November 21, 1951

Computation shows that on the basis of 6 hours on at 10 Kw and 18
hours off (repeated operation), the amount of Xe133 produced per 24
hours is ~ 12 curies.

It is evident that the same number of gas molecules that enter a
disposal system must leave the system under steady state conditions
unless they are removed by some means. It is assumed that the average
time required for a molecule to go through the system represents the
time which should be considered as the decay time of all of the mole-
cules introduced into the system.

If it is agreed that the dimunition achieved by delaying the gas 4
half lives is adequate, this implies that the disposal tank should have
a capacity equal to 21 times the daily output volume. Hence, the numerical
value of the daily output volume is decisive and should be kept as low
as practical. The size of the tank and the cement tank in which it is
to be enclosed can only be determined after a firm figure is given for
this daily output volume. It is to be noted that the same percentage
of .uncertainty involved in this figure is also involved in the gas
disposal volume.