The phrase "at a plenary session" is correct and usable in written English.
It is typically used to refer to a meeting or gathering where all members of a group or organization come together to discuss important matters.
Example: "The final decisions regarding the project will be made at a plenary session next week."
Alternatives: "during a general assembly" or "in a full meeting".
Results from the groups were briefed the following morning at a plenary session.
The subject could be raised at a plenary session tomorrow of its Human Contacts committee.
"This is the first year that the issue has been presented at a plenary session," she said.
That evening, at a plenary session, a delegate from Mississippi read a transcript of ten single-spaced pages of soul session, taken down the previous night.
A proponent of the Very Large Hadron Collider, Dr. Peter Limon, head of the technical division at Fermilab, described the machine at a plenary session here.
When they were asked at a plenary session how many had been separated by deportation from a parent or other close family member, hundreds of hands went up.
The work of these students was showcased when they presented at a panel during a plenary session at the 2010 SENCER Summer Institute.
At 3 AM, a plenary session was beginning to meet, with plans for talks to continue through Saturday.
On the plus side, the new American negotiator, Wendy Sherman, broke the ice with Jalili at Baghdad by engaging him in conversation at the end of a plenary session, I am told - a sort-of impromptu bilateral.
Tuesday's talks began at 1 30 p.m. with a plenary session that lasted about 2 hours, 30 minutes, largely taken up with the six laying out their latest modified proposal to the Iranians.
Brown will deliver keynote remarks at the conclusion of a plenary session featuring international scientists and government leaders focused on bridging the divide between climate research and policy making -- a longstanding priority in California.
