NHK and Yonhap have both reported on what Japan and South Korea have found in the atmosphere after the DPRK’s Monday test: bagel.
According to NHK:
Japan’s 47 prefectures say no radioactive substances have been detected at any measuring points in a survey conducted one day after North Korea’s claimed nuclear test.
The prefectures took samples of dust and rain from the air on Tuesday as part of an emergency government monitoring program.
They say the survey shows no trace of radioactive substances peculiar to a nuclear explosion, and that air radiation levels are normal.
Other government checks, including an air survey of radioactive substances from a Self-Defense Forces’ training plane, have also shown no unusual data.
Says Yonhap:
No signs of unusual radiation levels have been detected in South Korea after North Korea said it successfully detonated a nuclear device, the government said Thursday.
The Ministry of Science and Technology said none of the government’s 38 manned and unmanned monitoring centers had picked up any spikes in natural radiation from Monday noon to Thursday morning. The usual levels of radiation in South Korea are 10-20 Micro-Roentgen (mR).
ross | October 12, 2006
would a dud plutonium bomb leave a noticeable nuclear signature in the air?
Does this absence of radiation confirm that this was a conventional weapon of great power?
Thanks
Al | October 12, 2006
Does no unusual radiation=conventional explosive?
Lakshmi Krishnan | October 13, 2006
If it is a well contained test, only isotopes of noble gases like argon and xenon are likely to surface through barometric gas transport along faults. But, then soil gas sampling in on-site inspection operations alone can detect them. And that not before 50 days after the test for a 1 kT yield. With no access to the site for such sampling, all efforts at radionuclide monitoring from the air amount to fishing expeditions. Simple radiation level measurements will tell nothing. They may serve to give the lay public the impression that something is being done. And possibly to let DPRK believe that their tricks whatever they might be will be found out.
Robot Economist | October 13, 2006
This may be a dumb question, but does U.S. national technical means include monitoring for terrestrial gamma rays? One would think that a short, but intense burst of gamma rays would be a good thumbprint for subsurface nuclear tests.
CKR | October 13, 2006
Did I say that proper stemming of a 2-km shaft would prevent venting, or what?
Amit Joshi | October 13, 2006
Musharraf says it was a plutonium bomb.
http://news.yahoo.com/s/nm/20061011/wl_nm/korea_north_pakistan_dc
lawnorder | October 14, 2006
Mushy sez the obvious.
My money is still on a fake, because a “well contained” test would indicate a skill they don’t have.
AZ_Squeegee | October 16, 2006
It appears that the US overflights did detect the residuals of a nuclear test…..they are being pretty closed mouth about it, though. The isotope data should tell them alot about the nature of the explosion and whether it really was a fizzle.
Andy | October 16, 2006
I don’t think the US would claim a nuke unless there was evidence. It’s unlikely there were any particulates collected because of the low yield and apparently adequate stemming, so I’m betting the analysis is based on Argon or Xenon isotopes as Lakshmi suggested. This is assuming it’s possible these gasses could escape into the atmosphere faster than the 50 days referenced here .
AZ_Squeegee | October 16, 2006
Negroponte’s office claims “that there was “debris” collected from the test…..that implies more than gas isotope ratio measurements to me. This (http://www.dni.gov/announcements/20061016_release.pdf) statement implies that some radioactive particles were sampled during the overflights. That leads to a lot of interesting questions. Since it does not appear to be in the U.S.’s best interest here to keep the analysis secret, I hope a report will be forthcoming.