Gas Generation Testing of Neptunium Oxide at Elevated Temperature

Characterization of Neptunium Oxide Generated Using the HB-Line Phase II Flowsheet

“…8 For PuO 2 produced by calcination of the oxalate, SSA and moisture uptake of PuO 2 decrease with increasing calcination temperature. 7,8 Therefore, knowledge of the SSA and moisture content of the NpO 2 product as they relate to gas generation measurements is important for establishing processing controls to ensure the HB-Line NpO 2 product is adequately described by SRTC gas generation tests.…”

“…In gas generation tests with PuO 2 , we have observed increasing gas generation rates with increasing moisture content at constant SSA. 8 Moisture content and SSA are also expected to be important factors in gas generation tests with NpO 2 . Therefore, to evaluate the impact of moisture content on NpO 2 gas generation, gas generation tests were conducted with as-calcined NpO 2 (i.e., no additional moisture added) and with NpO 2 exposed to 75% RH for several days.…”

Flammability Analysis for Actinide Oxides Packaged in 9975 Shipping Containers

“…Experiments conducted by Duffey and Livingston [2] indicate that the maximum pressure that can be developed inside the PCV is limited by hydrogen back pressure within the PCV. Their experiments showed that a hydrogen back pressure of 25 psig was sufficient to prevent radiolytic hydrogen generation from fuel grade plutonium oxide calcined at 700 C, and that a back pressure of 82 psig was required to prevent hydrogen generation from weapons grade plutonium oxide calcined at 450 C.…”

“…The G-values are fit to measurements of hydrogen generation rates obtained for fuel grade plutonium oxide (Duffey and Livingston [2]) and for uranium oxide spiked with curium-244, a short half-life alpha emitter (Icenhour and Toth [3]). The calculated G-values are adjusted for the moisture content of the mixed oxide.…”

“…The mass fraction of adsorbed water bound to the surface is set at 0.005 (0.5 wt %), based on the results of the Duffey and Livingston tests [2].…”