ML19276G889

Discusses Anticipated Problems & Design Deficiencies of Westinghouse Waste Encapsulation Sys,In Ref to 790328 Meeting W/Nrc Effluent Treatment Sys Branch.Bids for Portable Solidification Sys Are Being Evaluated

ML19276G889
Person / Time
Site:	Sequoyah
Issue date:	08/23/1979
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	Rubenstein L Office of Nuclear Reactor Regulation
References
NUDOCS 7908280556
Download: ML19276G889 (2)

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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA, TENNESSEE 37401 400 Chestnut Street Tower II August 23, 1979 Director of Nuclear Reactor Regulation Attention: Mr. L. S. Rubenstein, Acting Chief Light Water Reactors Branch No. 4 Division of Project IIanagement U.S. Nuclear Regulatory Commission Washington, DC 20555

Dear Mr. Rubenstein:

In the Matter of the Application of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 In a meeting with the NRC Effluent Treatment Systems Branch on March 28, 1979, TVA indicated that a portable radwaste solidification system is a preferred alternate to the installed system at the Sequoyah Nuclear Plant.

The problems that are expected with the installed waste encapsulation system are described in the enclosure to this letter. TVA believes that these problems provide sufficient justification for not utilizing the installed system at the Sequoyah Nuclear Plant.

TVA is now evaluating bids for a portable solidification system from several vendors. The successful bidder will be required to supply a process control program to satisfy the requirements of the Sequoyah Nuclear Plant waste solidification technical specification as part of this contract. TVA believes a contract could be awarded in early November 1979, and a process control program could be submitted to the NRC for acceptance at that time.

Very truly yours, TENNESSEE VALLEY AUTHORITY b

L. M. Mills, M' anager Nuclear Regulation and Safety Enclosure s(

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ANTICIPATED PROBLEMS AND/OR DESIGN DEFICIENCIES OF THE WESTINGHOUSE WASTE ENCAPSULATION SYSTEM TVA has reviewed the Technical Manual for the Westinghouse Waste Encapsulation System at the Sequoyah Nuclear Plant and has identified the.following potential problems and/or design deficiencies:

1. The system requires that a vacuum of approximately 10 inches of mercury (absolute) be drawn on each group of 6 drums (either 55-gallon or 30-gallon drums) before waste is transferred into the drums. This process step is time consuming. Other plants with the Westinghouse Waste Encapsulation System have experienced difficulty in achieving and main-taining this vacuum because of vacuum leaks at the connections of the drums.

2. The system does not have positive flow indication; therefore, there is no way to verify whether insufficient or excess liquid waste has been transferred into the drum. Insufficient liquid waste would result in incomplete wetting of the cement-vermiculite mixture and subsequently incomplete solidification. Excess liquid waste would result in the presence of free liquid following solidification.

Either of the above situations is unacceptable under current NRC requirements.

3. The system provides no means for uniformly mixing the concentrate waste liquid with the cement-vermiculite mixture. This design concept does not satisfy current NRC requirements.

4. The system dewaters and encapsulates spent resins within cement. This does not meet the requirements of NRC Branch Technical Position ETS3 11-3 which states in item B.II.b that " spent resins. . .should be combined with a suitable binding agent. . .and formed into a solid matrix."

5. The system requires the operator to manually disconnect the drums, to remove the drum shields, and to move the unshielded drums to the storage area. This direct operator contact is anticipated to result in significant operator radiation exposure which violates current ALARA guidelines.

TVA believes that the time required to operate the Westinghouse system, the small amount of waste packaged per drum, the potential radiation exposure to operating employees, and the overall cost of operating the system make the installed system undesirable and provide sufficient justification for not utilizing the system at Sequoyah Nuclear Plant.

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