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Nicholas Tsoulfanidis—ANS member since 1969
We welcome ANS members who have careered in the community to submit their own Nuclear Legacy stories, so that the personal history of nuclear power can be captured. For information on submitting your stories, contact nucnews@ans.org.
As an undergraduate I studied physics at the University of Athens. I entered the university in 1955 after successfully passing a national exam (came up fourth in a field of about 700 candidates). Upon graduation and finishing my mandatory two-year military service, the plan was to teach physics either in a public high school or as a tutor for a private for-profit institution, preparing high school students for the national exam.
Leonid Golyand, Eugene Shwageraus, Yigal Ronen
Nuclear Science and Engineering | Volume 161 | Number 3 | March 2009 | Pages 289-302
Technical Paper | doi.org/10.13182/NSE161-289
Articles are hosted by Taylor and Francis Online.
The growing interest in innovative reactors and advanced fuel cycle designs requires more accurate prediction of various transuranic actinide concentrations during irradiation or following discharge because of their effect on reactivity or spent-fuel emissions, such as gamma and neutron activity and decay heat.In this respect, many of the important actinides originate from the 241Am(n,) reaction, which leads to either the ground or the metastable state of 242Am. The branching ratio for this reaction depends on the incident neutron energy and has very large uncertainty in the current evaluated nuclear data files.This study examines the effect of accounting for the energy dependence of the 241Am(n,) reaction branching ratio calculated from different evaluated data files for different reactor and fuel types on the reactivity and concentrations of some important actinides.The results of the study confirm that the uncertainty in knowing the 241Am(n,) reaction branching ratio has a negligible effect on the characteristics of conventional light water reactor fuel. However, in advanced reactors with large loadings of actinides in general, and 241Am in particular, the branching ratio data calculated from the different data files may lead to significant differences in the prediction of the fuel criticality and isotopic composition. Moreover, it was found that neutron energy spectrum weighting of the branching ratio in each analyzed case is particularly important and may result in up to a factor of 2 difference in the branching ratio value. Currently, most of the neutronic codes have a single branching ratio value in their data libraries, which is sometimes difficult or impossible to update in accordance with the neutron spectrum shape for the analyzed system.