| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and a device for treating radioactive wastes which heighten the containment performance for radioactive substances by converting sodium nitrate into a more stable and less soluble vitreous form in a simple process and make gaseous nitrogen oxide produced through the decomposition of the sodium nitrate harmless by reducing the gaseous nitrogen oxide into nitrogen. <P>SOLUTION: This treating device is so constituted that it heats and melts (11) the radioactive wastes containing sodium nitrate under the existence of at least one substance selected among B<SB>2</SB>O<SB>3</SB>(13), SiO<SB>2</SB>(14) and P<SB>2</SB>O<SB>5</SB>(15), converts the sodium nitrate into gaseous nitrogen oxide (NO and NO<SB>2</SB>) and a vitreous composition containing sodium and reduces the sodium nitrate into nitrogen by introducing the generated gaseous nitrogen oxide into a catalyst tower (16) consisting of a packed bed of granular activated carbon and that of alumina carrying noble metal. In this case, the alumina is selected from any of ternary catalysts (AL<SB>2</SB>O<SB>3</SB>, Rh, Pd and Pt), catalysts of an oxide base (TiO<SB>2</SB>, MoO<SB>3</SB>and V<SB>2</SB>O<SB>5</SB>) and catalysts of a palladium base (Al<SB>2</SB>O<SB>3</SB>and Pd). <P>COPYRIGHT: (C)2004,JPO |
