From our archivist colleagues, who confirmed their understanding with what was already sent to you directly:
Department of the Navy Telephone Directories for Nov. 1946 and Feb. 1947 do not mention the Chief of Naval Intelligence (CNI) having an organization that includes "nuclear" or "atomic" in the name. Also it was known as the Naval Intelligence Division during 1947. During that time span CNI was OP-32 A century of U.S. naval intelligence / Wyman H. Packard. - Full View | HathiTrust Digital Library | HathiTrust Digital … so any lower offices would start with OP-32. The link will take you to A Century of U.S. Naval Intelligence, which lists many of the OP numbers for CNI.
OP numbers are used as office symbols for offices a part of the Office of the Chief of Naval Operations (CNO) and the offices names changed over time using the same OP numbers, so you need to know what year he is looking at to determine the organization name of the OP numbers that are unknown. Looking at the variant organization names listed in DAS for CNI, none of them started with OP-34, OP-40, or OP-43, so they were not a part of CNI.
Furthermore, the Op-23 numbers are good through July 1947, reflecting the fact that the the Naval Intelligence Division was under the DCNO (Administration) who was OP-02. The change to OP-32 reflects their transfer to DCNO (Operations) who was OP-03.
I hope this helps!
Here's why I asked...
I've discovered a series of Japanese nuclear documents that fell into the hands of the Chief of Naval Intelligence Division. It was then distributed to a long list of Naval and other offices, including ONI. I recognize some of thise "offices" such as AAF, CIG, etc., but identifying each and every OP-number has proved difficult. So I asked a more general question: Did ONI have a nuclear section. But maybe my question was still too restrictive. What I should have asked was, "Did the Office of Naval Operations" have a nuclear section, and if so, what was it called?
What I suspect is, the Navy has no idea how important these nuclear documents were, so they made no attempt to get them into the right hands. I already know the Manhattan Project and the Atomic Energy Commission (AEC) never received a copy. Sooooo... if the Manhattan Project, the AEC, and the Navy's (supposed) atomic/nuclear section wasn't informed, someone goofed up.
The good news is I found out that the Navy had a "Special Weapons" division (chemical, nuclear, etc,), but it doesn't seem that Special Weapons didn't receive a copy either. I just wish I knew if Special Weapons had a code name, so I could look it up.
-- Bill Streifer