WASHINGTON — A nuclear engineer for the U.S. Navy and his wife have been charged with trying to share some of the United States’ most closely held secrets on submarine technology with another country, according to court documents unsealed on Sunday.
The engineer, Jonathan Toebbe, was accused of trying to sell information on the nuclear propulsion system of Virginia-class attack submarines — the technology at the heart of a recent deal that the United States and Britain struck with Australia.
While rivals like Russia and China have long sought details of U.S. submarine propulsion, based on the details in the court documents, some experts thought the unsolicited offer was aimed at a friendly country, not an adversary.
There is no allegation from the F.B.I. or the Justice Department that the foreign country obtained any classified information.
The F.B.I. affidavit described the…