In molten salt reactors, uranium or thorium exist as $\ce{UCl4}$ and $\ce{ThF4}$ in a 1:4 stoichiometric ratio. When a uranium is split into a barium and a krypton, the barium becomes $\ce{BaCl2}$ while the krypton is inert. As a result, two chloride ions are forced to give off their electrons and become elemental chlorine that can react with the structure. Does that mean as the chain reaction proceeds, the molten salt will become more and more oxidative? How can we maintain the stoichiometric balance in molten salt reactors?

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    $\begingroup$ Fission creates many different pairs, not just Ba and Kr. Each pair will have different salts. Plus there are buffers included to reduce any mismatch. $\endgroup$
    – Jon Custer
    Oct 26, 2021 at 18:53
  • $\begingroup$ And nuclear fission will produce so much energy that puny electrostatically driven chemical bonds with diffuse electron clouds are blown to the tenth dimension. You'll get a lot of ions (nuclei even?) and electrons until things cool down and recombine in some way. $\endgroup$ Oct 26, 2021 at 21:01
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    $\begingroup$ @OscarLanzi - Only 10 dimensions??? Ha! My string theory goes to 11... $\endgroup$
    – Jon Custer
    Oct 26, 2021 at 21:10
  • $\begingroup$ Tenth dimension is more poetic. Besides, I have heard of theories with 26 dimensions. $\endgroup$ Oct 26, 2021 at 21:57
  • $\begingroup$ Ah, “It goes to 11.” ;-) $\endgroup$
    – Ed V
    Oct 26, 2021 at 22:49

1 Answer 1


As mentioned in the comments including mine (now deleted), fission of uranium produces not only barium and krypton but various other pairs and its salts. You can find a detail explanation of all the fission product chlorides in the referenced paper. The free chlorine that you mention is also present in abundance when the fission product chlorides decomposes at high temperatures.


  1. Bradley, D. The preparation and properties of the chlorides of uranium, plutonium, and thorium and of the fission product chlorides. United Kingdom: N. p., 1957. Web. (link)

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