Underwater Nuclear Bomb Tests?

[ralph124c]

I understand that the USA detonated several atoic bombs underwater, in the 1950’s. My question: what sort of contamination would such a blast produce? And would most of the radioactive stuff just sink to the bottom? Has anyone gone to see what the bottom looked like, after these tests?

[Ottoerotic]

I have no idea, but I’d love to chime in to say that I’ve often wondered the exact same thing. I can imagine that you would have some incredibly shocked and confused whales before they were incinerated.

Although not quite as shocked as they would be if they suddenly appeared several miles above the earth and plummeted to their doom, but you get my drift

[anson2995]

There were only a handful… maybe three… but the military’s reports from those tests have been declassified and can be read online . The relevant tests were
Operation Crossroads (1946) Operation Castle (1954), and Operation Wigwam (1955) . (WARNING PDFs) Castle was a surface blast, Crossroads was a shallow underwater test, and Wigwan was a deep underwater test. I’m not a physicist, but my layman’s reading of the first two reports suggest they found almost no water contamination. Here’s an excerpt from the report on Wigwam:

In 1954, Shot BRAVO of Operation CASTLE, a surface shot, showed the extent to which a nuclear detonation on or slightly above a land or water surface could contaminate the environment. Another data point, Shot BAKER of Operation CROSSROADS, a shallow underwater shot, showed the contamination caused when a large amount of bottom material interacted with the explosion. In both of these, much of the contamination resulted from interaction with soil or sea bottom. Because the ranges of prompt neutrons and gamma rays are of the order of a meter or less in water, the prompt neutrons and gamma rays did not directly act as a radiological exposure source to personnel during WIGWAM. Indirectly, however, prompt neutrons acted as a potential cause of radiation exposure by activating ambient materials in the water (e.g., sodium and chlorine).

The full report for Wigwam is 266 pages, so there’s a lot more detail if you’re interested.

I don’t think there has been any followup testing of what it’s like under the surface other than what’s detailed in the report, and that was several weeks after the test.

[Harmonious_Discord]

I didn’t know where to point you for the underwater tests.

The Bikini Atoll tests have lots of documentation. They certainly dealt with exposing ships, and person to radiation. I found a link I really liked on a naval art page. It has paintings done by artists that were present for the tests. Many have explanations under them, and I think they help get a feel for what it was like to be there. One picture I found to capture the moment uniquely was the drawing titled

How We Looked to the Atom Bomb

On the third page you find a number of pictures about the burning naval vessels.

You may also wish to look into Trinity Test and Manhattan Project.

[Fear_Itself]

Details on Operation Wigwam:

Operation WIGWAM consisted of only one nuclear detonation, a deep underwater test conducted in the Pacific Ocean approximately 500 miles southwest of San Diego, California. The device was suspended by cable from an unmanned barge and detonated at a depth of 2,000 feet in water 16,000 feet deep. The test, which had a yield of 30 kilotons, occurred on 14 May 1955 at 1300 hours Pacific Daylight Time (16: 9).

The test site was chosen after careful deliberation. AT DOD request, Scripps Institution of Oceanography surveyed various locations in the Pacific, the Caribbean, and the Atlantic. The site had to be deep enough to contain the detonation, yet away from undersea or sea bottom perturbations, such as sea mounts, ridges, and islands. Migratory fishing areas were to be avoided. In addition, the site was to have fairly well-known currents and thermal gradients, a predominance of good weather, and isolation from shipping lanes. The area selected was judged the best to fulfill the requirements.

Video of complete government motion picture about Operation Wigwam (and Operation Argus).

[mhendo]

If you want to see some amazing color footage from Operation Crossroads, and from other nuclear tests of the WWII and post-war era, i highly recommend Trinity and Beyond: The Atomic Bomb Movie. It’s an excellent documentary, with narration by the inimitable William Shatner.