Patent Number: 
Section: claims

1. A method of managing gas production in a nuclear fission reactor, the method comprising: providing a sacrificial metal in direct physical contact with a molten salt fissile fuel, and preventing, with the sacrificial metal, accumulation of volatile iodine compounds released from the molten salt, wherein the sacrificial metal is one of or a combination of any of zirconium, vanadium, chromium and silver. 2. The method according to claim 1 wherein the molten salt fuel comprises actinide halides. 3. A method of managing gas production in a fission reactor comprising fuel tubes containing a molten salt fissile fuel, the method comprising: bringing into direct physical contact the molten salt with a sacrificial metal, and preventing, with the sacrificial metal, accumulation of volatile iodine compounds released from the molten salt, wherein the sacrificial metal is one of or a combination of any of zirconium, vanadium, chromium and silver. 4. The method according to claim 3, further comprising: permitting gasses produced during fission of the molten salt fissile fuel to pass out from the fuel tubes into a coolant surrounding the fuel tube or into a gas space in contact with the coolant. 5. The method according to claim 3, wherein the sacrificial metal is provided as a plating in the fuel tubes. 6. The method according to claim 3, wherein the sacrificial metal is provided as particles or as a coating on particles in the molten salt. 7. The method according to claim 3, wherein the sacrificial metal is provided as an insert immersed in the molten salt or as a coating on an insert immersed in the molten salt. 8. The method according to claim 3, wherein the molten salt fuel comprises actinide halides. 9. A fuel tube for a nuclear fission reactor, the fuel tube comprising: a molten salt fissile fuel and a sacrificial metal in direct physical contact with the molten salt, wherein the sacrificial metal is configured to prevent accumulation of volatile iodine compounds released from the molten salt, and wherein the sacrificial metal is one of or a combination of any of zirconium, titanium, vanadium, chromium and silver. 10. A fuel tube according to claim 9, wherein the fuel tube is configured to permit gasses to pass out from the fuel tube when the fuel tube is inserted into a nuclear fission reactor, the gasses passing out into coolant of the nuclear fission reactor or into gas space above the coolant. 11. The fuel tube according to claim 10, wherein an opening of the fuel tube is closed with a sintered plug, the sintered plug being configured to allow passage of gasses and not to allow passage of liquids. 12. A fuel tube according to claim 10, wherein the fuel tube extends vertically into the gas space when the fuel tube is inserted into the nuclear fission reactor, and comprises an opening within the gas space. 13. A fuel tube according to claim 12, wherein the fuel tube further comprises a capillary tube extending vertically into the gas space, and the opening is at an upper end of the capillary tube. 14. A fuel tube according to claim 10, wherein the fuel tube further comprises a diving bell assembly with an outer opening immersed in the coolant when the fuel tube is inserted into the nuclear fission reactor. 15. The fuel tube according to claim 9, wherein the sacrificial metal is provided as plating on a surface of the fuel tube. 16. The fuel tube according to claim 9, wherein the sacrificial metal is provided as particles or as a coating on particles in the fuel tube.