Chemistry Reference
In-Depth Information
loading in one direction and eluting in another direction, and providing a purge line
route that bypasses the column. This separation approach has also been adapted for
simultaneous determination of
90
Sr and
226
Ra with off-line radiometric determina-
tion.
126
The quantity of
90
Sr initially present is determined from the measured
90
Y
activity assuming secular equilibrium conditions existed in the original sample.
9.4.3 a
C t i n i d e S
Actinides have significant abundance in irradiated nuclear fuel, long radioactive
half-lives, and high radiological and chemical toxicities, and they raise concerns
with criticality and nuclear proliferation. Accordingly, actinide analyses are impor-
tant in process solutions, nuclear wastes, and environmental samples.
Actinides can be separated from matrix elements, other radionuclides, and each
other using extraction-chromatographic materials such as TEVA-Resin, TRU-Resin,
and UTEVA-Resin. The capacity factors for various actinides on these resins, as
a function of nitric or hydrochloric acid concentrations are shown in Figures 9.11
and 9.12.
30,31,127
Elution peaks or collected fractions from column separations can be
TEVA-Resin
TRU-Resin
UTEVA-Resin
10
6
10
6
10
6
Pu(IV)
Np(IV)
10
5
10
5
10
5
Pu(IV)
10
4
10
4
10
4
Np(IV)
Th(IV)
1000
1000
1000
Th(IV)
Pu(IV)
U(VI)
Am(III)
k
ยด
100
100
100
U(VI)
Np(IV)
U(VI)
10
10
10
Np(V)
Th(IV)
1
1
1
Np(V)
Am(III)
0.1
0.1
0.1
Am(III)
0.01
0.01
0.01
0.01 0.1 1 10
Nitric acid concentration, M
0.01
0.01
0.1
1
10
0.1
1
10
FIGURe 9.11
Capacity factor
s
, k
'
, against nitric acid concentration for three resins used
in actinide separations. (Data for these plots were originally published in Ref
s.
30, 31, 127,
and data traces were adapted from www.eichrom.com where they are shown in color. With
permission.) (From Horwitz, E. P., Dietz, M. L., Chiarizia, R., Diamond, H., Maxwell, S. L.,
and Nelson, M. R.,
Anal. Chim. Acta
, 310, 63-78, 1995. With permission.)
