New reprocessing system for spent nuclear reactor fuel using fluoride volatility method

Kani, Yuko; Sasahira, Akira; Hoshino, Kuniyoshi; Kawamura, Fumio

doi:10.1016/j.jfluchem.2008.07.006

Cited by 39 publications

(25 citation statements)

References 14 publications

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“…1,2 Many elements of UNF volatilize when fluorinated, including uranium and neptunium, while others remain stable in the solid form. The differences in thermophysical properties of these products can be utilized as a starting point to effectively separate, isolate and collect product streams with different elemental concentrations for further processing.…”

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

“…Table 1 lists the fluorinated compounds produced after fluorination of UNF elements. 1 The main compound in the volatile phase will be UF 6 , but other species will also be volatilized including PuF 6 , NbF 6 , MoF 6 , TcF 6 , RuF 6 , and TeF 6 . Non-volatile * Calculated for PWR used fuels, burnup rate of 55,000 MWD/t, 4-year cooling period.…”

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

“…The FLUOREX process combines elements of the fluoride volatility process with separation of some UNF elements using aqueous techniques similar to the PUREX process. 1 The FLUOREX process has mostly been proposed by Hitachi as a flexible method that can be adapted for both legacy light water reactors and future fast breeder reactors. The preparation and fluorination steps are similar to the fluoride volatility process with similar trapping of PuF 6 using UO 2 F 2 .…”

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

“…The advantage of the FLUOREX process compared to aqueous processes is that the volatilization step significantly reduces the amount of high level waste. 1 However, the use of pure fluorine gas involves complex safety issues for transportation and handling due to its highly toxic and corrosive nature. Consequently, the identification and application of safer and less harmful fluorinating agents would minimize some of these issues.…”

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

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Sulfur Hexafluoride Treatment of Used Nuclear Fuel to Enhance Separations

Gray¹,

Torres²,

Korinko³

et al. 2012

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SUMMARYReactive Gas Recycling (RGR) technology development has been initiated at Savannah River National Laboratory (SRNL), with a stretch-goal to develop a fully dry recycling technology for Used Nuclear Fuel (UNF). This approach is attractive due to the potential of targeted gas-phase treatment steps to reduce footprint and secondary waste volumes associated with separations relying primarily on traditional technologies, so long as the fluorinators employed in the reaction are recycled for use in the reactors or are optimized for conversion of fluorinator reactant. The developed fluorination via SF 6 , similar to the case for other fluorinators such as NF 3 , can be used to address multiple fuel forms and downstream cycles including continued processing for LWR via fluorination or incorporation into a aqueous process (e.g. modified FLUOREX) or for subsequent pyro treatment to be used in advanced gas reactor designs such metal-or gas-cooled reactors. This report details the most recent experimental results on the reaction of SF 6 with various fission product surrogate materials in the form of oxides and metals, including uranium oxides using a high-temperature DTA apparatus capable of temperatures in excess of 1000 o C . The experimental results indicate that the majority of the fission products form stable solid fluorides and sulfides, while a subset of the fission products form volatile fluorides such as molybdenum fluoride and niobium fluoride, as predicted thermodynamically. Additional kinetic analysis has been performed on additional fission products. A key result is the verification that SF 6 requires high temperatures for direct fluorination and subsequent volatilization of uranium oxides to UF 6 , and thus is well positioned as a head-end treatment for other separations technologies, such as the volatilization of uranium oxide by NF 3 as reported by colleagues at PNNL, advanced pyrochemical separations or traditional full recycle approaches.Based on current results of the research at SRNL on SF 6 fluoride volatility for UNF separations, SF 6 treatment renders all anticipated volatile fluorides studied to be volatile, and all non-volatile fluorides studied to be non-volatile, with the notable exception of uranium oxides. This offers an excellent opportunity to use this as a head-end separations treatment process because:

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Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

Section: Overview Of Fluoride Volatility Processesmentioning

confidence: 99%

See 2 more Smart Citations

Sulfur Hexafluoride Treatment of Used Nuclear Fuel to Enhance Separations

Gray¹,

Torres²,

Korinko³

et al. 2012

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“…These matters result in complexity of processes and an increase in products of radioactive wastes. In order to overcome such disadvantages, some innovative reprocessing methods for spent nuclear fuels have been developed, e.g., Fluorex [3,4], NEXT [5], Super-Direx [6], Urexþ [7], and pyrochemical methods [8].…”

Section: Introductionmentioning

confidence: 99%

A study on selective precipitation ability of cyclic urea to U(VI) for developing reprocessing system based on precipitation method

Suzuki¹,

Kawasaki²,

Kohara³

et al. 2012

Journal of Nuclear Science and Technology

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We have proposed a new reprocessing system based on precipitation method. In order to find out precipitants with high selectivity to U(VI) and to investigate factors controlling precipitation ability to U(VI) and U(IV), properties of 3,4,5,6-tetrahydro-1,3-dimethyl-2(1H)-pyrimidinone (DMPU) as a precipitant have been examined by using U(VI), U(IV) as a simulant of Pu(IV), and simulated fission products (FPs). We have evaluated precipitation ratios (P.R.) for U(VI) and U(IV), solubility of U(VI) precipitates to 3.0 mol dm 73 (M) HNO 3 solution, melting points (MPs) of U(VI) precipitates, log P (distribution ratio of a substance in 1-octanol/water biphasic system, a measure of hydrophobicity) of precipitants, and decontamination factors (DFs) of FPs. The properties of DMPU were compared with those in systems using N-n-butyl-2-pyrrolidone (NBP), N-cyclohexyl-2-pyrrolidone (NCP), and other pyrrolidone derivatives as the precipitant. The P.R. values of DMPU to U(VI) and U(IV) in 3. , and Sm(III)] used in the present study were found to be more than 100. Even in U(VI)-U(IV) coexisting system, the selectivity of DMPU to U(VI) was higher than those of NBP and NCP. This selective precipitation ability of DMPU to U(VI) was evaluated by the solubility of U(VI) precipitates on the basis of their MPs and the log P values of precipitants. As a result, it was found that the precipitants having low hydrophobicity and forming the U(VI) precipitates with high MPs have highly selective precipitation ability to U(VI).

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