Improving Reliability in a High-Temperature Environment

A method comprising:

• enclosing a heat-sensitive device in a housing, wherein:
• the housing has an internal volume,
• the heat-sensitive device consumes a device percentage of the internal volume, and
• the device percentage equals the percentage of the internal volume of the housing consumed by the heat-sensitive device;
• positioning a phase-change material within the housing to conduct heat from the heat-sensitive device, wherein:
• the phase-change material consumes a percentage of the internal volume equal to 100 percent minus the device percentage minus an expansion percentage, and
• the phase-change material expands in volume by an amount more than 75 percent of the expansion percentage upon occurrence of a phase-change event.

A method comprising:

• constructing a drill string, wherein the drill string comprises a tool section, wherein the tool section comprises:
• a housing containing an internal volume,
• a heat-sensitive device contained by the housing and consuming a device percentage of the internal volume, wherein the device percentage equals the percentage of the internal volume of the housing consumed by the heat-sensitive device, and
• a phase-change material positioned within the housing to conduct heat from the heat-sensitive device, wherein the phase-change material consumes a percentage of the internal volume equal to 100 percent minus the device percentage minus an expansion percentage, wherein the phase-change material expands in volume by an amount more than 75 percent of the expansion percentage upon occurrence of a phase-change event.