1. ANALYTICAL METHODS FOR OBTAINIG
„FINGERPRINTS“ OF NUCLEAR MATERIALS
IN ILLICIT TRAFICKING: A CASE OF HIGH
ENRICHED URANIUM SEIZED IN PRAGUE IN 1994
A REVIEW
Miloš BERAN, František SUS *
Nuclear Physics Institute, Czech Academy of Sciences
250 68 Rez near Prague, Czech Republic
Nuclear Research Institute Rez plc *
250 68 Rez near Prague
Czech Republic
5. After the event, the International Technical Working Group
(ITWG) for assisting to state and international safety offices
and agencies in suppresing an illicit nuclear trafficking, was
established in a short series of international meetings:
• International Conference on Nuclear Smuggling Forensic Analysis,
LLNL, Livermore (U.S.A)
November 7-9, 1995
• First Meeting of the Nuclear Smuggling International Technical
Working Group, ITU, Karlsruhe (Germany)
January 31-February 1, 1996
• International Workshop on Nuclear Material Illicit Trafficking,
Institute of Physics and Power Ingeneering, Obninsk (Russia)
December 2-4, 1996
6. Basic analytical methods recommended by ITWG for
forensic analyses of seized illicit nuclear material to
attribute its origin and possible use:
• High resolution gamma (for detection of enriched U-235 and/or
Pu) and alpha spectrometry
• Potentiometric oxidation-reduction titration to determine
stoichiometric composition (U-content) of material
• Mass spectrometric methods for determination of isotopic com-
position, e.g. ID-TI-MS, GD-MS or ICP-MS ( determination of
enrichment, impurities, …)
• Optical and electron (scanning or transmision) microscopy for
determination of structure and microstructure
• X-ray diffraction analysis (homogeneity of material)
• Determination of age of material from ratio of some generic
radionuclide pairs ( e.g. U-235/Pa/231, U-232/Th-228,
Pu-239/U-235, Pu-240/U/236,… )
8. Mass Spectrometric (TI-MS) Determination of
Isotopic Composition of the Material
Test Parameter Batch A Batch B
U-content (wt. %) 86,799 +- 0,001 86,735 +- 0,001
IC-NRI 232 U
232 U
234 U
235 U
236 U
238 U
<0,000002
< 0,000002
1,0781 +- 0,0003
87,731 +- 0,046
0,2108 +- 0,0001
10,9797 +- 0,004
<0,000002
<0,000002
1,0778 +- 0,0004
87,737 +- 0,035
0,2102 +- 0,0004
10,9438 +- 0,004
IC-ITU
(comparison in
collaboration)
234 U
235 U
236 U
238 U
1,078 +- 0,070
87,766 +- 0,046
0,210 +- 0,00
10,946 +- 0,046
9. Determination of Trace Impurities by ICP-MS
Test Element Batch A Batch B
Impurities (μg/g)
IC-MS
Elan 6000
(without
chem.
separation)
Ag
Al
Ba
Be
Cd
Cr
Cu
Fe
Li
Mg
Mn
Mo
Ni
Pb
Sb
Sn
Sr
Th
Ti
V
W
Zr
0,19
7,8
0,65
0,005
0,015
8,9
1,25
58,5
0,03
10,4
0,91
3,2
2,9
4,1
0,010
0,70
0,45
0,22
0,82
0,14
0,39
18,6
0,15
8,5
0,49
0,004
0,018
9,5
1,15
65,4
0,04
12,0
1,05
2,8
3,5
3,2
0,018
0,82
0,55
0,26
0,99
0,19
0,46
16,1
17. C o n c l u s i o n s:
• The material seized in Prague in December 1994 was according
to high resolution gamma spectrometry, potentiometric titration
and mass spectrometric measurement high enriched UO2
(87,7 % of 235U)
• The material consisted of irregular porous particles (size under
1 mm) with microcrystal structure according to scanning electron
microscopy
• Very low content of radionuclide (99Tc, 239+240Pu) and chemical
impurities (excepting traces of common construction materials of
production equipment – Fe, Cr, Al and Zr) vere found in the
material
• According to determination of „age“, 26-27 years elapsed from
last retreatment (separation or purification) of the material to the
moment of analysis
18. C o n c l u s i o n s:
• High chemical reactivity (e.g easy solubility in mineral acids)
suggests the material to be an intermediate product for
production of other products in nuclear technology
• The described case represent a most significant seizure of
weapon utilizable illicit shipment of nuclear matererial
• Radioanalytical chemistry can provide tools to retrace illicit
nuclear shipment to its source, supposing that nuclear material
database exists
