RMI Nuclear Justice Documents

24

FREILING, CROCKER, AND ADAMS

The program can be operated for 12 fission cases as follows:

1. Fission
Fission
Fission
Fission
Fission

of
of
of
of
of

7°U
7°U
7°U
7°U
**°U

by
by
by
by
by

thermal neutrons
fission-spectrum neutrons
14-Mev neutrons
thermal neutrons
fission-spectrum neutrons

. Fission of ?3U by 14~Mev neutrons

. Fission of 7°*Pu by thermal neutrons

. Fission of 72*Pu by fission-spectrum neutrons

9, Fission of 7*Pu by 14-Mev neutrons

10. Fission of 7°U by fission-spectrum neutrons
11. Fission of ““U by 14-Mev neutrons

12, Thermonuclearfission of *U

The program will also calculate abundances for any desired combina-

tion of the above fission cases.

Supplementary computer routines will convert the abundancelists
to activity lists and calculate gamma-photon emission rates and dose
rates or ionization rates.
.
Since the calculations made by the computer are exact, the limitations on the predictions are imposed by the limitations on the input
data supplied to the program. For this reason the input data used are
discussed in some detail.

input Data
The input data can best be discussed by dividing it into the fol-

lowing classes:

1, Chain and independent (i.e., primary) yields
2. Description of decay chains
3. Half-lives and branching fractions

4. Gamma-photon emission data

5. Gamma-energy conversion data

Chain- and Independent-yield Data* The values supplied for the amount of
each nuclide produced by the fission process are taken from Reports

USNRDL-TR-633 (Ref. 22) and USNRDL-TR-642 (Ref. 23). These val-

*Consider the average situation arising from the fission of 100 nuclei before
beta~decay processes have begun. The number of atoms of a given nuclide
formed under these conditions is called the primary, or independent, yield of
that nuclide in percent.

The total of independent yields for all nuclides of a

given mass is called the primary chain yield for that mass in percent. If no

members of the chain emit neutrons or are formed by neutron emission from
neighboring chains, the observed chain yield is always equal to the primary
chain yield.