlorine Detection System" The purpose of this letter is to provide a status report to you on our long term. investigations related to the improvement of the chlorine detection system.
In the referenced letter, we had listed 3 planned investigations for the long term improvement of the reliability of the system.
(1)
"We are intending to remove the onsite liquid / gas chlorine source and we need to determine the effect of that change on the level of chlorine detection capability."
Result:
We have removed the onsite chlorine source and a hypobromous acid feed system has been installed. We are currently investigating the necessity of chlorine detection capability by reviewing the offsite traffic sources of chlorine.
(2)
"We intend to determine the availability of qualified detectors that are inherently more reliable than those presently installed.
We would then need to make a cost / benefit evaluation of the available detectors."
Result:
More reliable ~ qualified detectors are availabic.
We need to perform the cost / benefit evaluation for a project for the procurement.
engineering and installation of new detectors.
The evaluation will review the success of the interim improvements (Reference 1) in l
preventing any detector-caused auto actuations of the control room l
special ventilation system.
l l
9011190100 90210o PDR ADOCK 05000292 PDC
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0 USNRC November 9, 1990 E'
Northern States Power Company (3)
"We may install a system which is capable of sampling chlorine from either #121 or #122 control room ventilation systems. This would allow the use of only four detectors and a 2 out of 4 logic.
This requires reanalysis of the response times involved to ensure timely isolation of the control room."
Result: The final configuration of the system is dependent on the results of the study and the cost / benefit evaluation, mentioned above.
To summarize, we have effectively resolved the problem of the frequent inadvertent auto actuations of the control room special ventilation system with our interim modification and we are proceeding with a study to determine the best long term solution.
Please contact us if you have any questions related to our plans for the chlorine monitoring system, Thomas M Parker Manager Nuclear Support Services c: Regional Administrator Ill, NRC Senior Resident Inspector, NRC NRR Project Manager, NRC C Charnoff
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