Dissolution of Irradiated Commercial UO₂ Fuels in Ammonium Carbonate and Hydrogen Peroxide

Abstract

We propose and test a disposition path for irradiated nuclear fuel using ammonium carbonate and hydrogen peroxide media. We demonstrate on a 13 g scale that >98% of the irradiated fuel dissolves. Subsequent expulsion of carbonate from the dissolver solution precipitates >95% of the plutonium, americium, and curium and substantial amounts of fission products, effectively partitioning the fuel at the dissolution step. Uranium can be easily recovered from solution by any of several means, such as ion exchange, solvent extraction, or direct precipitation. Ammonium carbonate can be evaporated from solution and recovered for reuse, leaving an extremely compact volume of fission products, transactinides, and uranium. Stack emissions are predicted to be less toxic, less radioactive, chemically simpler, and simpler to treat than those from the conventional PUREX process.

Sequestration of radioactive iodine in silver-palladium phases in commercial spent nuclear fuel

“…In Palomares and co-workers [24] reported on the composition of undissolved residues from the dissolution of ATM-109 fuel using concentrated nitric acid (CNA) and ammonium carbonateperoxide (ACP) dissolution methods. These ACP and CNA dissolution processes have been described elsewhere in detail [25][26][27]. The neutron activation results reported by Palomares and co-workers indicated that the CNA dissolved fuel had a slightly lower Mo and Ru concentration than the ACP dissolved material and that the residue material from the ACP process contained far more radioiodine (700% more) than the CNA dissolved material [24].…”

“…The material was dissolved using two dissolution solutions; hot concentrated nitric acid (termed CNA) and ammonium carbonate-peroxide (ACP). The dissolution process that produced the samples examined in this paper is described in detail in reference [25,26] Each of these treatments dissolved the UO 2 and nearly all of the fission products and transuranic elements, leaving an undissolved residue of fine, black material that consisted largely of the metals; Mo, Tc, Ru, Rh, and Pd, and with smaller amounts of other elements. Approximately 13 grams of fuel was used for each dissolution.…”

Nanostructure of metallic particles in light water reactor used nuclear fuel

“…The fuel was extracted from its Zircaloy cladding by mechanical means. Because of the strong bond between the rim of the irradiated fuel and the zirconium sheath and Zircaloy cladding, it was likely that the extracted sample did not contain a significant amount of the cladding metals [24,25]. Once removed from the cladding the material was crushed prior to any processing.…”

Purification of Uranium(vi) From Impurities of Fission Product Surrogates by Solvent Extraction in the Carbex Process

“…The PUREX process, a well-known technology for reprocessing of spent nuclear fuel (SNF), is based on the application of the SE technique for separation and purification of uranium and plutonium from nitric acid media using tri-n-butyl phosphate (TBP) as a solvent in a hydrocarbon diluent [1]. Recently, alternative hydrometallurgical non-acidic approaches to SNF reprocessing have been developed [2]- [4]. All of them are based on the use of carbonate/bicarbonate or carbonate/alkaline media.…”