after years of concealment from the public, the us administration revealed a small, lightweight nuclear device that was to be delivered to an enemy harbour using a navy or Marine parachutist. The information, along with 270,000 pages of materials kept secret for the last 50 years, was made public recently by the defence and energy department as a part of president Clinton's new policy of openness on atomic matters.

Although the device was never put in actual use, its yield of less than a kilotonne