A trial is underway in Vermont for six elderly Massachusetts women accused of trespassing at the Vermont Yankee nuclear power plant last year to protest the continued operation of the reactor. Police say the women, all members of the Shut It Down Affinity Group, traveled to the nuclear plant’s gate in Vernon on Aug. 30, 2011, used a chain and padlock to lock the entrance gate, and chained themselves to the fence, while officials were busy with the aftermath of Tropical Storm Irene. It was one of about 22 protests the group has mounted against the reactor’s continued operation in recent years. The women are from Northampton, Athol, Colrain, and West Springfield, Mass. The trial started Tuesday morning in Brattleboro.