I think you could change the thorium run into a new hazardous run
Info: Sort of a delivery contract to take radioactive waste from a power plant to a storage facility and paid for the delivery
Requirements: Hazmat Suit, Mask and secure vehicle (thorium truck could be renamed/skinned)
Waste has to be 'filled/processed' into barrels (progress bar)
'Barrels' need to be loaded into truck (progress bar)
'Barrels' need to be unloaded and secured at the storage facility (progress bar)
The run could be robbed however coming in to contact with the barrels would require Hazmat Gear or players would take health damage over time leading to death within a specified period of time.
It would be impractical for things like Plutonium as it's mainly a by-product of nuclear reactors.