Nuclide transuranium

Since the radioactive half-lives of the known transuranium elements and their resistance to spontaneous fission decrease with increase in atomic number, the outlook for the synthesis of further elements might appear increasingly bleak. However, theoretical calculations of nuclear stabilities, based on the concept of closed nucleon shells (p. 13) suggest the existence of an island of stability around Z= 114 and N= 184. Attention has therefore been directed towards the synthesis of element 114 (a congenor of Pb in Group 14 and adjacent superheavy elements, by bombardment of heavy nuclides with a wide range of heavy ions, but so far without success. 

Transuranium Nuclides in the Environment" International Atomic Energy Agency Vienna, 1976. 

C22-0100. The heaviest transuranium elements are formed by bombardment with relatively heavy nuclides such as 48... 

Rosner G, Hotzl H, Winkler R. 1978. Measurements of transuranium nuclides in the environment at the Institute for Radiation Protection of the Gesellschaft frir Strahlen- und Umweltforschung mbH, Munich. Environ Int 1 85-88. 

Guary, J.C. and S.W. Fowler. 1990. Experimental study of the transfer of transuranium nuclides in marine decapod crustaceans. Mar. Ecol. Prog. Ser. 60 253-270. 

Hetherington, J.A., D.F. Jefferies, N.T. Mitchell, RJ. Pentreath, and D.S. Woodhead. 1976. Environmental and public health consequences of the controlled disposal of transuranic elements to the marine environment. Pages 139-154 in Transuranium Nuclides in the Environment. IAEA-SM-199/11, Inter. Atom. Ener. Agen., Vienna. 

Tamura, J. In Transuranium Nuclides in the Environment - Proceedings of a Symposium at San Francisco, 17—21 November 1975. IAEA-SM-199/52, p. 213 Vienna International Atomic Energy Agency 1976... 

BERKELIUM. [CAS 7440-40-6]. Chemical element, symbol Bk, at. no. 97, at wt. 247 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. All isotopes of berkelium are radioactive all must be produced synthetically. The element was discovered by G.T. Seaborg and associates at the Metallurgical Laboratory of the University of Chicago in 1949. At that time, the dement was produced by bombarding 241 Am with helium ions. 4i Bk is an alpha-emitter and may be obtained by alpha-bombardment of ,4Cm. 245Cm. or 246Ciu. Ollier nuclides include those of mass numbers 243—246 and 248-250. Probable electronic configuration ... 

The third principal component of environmental radioactivity is that due to the activities of humans, the anthropogenic radionuclides. This group of nuclides includes the previously discussed cases of 3H and 14C along with the fission products and the transuranium elements. The primary sources of these nuclides are nuclear weapons tests and nuclear power plant accidents. These events and the gross nuclide releases associated with them are shown in Table 3.1. Except for 14C and... 

The transuranium elements are the elements following uranium in the periodic table. The elements from rutherfordium (Rf, Z = 104) through meitnerium (Mt, Z = 109) were formally named in 1997. The transmeitnerium elements, the elements beyond meitnerium (including hypothetical nuclides that have not yet been made), are named systematically, at least until they have been identified and there is international agreement on a permanent name. The systematic nomenclature uses the terms in Table 17.2. For example, the element with Z = 111, one atom of which was first made in 1994, will be called unununium, Uuu, until it is finally named. 

Zhu [58] described the use of liquid scintillation analysis for the monitoring of a-emitting and transuranium nuclides in environmental samples. 

Pentreath, R.J. (1981) The biological availability to marine organisms of transuranium and other long-lived nuclides. In International Symposium on the Impacts of Radionuclide Releases into the Marine Environment, IAEA, Vienna, pp. 241—272. 

Fig. 12. Production cross sections of transuranium nuclides in the interaction of 238U with 238U (solid lines) plotted versus mass number. Also shown are data for the l36Xe+238U interaction (dashed lines). FromM. Schadel et al. [104],...

Mass spectrometric techniques play a dominant role for the determination of transuranium elements in bulk samples as well as in microparticles. The radioactive element most frequently investigated by inorganic mass spectrometry is uranium. The determination of the concentrations and the precise isotopic analysis of naturally occurring radioactive elements (e.g. Th and the decay nuclides) by inorganic mass spectrometry as terrestrial... 

The most important method of production of the first transuranium elements is neutron irradiation of uranium. After the discovery of the neutron by Chadwick in 1932, this method was applied since 1934 by Fermi in Italy and by Hahn in Berlin. The method is based on the concept that absorption of neutrons by nuclides with atomic number Z leads to formation of neutron-rich nuclides that change by fi decay into nuclides with atomic numbers Z - -1. Unexpectedly, the experiments carried out by Hahn and Strassmann led to the discovery of nuclear fission in 1938. 

After long irradiation times, elements with atomic numbers Z -I- 2, Z -I- 3 etc. are generated in amounts that increase with irradiation time. The formation of transuranium elements by neutron irradiation of is illustrated in Fig. 14.5. (n, y) reactions and radioactive decay compete with each other. Formation of heavier nuclides is favoured if... 

Figure 14.11. Logarithm of the ratio of the cross sections (Tn,f and for various nuclides of the actinides as a function of the difference between the neutron binding energy B(n) and the energy barrier of fission E. (According to G. T. Seaborg The Transuranium Elements. Yale University Press 1958 Addison-Wesley Publ. Comp, Reading, Mass., S, 166/167 S. 240/241.)...

Sakanoue, M., Transuranium nuclides in the environment. Radiochim. Acta, 42 (1987) 103. 

This paper discusses that specific area of a monitoring program that deals with the determination of transuranium nuclides in water. The initial work in this area was to measure the concentration of plutonium in large volume water samples ), This method has been extended to include the determination of other transuranium elements. 

Sample Pretreatment. Water samples are acidified with nitric acid immediately after collection to inhibit hydrolytic loss of trace elements and then filtered to remove suspended solids. Surface water samples frequently contain suspended soil from runoff water. This soil contains some transuranium nuclides, particularly plutonium, from fallout of previous atmospheric nuclear tests. The amount of suspended soil in water may be substantial under certain conditions. This pretreatment is used to obtain the concentration of the soluble transuranium elements. The filtered residue can be analyzed if desired. 

This procedure has been used in the analysis of environmental water samples over the past 3.5 yr. Plutonium measurements have been made since mid-1971, neptunium-237 since mid-1972, and transplutonium since mid-1973. The application of this procedure to routine surveillance can be illustrated by previously published results for several transuranium nuclides (6-9). 

This procedure is designed to provide analytical data to show compliance with existing standards. In addition, it can be used to determine baseline concentrations of the transuranium nuclides in the environment. 

The separation of actinides has been studied for various purposes in Japan Atomic Energy Research Institute (JAERI). The works which have been carried out so far, are classified into four categories preparation studies of actinides nuclides, separation chemistry for chemical analysis, separation of actinides from radioactive waste, and studies on reprocessing of spent nuclear fuels. The present work is to review studies of actinide separation performed in JAERI, emphasizing the need of the separation for the main purpose of individual. Concern is focussed on the separation of transuranium elements and studies on thorium and uranium are put aside. 

Separation of Actinides from the Samples of Irradiated Nuclear Fuels. For the purpose of chemical measurements of burnup and other parameters such as accumulation of transuranium nuclides in irradiated nuclear fuels, an ion-exchange method has been developed to separate systematically the transuranium elements and some fission products selected for burnup monitors (16) Anion exchange was used in hydrochloric acid media to separate the groups of uranium, of neptunium and plutonium, and of the transplutonium elements. Then, cation and anion exchange are combined and applied to each of those groups for further separation and purification. Uranium, neptunium, plutonium, americium and curium can be separated quantitatively and systematically from a spent fuel specimen, as well as cesium and neodymium fission products. 

In this concept, the transuranium elements are considered as waste, due to their quantity and value (table 1), since they contribute only 0.6 % to the total spent fuel and from that amount only 5 % (239Pu and 2i+1Pu) are fissionable nuclides. 

---