"in a plenary" is correct and usable in written English.
It is typically used to indicate that a particular discussion, debate, or decision has been resolved by a full group of people or representatives attending a meeting. For example: The group came to a consensus in a plenary session on Thursday afternoon.
In a plenary session later that day, Supreme court judges voted 11-0 to uphold the suspension.
The working group had not met in a plenary session for more than a year, amid disputes between the two sides about its scope and format.
In a plenary session, a panel will discuss a 2018 National Academies report on this enduring problem, focusing on field situations, and how various institutions are responding.
"Criminalization is a poor tool for regulating H.I.V. infection and transmission," Edwin Cameron, a justice of the Supreme Court of Appeals in South Africa, said in a plenary session.
The scope, history and status of our chemical reaction engineering (CRE) discipline are briefly outlined complementing the broad review presented by Professor J. Schouten in a plenary lecture a day earlier (Schouten, 2008).
On the morning of September 23 , 2009 Rex Tillerson arrived at the Sheraton on Seventh Avenue in New York, to participate in a plenary session at the Global Initiative's annual conference.
Professor Agarwal will speak at Technology Review's annual EmTech MIT conference this October, where he will participate in a plenary session on the dramatic impact that emerging technologies are having in education worldwide.
This left the announcement of his groundbreaking findings to a mention by Bernice Hoppel during a paper presentation and a short video in a plenary lecture by Thomas Brady, the founding director of the NMR Center.
In his ruling on Thursday, Zavascki said Cunha's position as speaker "posed a risk to the criminal investigation" and represented "a harm that conspires against the dignity of the institution which he leads". In a plenary session later that day, Supreme court judges voted 11-0 to uphold the suspension.
Finally, all mini-scenarios were presented and briefly discussed in a plenary session by the end of the first day.
The final report is then debated in a plenary session in parliament and further used in the permanent parliamentary committees.
