Hydrided moderators for nuclear reactors

A method for producing a moderator, comprising:

• synthesizing at least one of a metal hydride, metal alloy hydride, or a combination thereof, into at least one monolith;
• breaking down the at least one monolith into pieces;
• crushing the pieces into a powder;
• pressing the powder into the compact;
• placing the compact into a furnace comprising a noble gas;
• raising a temperature in the furnace to a first temperature above about 1000° C., and maintaining the first temperature for a period of time, thereby sintering the compact;
• reducing the first temperature in the furnace to a second temperature lower than the first temperature;
• introducing a first gas comprising at least about 4% hydrogen into the furnace;
• maintaining the second temperature for a period of time until a target stoichiometry of a hydride material in the compact is reached;
• reducing the second temperature in the furnace to a third temperature that is lower than the second temperature;
• evacuating the first gas under vacuum for a period of time and then performing a noble gas purge;
• and
• cooling the compact, thereby producing a moderator, wherein
• the moderator has a density that is greater than about 85% of the theoretical density of the hydride material.

A method for producing a moderator, comprising:

• placing a compact comprising at least one of yttrium hydride, a yttrium alloy hydride, zirconium hydride, a zirconium alloy hydride, or a combination thereof, into a furnace comprising a noble gas;
• raising a temperature in the furnace to a first temperature above about 1000° C., and maintaining the first temperature for a period of time, thereby sintering the compact;
• reducing the first temperature in the furnace to a second temperature lower than the first temperature;
• introducing a first gas comprising at least about 4% hydrogen into the furnace;
• maintaining the second temperature for a period of time until a target stoichiometry of a hydride material in the compact is reached;
• reducing the second temperature in the furnace to a third temperature that is lower than the second temperature;
• evacuating the first gas under vacuum for a period of time and then performing a noble gas purge;
• and
• cooling the compact, thereby producing a moderator, wherein
• the moderator has a density that is greater than about 85% of the theoretical density of the hydride material.