ORNL-4191 - the Molten Salt Energy Technologies Web Site

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Fig. 15.7. Inner Surface of Unexposed Wostelloy N Tubing Used in Cold Leg and, After Slight Reaming, in Cora
Owtlet of In-Pile loop 2. 250~.
It was useful to estimate how much of a given
isotope (either fission product or activation prod-
uct in flux monitors, etc.) was to be expected in
the system at a particular time. This may be done
by detailed application of standard equations to
the individual irradiation and inventory periods with
appropriate adjustment for decay to a standard
reference time (reactor shutdown, 4-4-67, 0800).
Counting data on the various samples were also
referred to this time. In the in-pile period of the
experiment, 38 changes in ORR power and 122
changes in experiment position altered the neutron
flux, 3 salt additions altered the fuel composition,
and 18 withdrawals, including 9 samples, were made.
'J. M. West, pp. 7-14, 15 in Nriclear Engineering
Handhook, ed. by €I. Etheritigton, McGraw-Hill, New
York, 1958.
The equations described below, along with the
detailed flux and inventory history, were pro-
grammed for computer calculation and estimates
of activity of the respective isotopes made as
described below. The equations will be discussed
in terns of fission products but are readily adapted
to activation products. The activities (A-A, and
B-A,) of isotopes that are the first and second
significant members of a decay chain produced
by a given period, ti, of steady irradiation fol-
lowed by a decay period, td, are given' by
--A t -A r
A.X,=Y.F-(1 -e ")(e '),