Gaseous radioactive wastes treatment system of GAMA-AHR

GAMA-AHR is an aqueous homogeneous reactor designed to produce 2000 six-day Ci per week of ⁹⁹Mo with 200 kWth thermal power. During its operation, GAMA-AHR produces fission product gases, predominantly xenon and radiolytic gas. Radiolytic gas is dominated by H₂ and O₂ and poses the danger of explosion. The release of radioxenon disturbs the signals detected by International Monitoring System during the verification of the Comprehensive Nuclear Test Ban Treaty (CTBT). Therefore, a gas treatment system is required. The GAMA-AHR gas treatment system consists of hydrogen recombiner and adsorption columns. GAMA-AHR produces 0.016397 mol/s H₂, 0.009009 mol/s O₂, 0.00024 mol/s NO_x, and 6.81 ×10^-9 mol/s total xenon. The radioxenon activities are 459.4 Ci Xe-133, 30.3 Ci Xe-133m, 4050.8 Ci Xe-135, 1754.8 Ci Xe-135m, 10,135.3 Ci Xe-137, 10,067.1 Ci Xe-138, 8388.7 Ci Xe-139, 6091.2 Ci Xe-140, 2088.4 Ci Xe-141, 732.7 Ci Xe-142, 44.2 Ci Xe-143, and 7.6 Ci Xe-144. The GAMA-AHR hydrogen recombiner can recombine 92% of H₂ and 81% of O₂. Thus, the H₂ and O₂ concentrations in the plenum gas are reduced to 4.27% and 2.45%, respectively. Further, the radioxenon adsorption columns of the GAMA-AHR contain 1000 g of active carbon. These columns are operated in the adsorption mode for 1 day. The adsorbed radioxenon activities for 1 day adsorption are 344.4 Ci Xe-133, 22.7 Ci Xe-133m, 3017.4 Ci Xe-135, 1030.5 Ci Xe-135m, 2015.2 Xe-137, 5788.5 Xe-138, and 22.0 Xe-139. After the adsorption mode operation, the columns are operated in the storage mode. After six months of storage, Xe-131 activity decreases to 0.1 Ci. The other radioxenons vanish because of decay.