Day 7 - Socorro NM and Trinity Site

Table of Contents

	Google Map Track Log
	YouTube Video
	Trinity Site NM
	Elevation Changes During the Day
	Comments
	Other Blogs About This Trip

Google Map Track Log

YouTube Video

Trinity Site NM

As someone who enjoys reading about WWII and especially the Manhattan Project to build the atomic bomb, this place is near the top of my bucket list!

Most people know the US dropped two bombs on Japan in August 1945 which ended the war. You may not know the two bombs used two different types of fissile material.

"Little Boy" used enriched uranium U-235. The bomb was basically an artillery barrel with two sub critical pieces of U-235. One was the "bullet" which when fired, hit the target piece of U-235. The two sub critical pieces became super critical when they joined and created an atomic explosion.

U-235 exists naturally with U-238. U-235 only makes up 0.72% of natural uranium so it had to be separated from the U-238. This turned out to be very hard to do and many methods were tried in parallel. By the summer of 1945 the project had only enough U-235 to make one bomb. At this point the scientists were confident the bomb would work so "Little Boy" was dropped on Japan on August 6, 1945 without a prior test.

U-235 and U-238 exist in nature and the technical problem was separating the U-235 from the U-238. The "Fat Man" bomb used plutonium as the fissile material. Trace amounts of plutonium have been found in nature but the plutonium used in the bomb was entirely man made. Uranium was irradiated in huge nuclear reactors built at the Hanford Site in the state of Washington to produce plutonium.

Pu-239 is needed for a bomb. However the process to create Pu-239 also creates Pu-240. Pu-240 is chemically identical to Pu-239 so they can not be separated. The amount of Pu-240 created can be controlled by how long the uranium is irradiated to produce plutonium.

The problem with Pu-240 is that it undergoes spontaneous fission at a rate 41,500 times greater than that of Pu-239. Firing two pieces of plutonium into each other like the "Little Boy" bomb would result in a fizzle. The two pieces would go critical long before they were close enough to produce an explosion.

The scientists thought implosion would work. A sphere of plutonium with a hollow core containing a neutron source would be surrounded by chemical explosive lenses. When fired, the explosion would compress the plutonium from all sides into a smaller mass, quick enough to create an fission explosion instead of a fizzle. The theory was sound but creating a chemical explosion that compressed the plutonium inward without it "squirting" through a hole was actually very difficult. I won't go into all the details but there was significant doubt the bomb would work.

So it had to be tested first. That happened on July 16, 1945 at the Trinity Site, NM. Just before the bomb exploded someone asked if the test might ignite the atmosphere and destroy the earth. A scientists pulled out a slide rule, did some calculations and stated that was "unlikely."

The "Fat Man" bomb was dropped on August 9, 1945. A softball size plutonium core surrounded by 5,300 pounds of chemical high explosives was compressed to the size of tennis ball which resulted in an explosion roughly equal to 21,000 tons of TNT. I have read that only about 20% of the plutonium actually exploded. So a mass of plutonium probably the size of a golf ball created the atomic explosion.

I have read that the plan was to create about 3 plutonium bombs per month and drop them on Japan until they surrendered. A third bomb was ready to ship out when Japan surrendered on August 15, 1945.

I can't say for sure but I don't think another purely uranium "Little Boy" bomb was ever created. Probably because it was so difficult to separate U-235 from U-238.

Elevation Changes During the Day