ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site
ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site
ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site
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, . . . . . . ,<br />
-c%w<br />
probably still be mostly tri€%u~ride~, This oxidized system will<br />
be corrosive, but it should be manageable in equipment of nickel<br />
or nickel-elad Hastelloy.<br />
Step 2. Precipitate <strong>the</strong> insoluble oxides ushg water vapor diluted in<br />
helium. 'RE oxides UO2% Pa205, Pu02, Ce02, probably Np02, and<br />
possibly Am02 and @m02 should be obtairped, With <strong>the</strong> exception<br />
of %r02 and Pa205, <strong>the</strong>se will be largely in solid SUPU~FQ~. The<br />
oxide solid solution is likely to contain 15 to 20% of Tho2; this<br />
WQUP~ correspond to a few (less than 5) percent of <strong>the</strong> T%F4 pres-<br />
ent in <strong>the</strong> fluoride. Recover <strong>the</strong> oxides by decantation and fil-<br />
tration.<br />
Step 3. Hydrofluorinate <strong>the</strong> oxides from step 2 into <strong>the</strong> purified LIP-<br />
Step 4.<br />
Step 5.<br />
Step 6,<br />
BeP2-ThF4 melt from step 7 and reduce <strong>the</strong> melt with H2 and <strong>the</strong>n<br />
with lithium, thorim, or beryllium to reconstitute fuel with<br />
<strong>the</strong> desired UF~/UF~ ratio.<br />
Hydr~fluo~inate <strong>the</strong> liquid from step 2 to remove excess oxide<br />
ion. kidize to get samarium and (if possible) europium to SmF3<br />
and EuF3.<br />
Treat <strong>the</strong> melt from step 4 with an excess of CeF3. This might<br />
be done in a column or in a two- or three-batch countercurrent<br />
operation. This T ~ ~ Q V a ~ major S fraction of <strong>the</strong> rare earths but<br />
does essentially nothing for cesium, rubidium, strontium, and<br />
barium. (If neptunium, americium, and curium are appreciably<br />
harder to oxidize than plutonium, <strong>the</strong>y should remain in <strong>the</strong> salt<br />
in step 2 and should be removed on <strong>the</strong> CeF3 in step 5.)<br />
The LfF-BeF2-ThF4 melt from step 5 contains sdy a fraction of<br />
<strong>the</strong> rare earth poisons but, of course, is saturated with CeF3.<br />
oxidize <strong>the</strong> ee* to ~e4+.<br />
Step 7. ~recipitate <strong>the</strong> ce4+ as c~o~. some will accompany <strong>the</strong><br />
Step 8.<br />
Ce02, but <strong>the</strong> quantity should be small.<br />
by decantation and filtration.<br />
<strong>the</strong> fissile material recovery operation in step 3.<br />
Dissolve <strong>the</strong> solid &F3 (contaminated with rare earths) from step<br />
5 in some suitable salt (preferably not SLiF-BeP2) and oxidize<br />
<strong>the</strong> Ce3+ to @e4'@<br />
Separate <strong>the</strong> precipitate<br />
Feed <strong>the</strong> molten LiP-BeP2-ThF4 to