Part 2 of 2 Parts (Please read Part 1 first)
     Khaykovich says, “These are the fundamental issues we need to solve before commercializing molten salt reactors. How, at the basic level, will fuels and fission and corrosion products alter salt solutions? And how will changing salt compositions alter reactor behavior? We have to have answers to these questions as we design molten salt reactors.”
     In order to answer these questions, Khaykovich is making use of the Nanoscale-Ordered Materials Diffractometer (NOMAD) at Oak Ridge National Laboratory’s (ORNL) Spallation Neutron Source (SNS). NOMAD features high-temperature sample environments that permit samples to be heated to over fifteen hundred degrees Fahrenheit which are then studied with neutron diffractometry. Neutrons are perfect for this type of research because they are particularly sensitive to chromium-52 and chromium-53 which prominent isotopes found in molten salt samples.
    Through the use of NOMAD, Khaykovich was able to observe how each positively charged chromium ion attracted six negatively charged chlorine ions to create the octahedral network found in the molten salt solution under study. As a result of the attraction of chlorine by chromium, the chlorine atoms are closer together than they would be in a pure molten sodium chloride solution. The environment around the sodium in the solution containing chromium is unaffected by the chromium and looks about the same on average as it does in a pure molten sodium chloride solution.
    He pointed out that chromium would not be deliberately added to the molten salt solution circulating in a molten salt reactor. It is an undesired impurity which would only be dissolved in the molten salt from corrosion in the system. This is one of the reasons that it is important to understand the effects of impurities in molten salts.
   Khaykovich says, “Chromium-52 has a positive neutron scattering length, meaning neutrons are repulsed by the isotope. Chromium-53, on the other hand, has a negative neutron scattering length, which means it attracts neutrons. By including both isotopes in salt solutions, we can generate a comprehensive set of diffraction peaks that provide important insights into how chromium interacts with other constituencies in the melt, which can only be done with neutrons.”
      Khaykovich’s research is only the most recent chapter in ORNL’s long record of supporting science related to molten salt reactors. ORNL built and operated the only molten salt reactors ever tested. The lab continues to provide critical resources for researcher who are interested in further developing this promising technology.
   Lou Qualls serves as both the reactor technology integration lead in ORNL’s Nuclear Science and Engineering Directorate and the national technical director for DOE’s molten salt reactor research. He said, “Fundamental understanding of salt behavior in molten salt reactors is essential to the design and licensing process. Using our science tools to help build that understanding is much of what is ultimately going to make us successful.”  
     Khaykovich said “The models we want to generate with this data would be a great asset for engineers trying to design molten salt reactors. Neutrons have a big role to play in this new phase of nuclear energy.”