Nuclear forensic studies

Millions of radioactive sources exist around the world, usually distributed not only at nuclear power plants, but also medical radiotherapy facihties and industrial irradiators. Unfortunately, the radioactive materials housed in these places are often not under adequate control and are therefore susceptible to theft by terrorists.34 The appalling events of September 11, 2001, spawned a major international initiative to strengthen security for such materials and facihties worldwide. Highly toxic radionuchdes (plutonium radionuclides, 210Po or 137Cs) at trace level are increasingly being used as modern weapons to kill undesirable persons. 

SIMS is mostly employed for microlocal analytical investigations. For example, isotope ratio measurements by SIMS have been performed in nuclear forensic studies to determine the age of Pu particles. For the age determination of Pu particles, relative sensitivity coefficients (RSC) were determined as correction factors for the different ionization efficiency of Pu compared to U. The age of a sample of known origin calculated from Pu/ and °Pu/ U ratios agreed well with the reported age of 2.3 years. SIMS was employed for oxygen isotope ratio measurements in three different uranium oxide microparticles of nuclear forensic interest by Betti s working group. The 

Ultratraces of Po are distributed worldwide as nuclear contamination in the environment, bnt °Po also occurs as a natural radioactive decay product in the decay chain of and can be analyzed by a-spectrometry. In spite of the short Po half life (tj j = 138days), traces can also be detected after careful separation (due to isobaric interference with Pb in nuclear samples and environmental materials) using advanced mass spectrometric techniques such as CE-ICP-MS or AMS as demonstrated in references  

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Abstract A short history and treatment of the various aspects of nuclear forensic analysis is followed by a discussion of the most common chemical procedures, including applications of tracers, radioisotopic generators, and sample chronometry. Analytic methodology discussed includes sample preparation, radiation detection, various forms of microscopy, and mass-spectrometric techniques. The chapter concludes with methods for the production and treatment of special nuclear materials and with a description of several actual case studies conducted at Livermore. 

The application of nuclear forensic techniques to samples of purified heavy elements is well developed however, when applied to unseparated spent reactor fuel, the methods become more complicated. The radionuclide content of a spent fuel sample is not controlled solely by radioactive decay, but is strongly influenced by neutron-induced transmutation. Chronometry based on the decay of the light plutonium isotopes cannot be performed due to the initial presence of an overwhelming quantity of uranium. The isotopic distribution of the plutonium isotopes and the concentration of fission products can provide a means by which the degree of transmutation can be estimated, unless the material started out as MOX fuel (where reprocessed plutonium is incorporated into fuel fabricated from uranium with insufficient fissile content to support the reactor application). More study is needed to extend the methodology to unprocessed fuel. 

Although relevant exercises have been conducted, and Cold War nuclear weapons programs provide validated analytic platforms, there have been no actual post-det terrorist incidents involving an IND or RDD to date. Consequently, no technical investigations in the contemporary embodiment of nuclear forensic analysis exist for an actual post-det situation, and all discussed case studies necessarily focus on interdicted, pre-det materials. (However, a nuclear accident that is perhaps exemplary of maximum-credible consequences of successful terrorist activities was the uncontrolled criticality and resultant explosion of the Soviet RBMK power reactor at Chernobyl in 1986.)... 

Many other published reports serve as case studies and reveal how MS is used to help determine the provenance of illicit nuclear and radiological materials [94-97, 119-122]. In particular, Becker s 2005 article, Recent developments in isotope analysis by advanced mass spectrometric techniques, gives an in-depth review of methods that have and may be applied to the analysis of samples of interest to the nuclear forensic and counterproliferation conamunities [95]. These arti-... 

Waiienius, M., et al. (2006) Nuclear forensic investigations two case studies. Forensic Science International, 156,55-62. 

Due to its importance in safeguards, several studies developed analytical procedures for age dating of uranium-containing materials for nuclear forensics applications. As mentioned earlier, the °Th/ pair is the most useful followed by the pair. 

In its history, mass spectrometry has passed through fascinating scientific epochs of development and supplied important contributions to the world view in quite different fields of science (especially in the life sciences, environmental science and technology, material and nuclear sciences, geosciences, cosmochemistry,1 planetary and forensic sciences) and in basic studies in chemistry and physics. 

Accurate uranium analysis, particularly for isotope measurements, is essential in many fields, including environmental studies, geology, hydrogeology, the nuclear industry, health physics, and homeland security. Nevertheless, only a few scientific books are dedicated to uranium in general and analytical chemistry aspects in particular. Analytical Chemistry of Uranium Environmental, Forensic, Nuclear, and Toxicological Applications covers the fascinating advances in the field of analytical chemistry of uranium. 

If you have wondered about any of these things, then some of your curiosity will be satisfied by learning about spectroscopic methods such as nuclear magnetic resonance (NMR) spectrometry, which involves the same physical principles as MRI imaging, and MS (mass spectrometry), which is used in some airport screening processes as well as many forensic applications. NMR and MS are workhorse techniques for the study of both biological and nonbiological molecular structure. 

UV-visible spectroscopy has proved useful in biochemical analysis, environmental studies, in forensic science, drug kinetics, food quality, identification and quantification of chemical and biological substances but is limited as a tool for the investigation of molecular structure compared with infrared and nuclear magnetic resonance. However, it is quite useful for the study of reaction kinetics and equilibrium. 

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