ML20128C321
| ML20128C321 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/26/1993 |
| From: | Chrzanowski D COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9302030387 | |
| Download: ML20128C321 (4) | |
Text
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January 26, 1993 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Document Control Desk
Subject:
Dresden Station Unit 1 NRC Docket Number 50-10
References:
(1)
Letter from A.R. Checca to Dr. T.E. Murley, dated October 4, 1991 (2)
NUREG-0686, " Final Environmental Statement Related to Primary Cooling System Chemical Decontamination at Dresden Nuclear Power Station Unit No. 1"
Dear Dr. Murley:
The purpose of this letter is to provida revised information regarding the processing and disposal of NS-1 contaminated bead resin from the Dresden Unit 1 chemical cleaning.
This modification of resin bead processing, as discussed in the attached 'fescription, is provided as information and does not constitute any variation licensing commitment.
The specifics of slightly contaminated NS-1 bead rt.i disposal were not addressed in the Reference (2) document.
Reference (1) discussed the solidification of bead resin slightly contaminated with solvent NS-1 and the processing of these resins in large scale liners. As described in the attached technical discussion, the revised procedure involves dewatering the resin in a Chem-Nuclear high-density polyethylene (HDPE) high integrity container (HIC) and disposing the waste in a concrete overpack at the Beatty, Nevada, low-level radicactive (LLRW) disposal facility.
If there are any questions or comments, please contact me at (708) 663-7292.
o Stocerely, g
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010043 QCQ 0o David J. Chrzanowski sg Nuclear Licensing Administrator Eo oc<
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cc:
A. Bert Davis, Regional Administrator - RIII 0
@g M. Leach, Senior Resident Inspector (Dresden)
-g P. Erickson, Project Manager - NRR/PDNP
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ATTACHMEHl_
RS _LBea d_Re11LQent erjn9_ardJis pon1 HAckground The Environmental Impact Statement (EIS) written by the NRC for the D-1 chemical cleaning project specified the conditions under which the resulting waste should be disposed.
The primary conditions are (1) solidification in the Dow binder and (2) disposal of the resulting waste form at an arid disposal site - i.e., Beatty, Nevada, or Hanford, Washington, However, the EIS specifically addressed the NS-1 evaporator bottoms which contained the majority of the chelating agents - i.e., 37 weight percent.
No mention was made in this document regarding bead resin contaminated with relatively small amounts of NS-1 solvent.
The bead resin generated during the NS-1 project contains less than eight (8) weight percent chelates.
This concentration is consistent with chelate loadings experienced during LOMI decontaminations. Current industry practice is to dewater LOMI resin in an HDPE HIC and bury the waste in a concrete overpack at a LLRH disposal facility.
Regulatory Considentions Topical reports addressing the use of HDPE HICs were disapproved by the NRC in a December 1988 technical evaluation repo,'t.
The basis for this disapproval was the NRC's concern that material creep and radiation-induced embrittlement in combination with the burial trench overburden would lead to premature bu;kling of these HICs in the disposal trench.
However, the NRC did state in its report that HDPE HICs might be acceptable for low-level waste disposal in cases where an engineered structure such as a concrete caisson provides the structural stability.
The three states currently hosting LLRH disposal facilities - i.e., Nevada, South Carolina and Washington - have reviewed and approved the use of concrete 1
caissons in combination with HDPE HICs for stabilizing waste.
In particular, the State of Nevada has concurred with the State of Washington's technical evaluation report for steel-reinforced engineered concrete barriers.
The conclusion of this report was that these barriers in combination with HDPE HICs provide reasonable assurance that state and NRC structural stability requirements are met.
Technical Considera_tions 1.
NS-1 Chemical Compatibility with HOPE D
Dr. David Harmer has reviewed the list of chemicals incompatible with HDPE HICs and has concluded that none of these materials were used during the D-1 decontamination. On this basis, it can be stated that NS-~1 contaminated bead resin will not chemically degrade HDPE HICs.
Dr. Harmer was the Dow, and later IT Corp., Project Manager for the D-1 chemical cleaning.
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Itthnical Contiderationticantinued) 2.
Mixed Haste Concerns TCLP testing was performed on this beid resin to ensure the dewatered_ waste would 'not be mixed waste.
Results of this testing indicate that the_ bead resin is not a mixed waste and can be buried at any of the three'(3) LLRH disposal facilities.
3.
Bead Resin Dewaterability There are two (2) sources of NS-1 contaminated bead _ resin.. First, the NS-1 process, storage, and transfer equipment in the Chemical Cleaning Building has been rinsed with water and.the resulting NS-1 contaminated rinse water processed through portable-demineralizers.
The resulting bead resin is similar to resin generated during normal.' plant operations and has not been-exposed to conditions which would affect the dewatering process or final-waste form presented for disposal.
Be:d resin contaminated with spent NS-1 also resulted from concentration of the. original solvent used to decontaminate D-1 in 1984.
The overhead vapor from this evaporation process was processed through a demineralizer located-in the Chemical Cleaning Building.
The resulting bead resin has been in-storage since 1984.
Examination of this resin has revealed that storage conditions have not adversely affected its dewaterability.
All NS-1 contaminated bead resin will be dewatered in accordance with procedures and equipment which have been successfully utilized by Chem-Nuclear over the last seven (7) years. These procedures and equipment-have been in use at Commonwealth Edison for the past five (5) years.
The Chem-Nuclear dewatering process meets all NRC regulations and the criteria at the three (3) currently operating LLRN disposal sites.
Coatluilon Dewatered bead resin is currently accepted for disposal by the three (3) operating LLRH disposal facilities. Af.ter extensive-review, the states regulating' disposal of LLRW at these s3tes have concluded that dewatered resin placed in_HDPE HICs and engineered concrete overpacks:successfully meets stability requirements._ At.'the time _the EIS_was written for the D-1 chemical cleaning, this-disposal technique had:not been developed. Chemistry Services position is that the NS-1 resin can be successfully dewatered to meet regulatory requirements because:
(1) The D-1 EIS does not specify the disposal requirements for NS-1
-contaminated bead resin; ZNLD/2470/3 4
1
O Conc 1usion (conlinged).
(2) The-chelate concentration of the NS-1 resin is similar to that of LOMI resin which is currently dewatered; (3) There has been extensive regulatory review and approval of HDPE HICs in combination with engineered concrete overpacks for disposal of LLRH; (4) Chem-Nuclear has successfully dewatered thousands of containers of resin with its dewatering procedures and equipment; and (5) The physical and chemical condition of the NS-1 resin indicates this waste can be successfully dewatered to meet regulatory requirements.
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