ML20207C116
| ML20207C116 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/22/1986 |
| From: | Travers W Office of Nuclear Reactor Regulation |
| To: | Standerfer F GENERAL PUBLIC UTILITIES CORP. |
| References | |
| CON-NRC-TMI-86-119 NUDOCS 8612300054 | |
| Download: ML20207C116 (3) | |
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e-e DN 50-320 Local PDR NRC PDR TMI Site r/f TMI HQ r/f DCS FMiraglia December 22, 1986 WDTravers HRC/Till 86-119 MMasnik RHall JThomas CCowgill TMoslak Docket No. 50-320 LChandler I&E ACRS Hr. F. R. Standerfer M-town Office Vice President / Director, THI-2 Service List GPU Huclear Corporation P. O. Box 480 fliddletown, PA 17057
Dear ifr. Standerfer:
Subject:
Addition of Coagulants to the Reactor Coolant System
References:
(a) Lc'.ter 4410-06-L-0213, F. Standerfer to W. Travers, Safety Evaluation Report for the Addition of Coagulants to the Reactor Coolant Systen, dated liovember 15, 1986 (b) Letter NRC/Till 86-066, W. Travers to F. Standerfer, s
Safety Evaluation for the Operation of the Filter Aid Feed Systen and lise of Diatonaceous Earth as Feed Paterial, dated July 9, 1986 (c) Letter fiRC/Tlil 85-055, U. Travers to F. Standerfer, Defueling Water Cleanup System, dated August 6,1985 (d) Betz llandbook of Industrial Water Conditioning, Seventh Edition, 1976 Reference (a) submitted, for NRC staff review and approval, your proposal for the addition of coagulant chemicals and filter aid materials to enhance the performance of the Defueling Water Cleanup System (DWCS) filters. Experience to date with DUCS operation has shown the filters to be ineffective in efficiently controlling RCS weter clarit < due to unexpectedly short filter life. This is apparently caused by the presence of colloidal suspensions of hydrated metal oxides in the wat <.
Laboratory tests have shown that the addition of a coagulant caterial along with diatoaaceous carth as a filter aid significantly inproves filter perfornanca. This was further verified by a full scale test of a filter using water in the reactor coolant bleed taaks.
Ycur proposal involves the injection of a coagulant and filter aid upstreen of the DWCS filters. Additional lengths of hose will be added in appropriate locations to allow for sufficient contact tiae between the fluid and coagulant to pemit formation of a filterable flocculant i>efore the process flow reaches the filters. The systen also includes a coagulant mixing tank and feed systen.
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'!!r. F. R. Standerfer Decenber 22, 1986 k*e have evaluated your proposal for potential adverse consequences due to chenical effects of the coagulant, spills of RCS liquid, and inadvertent critical ity. The use of the filter aid feed systen and diatunaceous carth ucs previously reviewed and approved in reference (b).
The potential for and consequences of hose ruptures and line breaks in the DNCS were previously evaluated. The systen uadifications necessary to support the coagulant addition progran are very ainor and do not alter the conclusions stated in reference (c).
The coagulant chasen for your proposed process is a high nolecular weight polyner classified as a cationic polyelectrolyte. The use of the polyclectrolytes in the coagulation of colloidel suspensions is discussed in chapter 5 of reference (d). Laboratory tes:i a has shown that the coagulant does not cause precipitation or renoval 01 cen from solution, thus it does not present a potential deboration c.echanim.
It does however release chlorides to the RCS.
The level of chlorides caused by tha additives is smil, and if properly controlled will not result in RCS cheoistry paraneters exceeding the technical specification linits. The chemicals have been tested for reaction with the reconsiner catdlyst in the defueling canisters and have been shewn to have no unacceptable adverse effects.
The concentration of coagulants that will result in the LCS und defueling canisters is very low if controlled in eccordance with your proposal. This will not result in a criticality concern if the ECS boron concentation is naintained within the current technical specification-linits. The effects of the coagulant or criticality of a deustered filter canister has not been fully evaluated. Thus, eny filters containing coagulants will be stored in the borated water of the reactor vessel, the feal transfer canal, or the spent fuel pool. These filters will not be acceptable for dewatering and shipping until further evaluations are conplete.
He concur with your analysis that the proposed activities do'not pose a risk to the hcelth and safety of the public or the cccupational work force, nor do they exceed the scope of cctivities and associated enviranuentr.1 inpacts considered in the staff's prograumtic Environnental Impact Statenent. The proposal does not present the possibility of an/ accidunt not previously analyzed nor does it change the consequences of, or likelihood of any previously analyzed accident. Margins of safety as previously analyzed ere not reduced.
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We therefore approve ycur proposal for addition of coagulants to the reactor coolant system as described in reference (a). This approval is contingent upon our review of the asscciated procedures subject to Technical Specificication 6.8.2.
Sincerely,
. ORIGINAL SIGNED BY, I
William D. Iravers Willian D. Travers l
Director i
TilI-2 Cleanup Project Directorate cc:
T. F. Dtmitt R. E. Rogan
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