As an example of the use of these equations, we shall calculate the distribution of 236 U and the amount of separative work expended in a matched 23SU/238U cascade producing 1000 kg/day of uranium containing 3.2 w/o 233U from feed containing 0.711 w/o 235U and 0.4 w/o 236U, while stripping tails to 0.3 w/o 23S U. External conditions specified for the cascade are listed in Table 12.13.

Distribution of 236U is evaluated from the material-balance equation

(l) y6>F + 6.056 x6iW — 7.056 z6yF = 0 (12.326)

and application of Eq. (12.323):

__________ (1)Уб. р + 6.056 x6’W 7.056 z6J — =

[0.032/(0.968 — y6j)]1/3 [0.003/(0.997 — *«,„,)]173 [0.00711/(0.99289 — z6>F)]1/3

(12.327)

Values of y6j> and x6 w obtained from these equations using z6F =0.004 are tabulated below, together with weight fractions of 235 U and 238 U.

The amount of separative work expended per day in making 1000 kg/day of product, from Eq. (12.324) with these values of y6j> and х6 ц> is 3813.4 kg SWU/day. This may be compared with the amount of separative work needed in the absence of 236 U with the same weight fractions of 235U in product, tails, and feed and the same quantities of these streams:

D = 1000 0(0.032) + 6056 <K0.003) — 7056 0(0.00711) = 3787.5 (12.328)

using values of the separation potential 0 from Eq. (12.144).

Thus, the presence of 0.004 weight fraction 236 U in the feed increases the amount of

separative work needed for this example by 3813.4 — 3787.5 = 25.9 kg SWU/day, or 25.9/(7056X0.004) = 0.918 kg SWU/kg 236U in feed. This could serve as the basis for a penalty to be charged for 238 U present in feed to a uranium enrichment plant operating between the 235 U concentrations of this example. It should be noted that these results for the effect of 236 U on separative capacity are independent of the separation process under consideration.