neil thanks for the chem info and john b stone thanks for the clarification i have looked into high density and all are heavy heat insulators i thought diamond would work because it boils at a high temp 3000+ and would block the radiation
heres the deal diamond casing is must for the rod
i believe a retractable screen powered by an electic motor and controlled by sensors could enclose the rod and be made from heavy insulators and high density material
these "screens" could be used as emergency failsafe and to prevent gas expansion during the filling stage
ev on their own require a power source me idea is small scale mobile power generation
u get into an accident in hydrogen car you will die hydrogen is a level 4 explosive material
unless its the type of hydrogen car that converts water to hydogen mobily
but winter happens