ML20235S931
| ML20235S931 | |
| Person / Time | |
|---|---|
| Issue date: | 02/28/1989 |
| From: | Hurt R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Bixby W ENERGY, DEPT. OF, IDAHO OPERATIONS OFFICE |
| References | |
| REF-PROJ-M-32 NUDOCS 8903080067 | |
| Download: ML20235S931 (2) | |
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a47 FEB '2 81989 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 -
Dear Dr. Bixby:
A list of questions concerning off-gas treatment for the vitrification process under construction at the West Valley Demonstration Project is attached for your consideration. We received a preliminary Safety Analysis Report (SAR) on the vitrification system in 1987 and were briefed by your contractors in late 1988 on the latest work in this area. We plan to prepare a Safety Evaluation Report once we receive your final SAR, but hope in the meantime to begin to discuss some of the topics of greatest interest to us.
Please respond to the enclosed questions at your convenience.
Sincerely, Q(igin3i Sigr:ed i,:
R. Davis Hurt West Valley Project Manager Advanced Fuel and Special Facilities Section Fuel Cycle Safety Branch
Enclosure:
Questions Concerning the Vitrification Off Gas System g
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FEB 2 81989 sfE QUESTIONSCONCERNINGTHEVITRIFICATIONOFF-GASSYSTEM 1.
Table C.6.1-1 of the preliminary Safety Analysis Report (SAR) gives decontamination factors (DF's) for the various components of the off-gas system and for the melter itself. 'What is the basis for the assignment of DF values for the melter? Specifically, what-references or experiments can you quote to support the DF values listed in the SAR?
How would the melter DF's depend on melter operating conditions?
2.
What are the main mechanisms by which radioactivity may escape from the melter into the off-gas system? Experiments at Pacific Northwest Laboratories (PNL-5904-2, Sep 86) with a similar melter seem to show that.
under some ccnditions escape of semivolatile elements directly from the glass is the main mechanism, while under other circumstances gross entrainment of melter feed material predominates. The escape mechanism c will determine which isotopes get into the off-gas and which types of f
equipment will be needed to remove them.
~l 3.
It is clear that some cesium will volatilize at the molten glass temperatures at which you expect to operate.
It there any evidence that other elements of concern, such as strontium, technetium, plutonium, or americium will volatilize at such temperatures?
4.
What is the expected chemical form of the main radioactive constituents of the melter off-gas?
5.
What are the expected particle sizes of the main radioactive constituents of the melter off-gas?
6.
Are the surging characteristics of the melter well understood? Is it important in your operating strategy to avoid surging, and if so, how will it be avoided?
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