Element production was the entire point of the earliest reactor patent.
Awarded in Britain in 1934, it predated fission and was focused on transmutation and the production of elements for use in medicine and the sciences. The focus on chemistry is as important as the fission reaction, which was unknown. I occasionally wonder what a world like this might have looked like had nuclear weapons taken a back seat to power and medical uses, leeching the fear from fission and sparing us the horror show of Hiroshima and Nagasaki.
Improvements in or relating to the transmutation of chemical elements
https://worldwide.espacenet.com/data/publicationDetails/biblio?FT=D&date=19360330&DB=&locale=en_EP&CC=GB&NR=630726A&KC=A
630,726. Producing neutrons. SZILARD, L. June 28, 1934, Nos. 19157 and 19721. [Class 39 (i)] A neutron chain reaction generates power and produces radio-active isotopes. The reaction takes place in a mass 3, Fig. 1, comprising indium and beryllium, bromine or uranium. Fast deuterons from a canalray tube 1 bombard a deuterium target 28 to produce initiating neutrons which react with In<115> to produce In<112> and " tetra neutrons " of mass about 4.014. These tetra neutrons react with the Be, Br or U to produce double the number of simple neutrons, thereby providing a chain reaction. Emerging neutrons transmute a layer 9 to produce radio-active substances. Alternatively, Fig. 3, the initiating neutrons may be produced by passing cathode-rays through a sheet 402 of Pb or U to generate hard X-rays which react with beryllium in the mass 3 (or an inner mass 407) to yield neutrons. The critical thickness of the layer 3 for a self-sustaining chain reaction is stated to be of the order of 50 cms. Tetra neutrons are stated to be produced when neutrons of 100,000 e.v. to 8 m.e.v. energy react with the In<115>. Power is obtained by heat exchange from water or mercury passing through cooling tubes 107, 110, 111. Other methods of obtaining the initiating neutrons are described in Specification 440,023.