Jesson Hutchinson

Abstract The Np sphere is a 6070.4-g sphere of neptunium metal cast by Los Alamos National Laboratory in 2001. Neptunium is of interest to the nuclear community for applications such as space exploration and reactor fuel. The Np sphere is composed mostly of 237Np, which is a threshold fissioner. It requires an approximately 700-keV neutron to fission and therefore can go critical with only fast neutrons.

?Mathematical formulae have been encoded as MathML and are displayed in this HTML version using MathJax in order to improve their display. Uncheck the box to turn MathJax off. This feature requires Javascript. Click on a formula to zoom. Abstract The Chlorine Worth Study (CWS) was a critical experiment to address an urgent need for thermal chlorine nuclear data validation in plutonium systems.

1 Introduction Neutron transport simulations are essential to support nuclear criticality safety assessments, reactor design, nuclear astrophysics simulations, and so on. These simulations depend on evaluated data on physics quantities including neutron cross-section, total number of neutrons per fission ( ν ‾ $$ \overline{\nu} $$ ), and other information.