Patent Number: 
Section: claims

1. A getter element comprising:a getter body including a getter material reactive with a nuclear fission product, the getter body further including a void structure through the getter material forming at least one through-channel to facilitate a flow of an input stream through the getter body, the void structure formed by removal of a plurality of void forming structures that were mixed with the getter material in the getter body. 2. The getter element of claim 1, wherein the at least one through-channel comprises a reaction surface area sufficient to accommodate a chemical reaction between substantially all of the fission product within the input stream over a predetermined time interval. 3. The getter element of claim 1, wherein the at least one through-channel includes a plurality of voids. 4. The getter element of claim 3, wherein the plurality of voids have a volume sufficient to maintain a through-flow transmission above a selected flow level despite expansion of the getter material within a predetermined range of expansion. 5. The getter element of claim 1, wherein the getter material is formed of a metal oxide. 6. The getter element of claim 5, wherein the metal oxide includes one or more of zirconium oxide, titanium oxide, molybdenum oxide, niobium oxide, tantalum oxide, vanadium oxide, and chromium oxide. 7. The getter element of claim 5, wherein the metal oxide has an average particle size between 100 nm and 500 nm. 8. The getter element of claim 5, wherein the metal oxide has an average particle size of less than 100 nm. 9. The getter element of claim 1, wherein the getter material is configured to react with a fission product that comprises one or more of cesium and a cesium compound. 10. The getter element of claim 1, wherein the getter body has a density between 25% and 45% of a theoretical density of the getter body. 11. The getter element of claim 1, wherein the getter body has a density between 50% and 70% of a theoretical density. 12. The getter element of claim 1, wherein the getter body is formed of a first getter material to facilitate a reaction with a first fission product in the flow of the input stream and a second getter material to facilitate a second reaction with a second fission product in the flow of the input stream. 13. A getter element comprising:a getter body including a first getter material reactive with a first nuclear fission product, the getter body including a second getter material reactive with a second nuclear fission product, the getter body further including a void structure through the first getter material and the second getter material that forms at least one through-channel to facilitate a flow of an input stream through the getter body, the at least one through-channel comprising a plurality of substantially-spherical voids formed by removal a plurality of void forming structures that were mixed with the first getter material in the getter body. 14. The getter element of claim 13, wherein the at least one through-channel comprises a reaction surface area sufficient to accommodate a chemical reaction between substantially all of one or more of the first fission product and the second fission product within the input stream over a predetermined time interval. 15. The getter element of claim 13, wherein the plurality of voids have a volume sufficient to maintain a through-flow transmission above a selected flow level despite expansion of the first getter material and the second getter material within a predetermined range of expansion. 16. The getter element of claim 13, wherein one or more of the first getter material and the second getter material are formed of a metal oxide.