ENERGY Defense Nuclear Nonproliferation

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1 Argonne-Design Annular LEU Foil Target and Possible Use in Alkaline-Based Processes George F. Vandegrift Chemical Sciences and Engineering Division Argonne National Laboratory 1

2 Annular LEU-Foil Target Its use should allow substitution of LEU for HEU in all processes The size of the target and the amount of U in each target is set only by reactor irradiation limits Can be used in both acid-dissolution and alkaline-digestion processes Al fission-recoil barrier for alkaline Ni fission-recoil barrier for nitric acid LEU-foil targets have been successfully irradiated in Indonesia, Argentina, Australia, and the University of Missouri at fluxes up to 2x10 14 neutrons/cm 2 -sec 2

3 LEU-Foil Annular Target U FOIL LOCATED BETWEEN TUBES WELD END CLOSED Inner Tube (with undercut to position foil) 2 darker targets are Zr test targets Outer Tube 3

4 LEU-Foil Annular Target Targets Post Irradiation 4

5 U.S. DEPARTMENT OF Use of LEU Foil Targets An LEU foil target can meet 235U loading requirements. For example, the IRE target was reported to contain ~4 g of U at 89-93% enriched in 235U.* An LEU-foil target of the same dimensions with a standard 135-µm thick foil of 19.9% enriched uranium would contain 4.1 g of 235U If the LEU foil were made as thick as the current fuel meat (510 µm), the target would contain 16.6 g of 235U * J. Salacz, Production of fission Mo-99, I-131, and Xe-133, The Mo-99 Programme of the National Institute for Radioelements I.R.E., Review IRE Tijdschrift, Vol. 9, Nº 3 (1985) 5

6 Use of LEU Foil Targets by Current Producers Current processes digest UAl 3 dispersion targets in base Uranium and many fuel components precipitate and hydrated oxides and hydroxide salts Al, Mo, I, Cs are dissolved in the alkaline solution Mo is recovered from solution and purified In the past, Argonne developed a means to digest the LEU foil in alkaline solution High temperature/pressure required to do so--not appropriate for commercial production (safety concerns) Argonne is looking at two means to recover Mo for use in alkaline processes Acidic dissolution followed by Mo recovery on TiO 2 sorbent Electrochemical dissolution of U in carbonate media 6

7 Acidic Dissolution Followed by Mo Recovery Argonne has designed a production-scale dissolver for Ni-clad LEU foils by nitric acid Up to 250 g of LEU per batch Prototype will be fabricated and tested in October-January Nitric acid dissolution Ni, U, and all fission and activation products dissolve readily in nitric acid U + 4HNO3 UO2(NO3)2(aq) + 2H2O + 2NO(g) Off-gas will contain NO (some NO 2 ), noble gases, and iodine Based on the LEU-Modified Cintichem dissolver Dissolver is closed so that all gases must be removed and trapped before solution can be processed Mo can be recovered from solution using a titania sorbent Mo can be stripped from the column using 1 M NaOH or NH 4 OH 7

8 The Production-Scale Acid Dissolver Initial Nitric Acid Con. (molar) U metal (g) 40 ml 80 ml 120 ml 160 ml 200 ml 240 ml 280 ml 320 ml 360 ml 400 ml 440 ml 480 ml 520 ml 560 ml 600 ml 8

9 Effect of varying uranium concentration on uptake of tracer levels of 99 Mo from 1 M HNO 3 solutions Isosorb Radsorb Alumina PZC Sorbent K d ( 99 Mo), ml/g M HNO UO 2 (NO 3 ) 2, g/l 9

10 Low-Temperature Ambient-Pressure Dissolution Irradiated LEU foil target Mechanical Decladding NaOH Dissolution CCD -PEGof Al barrier NaOH/ NaAl(OH) 4 1 M NaHCO 3 U CCD electrolysis -PEG CaO solid U precipitation TRUEX filtrate 99Mo TALSPEAK sorption CaCO 3, Ca(OH) 2, An, FP s 10

11 Uranium Electrochemical Dissolution A two-step dissolution process in a single vessel Al fission-recoil barrier dissolved in NaOH solution Uranium dissolved electrochemically into a NaHCO 3 solution After dissolution, uranium, carbonate, and alkaline insoluble fuel components are precipitated from solution by adding CaO Filtrate composition <1 mm CO 3 2- Trace U All MoO 4 2- Other alkaline soluble fission products Saturated Ca(OH) 2 ph 12.7 Mo can be recovered from this solution using anion exchange K d for Mo(VI) on BioRad AGMP-1 is ~340 Should be higher than K d in current process because of less competition from OH - and Al(OH) 4-11

12 Prototype Laboratory-Scale Dissolver INSULATING TUBE LEAK DETECTION PORT VARIABLE SPEED MOTOR CATHODE POWER CONNECTION ANODE BASKET POWER CONNECTION ANODE BASKET RETAINER INSTRUMENTATION PORT OFFGAS PORT / FEED LINE DUAL O-RINGS VESSEL COVER ANODE BASKET FLANGE BAND CLAMP (MODIFIED for manipulator use) CATHODE SLEEVE VESSEL LINER (NON CONDUCTIVE) IMPELLOR DRIVE SHAFT (IMPELLOR NOT ILLUSTRATED) DUAL O-RINGS DRAIN LINE DUAL BALL BEARINGS DRIVE PULLEY WITH ROUND BELT LEAK DETECTION PORT SUPPORT STAND 12

13 Prototype Laboratory-Scale Dissolver Dissolver will be fabricated and tested to optimize process and to design a commercial-scale unit Prototype will dissolve 40-g of U foil per batch Foot-print is 38 cm by 18 cm After testing, design will be improved and retested Design of proto-type and the production model will be finalized Argonne will seek advice from commercial producers throughout the process. 13

14 Eliminating HEU in Waste from 99 Mo Production 99 Mo producers have historic inventories of HEU in waste residues from years of production. After 99 Mo production is converted from the use of HEU targets, eliminating the HEU in historic Mo-99 waste residue would achieve permanent threat reduction through the complete elimination of HEU in the production of medical isotopes. GTRI is currently assessing whether support can be provided to address the HEU in historic waste residue generated from the production of 99 Mo 14

15 Acknowledgements The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory ( Argonne ). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. Work supported by the U.S. Department of Energy, National Nuclear Security Administration's (NNSA's) Office of Defense Nuclear Nonproliferation, under Contract DE-AC02-06CH