Pressure resulting from an ITP waste tank deflagration

Assessment of combustion and related issues in the DWPF and ITP waste tanks

“…On the basis of the discussions given above, it is judged that the NFPA nomographs are not applicable to the waste tanks and that the conservatisms inherent in the DPAC models and input data, as discussed in Section 3.3.1 of Thomas and Hensel (1993), provide sufficient margin to account for any increase in combustion rate due to venting effects.…”

“…The internal tank pressure at which the vents are assumed to open (13 psig) is based on the riser plug mass and riser area for these tanks [Estochen (1993), discussed in Section 2.5 of Thomas and Hensel (1993)]. This is actually the pressure at which all plugs would be ejected from their risers, some of the plugs would eject at significantly lower pressures.…”

Potential for a solids fire during an ITP waste tank deflagration and the impact on gas pressure

“…The radiative heat flux -time profiles employed in this evaluation were calculated using the Deflagration Pressure Analysis Code (DPAC) for Tank 48 at a 1/10 fill level with a hydrogen to benzene mole ratio of 40/60 (the normal condition) and an initial temperature of 40°C (Thomas and Hensel 1993a). The DPAC code is described in Hensel (1993) and the radiative heat transfer model employed by DPAC is presented in Thomas (1993).…”

“…The specific cases employed are listed in Table 1; Table 2 gives the gas compositions for each of these cases. The case numbers, peak pressures, and burn time values given in Table 1 are taken from Thomas and Hensel (1993a). The time to peak pressure values and radiative heat fluxes were taken from the task records for SRTC/NRTSC Task 93-009-1 (Thomas and Hensel 1993b).…”

“…The pressures resulting from deflagrations of hydrogen-benzene (H2-C6H6) mixtures in an ITP waste tank were evaluated by Thomas and Hensel (1993a); however, they did not consider the potential contribution to gas pressure from a solids fire. Walker (1990) has p evaluated the contribution to the gas pressure developed during a deflagration as a result of a solids fire; however, Walker assumed that all solids present would burn, whereas the work reported here demonstrates that this will not occur and considers the pressure rise due to that portion of the solid which could burn.…”