THE RADIOCHEMISTRY OF PLUTONIUM - Sciencemadness.org

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chloroform into a 250-ml round-bottomed flask through a 7 cm
h-o. 41 filter paper as before. Return the water to the original aqueous
solution and add a further 5 ml of FeC13 and 2 ml of 5 % cupferron as
a scavenge. After shaking, leave the solution to stand for another
3/4 hr.
Extract the cupf errides with three 15-ml lots of chloroform – or
until the chloroform remains colorless — and filter each lot separately
into the 100-ml fumel. Wash the filter paper with chloroform from
a pipette to remove the ring of cupferrides which forms around the
top, and collect the washings in the 100-ml separating funnel.
Add 20 ml of distilled water to the chloroform extracts, and shake the
funnel. After they have settled out, filter the extracts into the 250-ml
round-bottomed flask and wash the filter paper with chloroform.
Evaporate off the excess chloroform in a fume cupboard using an
“Electro-Thermal” mantle. Remove the fiml drops by blowing in air.
Add 3 ml of cone. H2S04 and 1 ml of cone. HN03 to the residue and
heat. Evaporate the final trace 6 of H2S04 by blowing in air. If the
residue is not white, add further aliquots of the acids and take to dry-
ness again.
Counting Procedure
a- scintillation counter.
Dissolve the residue in 3 ml of cone. HC1 and transfer by means of a
pipette to a pt tray previously counted for background. Use two
further 3-ml aliquots of cone. HC1 to obtain a quantitative transfer.
Dry the final solution, then take up in a few drops of water and add
enough 2 N NH40H to ensure complete precipitation of ferric hydroxide.
—
Spread this precipitation evenly over the tray (15 cmz effective surface)
using a glass rod with a fine tip.
Dry the tray, and finally heat it over a bunsen to form the red oxide
Fe203 before counting.
Count the tray “background” and sample each for one period of 8 hr in an
Calculating Maximum Permissive Level in Urine
Maximum permissive level in the body is 0.04 EC for Pu 239 (solution).
Excretion rate assumed is 0.01% per day.
Corresponding Maximum Permissive Level in Urine is :, 4 p~c
With a method recovery of 90% and a counter efficiency of (say) ss~o, the
maximum permissive level in urine z 2.8 cpm above “background, ”
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