Thursday, December 11, 2008

Developments in High Explosives

The first atomic bombs, of the Hiroshima and Nagasaki variety, worked by basically crashing one piece of highly enriched uranium into another piece in order to start a chain reaction. To do that, I read that US government scientists built specially shaped blocks of explosive. The explosives were cut into precise hexagon and pentagon shapes.

When detonated, the uranium went exactly where it was supposed to go, and ka-boom! But, it's much harder to do than it sounds because of the difficulty in shaping High Explosive charges precisely.

The explosives were machined into shapes like this: -->

I don't think the world needs easier ways to cast high explosives into precise shapes, but the scientists at Los Alamos just announced precisely that: an easy to use, low melting point high explosive that can easily cast into precise shapes.

ScienceDaily (Oct. 14, 2008) — Since the discovery of nitroglycerin in 1846, the nitrate ester group of compounds has been known for its explosive properties. A whole series of other nitrate esters have been subsequently put to use as explosives and fuels.

A research team led by David E. Chavez at Los Alamos National Laboratory (USA) has now developed a novel tetranitrate ester. The compound has a particularly interesting characteristic profile: it is solid at room temperature, is a highly powerful explosive, and can be melt-cast into the desired shape.

1 comment:

Anonymous said...


Just several minor corrections:

1) The Hiroshima bomb type was never tested. That utilized a methodology of firing a chunk of U-235 into another chunk of U-235, in what has been described as a modified artillery piece. That was enough to create a critical mass of U-235 which led to, as they say, some rather rapid neutron replication.

2) The Nagasaki bomb was the same type as the original atomic bomb which was tested at Alamogordo. The builders were less sure of the potential success of this style -- thus the test before using. This was the bomb which utilized a compression design and used plutonium (U-239, if I remember correctly). This is the bomb type which you are discussing...