Traces of xenon detected in S. Korea following N. Korea's nuke test

Yonhap News ^ | 2017/09/08

[Robert A Cook PE]

Remember. It does “only” take that amount of U233 U235 to create the critical mass for a fission nuclear bomb. But only a very tiny amount of the fissionable material actually reacts. The rest (around the central exploding mass) is simply blown away with the blast.

More importantly, the equation actually is: energy = difference in mass x c^2.

It’s the DIFFERENCE in the mass of the nuclei (the difference between original mass of U235 and the sum of the masses of all of the fission products and neutrons afterwards) that is multiplied by c^2

So the exploding mass DOES react according to Einstein’s energy. But most definitely you do not multiply the 20 pounds of original U235. Only a “few grams” of U235 react to create the blast equivalent of 10,000 tons of chemical explosives.

[null and void]

Yeah, as a human, I care little for the clicks of Roentgen radiation on the Geiger counter, I do care about the Effects on my Man's body!

[RayChuang88]

The trace of a radioactive xenon isotope means the North Koreans did test a thermonuclear bomb. Not surprising given that North Korea has been making lithium deuteride—a critical fuel for a thermonuclear bomb—for some years.

[TRY ONE]

” It does “only” take that amount of U233 U235 to create the critical mass for a fission nuclear bomb. But only a very tiny amount of the fissionable material actually reacts.”

.....Agreed!

[AdmSmith]

The trace of a radioactive xenon isotope means the North Koreans did test a thermonuclear bomb

No, you may read this http://www.nature.com/news/what-kind-of-bomb-did-north-korea-detonate-1.19132

[Moltke]

Traces of xenon gas, a radionuclide

Xenon generally is not a radionuclide (unlike radon) - though some radioactive isotopes can occur.

[AdmSmith]

Is there a way to directly convert a concentration (mBq per cubic meter) value to a rate (nanosieverts per hour)?

No:

https://www.physicsforums.com/threads/becquerel-versus-sievert.767202/

[huldah1776]

what difference is there between NK and Japan?

Radiation at Japan’s Fukushima Reactor Is Now at ‘Unimaginable’ Levels

http://insider.foxnews.com/2017/02/08/unimaginable-levels-radiation-fukushima-pacific-ocean-leaks

[Bob]

Thanks for the additional information. It’s more than a bit confusing for us laymen.

[farming pharmer]

Remember Einstein’s equation: E = MC2

Technically true if the reaction was 100% efficient. Real world: 1-2% of the mass is converted into energy in a fission nuclear weapon.

[Robert A Cook PE]

I don’t follow you there: Why would the very heavy Xe gaseous by-products of fission be only possible from a two-stage (hydrogen bomb) design?

(It’s actually 1H2 or 1H3 or 3Li fusion in the seed material around the core that is the initiating fission weapon that is the “fusion” part of the hydrogen bomb. Very little H1+H1 -> 2He2 fusion occurs.)

[FreedomNotSafety]

Does that mean if I run some electric to it we can make NK into neon sign?

[radmanptn]

Here are a couple of links you can pursue to find an answer to that.
https://www.nrc.gov/about-nrc/radiation/protects-you/hppos/qa426.html
https://academic.oup.com/rpd/article/156/1/7/1597786/External-dose-rate-conversion-factors-of
I should add a warning, if you’re not a Health Physics professional the information at the links may make you become cross-eyed. For that matter you may end up cross-eyed even if you are a Health Physics professional.

[Bob]

Thanks for the links — they’re looking a bit deeper than my interest level. :=)

My initial confusion came from the use of a concentration (mBeq / m^3) versus a rate (nSv / hr). To me, that was similar to asking how many miles per hour is it from SF to LA.

[Tallguy]

It was a “boosted” A-bomb, not an H-bomb.

[AdmSmith]

Radiation at Japan’s Fukushima Reactor Is Now at ‘Unimaginable’ Levels
The radiation levels at Japan's crippled Fukushima nuclear power plant are now at “unimaginable” levels.

Adam Housley, who reported from the area in 2011 following the catastrophic triple-meltdown, said this morning that new fuel leaks have been discovered.

He said the radiation levels - as high as 530 sieverts per hour - are now the highest they've been since 2011 when a tsunami hit the coastal reactor.

“To put this in very simple terms. Four sieverts can kill a handful of people,” he explained.
http://insider.foxnews.com/2017/02/08/unimaginable-levels-radiation-fukushima-pacific-ocean-leaks

That is unfortunately very sloppy journalism.
We can assume that almost all of the radiation is due to beta radiation measured very close to the source. Beta radiation can be shielded by a piece of paper, a few meter of air, or, in this case, a few mm of water.

[huldah1776]

wow. I love learning something new every day! Thanks!