Lying next to the entrance of the chain link fence that still surrounds
Trinity Site are the rusty remains of Jumbo. Jumbo was the code name for
the 214-ton Thermos shaped steel and concrete container designed to hold
the precious plutonium core of the Trinity device in case of a nuclear
mis-fire. Built by the Babcock and Wilcox Company of Barberton, Ohio,
Jumbo was 28 feet long, 12 feet, 8 inches in diameter, and with steel
walls up to 16 inches thick.
The idea of using some kind of container for the Trinity device was
based on the fact that plutonium was extremely expensive and very
difficult to produce. So, much thought went into a way of containing
the 15 lb. plutonium core of the bomb, in case the 5,300 lbs. of
conventional high explosives surrounding the core exploded without
setting off a nuclear blast, and in the process scattering the costly
plutonium (about 250 million dollars worth) across the dessert. After
extensive research and testing of other potential containment ideas, the
concept of Jumbo was decided on in the late summer of 1944.
However, by the spring of 1945, after Jumbo had already been built and
transported (with great difficulty) to the Trinity Site by the Eichleay
Corporation of Pittsburgh, it was decided not to explode the Trinity
device inside of Jumbo after all. There were several reasons for this
new decision: first, plutonium had become more readily (relatively)
available; second, the Project scientists decided that the Trinity
device would probably work as planned; and last, the scientists realized
that if Jumbo were used it would adversely affect the test results, and
add 214 tons of highly radioactive material to the atmosphere.
Not knowing what else to do with the massive 12 million dollar Jumbo, it
was decided to suspend it from a steel tower 800 yards from Ground
Zero to see how it would withstand the Trinity test. Jumbo survived the
approximately 20 kiloton Trinity blast undamaged, but its supporting
70-foot tall steel tower was flattened.
Two years later, in an attempt to destroy the unused Jumbo before it
and its 12 million dollar cost came to the attention of a congressional
investigating committee, Manhattan Project Director General Groves
ordered two junior officers from the Special Weapons Division at Sandia
Army Base in Albuquerque to test Jumbo. The Army officers placed eight
500-pound conventional bombs in the bottom of Jumbo. Since the bombs
were on the bottom of Jumbo, and not the center (the correct position),
the resultant explosion blew both ends off Jumbo. Unable to totally
destroy Jumbo, the Army then buried it in the desert near Trinity Site.
It was not until the early 1970s that the impressive remains of Jumbo,
still weighing over 180 tons, were moved to their present location.