nuclear-news

Nuclear explosions: Preserving images of terrifying, swift power, CBS News 3333 Mar 19, The force of nuclear weapons has to be seen to be believed. Now, thanks to a project headed by Gregg Spriggs at Lawrence Livermore National Laboratory in California, the public can see the destructive power of atomic blasts as never before.Starting in 1945 the United States conducted 210 above-ground nuclear tests, all of them documented on film, from as many angles as possible.

That ended in 1963 when, for the good of the planet, the U.S. and the Soviet Union agreed to stop testing in the atmosphere.

Unlike most of us, Spriggs understands the physics that produces these spectacular images – fireballs that can spread two miles across, and reach temperatures of 10 to 15 million degrees kelvin. At the outer edge of the fireball is a shockwave; what the fireball doesn’t vaporize, the shockwave crushes.

“When it starts off, it’s moving at Mach 100, a hundred times the speed of sound,” Spriggs said, showing correspondent David Martin footage of one test’s shockwave.

And then there is the mushroom-shaped cloud, which climbs into the sky, spewing radiation. “That’s directly tied to the nuclear fallout which is very, very sensitive to the cloud height,” he said.

Using a computer to measure the cloud from one blast, Spriggs discovered the original calculations made 50 years ago were off by a full mile. “Instead of 35,000 feet, it was something like 40,000 feet, and it was because of the way they measured it,” Spriggs said.

That made him wonder if calculations from all the other blasts were wrong as well. It was more than just academic curiosity; those calculations are used to predict the performance (what Spriggs called the yield) of today’s nuclear weapons. “If you measure the shockwave radius and you’re off by one percent, you will be off by five percent in the yield,” he said.

So, Spriggs set out to re-analyze and then release to the public the estimated 9,000 rolls of unclassified film that had been shot. He found most of them in the archives at Los Alamos National Laboratory in New Mexico, birthplace of the atom bomb. ………

What do you hope the public gets out of watching this?”

“I hope they appreciate just how horrific these weapons are,” Spriggs replied. “This is something that can kill millions of people in the blink of an eye.”

Spriggs is one of the few nuclear weapons designers old enough to have actually witnessed a nuclear explosion – a high-altitude nighttime blast over the Pacific……..https://www.cbsnews.com/news/nuclear-explosions-lawrence-livermore-national-laboratory-film-preservation/