A minor but surprisingly crucial U.S.-U.K. scientific interaction in the early history of English reactors was a June 1948 trip to the mother country by Walter Zinn, who ran Argonne. I was amused to discover from this letter, four months earlier, from an English diplomat in Washington to John Cockcroft, presaging Zinn’s journey, that it might not have even occurred if Zinn’s allergies had misbehaved:

Under the exchange of information on the reactors on which the energy is not wasted, the U.S. will probably want to send a party to U.K. during the summer, probably consisting of Zinn, Weil and Wende. Incidentally, “summer” might mean as early as late April; I gather it depends on Zinn’s hay fever.

Woodward, F. N. 1948. Woodward to Cockcroft, Feb. 26, 1948. AB 16/388. National Archives, Kew, United Kingdom.