Production of Fissioning Uranium Plasma to Approximate Gas-Core Reactor Conditions

Abstract

The intense burst of neutrons from the d-d reaction in a plasma-focus apparatus is exploited to produce a fissioning uranium plasma. The plasma-focus apparatus consists of a pair of coaxial electrodes and is energized by a 25 kJ capacitor bank. A 15-g rod of 93% enriched ²³⁵U is placed in the end of the center electrode where an intense electron beam impinges during the plasma-focus formation. The resulting uranium plasma is heated to about 5 eV. Fission reactions are induced in the uranium plasma by neutrons from the d-d reaction which were moderated by the polyethylene walls. The fission yield is determined by evaluating the gamma peaks of ¹³⁴I, ¹³⁸Cs, and other fission products, and it is found that more than 10⁶ fissions are induced in the uranium for each focus formation, with at least 1% of these occurring in the uranium plasma. This technique is most convenient and inexpensive for the study of a fissioning uranium plasma and can be extended to the production of other metallic plasmas in a high neutron flux.