Subscribe to our free daily newsletters
. Military Space News .

Subscribe to our free daily newsletters

Gas-signature models can help identify underground nuclear tests
by Staff Writers
Livermore CA (SPX) Mar 18, 2016

The diagram illustrates gas distribution as it leaks from the chimney of a nuclear test cavity for two different gases: Xenon-133 and Argon-37. Both of these gases have often been referred to as "smoking guns" for detecting clandestine underground explosions. These gases also percolate to the surface where they can be detected during an inspection and are occasionally released into the atmosphere where they can be detected by the International Monitoring System.

Through experiments and computer models of gas releases, Lawrence Livermore National Laboratory scientists have simulated signatures of gases from underground nuclear explosions (UNEs) that may be carried by winds far from the detonation.

The work will help international inspectors locate and identify a clandestine UNE site within a 1,000 square kilometer search area during an on-site inspection that could be carried out under the Comprehensive Nuclear Test Ban Treaty. Jordan recently hosted such a simulated inspection, the Integrated Field Exercise 2014 (IFE14), sponsored by the Comprehensive Test Ban Treaty Organization (CTBTO) and involving more than 40 countries, which tested some aspects of noble gas signature detection.

In addition, the technique can potentially help interpret noble gas (radioactive xenon isotopes) signals captured in the atmosphere following UNEs such as the North Korean test that occurred in January.

The research also led to the development of the LLNL Smart Sampler, which was originally designed as a research instrument to automatically capture gases reaching the surface in remote locations following release of gas tracers underground. During its IFE14 exercise, the CTBTO deployed three of these samplers, which were designed and built by Lab engineers Steven Hunter and David Ruddle at LLNL.

The work combines novel field experiments involving injection of gas tracers using four large compressors into an old nuclear explosion cavity and sophisticated numerical simulations that employ a new method for tracking different parent/daughter isotopes produced in the detonation cavity. The simulations use the results of the field experiment as a basis for probing the isotopic evolution and gas transport processes of a UNE.

The team, made up of scientists from LLNL and National Security Technologies (NSTec), partially reproduced the subsurface conditions following a UNE responsible for the migration of explosion gases to the surface where they can be detected locally at a test site. Such results can provide inspectors with a better idea of what to expect when they are in the inspection area searching for a suspected UNE.

With LLNL computer models using information from the tracer experiment, the team was able to track the evolution of gases in the explosion cavity, which may be detected downwind thousands of kilometers away. This actually occurred after the third North Korean UNE in 2013.

"The work is novel in part because of how we did it by injecting gases into an old UNE cavity and then using computer models informed by the experiment to extend our understanding of how xenon gas evolves following the UNE," said Charles Carrigan, LLNL geoscientist and lead author of a paper appearing in the March 16 edition of the journal Scientific Reports.

Using computer models developed by LLNL physicist Yunwei Sun, the team showed that including thermally driven migration of telltale gases from the explosion cavity or chimney may substantially shorten their arrival times at the surface when compared to migration of gases caused only by atmospheric pressure fluctuations or barometric pumping. Previous research has focused on barometric pumping as the primary subsurface gas migration mechanism.

"From monitoring gases coming to the surface during the course of our pressurized field experiment, we also found that background radon gas levels were anomalously high (10 to 15 times normal) at the surface over the explosion cavity," Carrigan said.

The research indicates that the weak subsurface pressurization mimicking the thermal drive following the explosion enhanced the amount of radon that was captured. This suggests that radon anomalies could be potential indicators of hidden or clandestine UNEs that are otherwise difficult to detect during an on-site inspection.

Additionally, the simulations showed that the explosion cavity or chimney behaves something like a leaky chemical reactor or pressure cooker. The gases migrating away from the cooker change the overall chemical makeup (isotopic ratios) of the gases left behind in the cooker or reactor, which continues to make new gases. The team modeled the evolution of these gases out to several months following a UNE.

"The 2013 UNE carried out in North Korea has allowed us some validation of our model of explosion-gas evolution," Carrigan said. "We find that the gases detected almost two months afterward in Russia are best matched by our evolutionary model for the mixture of different xenon isotopes when we assume a range of yields that is consistent with seismic estimates, less than 10 kilotons, for that event. This is a cool result as no one has suggested that isotopic ratios should depend on nuclear yield."

The research also may have applications in monitoring other heated or pressurized subsurface regimes such as in situ coal gasification, deep sequestration of supercritical CO2 and nuclear waste disposal.

Other Livermore team members include Jeffrey Wagoner and Katherine Myers along with Dudley Emer, Sigmund Drellack and Veraun Chipman from National Security Technologies.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only


Related Links
Lawrence Livermore National Laboratory
Learn about nuclear weapons doctrine and defense at
Learn about missile defense at
All about missiles at
Learn about the Superpowers of the 21st Century at

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Previous Report
North Korean leader orders further nuclear tests
Seoul (AFP) March 11, 2016
North Korean leader Kim Jong-Un has ordered further nuclear tests, state media said Friday, as military tensions surge on the Korean peninsula with South Korean and US forces engaged in large-scale joint exercises condemned by Pyongyang. Since the joint drills began Monday, the North has issued daily warnings and statements, talking up its nuclear strike capabilities and threatening to turn ... read more

S. Korea, US open missile shield talks

Israeli Air Force deploying 'David's Sling' missile defense system

US Missile Defense Outdated

China Interfering in THAAD Deployment Decision Process Preposterous

Raytheon to offer new tactical missile design to U.S. Army

Missile tests don't violate nuclear deal: Iran FM

Russia opposes UN sanctions on Iran over missile tests

US asks UN Security Council to meet on Iran missile tests Monday

Drones promise to improve ecological monitoring

Pentagon, Other Federal Agencies Use Drones for Domestic Surveillance

Researchers develop miniaturized fuel cell that makes drones fly more than 1 hour

Inside the Pentagon's Drone Proving Ground

In-orbit delivery of Laos' 1st satellite launched

Upgrade set for Britain's tactical communications system

Airbus continues operating German military satellites

BAE Systems supports Navy communications and electronics

Northrop to develop new IMU guidance system for weapons

DynCorp wins U.S. intelligence support contract

Ford offers police greater ballistic protection for vehicles

Factory for Ajax armored vehicles inaugurated

Lockheed Martin plans voluntary layoffs for 1,000

Defense Industry center opens in South Australia

China defence spending to rise '7 to 8%' in 2016: official

EU lawmakers urge Saudi arms embargo

Hong Kong tycoon Li dismisses independence, calls for unity

Japan submarine to visit Philippines, other ships to Vietnam

Tiananmen dissident warns of Trump danger

Vietnam anti-China activists mark Spratly island battle

NIST invents fleet and fast test for nanomanufacturing quality control

Atomic vibrations in nanomaterials

Building a better mouse trap, from the atoms up

From backyard pool chemical to nanomaterial

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement