Development of high-pressure ice brasting method (II) (Confirmation of most auitable condition for decontamination)

Fukui, Yasutaka ; not registered; Tanimoto, Kenichi; Terunuma, Seiichi

It is must deceasse the pool risk for the radio active wastes. So it is necessary to decontaminate the wastes low level (500Sv/h) during control the secendry wastes. Exfoliation velocity (aria of exfoliated paint per unit time) was measured on various cndition changed parameter brasting pressure, feed rate, stand off distance between nozzle and waste surface, angle of nozzle, therefore most suitable condition for decontamination was decide on high-pressure ice brasting method, results are as follows. (1)Feeding dry-ice pellets of most suitable condition was decided on that brasting pressure is 15Kgf/cm, feed rate is 30%. Same exfolation ability was gained on condition that brasting pressure is 15Kgf/cm, feed rate is 50%. (2)Brasting dry-ice flow of most suitable condition was dicided on that stand off distance is between 50㎜ and 100㎜ angle of nozzle is 30 with vertical. (3)In case of a pipe form, exfolation ability was gained on condition that angle of nozzle is 60 with vertical after the waste was settled on the turn-table and turning. In case of angle iron form, on condition that angle of nozzle was 0 or 60 with vertical. In case of inner can on condition that angle of nozzle was 45 with axis. When these were such small parts as bolts in the barrel basket which leand 30 with vertical and turned 120rpm, exfolation ability was gained on condition that angle of nozzle was vertical. (4)In decontamination hood designing, negative pressure was maintaind in the cell, and freeze preventing heat capacity of ventilation filter (-78C) was calculated at 73kw.