Patent Number: 054897378
Section: summary

BACKGROUND OF THE INVENTION The present invention relates to a radioactive waste processing method, especially to a processing system for radioactive waste resin, condensed waste liquid, incinerated ashes, and non-burnable miscellaneous solid bodies etc. Hitherto, as for solidification technique, cement solidification (JP Appl. No. 62-124872 (1987)) and plastic solidification (JP Appl. No. 62-268055 (1987)) have been used. As for methods for solidification process, JP Appl. No. 63-33541 (1988), JP Appl. No. 63-11687 (1988) were disclosed. The above described methods for solidification have been established, and packages having superior integrity can be, actually have been, prepared by the above described methods,. As storage in land becoming concrete, measurement of exact inventory of radioactivity per a package has become a problem. Accordingly, research on transportation managing system has progressed in order to measure radioactivity per a package which is processed by the solidification process, and measuring methods have been disclosed in JP Appl. No. 61-26345 (1986) and JP Appl. No. 2-157340 (1990). Farther, a method wherein radioactivity of nuclides other than Co-60 and Cs-137 are estimated by evaluating safety factor higher than radioactivity of Co-60 and Cs-137 (scaling factor method) is going to be applied to transportation management. However, reproducibility of correlation between Co-60, Cs-137, and other nuclides, which is one of fundamentals of the scaling factor, is not so well established, and accordingly, the correlation obtained by experiments or actual measurement is multiplied by 10-100 as a safety factor in actual use. That means, the above described method evaluates the correlation in safety side as much, but there is a possibility to overestimate the radioactivity of a package. By the above described conventional technique, it was difficult to grasp exactly sort and quantity of nuclides in a package even though total approximate inventory of the radioactivity per a package could be grasped. And, by the scaling factor method, radioactivity was evaluated in safety side more than necessity, and there was such a problem that actually transportable package was reprocessed or kept in storing at the site. All the above mentioned problems are caused by a fact that exact grasp of radioactivity and sort of contained nuclides per a package was impossible. SUMMARY OF THE INVENTION The object of the present invention is to solve the above described problems. In order to solve the above described problems, a part or all of radioactive waste in a storage tank is transferred to an adjusting tank, and after measurement of radioactive concentration of each nuclide in the waste, the waste is processed by one of processing methods in one or a plurality of choices which contain at least one of the processing methods described hereinafter. (1) Returning to the storage tank without introducing to a solidifying processing system. PA0 (2) Processing residue for solidification after incinerating process. PA0 (3) Processing the residue for solidification after removal of functional groups and radioactive nuclides by thermal decomposition. PA0 (4) Processing the residue after separation and removal of radioactive nuclides by dissolution process. PA0 (5) Introducing directly to a solidifying processing system and solidifies with inorganic solidifying agents or organic solidifying agents. PA0 (6) Introducing gaseous waste generated at intermediate processes to an exhausted gas processing system. PA0 (7) Mixing with other waste so as to adjust radioactivity per a package to a predetermined value in order to facilitate handling. That means, a process for exact grasp of contained radioactive nuclides and radioactive concentration in waste is introduced into a waste processing system at prior step to the solidifying process. Besides, in order to grasp inventory per a package more precisely, weight and surface dose of the package after the solidifying process is measured, and the obtained data are combined with the data obtained before the solidifying process. At least one of the above described two processes is introduced into the radioactive waste processing system. By introducing the process for exact grasp of contained radioactive nuclides and radioactive concentration in waste at prior step to the solidifying process, waste management after preparation of the package is facilitated and can be performed correctly. That means, as the inventory of radioactivity in the waste is previously grasped exactly, handling of the waste at transportation can be performed by only a sampling inspection. Farther, by measuring weight and surface dose of the package after the solidifying process and combining the obtained data with the data before the solidification process, exact labelling for each package becomes possible.