Development of NOx Recycle Process for Practical Use at Reprocessing Plant

To realize the NOx recycle process using the vacuum pressure swing adsorption method reported previously, development experiments were carried out. Among such experiments were the removal of volatile ruthenium tetroxide from the off-gas, 23-month operation of a bench-scale apparatus and 100-day operation of a pilot plant 1/5 the size of the actual scale. After evaluation of the results for operability and durability of components under acidic conditions, this process was concluded applicable to an actual plant. Compared to the conventional NOx production method using chemical reaction, it has the great advantage of reducing largely low-level radioactive and non-radioactive sodium nitrate waste. With this conclusion, the procedure to install the process at the Rokkasho Reprocessing Plant has been commenced.