Process and device for reducing radioactive material of object containing radioactive material to safe level in living environment
A process for reducing a radioactive material of an object containing a radioactive material to a safe level in a living environment includes releasing pressure including carrying out a heating process on an aqueous liquid that includes water, water-soluble liquid, or a mixture of water and water-soluble liquid, and the object in a state where temperature is less than or equal to a critical temperature of the aqueous liquid and pressure is greater than or equal to a saturated vapor pressure of the aqueous liquid when the object is immersed in the aqueous liquid to such a degree that the object is covered or to a greater degree and then abruptly releasing the pressure, and separating, after the releasing pressure, the mixture of the object and the aqueous liquid into liquid and solid.
1. A process for reducing a radioactive material of an object containing a radioactive material to a safe level in a living environment,
the process comprising:
releasing pressure including carrying out a heating process on an aqueous liquid that includes water, water-soluble liquid, or a mixture of water and water-soluble liquid, and the object in a state where temperature is less than or equal to a critical temperature of the aqueous liquid and pressure is greater than or equal to a saturated vapor pressure of the aqueous liquid when the object is immersed in the aqueous liquid to such a degree that the object is covered or to a greater degree and then abruptly releasing the pressure; and
after the releasing pressure, separating a mixture of the object and the aqueous liquid into liquid and solid,
the object being at least one selected from the group consisting of an organism, a sewage sludge, a soil and an incineration ash.
2. The process according to claim 1 , wherein, before the releasing pressure, the aqueous liquid is added to the object.
3. The process according to claim 1 , further comprising:
applying an adsorbent to adsorb the radioactive material in a separated liquid.
4. The process according to claim 3 , further comprising:
when the object includes a plant, carrying out a fermentation process on a liquid from which the adsorbent has been removed.
5. The process according to claim 1 , further comprising
concentrating the radioactive material by vaporizing a separated liquid content.
6. The process according to claim 5 , wherein, at the concentrating the radioactive material, the liquid is frozen.
7. The process according to claim 5 , wherein, at the concentrating the radioactive material, the liquid is evaporated under a reduced pressure.
8. The process according to claim 1 , wherein at the releasing pressure, after the releasing of pressure, if the pressure cannot be released to a normal pressure, condensing the gaseous aqueous liquid is followed so that an exhaust gas is not discharged to outside.
9. The process according to claim 1 , wherein the separating includes filter-pressing at least a part of the solid of the object.
10. The process according to claim 9 , further comprising
washing with water the solid obtained by the filter-pressing.
11. The process according to claim 9 , wherein at least a part of the solid of the object contains fine particles of the solid of the object.
12. The process according to claim 1 , wherein the heating process comprises a hydrothermal process, and the abruptly releasing the pressure comprises a blasting process.
13. The process according to claim 12 , wherein the blasting process is performed after the hydrothermal process.
14. The process according to claim 1 , wherein the heating process comprises a hydrothermal process performed in a range from 240 ° C. to 270 ° C.
15. The process according to claim 1 , further comprising:
applying an adsorbent to adsorb cesium in the radioactive material which is migrated into the liquid after the heating process.
16. The process according to claim 15 , wherein the adsorbent comprises iron ferrocyanide.
17. The process according to claim 1 , wherein, in the releasing pressure, vapor is dispersed without being cooled and liquefied.
18. The process according to claim 17 , wherein, in the releasing pressure, a part of the radioactive material is dispersed accompanied with the vapor.
19. The process according to claim 1 , wherein the abruptly releasing the pressure comprises a blasting process in which water in a liquid state becomes vapor by releasing the pressure by the blasting process.