John Dunworth was one of the smart, opinionated physicists collected post-war by John Cockcroft for his Harwell laboratory. Over time Dunworth’s role became that of overall reactor guru. Here I catch him in 1953, eleven pages of him poring over all the technical literature and summing up recent British scientists’ tours of America. I enjoyed his put-down of a General Electric design – called the Intermediate Breeder Reactor – that had by then proven to be a flop. England never did investigate that design, no doubt based on Dunworth’s gathered intelligence.
. . . it appears almost certain that this [GE intermediate breeder] project ran into major nuclear difficulties on account of severe capture resonances and there is strong reason to believe that it was shown that the energy of the neutrons causing fission has to remain fairly high. Under these conditions the amount of moderating material becomes so much that the project is scarcely distinguishable from a fast breeder project . . . the fast and intermediate breeder projects may merge into the same system.
Dunworth, John V. 1953. U.S. Reactor Programme: TC/148. AB 16/4875, National Archives, Kew, United Kingdom.