SECRET SESSIONS OF CONGRESS
Congress has the constitutional authority to conduct its business in secret and to close its proceedings to the public whenever it deems secrecy necessary. A new report from the Congressional Research Service reviews the justification, history and frequency of secret sessions of Congress.
"Since 1929, the Senate has held 56 secret sessions, generally for reasons of national security or for consideration of impeachment questions. On December 20, 2010, for example, the Senate met in closed session to discuss the New START Treaty with Russia," the CRS report said. "Since 1830, the House has met behind closed doors only four times: in 1979, 1980, 1983, and 2008."
"The proceedings of a secret session are not published unless the relevant chamber votes, during the meeting or at a later time, to release them. Then, those portions released are printed in the Congressional Record." See "Secret Sessions of the House and Senate: Authority, Confidentiality, and Frequency," November 30, 2011.