The Energy Department carried out an underground explosion in the Nevada desert yesterday that was designed to simulate a small nuclear test, the Energy Department’s National Nuclear Security Administration (NNSA) said Tuesday.
The blast, caused by 2,200 pounds of high-explosives, was detonated in a hole 150 feet below the Nevada National Security Site, where U.S. underground nuclear tests were carried out until the government-imposed moratorium on nuclear testing in 1992.
The test was the third seismic "source physics experiment," NNSA said in a statement. Four additional tests are planned.
"The experiment’s findings are intended to advance the U.S.’s ability to detect and discriminate low-yield nuclear explosions amid the clutter of conventional explosions and small earthquake signals," the statement said.
The test is part of research that "aims at improving arms control and nonproliferation treaty verification," the agency said.
The Obama administration, through Vice President Joe Biden, has sought Senate ratification of the Comprehensive Nuclear Test Ban Treaty, which was rejected by the Senate in 1999 as not in the U.S. national interest.
A procedural move by Democrats at the time spared the treaty from being completely voted down, allowing for possible ratification in the future.
The test ban treaty is said to be a part of the administration’s arms control-centered national security agenda. However, the presidential election and opposition from Republican senators to the test ban treaty have left plans for a new ratification effort in limbo.
U.S. officials said the government is working to improve its ability to detect small underground nuclear blasts after having difficulty determining whether North Korea’s underground nuclear tests were in fact caused by a nuclear chain reaction and not high-explosives.
Critics have said that the agency lacks intelligence-gathering capabilities to determine adequately whether a rogue state or terrorist group carries out a nuclear explosion, despite spending nearly $12 billion annually on nuclear weapons maintenance and security.
North Korea conducted underground nuclear tests in 2006 and 2009, and in each case U.S. intelligence agencies had trouble determining right away if the tests were nuclear blasts or caused by conventional explosives.
Both tests were carried out in a mountainous area of North Korea called Kilju.
It took several days for U.S. intelligence to determine that the 2006 test, using a device fueled by a plutonium pit, was a nuclear blast, after radioactive particles were gathered in the air from areas surrounding the communist state.
The bomb was estimated to have been a tenth of the size of the bomb dropped by the United States on the Japanese city of Hiroshima in 1945 that helped end World War II.
The 2009 test used highly enriched uranium for fuel and was estimated by U.S. intelligence to have been larger than the 2006 test, about 20 kilotons or about the size of the bombs used at Hiroshima and Nagasaki.
That test was gauged to have been a nuclear blast based on seismic readings from monitoring stations in neighboring countries.
U.S. officials have said North Korea could carry out a third underground nuclear test, based on the pattern used in 2006 and 2009 of preceding the tests with a long-range missile flight test.
North Korea carried out the flight test of a long-range Taepodong-2 missile in April that failed shortly after launch.
The nuclear security agency said the chemical explosive test in Nevada was monitored using several types of sensors, including a high-resolution accelerometer, infrasound, seismic, explosive performance, ground-based, light detection and ranging, ground-based hyperspectral imagery, and satellite data.
"These data will advance current, state-of-the-art strong ground motion and seismic wave propagation models and algorithms toward a predictive capability," the statement said.
"These seismic source physics experiments are significant achievements in the United States’ efforts to develop, validate, and improve on emerging technology that will be used to assure compliance with the Comprehensive Nuclear Test Ban Treaty," said Anne Harrington, NNSA deputy administrator for defense nuclear nonproliferation.
The tests are part of efforts to advance Obama’s nuclear nonproliferation agenda, she said.
The United States’ three nuclear laboratories took part in the experiment. They include Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Sandia National Laboratories. The Pentagon’s Defense Threat Reduction Agency also participated.
The unratified test ban treaty "is an integral part of the U.S.’s nuclear nonproliferation and arms control agenda that prohibits all nuclear explosive testing," the statement said.
"In the absence of nuclear explosive testing, the U.S. government employs a number of programs to verify a safe, secure and reliable nuclear stockpile."
Some data for the seismic experiments are used to "to better monitor and characterize foreign weapons programs to verify treaty compliance," the statement said.