U.S. Reveals Equipment Loss in Nuclear Test

The government lost $32 million in equipment when a 1986 underground nuclear test accidentally vented radiation into adjoining tunnels, the Energy Department said Friday.

Another $2.5 million was spent in recovery and mining efforts to get into the tunnel area where the safety system apparently failed, said Thomas Clark, manager of the Energy Department’s Nevada operations office.

The April 10, 1986, Mighty Oak nuclear test was a weapons-effects blast conducted 1,300 feet below the surface of Rainier Mesa in the T-tunnel complex at the Nevada Test Site.

The DOE does not know what went wrong, and “it is highly likely we may never know what went wrong with the experiment,” Clark said.

There was no accidental release of radiation into the atmosphere from the test and later controlled releases of radiation from the tunnels were insignificant, the DOE said.

The first line of defense against the blast escaping from the tunnel--doors that slam shut within milliseconds of a blast--worked properly, he said, but 50 to 60 seconds after the detonation, heat and pressure had built up so high that the doors failed.

A second series of doors farther down the tunnel managed to block the explosion, Clark said, but the instruments in alcoves off the tunnel were destroyed.