Plutonium loss, calculated

Contactor III Data. A typical experimental Pu concentration profile for Contactor III where hydrazine-stabilized HAN was used as reductant is shown in Figure 5. Plutonium in the feed solution was initially reduced to Pu(III) using HAN. At acidities of less than 1.5 mol/L HNOo, more than 99% of the Pu is reduced, and it should be inextractable. The calculated profile for both phases for Pu(III) is shown as dashed lines on the plot. For stage numbers less than 10, the Pu is predicted to be easily scrubbed from the solvent. Experimentally, the behaviour was very different and substantial amounts of Pu were extracted and carried with the solvent, leading to a loss of v 12% with the 3SP stream. This behaviour is attributed to the oxidation of some of the Pu(III) in the organic phase and an excessively low reduction rate of Pu(IV) by HAN which operates only on the aqueous phase. 

The first two methods require rigid process control except in natural or slightly enriched reprocessing plants before plutonium partitioning. Other features of the layout include a calculated pitch on the process cell floors so that a major spill will not cause the solution depth to exceed criticality. A steam jet and sump pump with alarm devices are located in a geometrically safe sump at the low point in the cell area. To avoid loss of fissionable-fuel material, there should be no gravity connections between the process tanks and the waste storage area. 

Calculations of the reactivity gains In a reactor due to plutonium buildup assume Instantaneous formation of plutonium. The fact that plutonlum-239 formation Is delayed throuc the beta-decay of 2.33 day neptunium-239 makes It necessary to correct the calculated reactivity gains. This Is most conveniently done by assigning a reactivity loss for the neptunium holdup effect. The equilibrium neptunium holdup defect Is. 41 k. 

Calculations indicate. that batch-type operation of a plutonium producer is undesirable if plutonium has a value of 40/g any savings in fuel-proces.sing costs using batch-type operation is more than compensated by a loss ill product value associated with the decrease in plutonium production. 

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