ML20247P898
| ML20247P898 | |
| Person / Time | |
|---|---|
| Issue date: | 03/31/1989 |
| From: | Hurt R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Bixby W ENERGY, DEPT. OF |
| References | |
| REF-PROJ-M-32 NUDOCS 8904070018 | |
| Download: ML20247P898 (2) | |
Text
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. MAR 31 1989 -
.c Project No. M-32 Willis W. Bixby, Director West Valley Project Office U.S. Department of Energy Idaho Operations.
P.O. Box 191 West Valley, NY 14171 4
Dear Dr. Bixby:
We have reviewed Revision 5 to the Supernatant Treatment System (STS) Safety Analysis Report,L WVNS-SAR-004, mailed to us on February 7,1989. The revision describes changes you plan to make to the STS to permit use of a new procedure for removing cesium-loaded zeolite frc1 the ion-exchange columns.
It.is our understanding that the changes are necessary because the column dump valves already installed have proved unreliable and an alternative method of removing loaded zeolite would-be preferred. The alternative method will be to force the. zeolite through a tube that exits from the top of the column and reaches nearly to.the bottom. The tubes are already in place, but to use this method effectively.it is also necessary to be able to remove the heel of loaded zeolite that ~ lies below the mouth of the tube.
For this purpose, you propose
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-to instal.1 air sparging lines in the bottom of each column so that the zeolite-heel can be levitated and siphoned out.
- We have' considered the possibility that the addition of air spargers as proposed in Revision 5 could increase public exposure to radiation or contribute to new types of accidents. To ensure that public safety is protected, there are two contingencies that must be guarded against: the possibilit;- that supernatant may back up the air sparger lines; and the possibilit, that gamma radiation through the unshielded riser openings may cause slig cly elevated skyshine exposure at the site boundary.
Based on review of. 1e information you provided us, consultation with your staff, and some indepmdent calculations on our part, we are convinced that the precautions, you are planning will be adequate to protect the public.
Concerning the possibility that supernatant might bWk up the sparger lines and reach the environment, the combination of passive blocking devices, such as the double check valves and Johnson screen, and active control equipment, such as the air-actuated stop" valve and pressure alarm system, will make it extremely unlikely that the air sparge lines could act as a pathway to the environment. Excessive gamma radiation through the unshielded riser openings
' could be prevented by ensuring that the water covering the loaded zeolite in the bottom of Tank 8D-1 is always deep enough to attenuate the radiation to a safe qd I
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Willis W. Bixby 2
level. Further assurance would be gained iy installing permanent gamma monitors in the two riser openings in question.
Your staff has agreed (per telephone conversation of March 22, 1989 with Alan Yeazel) to calculate the minimum safe water depth and to consider installing the two radiation monitors.
We do not think it necessary to revise our Safety Evaluation Report on the STS.
Sincerely, 0(ighlaj Signed by R. Davis Hurt West Valley Project Manager Advanced Fuel and Special Facilities Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NMSS I
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