1. N UCLEAR F UEL R EPROCESSING T HE UNEX M ETHOD By: Lacy Bishline

2. O UTLINE Nuclear fuel cycle NRC waste policy UNEX solvent development UNEX method flowsheet Spent UNEX solvent reprocessing Questions

3. N UCLEAR F UEL C YCLE www.nrc.gov

4. N UCLEAR F UEL C YCLE Reprocessing facilities are not licensed by the United States Federal waste repository is not approved by the United States All spent fuel is in interim storage

5. N UCLEAR R EGULATORY C OMMISSION W ASTE S TORAGE P OLICY The NRC only regulates radioactive waste storage from non-weapon sources Low Level Waste Three sub levels based on radionuclide concentration High Level Waste www.nrc.gov

6. C LASS A LLW C ONCENTRATION R EQUIREMENTS RadionuclideConcentration Ci/m 3 Cesium-1371 Technitium-993 Plutonium-2411/3500 Strontium-900.04

7. UNEX M ETHOD Current methods (PUREX) used multiple solvents and multiple extraction processes Mixture of three compounds in a diluent 0.08M CCD 0.5 vol % PEG-400 0.02M BNOC FS-13 (diluent)

8. UNEX S OLVENT : CCD Chlorinated cobalt dicarbollide (CCD) Selectively extracts cesium through cation exchange mechanism Strong acid High resistance to radiation Good thermal stability When paired with PEGs Allow for extraction of Cs and Sr in HAW with low pH

9. UNEX S OLVENT : BNOC BNOC: bifunctional neutral organophosphorus compounds Extracts Am and Eu In the presence of CCD distribution coefficients increases by orders of magnitude Diphenyl-N-N-dibutylcarbamoylmethylphosphine oxide (Ph 2 Bu 2 ) Best overall extraction properties of Eu, Pu, and Np

10. UNEX S OLVENT : FS-13 Nitrobenzenes originally picked Diluent Needed high chemical and radiation stability Low aqueous solubility Low viscosity Nontoxic CCD and its salts are very polar Low extraction properties if in solution of other polar substances (ketones, alcohols) Phenyl trifluromethyl sulfone

11. UNEX F LOWSHEET (Law, et al, 2001)

12. S TREAM C OMPOSITIONS (Law, et al, 2001)

13. B ENEFITS OF THE UNEX M ETHOD Has demonstrated 99.95% removal of Cs-137 99.995% removal of Sr-90 99.96% removal for total α emitters (Am-241, Pu-238, Pu-239) Reduces the activity level to below the NRC Class A LLW requirement for grout waste

14. S PENT S OLVENT P ROCESSING React the solvent with phenol, paraform and H 2 SO 4 New polymer is insoluble in several solutions Meets radioactive waste disposal requirements ( St. Petersburg, 2006)

15. Q UESTIONS ?