sentences:  The movement "reached critical mass" with the arrests at Seabrook Station Nuclear Power Plant on May 1, 1977, when 1,414 anti-nuclear activists from the Clamshell Alliance were arrested at the Seabrook site.Harvey Wasserman, Howard Morland, Paul Gunter and Frances Crowe played key roles in the movement.In 2002, the USA had what former NRC Commissioner Victor Gilinsky termed "its closest brush with disaster" since Three Mile Island's 1979 meltdown; a workman at the Davis-Besse reactor found a large rust hole in the top of the reactor pressure vessel.