Without speculating, this is what can be said.
Mr. Simon junior recalls that it was important for Mr. Robbiati that his machines be stamped with the name Atomic as he sold the license in Hungary. If this was orally mentioned or written on the license agreements is to this point of time unknown.
Mm. Notaras told me that Mr. Robbiati related the Atomic bombing in Japan with the end of the 2nd WW with positive feelings.
On the 8th of September 1943, Italy signed an armistice with the allied. But because Germans occupied the north of Italy until the end of the war, Milan, which was (and still is) an industrial town was severely bombed by the Americans and English. Mr. Robbiati's foundry blew up in the air. Of this sad event, 4 pictures remain.
Hiroshima was bombed on the 6th of August 1945, Nagasaki on the 9th.
Politically, in Italy, the wind of change was blowing.
After the referendum of the 2nd of June 1946 (the first time women voted), Italy became a Republic.
The rest of course is speculation... but it is understandable that for people who survived the 2nd WW, the tragedy of Hiroshima and Nagasaki are related to positive memories back in Europe: the end of the bombings, of dictatorship, the beginning of democracy, peace.
A name which has less to do with the "atomic era" (in terms of nuclear optimism) ... but more with the celebration of peace... an explosion of happiness.