Watch FMovies. In April 1977, the small coastal town of Seabrook, New Hampshire became an international symbol in the battle over atomic energy. Concerned about the dangers of potential radioactive accidents, over 2,000 members of the Clamshell Alliance, a coalition of environmental groups, attempted to block construction of a nuclear power plant. 1,414 people were arrested in that civil disobedience protest and jailed en masse in National Guard armories for two weeks.