High Temperature Reactor With Reduced Silo Height

A nuclear reactor comprising:

• a core of nuclear fuel;
• a pressure vessel surrounding the core of nuclear fuel to allow circulation of gas there through;
• a set of neutron-absorbing control rods movable for insertion and withdrawal into and out of the core along a respective axis for control of a nuclear reaction in the core, each of the neutron-absorbing control rods comprising mutually sliding elements moving relative to each other between an extended position separated along the axis in a first direction over a first length and a compacted position overlapping over a second length less than the first length;
• and
• a control rod mechanism communicating with the control rods to move them for insertion and withdraw into and out of the core;
• and
• wherein the sliding elements provide petals extending away from the axis along lines of radius wherein a line of radius for each different sliding element is angularly displaced from the others about the axis so that the sliding elements may interfit in the compacted position.

A nuclear reactor comprising:

• a core of nuclear fuel;
• a pressure vessel surrounding the core of nuclear fuel to allow circulation of gas there through;
• a set of neutron-absorbing control rods movable for insertion and withdrawal into and out of the core along different axes for control of a nuclear reaction in the core, each of the neutron-absorbing control rods comprising mutually sliding elements moving relative to each other between an extended position separated along the axis in a first direction over a first length and a compacted position overlapping over a second length less than the first length;
• and
• a control rod mechanism communicating with the control rods to move them for insertion and withdraw into and out of the core;
• and
• wherein the sliding elements provide a set of adjacent elements whose respective cross-sectional centers of mass are displaced from each other along a plane perpendicular to their axes of motion.