scholarly journals The impact of hydrogen valence on its bonding and transport in molten fluoride salts

Author(s):  
Stephen T. Lam ◽  
Qing-Jie Li ◽  
Jonathan Mailoa ◽  
Charles Forsberg ◽  
Ronald Ballinger ◽  
...  

In molten fluoride salt systems, the chemistry and transport of hydrogen are coupled to its valence state, which controls the balance of tritium leakage and corrosion.

2020 ◽  
Author(s):  
Stephen T. Lam ◽  
Qing-Jie Li ◽  
Jonathan P. Mailoa ◽  
Charles Forsberg ◽  
Ronald Ballinger ◽  
...  

<p>Interest in molten salts has increased significantly over the last decade due to their potential application in various clean-energy technologies including hydrogen generation, solar heat storage, and advanced nuclear power plants. In the development of new molten salt-based fission and fusion systems, controlling hydrogen poses a critical challenge due to its ability to corrode structural materials as <sup>3</sup>H<sup>+</sup>, and its potential to cause significant radioactive release as diffusive <sup>3</sup>H<sup>0</sup>. Yet, the chemistry and transport behavior of the hydrogen species remain poorly understood despite several decades of research. Using ab initio molecular dynamics, we present a coupled examination of hydrogen valence, speciation and transport in the prototypical salts 66.6%LiF-33.3¾F<sub>2</sub> (Flibe) and 46.5%LiF-11.5%NaF-42%KF (Flinak). We discovered significant differences between <sup>3</sup>H<sup>0</sup> and <sup>3</sup>H<sup>+</sup>transport behaviors. <sup>3</sup>H<sup>+</sup> diffuses 2-4 times slower than <sup>3</sup>H<sup>0</sup>, which can be ascribed to hydrogen bonding and complexation in solution. This work helps explain varying experimental results and provides useful species transport data for designing hydrogen control systems for molten salts. </p>


2020 ◽  
Author(s):  
Stephen T. Lam ◽  
Qing-Jie Li ◽  
Jonathan P. Mailoa ◽  
Charles Forsberg ◽  
Ronald Ballinger ◽  
...  

<p>Interest in molten salts has increased significantly over the last decade due to their potential application in various clean-energy technologies including hydrogen generation, solar heat storage, and advanced nuclear power plants. In the development of new molten salt-based fission and fusion systems, controlling hydrogen poses a critical challenge due to its ability to corrode structural materials as <sup>3</sup>H<sup>+</sup>, and its potential to cause significant radioactive release as diffusive <sup>3</sup>H<sup>0</sup>. Yet, the chemistry and transport behavior of the hydrogen species remain poorly understood despite several decades of research. Using ab initio molecular dynamics, we present a coupled examination of hydrogen valence, speciation and transport in the prototypical salts 66.6%LiF-33.3¾F<sub>2</sub> (Flibe) and 46.5%LiF-11.5%NaF-42%KF (Flinak). We discovered significant differences between <sup>3</sup>H<sup>0</sup> and <sup>3</sup>H<sup>+</sup>transport behaviors. <sup>3</sup>H<sup>+</sup> diffuses 2-4 times slower than <sup>3</sup>H<sup>0</sup>, which can be ascribed to hydrogen bonding and complexation in solution. This work helps explain varying experimental results and provides useful species transport data for designing hydrogen control systems for molten salts. </p>


2019 ◽  
Vol 524 ◽  
pp. 119-134 ◽  
Author(s):  
Jo Jo Lee ◽  
Stephen S. Raiman ◽  
Yutai Katoh ◽  
Takaaki Koyanagi ◽  
Cristian I. Contescu ◽  
...  

Alloy Digest ◽  
1990 ◽  
Vol 39 (12) ◽  

Abstract NICKEL VAC N was originally developed as a container material for molten fluoride salts. It is a moderate strength, solid solution strengthened alloy with good oxidation resistance to 1800 F. It has excellent resistance to fluoride salts in the range 1300-1600 F. It is produced by vacuum induction melting followed electroslag remelting. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-388. Producer or source: Teledyne Allvac.


2021 ◽  
Vol 375 ◽  
pp. 111094
Author(s):  
P.R. Hania ◽  
D.A. Boomstra ◽  
O. Benes ◽  
P. Soucek ◽  
A.J. de Koning ◽  
...  

2007 ◽  
Vol 62 (12) ◽  
pp. 769-774
Author(s):  
Tomáš Šimo ◽  
Oldřich Matal ◽  
Lukáś Nesvadba ◽  
Vladimír Dvořák ◽  
Viktor Kanický ◽  
...  

Molten fluoride salts are very promising carriers for the transport of large amounts of heat for example from a high temperature nuclear reactor to a plant which generates hydrogen by chemical processes or from a nuclear reactor to a heat exchanger being a part of the equipment needed to realize the Brayton cycle with a very high power efficiency. Therefore, in the framework of our project, experimental and theoretical investigations of the interactions of fluoride salts as heat carriers needed as high potential and structural materials for pipelines in order to transport heat at temperatures above 600◦C were started. Experimental investigations of Fe-based and Ni-based materials in molten fluoride salts at high temperatures and with different exposure times were performed. Two components salts (LiF-NaF and NaF-NaBF4) and three components salts (LiF-NaF-ZrF4 and LiF-NaF-RbF) were chosen in the experiments. The salt analysis was focussed on the content of metallic elements before and after the exposure of the samples to the salt melts. It was done by inductively coupled plasma-optical emission spectrometry (ICP-OES) and by titrimetric techniques. The thickness of the material zone affected by the salt melts, characterized by an enriched / reduced content of elements in comparison to the mean original content, and the material attacked zone, characterized by very tiny channels or chains of pores or pits formed preferably at grain boundaries, were the subject of the analysis performed by electron microscopy / microprobe techniques. Theoretical models for the transport of elements in the material samples exposed to salt melts using experimental data were also developed.


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