Castle Bravo

On March 1, 1954 in the Marshall Islands, on the Bikini Atoll, the US fired the Castle Bravo thermonuclear weapon. Less than 2 years after the Ivy Mike Shot proved that a hydrogen bomb was possible, the Castle Bravo device was the first thermonuclear weapon small enough to be carried by an aircraft. (The Ivy Mike shot had depended on cryogenic equipment making the device weigh 80 tons or more.) This opened the door to the 2nd stage of the Cold War.

The Castle Bravo shot was the first detonation of a dry thermonuclear bomb. It was also a complete catastrophe.

Officially it was Operation Castle, Bravo Shot. (For whatever reason there was no Alpha Shot in Operation Castle.

Scientists working on the shot had used a lithium-6 isotope but also included a lot of lithium-7. They calculated that the lithium-7 would be inert, and that the resulting explosion would be in the 6-megaton range. They were completely wrong.

The explosive power of the Castle Bravo shot was 250 percent ABOVE expectations. In other words, instead of the 6 megaton explosion they expected, they got 15 megatons. The base – built to conduct nuclear testing in the Marshall Islands – was destroyed. The shot crew were trapped in their bunker by high radiation. Several islands – where no one was even supposed to know what was going on – had to be evacuated. The people on those islands suffered for a long time as the result of radiation exposure. A Japanese fishing crew was exposed and at least one death from radiation exposure occurred. This lead to an international call for an end to atmospheric testing.

Remember this when scientists tell you that they know exactly how bad (or how good) something is going to be based on their equations, but in the absence of observation. They often get it right, but not always. “In theory, there is no difference between theory and practice. In practice, there is.” (Yogi Berra)

It isn’t surprising that A Capella Science has a take on nuclear weapons. (That does mention Castle Bravo)

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One thought on “Castle Bravo

  1. Some stats on the Castle Bravo explosion (known as the Shrimp device)

    At 15 megatons TNT-equivalence, it was 1000 times more powerful than the bombs dropped on Hiroshima and Nagasaki.

    The device weighed in at 23,500 pounds.

    The mushroom cloud was 4.5 miles in diameter and reached a height of 135,000 ft 4 minutes after detonation.

    The crater left was 6510 ft in diameter and was 250 ft deep.

    Fallout spread over a range of 7000 square miles.

    Many people were overexposed to radiation, and at least one person died as a direct result of that exposure shortly after detonation.

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