Transmutation products

Geber dealt with corpuscles that could in principle be divided. His mercury could penetrate into metals and modify their inner structure, a step on the way to the transmutative production of gold. 

The production of neutron transmutation products involves the neutron irradiation of target materials followed by chemical separa-... 

Plutonium-239 and tritium for use as military explosives are the two major transmutation products. The nuclear process for Pu-239 production is the same as for energy generation, but there are some differences (a) metallic natural uranium clad with aluminum facilitates later dissolution for plutonium recovery, and the reactor operates at a relatively low temperature because of the aluminum clad and better heat transfer (due to the metallic natural uranium) (b) the irradiation cycle is limited to a few months to minimize the Pu-239 conversion to Pu-240 and Pu-241 and (c) a carbon or a heavy water moderator is used to increase the neutron efficiency. 

It is not clear whether the still higher activities for the reprepared samples are accidental or have something to do with the distribution or location of the promoter. It would be of great interest to perform careful annealing experiments on samples with transmutation products to try to establish the influence, if any, of the location of the impurity atoms. Also, measurements over a series of doses should give important information about the true shape of the activity-concentration curve at low nickel content. 

Transmutation can frequently be eliminated as a possible explanation by the minute amounts of product atoms that can be obtained. In silica gel, for example, natural impurities normally far outweigh any possible transmutation products (10). 

External rad n and transmutation product both raise Fermi level... 

The three other missing elements —technetium, promethium, and astatine—were produced as transmutation products by synthetic means, either in the cyclotron or the atomic reactor. 

M. T. Simnad and L. R. Zumwalt, Diffusion of fission products (and transmutation products) in nonfuel materials—a review. USAEC Rept. GA-6543, General Atomic, August 31, 1965. 

W. B. Lewis, Reactivity Change Expected and Observed in the Long Irradiation of Natural Uranium in the NRX Reactor, DR-21, Feb. 4, 1952 L. D. P. King, Los Alamos Power Reactor Experiment and Its Associated Hazards, LAMS-1611, Dec. 2, 1953 J. Halperin and R. W. Stoughton, Some Effects of Transmutation Products on U Breeder Pile Operation, ORNL-1368, Sept. 29, 1952,... 

Do all fission and transmutation products significantly affect pile reactivity ... 

The transmutation products would include a high percentage of Pu-238 and Cm-244. A limit has to be placed on the Pu-238 concentration if the irradiated targets are to be reprocessed by the Purex process because its high alpha activity degrades the reprocessing solvent. 

The calculated change is small but negative at this exposure. Again, the results should be viewed as conservative because Doppler broadening is not treated in - Eu. The contributions from europium transmutation products (primarily gadolinium) have not yet been evaluated. Mo.st of the observed negative contribution is from Pu. 

The production of neutron transmutation products involves the neutron irradiation of target materials followed by chemical separation. Although this promises high purity with high specific activity, the isotopic composition of the target along with other competing reactions frequently yields a spectrum of isotopes of the desired nuclide (see Table 31.8). 

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