Monday, April 3, 2017




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Declassified clips of blasts are put online because the original film is decomposing

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The team at the Lawrence Livermore National Laboratory (LLNL) has been working to track down and declassify the films for the last five years.

Doing so will allow them not only to preserve these important historical materials, but to reanalyse the data for more accurate figures.

But, many of these film canisters have sat unopened for decades.

‘You can smell vinegar when you open the cans, which is one of the by-products of the decomposition process of these films,’ said weapon physicist Greg Spriggs.

‘We know that these films are on the brink of decomposing to the point where they’ll become useless.

‘The data that we’re collecting now must be preserved in a digital form because no matter how well you treat the films, no matter how well you preserve or store them, they will decompose.

‘They’re made out of organic material, and organic material decomposes. So this is it.

‘We got to this project just in time to save the data.’

The team has so far located roughly 6,500 of the films from the atmospheric tests.

Of this batch, about 4,200 have been scanned to date, and 400-500 have been reanalyzed.

And, they’ve declassified 750 of the dramatic tapes.

Some of the footage has now been published on the LLNL's Youtube channel. 

In the post-nuclear-testing-era, these data are critical in ensuring the effectiveness and safety of today’s nuclear stockpile, the researcher explains.

Decades ago, analysts manually went through the footage using a tool called a kodagraph to enlarge the image on a single frame, shine it onto a grid, and measure the fireball and shockwave.

Now, with the help of modern technology and software experts, the team has developed tools to automate many of the processes, including determining the frame rate of each camera.

But, the new effort has revealed major discrepancies in the numbers, indicating that many of the original analyses are wrong.

‘When you go to validate your computer codes, you want to use the best data possible,’ Spriggs said.

‘We were finding that some of these answers were off by 20, maybe 30 percent.

‘That’s a big number for doing code validation. One of the payoffs of this project is that we’re now getting very consistent answers.

‘We’ve also discovered new things about these detonations that have never been seen before.

‘New correlations are now being used by the nuclear forensics community, for example.’

THE UNITED STATES' ATMOSPHERIC NUCLEAR TESTS

The United States conducted over 1,000 nuclear tests from 1945-1992.

Of the bunch, over 200 tests were atmospheric – meaning they are carried out in the atmosphere, being dropped from airplanes, detonated on barges or islands, or being buried at a shallow depth to create a surface-breaking crater.

The first atmospheric test took place on July 16, 1945 in New Mexico, on what was then the Alamogordo Bombing Range, according to a report from the US Department of Energy.

And, between June 1946 and November 1962, both atmospheric and underground tests were conducted in the Marshall Islands, Christmas Island, Johnston Atoll in the Pacific Ocean, and over the South Atlantic Ocean.

On March 1, 1954, scientists conducted a hydrogen bomb test at Bikini Atoll.

Code-named Castle Bravo, the size of the event expectations, leading to radioactive fallout.

This travelled to the nearby inhabited atolls of Rongelap and Utrik, and led to the evacuation of 253 people from the two islands for medical care.

While some returned to Utrik just a few months later, the inhabitants of Rongelap did not return until 1957, and they later chose to leave again.

The catastrophic test prompted many to call for the ban of atmospheric testing.

After 1962, all nuclear tests in the US were conducted underground, many of which took place at the Nevada Test Site.


The researchers are now able to determine frame rate in just five minutes – a process that would take eight hours to do manually for just a two-second film.

This has allowed them to get a more accurate measure of the fireball growth, and better determine the test’s yield.

The team estimates it will take another two years to complete the scanning, and even longer to go through and declassify all the data.

But, the effort could help to ensure we ‘never have to use a nuclear weapon ever again,’ according to Spriggs, as long as the stockpile continues to be a deterrent.

‘We need to be able to validate our codes and trust that the answers that are being calculated are correct,’ said Spriggs.

‘The legacy that I’d like to leave behind is a set of benchmark data that can be used by future weapon physicists to make sure that our codes are correct so that the US remains prepared.

‘It’s just unbelievable how much energy’s released. We hope that we would never have to use a nuclear weapon ever again.

‘I think that if and how much devastation they can wreak, then maybe people will be reluctant to use them.’



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