Degradation flowsheet

TBP is a sufficiently powerful extractant for actinides that it may be used in diluted form. Dilution improves the hydrodynamic properties of the solvent, allowing more complete and rapid phase disengagement. Typically concentrations of 20-30 v/o TBP in OK are used in process flowsheets. Although TBP is relatively stable as an extractant, radiolysis does lead to the formation of some acidic phosphate esters, HDBP and H2MBP, which can impair process performance.289 An aqueous alkali wash of the recycled solvent is usually carried out to remove those by products. Radiolytic degradation of the diluent in the presence of nitric acid can result in the formation of hydroxamic acids,290 which can lead to fission product retention by the organic phase. Again the solvent wash is used to prevent the accumulation of such species. A comprehensive account of the industrial utilization of TBP has recently been published.291... 

Selection of the radiolysis conditions is of primary importance. If studies carried out with a pure extractant enable the intrinsic stability of the molecules to be verified, radiolysis in solution and especially in a basic medium are indispensable to guarantee the approaches good representativity, as much from the point of view of species formation as from that of their distribution (potential elimination of the shortest degradation products, the most polar to the aqueous phase). The characteristics of the irradiation source (nature, dose rate, integrated dose) and also the temperature are essential parameters. Thus, the nature of the irradiation depends on the composition of the fuel, and the dose rate is dependent on the bum-up and cooling time of the fuel, while the exposure time of a solvent depends on the implementation conditions of the proposed process (flowsheet and nature of the contactors). 

Hydraulic Behavior. The influence of the main DMDOHEMA degradation products on the hydraulic performances of the process flowsheet was investigated by the determination of the emulsion settling time after mixing the irradiated solvent with nitric acid solution (0.1 mol I. ). This settling time increased with the irradiation dose. Experiments performed with synthetic solutions of monoamide and... 

Since the Estimation task is not defined in the class diagram, the manager makes use of the unconstrained type Task to insert it into the task net as an untyped task. This modification degrades the consistency level of the task net to weakly consistent. Unfortunately, inconsistencies are introduced, as well The flowsheet design task has to be supplied with the estimation as input parameter. This was excluded in the process definition by the value false of the tag AllowStandardParameters. Therefore, the manager has to switch off consistency enforcement explicitly to make the modification feasible. 

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