A $40 million barge was stationed about 15 miles off the North Carolina coast Tuesday for the Navy's controversial and long-delayed Empress II experiments, which will simulate the electronic aftermath of a nuclear explosion.

The experiments were to begin Tuesday and run through Friday.That the tests are vital to national security - the defense community was stunned in the mid-1960s when a Pacific Ocean nuclear test blast caused a power outage in Honolulu 800 miles away - has never really been questioned.

Critics have questioned the wisdom of shooting 7 million volt bursts of electricity through environmentally sensitive areas.