ML19257D808

Forwards Proposed Mods to Improve post-accident Monitoring Capability.Mods Adequately Address Lessons Learned Task Force Category a Design Review Items & Description of Mods Contained in Section 2.1.8 of NRC 791030 Ltr

ML19257D808
Person / Time
Site:	Davis Besse
Issue date:	01/31/1980
From:	Crouse R TOLEDO EDISON CO.
To:	Reid R, Reid R Office of Nuclear Reactor Regulation
References
586, TAC-44432, TAC-44912, TAC-44983, TAC-45054, NUDOCS 8002060515
Download: ML19257D808 (3)

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TMEDO Docket No.50-34o

%ms EDISON License No. NPF-3 Serial No. 586 A c+c P C: ause e C e NS C8t January 31, 1980 '-

n m ur D! rector of Nuclear Reactor Regulation Att ention: Mr. Robert N. Reid, Chief Operating Reactors Branch No. 4 Division of Operating Reactors United States Nuclear Regulatory Commission Washington, D. C. 20555

Dear Mr. Reid:

By letter dated November 21, 1979 (Serial No. 559) Toledo Edison identified its plans to conduct a design review to identify plant modifications that would enhance onsite sampling and analytical capabilities for highly radioactive reactor coolant, station vent gases, and containment vessel gases and atmosphere. This review was in direct response to recommendation 2.1.8 of NUREG 0578 "TMI-2 Lessons Leamed Task Force Status Report and Short Tem Recommendations", as discussed in your letters of September 13 and October 30,1979 (Log Nos. 430 and 454).

The review indicated that expanded ranges of monitoring systems and modified sampling techniques are needed to ensure the proper quantification of extremely radioactive conditions, while minimizing radiation exposure to plant personnel. The attachment to this letter functionally discusses the proposed modifications to improve post-accident monitoring capability at the Davis-Besse Nuclear Power Station, Unit 1.

It should be noted that proposals in several areas provide descriptions of alternative methods to accomplish similar functions which are not finalized. This flexibility is required at this time due to the lack of currently available equipment that can meet the performance and qualification criteria of Toledo Edison and the NRC. Detailed discussions are proceeding with potential equipment suppliers, however, in these areas the commitment schedules remain flexible. In the interim, Toledo Edison feels the techniques for monitoring highly radioactive conditions discussed in our letters of January 18 and 31,1980 (Serial Nos. 578 and 585) are adequate for event assessment.

This submittal is considered to adequately address the " Category A" items of design review and description of modifications addressed in Section 2.1.8 of your October 30, 1979 letter (Log No. 454).

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Very truly yours,

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Docket No. 50-346 License No. NPF-3 Serial No. 586 January 31, 1980 NUREG 0578 Section 2.1.8 Proposed Design Modifications for the Davis-Besse Nuclear Power Station Unit 1 (DB-1)

I. Recomnaadation 2.1.8a Post Accident Sampling Capability A. Rr actor Coolant Liquid Sampling la order to Unprove the reactor coolant liquid sample location DB-1 will i e modified to add a sample line directly off a reactor coolant loop drain.

ibis line will join with an existing pressurizer sample line to allow sample location selection remotely f rom the control room. This modification is planned to be completed during the refueling outage currently scheduled to start March, 1981.

A decision on the basic approach to on-site reactor coolant analysis has not been finalized. However, reactor coolant analytical capability will be provided either through the use of on-line monitoring systems or on-site laboratory evaluation of grab samples. This analytical capability is pre-sently planned to include:

1) Radiological isotopic quantification

2) Boron concentration determination

3) Dissolved gas (hydrogen and oxygen) determination The implementation schedule for the analytical capability is dependent on

t. e method of analysis yet to be selected. The current target date for c;mpletion of this capability is the 1981 DB-1 refueling outage.

B. Containment Vessel Atmosphere Sampling Hydrogen concentration of the containment vessel is currently provided by a hydrogen analyz: with a 0-5 percent range. This capability will be maintained and the current system modified to include a 0-10 percent range capability. This conversion is presently scheduled to be completed by January 1, 1981. _ ,

The method of radiological sampling and analysis of the containment vessel atmosphere has not been finalized. Evaluations of both on-line monitors and grab sample techniques with laboratory analysis are unresolved due to the problem of currently available equipment and its qualifications. Although the methodology has not been selected, Toledo Edison will install one such system. Due to the above uncertainties schedular commitments cannot be made at this time.

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Docket No. 50-346 License No. NPF-3 Serial No. 586 January 31, 1980 Page Two II. Recommendation 2.1.8b Increased Range of Radiation Monitors A. Noble gas Ef fluents Toledo Edison will modify the plant to provide a high range noble gas effluent monitoring capability for the containment vessel atmosphere and the station vent. We are currently evaluating the possibility of a combined monitoring system that could provide on-line isotopic analysis. If this system is not selected, a gross monitor with grab sample capability will be provided.

Equipment selection has not been completed, caused by factors such as question-able qualification data. As a result,no schedular commitment can be made at this time.

B. Radioiodine Effluents A combined system as discussed above is under consideration. Pending further equipment selection and qualification review, the schedular and sample point commitment are consistent with those of Section IIA.

C. High Range Containment Vessel Area Radiation Monitors Toledo Edison plans to provide extended range containment vessel area radiation monitors. However, currently available equipment does not meet the performance or qualifications criteria required. No implementation schedule can be projected. due to the lack of available instrumentation.

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