Composite neutron absorbing coatings for nuclear criticality control

A composite neutron absorbing coating on a substrate surface, the coating comprising:

• a graded coating layer overlying at least a portion of the substrate surface, the graded coating layer comprising:
• a metal alloy matrix;
• and
• a plurality of neutron absorbing particles disposed in the metal alloy matrix such that there is a gradual decrease in the amount of neutron absorbing particles toward an outer surface of the graded coating layer opposite from the substrate surface.

A composite neutron absorbing coating on a substrate surface, the coating comprising:

• a neutron absorbing layer overlying at least a portion of the substrate surface;
• the neutron absorbing layer comprising:
• a metal alloy matrix;
• and
• a plurality of neutron absorbing particles dispersed in the metal alloy matrix, the neutron absorbing particles comprising a material selected from the group consisting of gadolinium oxide, gadolinium phosphate, and mixtures thereof.

A composite neutron absorbing coating on a substrate surface, the coating comprising:

• a neutron absorbing layer overlying at least a portion of the substrate surface;
• the neutron absorbing layer comprising:
• a ceramic material matrix;
• and
• a plurality of neutron absorbing particles dispersed in the ceramic material matrix, the neutron absorbing particles comprising a material selected from the group consisting of gadolinium oxide, gadolinium phosphate, and mixtures thereof.

A thermal neutron absorbing storage system, comprising:

• one or more internal surfaces configured to be exposed to thermal neutrons from spent nuclear fuel or other radioactive waste;
• and
• a composite neutron absorbing coating on the one or more internal surfaces, the coating comprising:
• a neutron absorbing layer overlying at least a portion of the one or more internal surfaces;
• and
• a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer.