Evaluation of a low temperature fluoride route to synthesize actinide mononitrides

NUCL 11

G. W. Chinthaka Silva, silvag2@unlv.nevada.edu, Department of Chemistry, Harry Reid Center for Environmental Studies, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, Charles B. Yeamans, yeamans@nuc.berkeley.edu, Department of Nuclear Engineering, University of California, Berkeley, 4164A Etcheverry Hall, UC Berkeley, Berkeley, CA 94720, Gary Cerefice, cerefice@unlv.nevada.edu, Harry Reid Center, UNLV, 4505 South Maryland Parkway, Box 454009, Las Vegas, NV 89154-4009, Frederic Poineau, fredericpoineau2001@yahoo.fr, Harry Reid Center for Environmental Studies, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, and Ken Czerwinski, czerwin2@unlv.nevada.edu, Department of Chemistry and Harry Reid Center, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154.
A low temperature fluoride route to convert AcO2 into AcN (where Ac is an actinide) is explored using UO2 and ThO2. The actinide dioxides are converted to the fluoride ammonium salt through a reaction with ammonium bifluoride. The reaction products are examined by X-ray diffraction, X-ray absorption spectroscopy, thermal analysis, and microscopy. For the uranium system, the fluoride product is reacted with ammonia at 800 0C, resulting in uranium oxidation and the formation of UN2. The synthesis of UN at elevated temperatures proceeds through the U2N3 intermediate phase. The UN formation kinetics and activation energy are evaluated. For the thorium system the reaction of the ammonium fluoride material under ammonia produces ThNF. The characterization of ThNF is provided. The thorium nitride product differs from the uranium product due to variation in redox properties of these actinides. The results are used as a basis for nitride synthesis experiments with the transuranics.
 

Meeting the Diverse Needs of the 21st Century Nuclear Science Workforce: A Symposium by Graduate Student Scientists in Nuclear and Radiochemistry
8:30 AM-12:05 PM, Sunday, August 19, 2007 Boston Park Plaza -- Lexington Room, Oral

Division of Nuclear Chemistry & Technology

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007