Analysis of the burping behavior of the cold solid methane moderator at IPNS [Intense Pulsed Neutron Source]

Examination of the cold solid methane moderator at IPNS (Model II) revealed that a circumferential weld failed due to high internal pressure, such as would be caused by thermal expansion of solid methane or the release of Hydrogen gas upon spontaneous heating. This weld is the main object of current attention for a design of a replacement. The present paper deals with the processes which lead to the burping behavior and outlines the analysis of some of the consequences. The purpose is to determine conditions under which the system can operate at the lowest possible temperature, avoiding the problems experienced to data