Application of a One-Dimensional Transient Electrorefiner Model to Predict Partitioning of Plutonium from Curium in a Pyrochemical Spent Fuel Treatment Process

Gonzalez, Mario Alberto; Hansen, Lauryn C.; Rappleye, Devin; Cumberland, Riley; Simpson, Michael F.

doi:10.13182/nt15-28

Cited by 17 publications

(10 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Cm deposition on a solid cathode in the LiCl‐KCl melt was studied by Gonzalez et al 37 Assuming that the exchange current density includes effectively the activity coefficient and the molar fraction of CmCl and following the Butler‐Volmer equation, one can present the slope in the cyclic voltammetry characteristic in the following form:

italicslope = i_{0}^{0} A {(x_{b}^{ox})}^{α} \frac{nF}{RT},

where

i_{0}^{0}

is the standard exchange current density (A cm −2 ), A is the surface area (cm 2 ),

x_{b}^{ox}

is the mole fraction of the oxidized species in the bulk, α is the transfer coefficient, and n is the number of electrons transferred.…”

Section: Mass Transfermentioning

confidence: 99%

Processing of fast neutron reactor fuel by electrorefining: Thematic overview

Галашев

2020

Int J Energy Res

View full text Add to dashboard Cite

Summary This work provides basic knowledge on the spent fuel management on the basis of the published literature data on electrorefining. This review examines three main areas of work devoted to electrorefining. These are electrodeposition and electrodissolution using solid and liquid electrodes, as well as mass transfer in phases present during electrorefining. As part of this research, the composition of the irradiated metallic fuel was estimated. Due to the great potential difference between solid cathodes, it is possible to separate actinides from lanthanides. The co‐deposition of metallic Pu and U in the eutectic LiCl‐KCl melt containing UCl3 and PuCl3 indicates stable co‐precipitation of U and Pu at U3+ concentration less than ~0.2 wt. Periodically performed electrical transport of ions to liquid (Cd) and solid cathodes in the galvanic mode made it possible to deposit preferentially U on the solid cathode, and Pu and Am on the liquid cathode. Oxidation of these metals caused fluctuations in the anode potential. The electrode processing after electrorefining is investigated. This process consists of oxidizing the actinides remaining in the liquid electrode by adding CdCl2 and removing the associated chloride by high‐temperature distillation. During the electrorefining of irradiated metallic fuel, the fission products accumulate in the molten salt. Reduction of uranium on a solid cathode from a spent molten salt using a liquid Cd‐Li anode is considered. A model that describes electrorefining with a liquid metal anode, solid cathode, and molten LiCl‐KCl salts, is presented. The formation of plutonium at the surface of a solid cathode is analyzed. In a one‐dimensional model of an electrorefiner, it is shown that the concentration of Pu at the cathode cannot be predicted from the Cm concentration in the melt.

show abstract

italicslope = i_{0}^{0} A {(x_{b}^{ox})}^{α} \frac{nF}{RT},

where

i_{0}^{0}

is the standard exchange current density (A cm −2 ), A is the surface area (cm 2 ),

x_{b}^{ox}

is the mole fraction of the oxidized species in the bulk, α is the transfer coefficient, and n is the number of electrons transferred.…”

Section: Mass Transfermentioning

confidence: 99%

Processing of fast neutron reactor fuel by electrorefining: Thematic overview

Галашев

2020

Int J Energy Res

View full text Add to dashboard Cite

show abstract

“…44 Curium has been proposed as a tracer element to roughly monitor plutonium content in pyroprocessing based on the assumption that the elemental ratio of curium to plutonium remains fixed (i.e., that the two elements codeposit at the cathode at approximately the same rate). 45 However, quantifying this ratio within acceptable precision and accuracy to support safeguards decision making has proven a challenging task. 10,46 In particular, the spatial dependency of 244 Cm atom density (given the nonuniform burnup profile of typical fuel assemblies) leads to a strong spatial dependence of the Pu-to- 244 Cm ratio through the fuel.…”

Section: Iiia2 Passive Neutron Measurementsmentioning

confidence: 99%

“…10 More significantly, differences between the Gibbs free energy of formation of the actinides results in the extraction of Pu and Cm at different rates in the electrorefiner, challenging the assumption of a constant codeposition ratio. 45,47,48 As such, the use of 244 Cm as a proxy for plutonium tracking has been generally determined to be unreliable as a safeguards measurement. 45 Alternatively, the chemical makeup of the eutectic salt may offer the potential for direct plutonium quantification through (α,n) emissions.…”

Section: Iiia2 Passive Neutron Measurementsmentioning

confidence: 99%

“…45,47,48 As such, the use of 244 Cm as a proxy for plutonium tracking has been generally determined to be unreliable as a safeguards measurement. 45 Alternatively, the chemical makeup of the eutectic salt may offer the potential for direct plutonium quantification through (α,n) emissions. Because of the relatively low atomic number of the salt constituents, preliminary studies have indicated that the intensity of (α,n) neutron emissions from the electrorefiner may prove as strong as those arising from the spontaneous fission of 244 Cm in some energy regimes.…”

Section: Iiia2 Passive Neutron Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

Review of Candidate Techniques for Material Accountancy Measurements in Electrochemical Separations Facilities

et al. 2020

View full text Add to dashboard Cite

Electrochemical reprocessing (also commonly known as pyroprocessing) of used nuclear fuel is an alternative to aqueous reprocessing that confers a number of advantages, including the ability to process more recently discharged fuel, smaller resultant waste volumes, and the lack of isolation of plutonium in the product stream. While electrochemical reprocessing systems have seen a significant research and development effort, nuclear safeguards and the security of these systems remain underdeveloped, particularly given the significant differences in operating environment and process flow sheet compared with established aqueous methods. In this paper we present an overview of the current state of the art for several of the most promising candidate techniques for material accountancy and process monitoring measurements for electrochemical separations facilities for used nuclear fuel, specifically passive radiation signatures (gamma spectroscopy, neutron spectroscopy, alpha spectrometry, calorimetry, and microcalorimetry), active radiation signatures (X-ray interrogation and its derivatives, high-resolution X-ray, k-edge densitometry, and hybrid k-edge densitometry; laser-induced breakdown spectroscopy; active neutron interrogation and neutron coincidence counting; inductively coupled plasma mass spectrometry; and optical measurements such as ultraviolet visible spectroscopy, near-infrared spectroscopy, and Raman spectroscopy), and control and process state variable monitoring (cyclic voltammetry and bulk measurements such as level and density, load cell forces, and off-gas monitors). This assessment includes an evaluation of each measurement's respective modality (i.e., whether the measurement relates to elemental, isotopic, or other properties), published best estimates of measurement precision, measurement latency, and an overall evaluation of each technique's level of technical maturity. Additionally, this study assesses the most likely locations within the pyroprocessing flow sheet where measurements may be deployed, the physical information required to properly capture the behavior of such measurements, and potential modeling strategies for such measurements. This latter component thus serves to inform future development of process monitoring models in existing and proposed electrochemical separations simulation models.

show abstract

“…2 The chemical makeup and operations of the electrochemical process make the last point, i.e., the consistency of the Pu/Cm ratio, of particular concern because the ratio does not remain constant within the electrorefiner thus complicating the quantification of plutonium by the previously mentioned ratio method. 4,5 These points make the safeguards application for electrochemical systems of vital importance. The area of proliferation resistance at the electorefiner is of particular concern due to the complex sample matrix complicating plutonium quantification.…”

Section: Introductionmentioning

confidence: 99%

Examination of (α,n) Signatures as a Means of Plutonium Quantification in Electrochemical Reprocessing

Gilliam

Coble

Skutnik

2021

Nuclear Science and Engineering

View full text Add to dashboard Cite

In this paper, we investigate the possibility of plutonium quantification within the electrorefiner vessel of an electrochemical separation facility via the use of the (α,n) neutron signature from dissolved actinides. As a potential alternative means to traditional spontaneous fission tracking, such an analysis may provide a more reliable tracking capability of plutonium within systems that produce a mixed matrix sample that yields a large (α,n) source term relative to that of spontaneous fission. This assessment includes an evaluation and breakdown of nuclides within the refining unit to differentiate the source of neutrons and then the ratio between (α,n) emissions to total neutron emissions given a range of fuel parameters. Next, we provide an assessment of the origin of (α,n) neutrons in relation to multiple isotopes of plutonium to determine the potential of a direct tracking method. Preliminary results indicate that the (α,n) contribution for electrochemical systems is much higher than in its aqueous counterpart and rivals spontaneous fission yield in terms of magnitude. Furthermore, 238 Pu is shown to be a main contributor to the (α,n) yield for the fuel examined in this study.

show abstract

Application of a One-Dimensional Transient Electrorefiner Model to Predict Partitioning of Plutonium from Curium in a Pyrochemical Spent Fuel Treatment Process

Cited by 17 publications

References 11 publications

Processing of fast neutron reactor fuel by electrorefining: Thematic overview

Processing of fast neutron reactor fuel by electrorefining: Thematic overview

Review of Candidate Techniques for Material Accountancy Measurements in Electrochemical Separations Facilities

Examination of (α,n) Signatures as a Means of Plutonium Quantification in Electrochemical Reprocessing

Contact Info

Product

Resources

About