High Radiation Remains in Tunnels Used for Nuclear Test

A series of tunnels where a nuclear test malfunctioned last month remain contaminated with dangerous levels of radiation and it may be weeks or months before tests can resume there, officials said.

The April 10 weapons effects test, code-named Mighty Oak, damaged $20 million in equipment and left high levels of radiation in a labyrinth of tunnels where scientists determine the survivability of space and military hardware.

Department of Energy officials said they will not know what went wrong with the test until they can reach the damaged equipment--and that could be months.

“We just don’t know what went wrong,” Tom Clark, manager of the Department of Energy’s Nevada Operations Office, said at a Wednesday news conference.

The damage to the instruments had been announced by the Energy Department earlier this month. And the agency announced Monday that two workers had received doses of radiation when they went into one of the tunnels Friday. Clark said the dosage received by the men poses no health hazard.

Clark said the mishap might cause some delays in the nation’s weapons effects testing, “but probably not in the near-term.”

Weapons effects shots are designed to test the survivability of U.S. space and military hardware. Such tests involve detonating a nuclear device in a huge pipe within a tunnel to determine how the hardware can withstand radioactivity from a nuclear blast.

Instruments and hardware are placed in alcoves and branches along the tunnel. Doors and plugs seal off sections of the pipe and tunnel immediately after detonation, stopping debris that follows the radiation caused by the blast.

Department of Energy officials first thought the doors might have malfunctioned, allowing some of the debris to damage the instruments.

“We now believe the doors worked reasonably proper,” Clark said. “We need to get back into the tunnel to determine just what went wrong.”

Clark said workers would mine down to the instrument chambers rather than work their way back into the tunnels because of continued high concentrations of radioactive gases.