The aim is to create a sealed reactor that can be delivered to a site, left to generate power for up to 30 years, and retrieved when its fuel is spent. The developers claim that no one would be able to remove the fissile material from the reactor because its core would be inside a tamper-proof cask protected by a thicket of alarms
The 100 megawatt version is expected to be 15 meters high by 3 meters wide, and weigh 500 tonnes. A 10 megawatt version is expected to weigh less than 200 tonnes. To obtain the desired 30 year life span, the design calls for a moveable neutron reflector to be placed over a column of fuel. The reflector’s slow downward travel over the column would cause the fuel to be burned from the top of the column to the bottom. Because the unit will be sealed, it is expected that a breeder reaction will be used to further extend the life of the fuel.
Read up on your ‘small nuclear power reactors’ : see “Liquid Metal cooled Fast Reactors”