Scope
This International Standard specifies a method for the determination of uranium concentrations in nitric
acid or TBP-kerosene solutions from nuclear reprocessing plants or other radiochemical process. The
method is directly applicable to the solutions, which contains about 10 gL-1 to 300 gL-1 uranium
with -activity of less than 109 BqL-1, and the content of neptunium and plutonium impurities should
be 1% lower than that of uranium respectively.
Purpose
The purpose of this proposal is to establish an international standard method for determination of
uranium concentration by L-absorption edge spectrometry, so as to standardize the analytical method
elements such as sample scope, instrument performance index, calibration method and operation
steps of this method, and promote the promotion and use of this method in the reprocessing plant or in
other nuclear facilities.
The concentration of uranium in reprocessing solutions is key data related to the operation of the
process and the accountancy of uranium materials, so it is necessary to accurately determine the
uranium concentration in the reprocessing solutions. There are many sampling points with 10-300 gL-
1 uranium in nuclear fuel processing process, such as samples from uranium purification cycle. and the concentration of uranium in these samples can be rapidly and accurately determined by L-absorbing edge spectrometry.
L-absorption edge spectrometry has the advantages of wide measuring range (10-300gL-1), high
precision (better than 0.5%) and accuracy.
Due to the high selectivity for determining uranium by L-absorption edge spectrometry, the matrix
influence can be ignored. The samples can be determined directly without any pretreatment. More
importantly, the same calibration curve can be employed for both aqueous phase and organic phase.
The structure of L-absorbing edge spectrometer is simple, and can be configured in a small space. So
it is easy to realize shielding or sealing installation in a small chamber or glove box. And the
construction cost is also inexpensive.
According to the above reasons, L-absorption edge spectrometry is bound to become an important
analytical method for process control and nuclear safeguards in nuclear fuel reprocessing plants and
facilities. L-absorption edge spectrometry has obvious advantages over the international standard
method " Iron(II) reduction/potassium dichromate oxidation titrimetric method" for uranium
determination, the method is precision titration, it is complex and long cycle.
Now, L-absorbing edge spectrometry has been used in the determination of uranium in nuclear fuel
reprocessing process samples for a few years in CIAE, and a nuclear industry standard of this method
has been documented in China. This proposal aims to spread this practice worldwide and benefits
relative industries.
Comment on proposal
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