Neutron moderation modules

1. A neutron moderation module comprising:

a metal hydride core; and

a shell surrounding the core, the shell comprising:

at least one H 2 permeation barrier layer;

at least one transition metal layer;

at least one diffusion barrier layer; and

at least one ceramic matrix composite layer,

wherein:

the at least one H 2 permeation barrier layer is disposed between the at least one transition metal layer and the core,

the at least one H 2 permeation barrier layer and the at least one diffusion barrier layer are separate separated by the at least one transition metal layer, and

the at least one diffusion barrier layer is disposed between the at least one transition metal layer and the at least one ceramic matrix composite layer.

2. The moderation module of claim 1 , wherein the metal hydride core comprises a compound represented by the formula AR x , wherein A is one or more of Zr, Y, Ti, Li, Ca, Sc, or combinations thereof; each R is independently H or D; and x is in a range of 0.1 to 10.

3. The moderation module of claim 1 , wherein the H 2 permeation barrier layer comprises one or more of Al 2 O 3 , Y 2 O 3 , ZrO 2 , TiO 2 , SiO 2 , Cr 2 O 3 , ZrN, TiN, AlN, SiN, ZrC, TiC, SiC, NbC, TiAlC, ZrTiC, FeAl, FeAl 2 , Fe 2 Al 5 , ZrAl 3 , MoSi 2 , NbSi 2 , Si, (ZrO 2 .SiO 2 ), and (ZrO 2 .xY 2 O 3 ).

4. The moderation module of claim 1 , wherein the diffusion barrier layer comprises one or more of Al 2 O 3 , Y 2 O 3 , ZrO 2 , TiO 2 , SiO 2 , Cr 2 O 3 , ZrN, TiN, AlN, SiN, ZrC, TiC, SiC, NbC, TiAlC, ZrTiC, FeAl, FeAl 2 , Fe 2 Al 5 , ZrAl 3 , MoSi 2 , NbSi 2 , Si, (ZrO 2 .SiO 2 ), and (ZrO 2 .xY 2 O 3 ).

5. The moderation module of claim 1 , wherein the H 2 permeation barrier layer comprises alternating ceramics layers and metal layers, wherein the ceramics layers comprise one or more of oxides, nitrides, carbides, aluminides, silicides, elemental ceramics, and complex oxides; and the metal layers comprise one or more of refractory metals, refractory metal alloys, metals capable of resisting a temperature of at least 600° C., alloys of metals capable of resisting a temperature of at least 600° C., and intermetallic compounds.

6. The moderation module of claim 5 , wherein each metal layer and each ceramic layer, independently, have a thickness of about 5 nm to about 1000 nm.

7. The moderation module of claim 1 , wherein the H 2 permeation barrier layer has a thickness of about 500 nm to about 10 μm.

8. The moderation module of claim 1 , wherein the diffusion barrier layer has a thickness of about 500 nm to about 10 μm.

9. The moderation module of claim 1 , wherein the H 2 permeation barrier layer is monolithic and pinhole free.

10. The moderation module of claim 1 , wherein the transition metal layer comprises one or more of Ce, Yb, Mo, W, Nb, Ta, Ni, Co, and Fe, and alloys thereof.

11. The moderation module of claim 1 , wherein the ceramic matrix composite layer comprises a reinforcement phase (A) and a matrix phase (B).

12. The moderation module of claim 1 , wherein the ceramic matrix composite layer has a thickness of about 0.1 mm to about 5 mm.

13. The moderation module of claim 1 , wherein an inner surface of the transition metal layer is coated with the H 2 permeation barrier layer.

14. The moderation module of claim 1 , wherein the shell further comprises a ceramic matrix composite layer, and the ceramic matrix composite layer is provided radially outbound from the diffusion barrier layer and surrounds the diffusion barrier layer entirely.

15. The moderation module of claim 1 , wherein the moderation module can withstand temperatures of greater than 600° C. without degradation.

16. A thermal neutron nuclear reactor comprising a composite matrix, wherein the composite matrix comprises the moderation module of claim 1 , a fuel, a reactor matrix, and a heat transfer module.

17. A thermal neutron nuclear reactor comprising a composite matrix, wherein the composite matrix comprises the moderation module of claim 1 , a fuel, and a fluid coolant or a heat transfer module.

18. A neutron moderation module, comprising:

a metal hydride core; and

a shell surrounding the core, the shell comprising:

at least one H 2 permeation barrier layer;

at least one transition metal layer; and

at least one diffusion barrier layer,

wherein:

the at least one H 2 permeation barrier layer is disposed between the at least one transition metal layer and the core,

the at least one H 2 permeation barrier layer and the at least one diffusion barrier layer are separated by the at least one transition metal layer, and

the diffusion barrier layer comprises alternating ceramics layers and metal layers, wherein

the ceramics layers comprise one or more of oxides, nitrides, carbides, aluminides, silicides, elemental ceramics, and complex oxides; and

the metal layers comprise one or more of refractory metals, refractory metal alloys, metals capable of resisting a temperature of at least 600° C., alloys of metals capable of resisting a temperature of at least 600° C., and intermetallic compounds.

19. A neutron moderation module comprising:

a metal hydride core; and

a shell surrounding the core, the shell comprising:

at least one H 2 permeation barrier layer;

at least one transition metal layer; and

at least one diffusion barrier layer,

wherein:

the diffusion barrier layer is a pinhole free monolithic diffusion barrier layer,

the at least one H 2 permeation barrier layer is disposed between the at least one transition metal layer and the core, and

the at least one H 2 permeation barrier layer and the at least one diffusion barrier layer are separated by the at least one transition metal layer.