Chemical changes percent yield

Irradiated fuel may contain up to several percent by mass of fission products, consisting of nearly 200 different isotopes of about 40 different chemical elements whose atomic numbers range from 30 to 66. Nuclides with mass numbers of 85-105 and 130-150 have the highest yields. The precise calculation of the quantities of the various fission products present in fuel at any time during and after irradiation is complicated and best carried out using a computer. A preliminary calculation of the changing... 

As indicated in the reaction sequences of equation 1, fractionation of the tritium does occur between the calciiom hydroxide and acetylene formed as products of the initial reaction of the water sample with the calcium carbide. However, the isotopic effect was found by Hohndorf and Oro (14) to be constant at 31.4 1.2 percent, thus indicating that the isotope fraction is independent of chemical yield for the reaction. For the system under consideration, the production of a constant volume of benzene was not attainable due to the restrictions of varying sample size, changes in the efficiency of trimerization due to catalyst depletion from previous samples, and the potential for varying rate of reaction of the water-carbide system. This fact, coupled with the lack of adequately documented tritiated benzene standards, led to the adoption of a system calibration rather than a yield determination for each sample in conjunction with a separate instrument calibration. 

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