APPLICATION OF ELECTROOSMOTIC EFFECT FOR UNWATERING SAFETY BARRIERS DURING DECOMMISSIONING NUCLEAR LEGACY

The relevance of the discussed issue is caused by the need to develop new innovative non-destructive technologies of integrity reinstating and unwatering safety barriers based on mixture of natural clays, developed during decommissioning nuclear legacy. The main aim of the study is to detect physical and chemical features of clay-based barrier materials, used at development of additional safety barriers during decommissioning nuclear legacy; as well as to design and implement the method of unwatering such barriers by electroosmotic effect. The methods: analytical and experimental investigation of the electroosmotic effect occurred under unwatering safety barriers based on mixture of natural clays. The results. The paper shows that the barrier materials based on bentonite used during decommissioning nuclear legacy are capable of retaining the unique antifiltering and antimigraion properties over the time of potential hazard of nuclear legacy object. The attention was accented on the fact that these safety barriers can be subjected to external negative impact (technogeneous or natural), that results in partial degradation of it antifiltering and antimigraion properties. It was proved that for integrity reinstating and working capacity of clay-based safety barriers it is appropriate to use the methods not resulting in degradation of barrier material. The authors propose to apply the electroosmotic method based on capillary flow of a fluid in electromagnetic field for these purposes. The stated electroosmotic method of integrity reinstating safety barriers allows accumulating liquid near one of electrode and thereby unwatering the adjacent area of clay. It is shown that the solution imitating groundwater is more effective removed from clay-based material from deep burial ground of radioactive waste. The linear travel of fluid was approximately 2,5 mm/min at 31,8 V and distance between electrodes about 40 mm. This allows draining completely a clay-based safety barrier, water-encroached by 70 ml of solution during 7-8 hours. The authors revealed the adhesion, sintering and consolidation of barrier material at near-electrode area as a result of recombination of dissociated ions of saline and water on electrodes. This allows removing degraded barrier material coupled with electrode. Chemical re-actions occur in the region of fluid accumulation near cathode and gases exude in this area. This allow exhausting liquid from clay with-out special devices in continuous regime.