Patent Number: 
Section: claims

1. A method of providing a nuclear fission igniter for initiating a nuclear fission deflagration wave in a nuclear deflagration wave reactor, the method comprising:inserting at least one nuclear fission igniter into at least one cavity of a housing of the nuclear fission deflagration wave reactor for initiating at least one nuclear fission deflagration wave in the nuclear fission deflagration wave reactor, the nuclear fission deflagration wave reactor comprising fertile nuclear fuel;shielding the at least one nuclear fission igniter;providing a sufficient amount of neutrons from the at least one nuclear fission igniter to the fertile nuclear fuel to convert the fertile nuclear fuel to fissile nuclear fuel and to initiate and maintain a steady-state deflagration wave; andremoving the at least one nuclear fission igniter from the nuclear fission deflagration wave reactor after initiation of the at least one nuclear fission deflagration wave and obtaining the steady-state deflagration wave. 2. The method of claim 1, wherein the at least one nuclear fission igniter includes:a portion of nuclear fission fuel material insertable in the nuclear fission deflagration wave reactor, wherein:the portion of nuclear fuel material has a keffective less than 1 when the at least one nuclear fission igniter is outside the nuclear fission deflagration wave reactor; andthe portion of nuclear fission fuel material is arranged to establish a keffective of at least 1 when the at least one nuclear fission igniter is installed in the nuclear fission deflagration wave reactor. 3. The method of claim 1, wherein shielding the at least one nuclear fission igniter shields against neutrons and radiation, the method further comprising removing the shielding from the nuclear fission igniter prior to removing the at least one nuclear fission igniter from the nuclear fission deflagration wave reactor. 4. The method of claim 1, further comprising transporting the at least one nuclear fission igniter to at least one nuclear fission deflagration wave reactor core. 5. The method of claim 1, further comprising removing decay heat from the at least one nuclear fission igniter. 6. A method of providing a nuclear fission igniter for initiating a nuclear fission deflagration wave in a nuclear fission deflagration wave reactor core, the method comprising:placing at least one nuclear fission igniter in at least one nuclear fission deflagration wave reactor core, the core further comprising fertile nuclear fuel;providing a sufficient amount of neutrons from the at least one nuclear fission igniter to at least a portion of the fertile nuclear fuel in the reactor core to convert the fertile nuclear fuel to fissile nuclear fuel and to initiate the nuclear fission deflagration wave;propagating the nuclear fission deflagration wave due to continued conversion of the fertile nuclear fuel to fissile nuclear fuel; andremoving the at least one nuclear fission igniter from the at least one nuclear fission deflagration wave reactor core upon obtaining a steady-state condition of the nuclear fission deflagration wave. 7. The method of claim 6, further comprising:if nuclear shielding material is present around the at least one nuclear fission igniter, removing the nuclear shielding material from the at least one nuclear fission igniter prior to providing a sufficient amount of neutrons from the at least one nuclear fission igniter. 8. The method of claim 6, wherein the at least one nuclear fission igniter includes:a portion of nuclear fission fuel material insertable in the nuclear fission deflagration wave reactor core, wherein:the portion of nuclear fission fuel material has a keffective less than 1 when the nuclear fission igniter is outside the nuclear fission deflagration wave reactor core; andthe portion of nuclear fission fuel material is arranged to establish a keffective of at least 1 when the nuclear fission igniter is installed in the nuclear fission deflagration wave reactor core. 9. The method of claim 8, wherein placing the at least one nuclear fission igniter includes mating a plurality of channels defined on an outer surface of the portion of nuclear fission fuel material with a plurality of coolant channels defined in the nuclear fission deflagration wave reactor core. 10. The method of claim 6, wherein placing the at least one nuclear fission igniter places a plurality of housed nuclear fission igniters in one nuclear fission deflagration wave reactor core. 11. The method of claim 6, wherein placing the at least one nuclear fission igniter places a plurality of housed nuclear fission igniters in a plurality of nuclear fission deflagration wave reactor cores. 12. The method of claim 6, further comprising, if at least one decay heat removal device is present, removing the at least one decay heat removal device from the at least one nuclear fission igniter. 13. The method of claim 6, if the at least one nuclear fission igniter is in a housing body, further comprising removing the at least one nuclear fission igniter from the housing body prior to providing a sufficient amount of neutrons from the at least one nuclear fission igniter. 14. The method of claim 6 wherein placing the at least one nuclear fission igniter in the at least one nuclear fission deflagration wave reactor core includes:placing the at least one nuclear fission igniter having a second nuclear fuel material different from a first nuclear fuel material of the nuclear fission deflagration wave reactor core. 15. The method of claim 14, wherein propagating the nuclear fission deflagration wave includes removing neutron absorbing material from at least one of the first nuclear fission fuel material and the second nuclear fission fuel material. 16. The method of claim 14, wherein propagating the nuclear fission deflagration wave includes adding neutron moderating material to at least one of the first nuclear fission fuel material and the second nuclear fission fuel material. 17. The method of claim 14, wherein propagating the nuclear fission deflagration wave includes adding neutron reflecting material to at least one of the first nuclear fission fuel material and the second nuclear fission fuel material. 18. The method of claim 14, wherein propagating the nuclear fission deflagration wave includes adding neutron multiplicative material to at least one of the first nuclear fission fuel material and the second nuclear fission fuel material. 19. The method of claim 14, wherein initiating the nuclear fission deflagration wave includes providing neutrons from the nuclear fission igniter to fertile material in the first nuclear fission fuel material.