Simulation study of energy deposition, damage and gas/neutron production in molten FLiBe and FLiNaK salts under proton and alpha irradiation

FLiBe and FLiNaK are candidate coolant and tritium breeding salts for molten salt and fusion reactors, yet their response to energetic light ions is far less studied than their neutronics and corrosion. This work reports the energy deposition, displacement damage and gas production of the 14.7 MeV proton and 3.6 MeV alpha of the D– 3 He reaction in both salts and their five constituents. Stopping and Range of Ions in Matter (SRIM), OpenTRIM and GEANT4 give energy deposition and damage, and TALYS reaction cross sections. Ranges are compared with ATomic Interaction with MAtter (ATIMA), cross sections with measurement. Ionization carries 99.96%–99.98% of the beam energy, and the displacement production is 33–68 Norgett–Robinson–Torrens (NRT) vacancies per ion. The SRIM and GEANT4 projected ranges reproduce ATIMA to within −1.3% to ＋2.7% for every target except sodium, at ＋7.4 to ＋8.4%. The non-ionizing energy partition differs by a factor of two between SRIM and GEANT4, though their displacement counts agree to within 15%–29%. Gas production is resolved by isotope: tritium comes almost entirely from 7 Li, while 6 Li produces helium instead, a split transport codes cannot give. Below A = 12 the TALYS statistical model is not quantitative, so data from the experimental nuclear reaction data library (EXFOR) are used where they exist. The alpha gives about twice the per ion displacement and makes FLiBe a far stronger secondary neutron source than FLiNaK through 9 Be( α , n ) 12 C. The results are converted into displacement dose, gas production and neutron source terms for a representative accelerator irradiation scenario.