acid and 10 ml of concentrated HCl.to this solution and boil for about
10 min to about 25 ml in 6N-HCl.
15. Dilute this solution to 2N-HCl and then extract with 10 ml of
0.4 M TTA in benzene for 10 min,
16.
The aqueous phase containing the fission products, U, and
other heavy metals is discarded.
17. Wash the benzene phase containing Np IV with 5 ml of 2N-HCl]
(saturated with TTA) for 2 min and discard the wash solution.
18.
Back-extract the Np for 10 min from the benzene with the 5 ml
of 8N-HCl retained in step 12.
Discard the benzene,
19. Add 1 ml of concentrated formic acid and 10 ce HCl to the
solution in 8N-HCl and boil for 10 min under a watch glass cover,
20,
Transfer the solution to a separatory funnel, dilute to 2N-HCl,
and extract with 10 ml of 0.4 { TTA in benzene for 10 min.
21. Discard the aqueous phase.
22. Wash the benzene phase with 2 ml of 2N-HCl (saturated with TTA)
for 2 min,
23.
24.
'
Wash with 1 ml 0.1N-HCl (saturated with TTA) for 2 min,
Back-extract the Np from the benzene rith 5 to 10 ml SN-HCl
(saturated with TTA) for 10 min.
25. Separate the phases. Measure the total volume,
aliquot for assay, gamma spectrum, and decay.
A.2
SEPARATION OF SODIUM
Take an
ACT
The procedure used for the isolation of sodium activity from the
gross activity was accomplished in two parts, Part I consisting of
separating the alkali fraction from other radionuclides by ion exchange
is discussed more fully in Appendix B,
Part II consisted of a gravi-
metric procedure employing the specific precipitation of sodium zino
uranyl acetate, The complete procedure is given below,
Step 1. Transfer an aliquot of the original sample to a 100-nl
beaker. Acidify solution with a minimm amount of HCl (usually to a pa
This is usually sufficient to dissolve any of the solids present
of 5).
in the sample. Then the solution is evaporated down to approximately
2 ml.
Step 2. This volume is absorbed on the top of a cation exchange
resin column along with added Na carrier (5 mg). after rinsing the
column with de-ionized water, the colum is eluted with 0.5N-HCl. In the
water wash, I, Cl, Br, other anions, and some colloids are eluted. In
the 0,5N-HCl elution, U and Np are first eluted. The second peak of
activity contains the alkali metals. The Na breakthrough is determined
by a Ptewire flame test for the Na carrier. The alkali fraction is removed in approximately 50 ml of solution at a rate of 8 to 10 drops per
minute.
Step3.
Evaporate the alkali fraction to 2 ml.
carrier plus 10 to 20 mg of Ce* and X* carriers,
Add 20 mg of Na
Acidify with 10 ml of
dil, HCl and then add 5 drops of 0.13 M silicowolframic acid (see Note 1).
Allow to stand with occasional stirring for about 5 min.
and wash the precipitate twice with 5 ml of 6N-HC1,
and washes (see Note 2).
136
Centrifuge,
Combine supernatant