PLENTIFUL ENERGY

eference 7. The important calculations given in Table A-7 below were done by
John Ackerman [4] and we are indebted to him for their use.
Table A-6. The Input Data Used
Atomic weight of plutonium-239 239
Atomic weight of uranium-238 238
Atomic weight of chlorine naturally occurring 35.5
Atomic weight of cadmium naturally occurring 112.4
Activity coefficient ratio of PuCl 3 /UCl 3 1.14
Activity coefficient of uranium in cadmium 89
Activity coefficient of plutonium in cadmium 2.3x10 -4
Tracing through the calculation, it starts with the state of saturation of the
actinide elements in the cadmium. All calculations are based on molar amounts, not
weights, so we calculate the total molar amounts, and then the molar amounts
actually in solution. The cathode contained 26 kg of cadmium, as shown in line 1,
and the other experimentally determined quantities follow in lines 2 to 7. From
these numbers, the activity ratio of the chlorides in the salt and the moles of
cadmium, uranium, and plutonium in the cathode are calculated and shown in lines
8 to 12. Knowing that uranium saturates at a concentration of 1.12% and plutonium
at a concentration of 1.81% gives the maximum possible moles of the two actinides
in solution; this is shown in lines 13 and 14.
The maximum saturation amounts are 2.59 moles or 616.4 grams of U and 4.19
moles or 1001.4 grams of Pu. (The amounts can be smaller due to the loss of
cadmium to PuCd 6 formation, as shown in lines 15 to 21. Line 15 was obtained by
iteration, changing line 15 until the sum of line 21 and line 15 is equal to line 12.
The corrections however are small.)
The amounts in solution and in the metal phase phases are summarized in lines
22 to 25. The final mol fractions in solution are given by lines 19/(17 +18+19) for
uranium, and line 17/(17+18+19) for plutonium. Multiplication by the appropriate
activity coefficients, 89 and 2.3x10 -4 respectively, gives the relevant activities, and
their ratio divided by the same ratio of the actinide chlorides gives the calculated
equilibrium constant.
The calculated Keq for each run is given in line 34, the Keq given by the free
energy exponential is given in line 35, and the difference is given in line 36, defined
for this purpose as the difference between the two divided by the average of the
two, to imply that neither is a standard by which the other result should be judged.
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