Plutonium Critical Mass Math

Note that each element may contain more isotopes therefore this resulting atomic mass is calculated from naturally occuring isotopes.

Plutonium critical mass math. This problem was discovered in mid 1944 well after the start of the construction of the massive hanford plutonium production facilities. The chemical symbol for plutonium is pu. Thus it is very probable that a neutron from pu 240 will initiate a premature chain reaction during the critical last 100 microseconds of the critical mass in a gun type assembly. The higher the density the lower the critical mass.

The question which scientists have asked for the first time at the beginning of the manhattan project and which every nuclear weapon state has asked since then. The bare sphere critical mass of weapons grade uranium and weapons grade plutonium is approximately 52 kg and 10 kg respectively. The effects on the critical mass of the displacement of hydrogen and the addition of poisons to the fuel were measured in water tamped and bare reactors. An ideal mass will become subcritical if allowed to expand or conversely the same mass will become supercritical if compressed.

Plutonium has a specific gravity of 19 84 a modification at 25 c melting point of 641 c boiling point of 3232 c with a valence of 3 4 5 or 6. Atomic mass of plutonium is 244 u. The density of a material at a constant temperature can be changed by varying the pressure or tension or by changing crystal structure see allotropes of plutonium. The correct calculation of and values for the critical mass of uranium or plutonium necessary for a nuclear fission weapon have long been understood and publicly available.

The critical mass of fissile material informs the most fundamental question of nuclear weapon design. Changing the temperature may also change the density. Even at a concentration of 1 pu 240 in the fissile pu 239 the required mass of pu emits 52 000 neutrons per second or one neutron every 20 microseconds. However the effect on critical mass is then complicated by temperature effects see.

Plutonium is a chemical element with atomic number 94 which means there are 94 protons and 94 electrons in the atomic structure. Some preliminary analysis has been made yielding the results. I the absorption cross section. The calculation requires solving the radial component in spherical coordinates of a diffusion equation with a source term so is beyond the reach of most public policy and many first year college physics students.

Atomic number of plutonium. The chain reacting conditions for plutonium nitrate in water solution have been examined experimentally for a variety of sizes of spheres and cylinders.