Thursday, July 09, 2015
Blast from the Past
The USS Independence survived World War II and two A-bomb blasts before it was scuttled near the Farallon Islands in 1951. In 1946, in the joint army/navy Operation Crossroads, the navy had assembled more than ninety vessels at Bikini Atoll in the Marshall Islands, ostensibly to test the effects of atomic weapons on ships. Another motive, perhaps the real one, was to scare the Soviets, who had been invited to observe. There was nothing novel about the bombs; they were the same kind that had destroyed Nagasaki less than a year earlier, the spherical, plutonium implosion type called called Fat Man. They were straight from the US nuclear arsenal—a very small arsenal, but the Soviets didn’t know that.
In Crossroads Able the army air force dropped the first Fat Man and missed its target by almost half a mile. On the second try, Crossroads Baker, the navy made sure they hit something by hanging their bomb from a landing craft in the middle of the flotilla. The result was the most poisonous fountain of water in history, accompanied by a radioactive fog that engulfed the surviving ships and a tsunami that washed over the surrounding islands. The third test had to be canceled, and no one has settled in the atoll since.
As for the propaganda effect on the Soviet scientists, it was nil, and, in fact, possibly a stimulant; the Soviets exploded their first A-bomb, closely based on the stolen Fat Man design, just three years later.
After Crossroads came to an end, the damaged, radioactive Independence was among ten ships towed back to San Francisco. Clean-up experiments failed, and it was scuttled four years later, thirty miles west of Half Moon Bay in what’s now the northern part of the Monterey Bay National Marine Sanctuary. The sunken ship was revisited this April by NOAA scientists headed by James Delgado, using the Boeing autonomous underwater vehicle Echo Ranger to image the ship with sonar—but not before UC Berkeley and Lawrence Berkeley Lab radiation expert Kai Vetter calculated the risks to equipment and personnel. In a release titled “Radiation Safety for Sunken-Ship Archaeology,” Berkeley Lab’s Kate Greene gives the details.
The rusty wreck, lying 2,600 feet underwater for the past sixty-four years, poses no significant risk of radiation poisoning. Even a significant risk of that kind is a small part of the much greater risk posed by countries who refuse to draw down their nuclear arsenals, or secure them sloppily, or are trying to build their own, or who lie about trying to build their own, or who lie about the hidden arsenals they already possess.
Have I left anybody out?