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A device and method for removing radioactive crud material deposited on surfaces of a nuclear fuel assembly in a nuclear plant is provided. The device comprises a container arranged to accommodate the nuclear fuel assembly, a first pumping means to pump a fluid, composed of water and ice, through th

A device and method for removing radioactive crud material deposited on surfaces of a nuclear fuel assembly in a nuclear plant is provided. The device comprises a container arranged to accommodate the nuclear fuel assembly, a first pumping means to pump a fluid, composed of water and ice, through the container in order to release the deposit from the nuclear fuel assembly by abrasion and to transport the released radioactive material out from the container. The first pump means also enables the feeding of a gas or steam or both to the fluid that is fed into and through the container in order to create a turbulence in the fluid. The device further comprises means, arranged in a γ-radiation-dampening medium, disposed to receive the radioactive deposit transported out of the container by the fluid.

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1. A method of removing a radioactive deposit from a nuclear fuel assembly in a nuclear plant, the method comprising: providing a container (2) arranged to accommodate the nuclear fuel assembly, and arranging said container (2) in a γ-radiation-dampening medium, wherein said γ-radiation-dampening me

1. A method of removing a radioactive deposit from a nuclear fuel assembly in a nuclear plant, the method comprising: providing a container (2) arranged to accommodate the nuclear fuel assembly, and arranging said container (2) in a γ-radiation-dampening medium, wherein said γ-radiation-dampening medium comprises water, providing a first pumping means (3, 4, 5) for feeding by pumping a fluid through the container in order to release the deposit from the nuclear fuel assembly by abrasion and to transport radioactive deposit out of the container, said first means (3, 4, 5) also being provided for the feeding of a gas or steam or both to a fluid comprising a mixture of water and ice that is fed into and through the container in order to create a turbulence in the fluid; and further comprising feeding with said first means, a gas or steam or both to said fluid that is fed into and through the container (2) such that a turbulence is created in the fluid; providing a second receiving means (6, 7) arranged to receive the radioactive deposit transported out of the container (2) by the fluid, and wherein said second receiving means comprises a filter (6) arranged to separate released radioactive material from said fluid; arranging at least said second means (6, 7) in said γ-radiation-dampening medium, arranging a nuclear fuel assembly (1) in said container (2), feeding by pumping with said first pumping means (3, 4, 5) said fluid comprising a mixture of water and ice and said gas or steam or both through said container (2), thereby releasing, by abrasion, a radioactive deposit from said nuclear fuel assembly (1) and transporting the radioactive deposit out of the container (2), receiving the transported radioactive deposit in said second means (6,7), and further comprising filtering with said filter to separate from said fluid the radioactive material that is released. 2. The method, according to claim 1, which comprises feeding a gas to said fluid that is fed into and through the container such that a turbulence is created in the fluid. 3. The method, according to claim 1, which comprises feeding air to said fluid that is fed into and through the container such that a turbulence is created in the fluid. 4. The method according, to claim 1, which comprises feeding steam to said fluid that is fed into and through the container such that a turbulence is created in the fluid. 5. The method of claim 4 wherein said steam comprises water steam. 6. The method according to claim 1, which further comprises arranging said container (2) and said receiving means in a basin filled with said γ-radiation-dampening medium. 7. The method according to claim 1, further comprising irradiating said fuel assembly with infrasound. 8. The method according to claim 1, further comprising rotating said fuel assembly. 9. The method according to claim 1, further comprising heating at least a portion of said fluid that is fed into said container. 10. The method according to claim 1 wherein said deposit comprises loose crud. 11. The method according to claim 1 wherein the nuclear fuel assembly is a boiling water nuclear fuel assembly and the flow rate of said fluid is about 10-50 kg/s. 12. The method according to claim 11 wherein the ice flow is about 30-70% of the water flow. 13. The method according to claim 11 wherein said flow rate is 15-35 kg/s. 14. The method according to claim 11 wherein said flow rate is 20-25 kg/s. 15. The method according to claim 1 wherein the nuclear fuel assembly is a pressure water nuclear fuel assembly and the flow rate of said fluid 50-200 kg/s. 16. The method according to claim 15 wherein the flow rate of said ice is about 30-70% of the flow rate of said fluid. 17. The method according to claim 15 wherein said flow rate is 75-150 kg/s. 18. The method according to claim 15 wherein said flow rate is 100-125 kg/s. 19. The method of claim 1 which comprises recycling fluid after the filtering back to said first pumping means.