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Remembering Charles E. Till
Charles E. Till
Charles E. Till, an ANS member since 1963 and Fellow since 1987, passed away on March 22 at the age of 89. He earned bachelor’s and master’s degrees from the University of Saskatchewan and a Ph.D. in nuclear engineering from Imperial College, University of London. Till initially worked for the Civilian Atomic Power Department of the Canadian General Electric Company, where he was the physicist in charge of the startup of the first prototype CANDU reactor in Canada.
Till joined Argonne National Laboratory in 1963 in the Applied Physics Division, where he worked as an experimentalist in the Fast Critical Experiments program. He then moved to additional positions of increasing responsibility, becoming division director in 1973. Under his leadership, the Applied Physics Division established itself as one of the elite reactor physics organizations in the world. Both the experimental (critical experiments and nuclear data measurements) and nuclear analysis methods work were internationally recognized. Till led Argonne’s participation in the International Nuclear Fuel Cycle Evaluation (INFCE), and he was the lead U.S. delegate to INFCE Working Group 5, Fast Breeders.
N. Meynet, A. Bentaib
Nuclear Technology | Volume 178 | Number 1 | April 2012 | Pages 17-28
Technical Paper | Safety and Technology of Nuclear Hydrogen Production, Control, and Management / Hydrogen Safety and Recombiners | doi.org/10.13182/NT12-A13544
Articles are hosted by Taylor and Francis Online.
A detailed model is proposed for numerical simulation of hydrogen ignition inside box-type passive autocatalytic recombiners (PARs). The model is focused on the reactive channel flow between two catalytic sheets of a recombiner. It includes complex chemistry and multicomponent transport for homogeneous hydrogen combustion and complex surface chemistry for heterogeneous hydrogen recombination. First calculations are dedicated to H2/air mixtures without steam at atmospheric pressure and room temperature. The analysis of the total homogeneous and heterogeneous heat release rates according to the inlet hydrogen molar fraction reveals three possible operation regimes for the recombiners from pure catalytic conversion to pure gaseous combustion. A physical criterion is then proposed for the ignition of H2/air mixtures inside the recombiners. The numerical ignition threshold at 5.4% of hydrogen without steam is in good agreement with experimental data. The criterion is then applied to the ternary diagram including all representative H2/air/H2O mixtures for severe accident conditions in pressurized water reactors. It shows a sharper transition from the catalytic regime to the gaseous one for high hydrogen concentrations. A specific strategy finally allows defining an extended PAR hydrogen ignition limit in the entire ternary diagram, which is well corroborated by the available experimental database.