IMPROVING THE ALPHA WASTE INCINERATOR AT CEA VALDUC

摘要

The Valduc center, which belongs to CEA's Military Applications, owns the alpha waste incinerator, in order to treat the contaminated combustible waste. The process allows to reduce volume and weight, but also to produce ash in a grade suitable for in-line vitrification, or plutonium recovery by argentic dissolution. The active waste incineration has been operated for five years, and more than 6000 kg of waste have been treated [1]. The Valduc incinerator is efficient and ashes have the required quality and the reduction factor is quite satisfactory. Inspections performed after incineration runs revealed the absence of corrosion in the equipment; furthermore the retention is weak [2]. But the major problem was the deposit on the tube at the exit of the post-combustion furnace. This problem, well known in the field of incinerators, causes an important pressure drop, limiting the extraction, and reducing the incineration feed, and effective incineration time. This paper presents the salient facts concerning the work we made to clean up this pipe. First tests have shown tungsten carbide tools have no effect on the deposit. The main difficulties were the hardness of the deposit and the nuclear contamination. Thus particular tools and a special process were developed, which allowed clearing the exhaust of the post-combustion furnace.