scholarly journals Thermodynamic properties of fission products in liquid bismuth

2021 ◽  
Vol 2125 (1) ◽  
pp. 012048
Author(s):  
Guohua Ding ◽  
Limeng Liang

Abstract The thermodynamic properties of fission products in molten salt and liquid metal have a great influence on the disposal of nuclear waste in the nuclear fuel cycle industrial system. This paper attempts to extract useful thermodynamic information from the only few experimental activities of lanthanides (Ce, Pr, La) in liquid Bi at different temperatures. The molecular interaction volume model (MIVM) was adopted to model and predict some temperature-dependent thermodynamic functions, including activity, infinite dilute activity coefficient, and molar excess Gibbs energy. The minor average of Δ G ¯ error indicated that assuming εji − εii is a constant is reasonable. On this basis, the natural logarithm of the interaction coefficients and the natural logarithm of the infinite dilute activity coefficient of lanthanides (Ce, Pr, La) in the Bi-based metal melt, these two parameters, show the linear relationship with the reciprocal of temperature. The reasonable agreement of the modeled thermodynamic parameters with the existing experimental data verified that the MIVM is quite convenient and reliable, which can provide guidance for separating fission products from molten salt reactors.

Author(s):  
Takatoshi Hijikata ◽  
Tadafumi Koyama

Pyro-reprocessing is one of the most promising technologies for advanced fuel cycle with favorable economic potential and intrinsic proliferation resistance. The development of transport technology for molten salt is a key issue in the industrialization of pyro-reprocessing. As for pure molten LiCl-KCl eutectic salt at approximately 773 K, we have already reported the successful results of transport using gravity and a centrifugal pump. However, molten salt in an electrorefiner mixes with insoluble fines when spent fuel is dissolved in porous anode basket. The insoluble consists of noble metal fission products, such as Pd, Ru, Mo, and Zr. There have been very few transport studies of a molten salt slurry (metal fines - molten salt mixture). Hence, transport experiments on a molten salt slurry were carried out to investigate the behavior of the slurry in a tube. The apparatus used in the transport experiments on a molten salt slurry consisted of a supply tank, a 10° inclined transport tube (10 mm inner diameter), a valve, a filter, and a recovery tank. Stainless steel (SS) fines with diameters from 53 to 415 μm were used. To disperse these fines homogenously, the molten salt and fines were stirred in the supply tank by an impeller at speeds from 1200 to 2100 rpm. The molten salt slurry containing 0.2 to 0.4 vol.% SS fines was transported from the supply tank to the recovery tank through the transportation tube. In the recovery tank, the fines were separated from the molten salt by the filter to measure the transport behavior of molten salt and SS fines. When the velocity of the slurry was 0.02 m/s, only 1% of the fines were transported to the recovery tank. On the other hand, most of the fines were transported when the velocity of the slurry was more than 0.6 m/s. Consequently, the molten salt slurry can be transported when the velocity is more than 0.6 m/s.


2021 ◽  
Vol 247 ◽  
pp. 13003
Author(s):  
Valeria Raffuzzi ◽  
Jiri Krepel

The Molten Salt Reactor (MSR) is one of the most revolutionary Gen-IV reactors and it can be operated, especially with chloride salts, in the so-called breed and burn fuel cycle. In this type of fuel cycle the fissile isotopes from spent fuel do not need to be reprocessed, because the excess bred fuel covers the losses. The liquid phase of the MSR fuel assures its instant homogenization, and the reactor can be operated with batch-wise refueling thus reaching an equilibrium state. At the same time, the active core of the chloride fast MSR needs to be bulky to limit neutron leakage. In this study, the code Serpent 2 was coupled to the Python script BBP to simulate batch-wise operation of the breed and burn MSR fuel cycle. The script, previously developed for solid assemblies shuffling, was modified to simulate fuel homogenization after fertile material addition. Several fuel salts and fission products removal strategies were simulated and their impact was analyzed. Similarly, the influence of blanket volume was assessed in a two-fluid core layout. The results showed that the reactivity initially grows during the irradiation period and later decreases. The blanket has a large impact on the performance and it can be used to further increase the fuel burnup or to shrink the active core size. The breed and burn fuel cycle in MSR can reach high fuel utilization without fuel reprocessing and a multi-fluid layout can help to decrease the core size.


2021 ◽  
Vol 11 (15) ◽  
pp. 6673
Author(s):  
Bruno Merk ◽  
Anna Detkina ◽  
Seddon Atkinson ◽  
Dzianis Litskevich ◽  
Gregory Cartland-Glover

Molten salt reactors have gained substantial interest in the last years due to their flexibility and their potential for simplified closed fuel cycle operation for massive expansion in low-carbon electricity production, which will be required for a future net-zero society. The importance of a zero-power reactor for the process of developing a new, innovative rector concept, such as that required for the molten salt fast reactor based on iMAGINE technology, which operates directly on spent nuclear fuel, is described here. It is based on historical developments as well as the current demand for experimental results and key factors that are relevant to the success of the next step in the development process of all innovative reactor types. In the systematic modelling and simulation of a zero-power molten salt reactor, the radius and the feedback effects are studied for a eutectic based system, while a heavy metal rich chloride-based system are studied depending on the uranium enrichment accompanied with the effects on neutron flux spectrum and spatial distribution. These results are used to support the relevant decision for the narrowing down of the configurations supported by considerations on cost and proliferation for the follow up 3-D analysis. The results provide for the first time a systematic modelling and simulation approach for a new reactor physics experiment for an advanced technology. The expected core volumes for these configurations have been studied using multi-group and continuous energy Monte-Carlo simulations identifying the 35% enriched systems as the most attractive. This finally leads to the choice of heavy metal rich compositions with 35% enrichment as the reference system for future studies of the next steps in the zero power reactor investigation. An alternative could be the eutectic system in the case the increased core diameter is manageable. The inter-comparison of the different applied codes and approaches available in the SCALE package has delivered a very good agreement between the results, creating trust into the developed and used models and methods.


1984 ◽  
Vol 62 (3) ◽  
pp. 457-474 ◽  
Author(s):  
A. D. Pelton ◽  
C. W. Bale ◽  
P. L. Lin

Phase diagrams and thermodynamic properties of five additive molten salt ternary systems and nine reciprocal molten salt ternary systems containing the ions Li+, Na+, [Formula: see text], OH− are calculated from the thermodynamic properties of their binary subsystems which were obtained previously by a critical assessment of the thermodynamic data and the phase diagrams in these binary systems. Thermodynamic properties of ternary liquid phases are estimated from the binary properties by means of the Conformal Ionic Solution Theory. The ternary phase diagrams are then calculated from these thermodynamic properties by means of computer programs designed for the purpose. It is found that a ternary phase diagram can generally be calculated in this way with a maximum error about twice that of the maximum error in the binary phase diagrams upon which the calculations are based. If, in addition, some reliable ternary phase diagram measurements are available, these can be used to obtain small ternary correction terms. In this way, ternary phase diagram measurements can be smoothed and the isotherms drawn in a thermodynamically correct way. The thermodynamic approach permits experimental data to be critically assessed in the light of thermodynamic principles and accepted solution models. A critical assessment of error limits on all the calculated ternary diagrams is made, and suggestions as to which composition regions merit further experimental study are given.


2022 ◽  
Vol 165 ◽  
pp. 108638
Author(s):  
Jianhui Wu ◽  
Jingen Chen ◽  
Chunyan Zou ◽  
Chenggang Yu ◽  
Xiangzhou Cai ◽  
...  

Author(s):  
Tatiana Grebennikova ◽  
Abbie N Jones ◽  
Clint Alan Sharrad

Irradiated graphite waste management is one of the major challenges of nuclear power-plant decommissioning throughout the world and significantly in the UK, France and Russia where over 85 reactors employed...


Author(s):  
Jiři Křepel ◽  
Valentyn Bykov ◽  
Konstantin Mikityuk ◽  
Boris Hombourger ◽  
Carlo Fiorina ◽  
...  

The Molten Salt Reactor (MSR) represents an old concept, but its properties are qualifying it for the advanced utilization: inherent safety, excellent neutron economy, possibility of continuous or batch reprocessing without fuel fabrication. The aim of this paper is to characterize the MSR unique fuel cycle advantages in different neutron spectra using the results of ERANOS-based EQL3D and ECCO-MATLAB based EQL0D procedures. It also focuses on the low production of higher actinides in the Th-U cycle and based on the results, it proposes a simplified in situ recycling of the fuel and the delayed ex situ carrier salt cleaning or direct disposal by vitrification.


1981 ◽  
Vol 34 (3) ◽  
pp. 479 ◽  
Author(s):  
H Bloom ◽  
MS White

The electromotive forces of galvanic cells for the formation of PbBr2 in the molten binary salt systems, PbBr2-KBr, PbBr2,-RbBr and PbBr2-CsBr, have been measured. Activities, activity coefficients and partial molar free energies have been calculated for each component of the three systems. Integral free energies of mixing have also been calculated. Various models of mixing of molten salts have been applied to the results. The systems contain complex ions, probably mixtures of PbBr42-, PbBr64- with some PbBr3-.


2015 ◽  
Vol 1092-1093 ◽  
pp. 1455-1459
Author(s):  
Chu Yue Hou ◽  
Gui Ying Zhou ◽  
Jian Kang Wen ◽  
Biao Wu

In this paper, we jointly use the Pitzer model and the Meissner model to study thermodynamic laws of bioleaching solution in a lean nickel-cobalt ore in the Jilin Baishan, by using the Pitzer model to calculate activity coefficients of single electrolyte aqueous solutions and the Meissner model to calculate activity coefficients of components in the bioleaching solution. Also we studied the rules of activity coefficient of NiSO4 and CoSO4 in the solution. Results show that when separating and purifying foreign ions from bioleaching solution of the lean nickel-cobalt ore, the descending sequence of their ion concentration’s effect over the solution is Mg2+, Fe3+, Fe2+, Ni2+, Co2+ and Ca2+.


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