The women - all Massachusetts residents and members of the Shut It Down Affinity Group - cited the ongoing court battle between Vermont officials lobbying for the plant's closure and federal regulators who have granted a license renewal to plant operator Entergy.
They also raised concerns about the ecological and health effects of the facility.
"Entergy is trespassing on my welfare and all of yours," said Mary Kehler of Colrain.
The defendants are representing themselves, and their approach drew frequent objections from Windham County Deputy State's Attorney Steven Brown. At times, Judge John Wesley ordered the suspects to stay away from certain topics having to do with political wrangling over the plant's future or alleged environmental effects from its operation.
Brown called Vernon Police Chief Mark Beth Hebert and Patrick Ryan, Vermont Yankee security manager, to testify. Both said the women were trespassing and were repeatedly warned to leave before their arrest.
Testimony also showed that all of the women had been arrested for previously protesting at the plant.
Also charged in the Aug. 30, 2011 incident are Frances Crowe, Nancy First and Patricia Wieland, all of Northampton; Hattie Nestel of Athol; and Ellen Graves of West Springfield.