How to dismantle a nuclear arsenal? An MIT team devised a new technique to verify the destruction of these weapons

2023-08-29 16:00:00

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How do weapons inspectors verify that a nuclear bomb has been dismantled? A rather disturbing answer is: for the most part they don’t. When countries sign nuclear arms reduction pacts, they often do not give international inspectors full access to their nuclear technology, for fear that their military secrets will be revealed.

So far, previous US-Russian nuclear arms reduction treaties have provided for the destruction of nuclear warhead delivery systems such as missiles and aircraft, but not the warheads themselves. For example, to meet the pSTART treaty (Strategic Arms Reduction Treaty)The United States severed the wings of its B-52 bombers and stored them in the Arizona desert, where Russia was able to visually confirm the dismemberment of the planes.

To comply with the START treaty, the United States amputated the wings of its B-52 bombers and stored them in the Arizona desert.

This is a logical but not perfect approach. Stored nuclear warheads cannot be delivered in a war, but they can still be stolen, sold, or accidentally detonated, with disastrous consequences. “There is a real need to avoid these types of dangerous scenarios and to make sure that these weapons stocks disappear,” he explains. AregDanagoulian, nuclear scientist Massachusetts Institute of Technology (WITH). This involves verification of the actual dismantling of the weapons themselves,” he adds.

So now the team led by Danagoulian has successfully tested a new high-tech method that could help inspectors verify the destruction of nuclear weapons. The method uses neutron beams to obtain reliable information about the warheads in question, and using an isotopic filter transforms this information into weightable data. The results of the experiment are detailed in the article titled “A physically cryptographic warhead verification system using neutron induced nuclear resonances”published in the magazine Nature Communications.

Photo: iStock

exposed bombs

The tests for the experiment were carried out at the facilities of the Gaerttner Linear Accelerator –LINAC– on campus Rensselaer Polytechnic Institute, using a 15 meter long section of the facility’s neutron beam.

Nuclear warheads have a couple of crucial features for the experiment. On one hand they tend to use iparticular atotopes of plutonior -varieties of the element that have different numbers of neutrons-; for another, nuclear warheads also have a characteristic spatial arrangement of the materials inside them.

The Hiroshima and Nagasaki bombings

Thus, the experiments consisted of sending a horizontal neutron beam first through the nuclear warhead, and then through a lithium filter to encode the information. The beam signal was sent to a glass detector, where it sThe data was recorded, revealing some of the key properties of the warhead materials.. The MIT tests were conducted with molybdenum and tungsten, two metals that share significant properties with plutonium and served as viable surrogates for the experiments.

“The test works, firstly, because the neutron beam can identify the isotope in question. In the low energy range, neutron interactions are extremely specific for each isotope.“, Danagoulian explains. “We made a measurement of an isotopic label, a signal that itself incorporates information about the isotopes and their geometry. But we went a step further by physically encrypting that information,” he adds.

Mutual Inspection Assured

The physical encryption of the neutron beam information alters some of the exact details, but still allows scientists to record a distinct signature of the object and then use it to make comparisons between various objects. Thanks to this encryption, a country can undergo the test without divulging all the details about how its weapons are designed.“This filter basically hides the intrinsic properties of the classified object itself,” explains Danagoulian.

Thanks to this encryption, a country can undergo the test without divulging all the details about how its weapons are designed.

It would also be possible to send the neutron beam through the warhead, record that information, and then encrypt it in a computer system. But the physical encryption process is more secure, notes Danagoulian: “In principle, you could do it with computers, but these are unreliable: they can be hacked, while the laws of physics are immutable.”

The MIT tests also included checks to make sure inspectors couldn’t reverse engineer the process. and thus deduce information about weapons that countries want to keep secret. To carry out an inspection, a host country would present a nuclear warhead to weapons inspectors, who could perform the neutron beam test.

The MIT tests also included checks to make sure inspectors couldn’t reverse engineer the process.

If approved, they could also run the test on any other warhead and make sure that the data signatures of those additional bombs match the signature of the original warhead. And while many additional protocols would have to be put in place for the entire disarmament process to be carried out reliably, This new method ensures both the reliability of the weapons destruction process and guarantees technological secrecy for the parties involved.

The human factor

In the future, Danagoulian would like to build a smaller version of the device that, at just 5 meters long, could be portable and usable in all weapons stores. The scientist also emphasizes the great importance of nuclear disarmament. “A small group of various modern nuclear warheads -points- equals the destructive force of all weaponry deployed in World War II, included the atomic bombs dropped on Hiroshima and Nagasaki. And the United States and Russia together possess about 13,000 nuclear weapons,” she adds.

A small group of several modern nuclear warheads is equivalent to the destructive force of all the weaponry deployed in World War II.

“The concept of nuclear war is so big that it does not fit in the human brain”Danagoulian continues. “It’s so scary, so horrible, that people ignore it.” In his case, the scientist also emphasizes in a personal way that, in his case, becoming a father greatly increased the feeling that effective action is necessary on this issue, which helped him move forward with his investigation project. “Being a father put me on alert. I said to myself: can I use my knowledge and my ability and my knowledge of physics to do something for society and for my children? And this is the human aspect of our work,” says the investigator.