A Proposal of Verification Means for the Pulse Column Inventory

The direct verification of Plutonium inventory in pulse columns installed in reprocessing plant is almost impossible during operation.For timeliness purpose, however, near real time material accountancy (NRTA) is required to the columns and some kind of means verifying the inventory estimated through NRTA is desired from the inspector's standpoint. A possibility of indirect verification or the checking of estimated inventory is presented in this report, which proposes the monitoring of the axial temperature distribution of the extraction column. The distribution changes with the inventory change in the column caused by the flow-rate change of solutions. Numerical analyses are made on a system with extraction and scrub columns using a refined simulation code DYNAC. Solvent feed flow-rate to the extraction column is parametrically changed, which results in the change of peak region of exothermic reaction. It also causes the change of the extraction efficiency and so the change of plutonium inventory in the column. Calculated results indicate a correlation between the maximum temperature position and the plutonium inventory in the extraction column. So if the quantitative correlation curves between them can be prepared they can afford a verification means for timeliness purpose.