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How Scientists Actually Dismantle a Nuclear Bomb

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nuclear warhead

A Mark 28 thermo-nuclear bomb is unloaded from a U.S. Air Force Boeing B-52H Stratofortress aircraft. Credit: TSgt. Boyd Belcher, USAF)

(Inside Science) — There are enough nuclear weapons in the world to cause atomic Armageddon many times over, according to scientists, who estimate that no country could fire more than 100 nuclear warheads without wreaking such devastation that their own citizens back home would be killed.

Most nuclear nations recognized by the Treaty on the Non-Proliferation of Nuclear Weapons — namely, France, Russia, the United Kingdom and the United States — have set about reducing their arsenals. China is a notable exception. The exact number of the country’s warheads is unknown, but many analysts say its cache is slowly growing in size. North Korea, on the other hand, while notoriously difficult to predict, could eventually scale back its nuclear program if its diplomatic rapprochement with the West continues.

Negotiations on nuclear disarmament are politically tricky. But when agreements are reached, scientists and engineers can provide a variety of tools to take apart some of humanity’s most deadly weapons and store or repurpose the dangerous nuclear material. It’s a long and complex procedure, but experts say it’s one worth doing.

How to disassemble an armed “Swiss watch”

Nuclear disassembly is a coordinated process, which involves politicians, scientists and engineers working together.

It all begins with the blueprints that designers used to build the weapon in the first place, according to experts.

“It’s like any other kind of machine,” explained Robert Rosner, chair of the Bulletin of the Atomic Scientists Science and Security Board. “It’s a case of taking it apart piece by piece.”

To unpick a nuclear device, engineers need to know the exact sequence in which the pieces were originally put together.

“The design of atomic bombs is what I’d call an open secret. There aren’t that many ways of designing them and so if the Americans had to deal with the North Korean bombs, for example, it wouldn’t be much of a mystery to them,” said Rosner.

But the more sophisticated and destructive hydrogen bombs that the Americans, British, Chinese, French and Russians possess is a different story.

“There are many different designs and so the disassembly is very difficult. You have to be awfully careful,” said Rosner. “From a mechanical engineer’s perspective, they’re like a highly tuned Swiss watch. They’re mechanical artwork with amazingly clever designs.”

Other experts agree that unpacking the design is the most challenging part of the process.

“It’s less about the nuclear material and more about the engineering,” said Tom Plant, director of Proliferation and Nuclear Policy at the Royal United Services Institute for Defence and Security Studies, an independent think tank in the United Kingdom.

It would be significantly harder and therefore less likely that a team of engineers could disassemble a hydrogen bomb without knowing the exact design sequence, but still not technically impossible.

“It’s very unlikely that it would blow up if a mistake was made in the process of disassembly, unless it was designed to blow up in that eventuality, which is possible though not likely,” said Rosner.

Plant agrees the worst-case scenario is accidental detonation, but there are other possible perils if disassembly goes wrong. The people doing it could be electrocuted or exposed to the nuclear material or other toxic chemicals.

But a country, knowing its own design, should be able to disassemble its own modern nuclear weapons, and many have. As of 2014, the U.S. had dismantled 85 percent of its declared stockpile of nuclear weapons since 1967 when it had more than 31,000 war-ready nuclear warheads, according to the U.S. Department of State.

Before any nuclear dismantling can even take place, the right political atmosphere needs to exist, said Plant. He still isn’t optimistic that the current dialogue between Pyongyang and Washington has enough political will to see the Korean peninsular through to denuclearization. “The overwhelming likelihood is that everything falls apart as before.”

What do you do with the leftover uranium or plutonium?

Once the weapon has been taken apart, the process of dealing with what’s left is identical for both the older and the more sophisticated bombs.

“When the great powers decided to reduce their stockpiles, we were left with fairly substantial quantities of plutonium,” said Rosner. “So, what do you do?”

One obvious answer is to repurpose the radioactive material — either plutonium or uranium — to produce electricity. To make it suitable for a power plant, the material needs to be diluted with less enriched versions.

“There are no power reactors anywhere in the world that are designed to deal with weapons-grade material,” said Plant. “You have to down-blend it before you can turn it into fuel.”

But that isn’t what actually happens to most of the radioactive material.

“It’s not always economically viable. It can be cheaper to enrich new material than it is to downgrade it and repurpose it,” said Rosner. “Shipping plutonium or uranium all over the place from storage to reactor isn’t popular either.”

“Mostly it’s just stuck in storage facilities,” said Rosner.

Decommissioning the radioactive waste and keeping it safe is a science in its own right. The extracted uranium or plutonium will contain different isotopes — variants of themselves that have different atomic masses, which means their radioactivity decays at different rates.

The highly radioactive isotopes have short half-lives, which means they decay much faster than the less radioactive ones, and that creates a lot of heat.

“The material has to be put in water pools for about half a decade to cool the rods while they decay,” said Rosner. “Then you’re left with relatively low-level waste that’s less radioactive.”

The less radioactive isotopes are slower to decay, which presents its own problem.

“They have nuclei that are heavier, so they have very long half-lives of millions of years and you still have to do something with them. You can’t just leave them hanging around,” said Rosner.

The answer is to store the radioactive rods in specially designed containers, often called “dry casks.” These vessels are usually made from steel and welded shut to prevent leaking. Each of the casks is then encased in another steel shell and then in a thick layer of concrete to prevent radiation escaping.

“If you were standing outside of the container then you wouldn’t be able to detect radiation,” explained Rosner.

But even this containment option has its drawbacks — the cost of building, maintaining and monitoring these facilities will never go away so long as the rods inside are producing radiation. “That’s basically eternity for humans,” said Rosner.

Additionally, there’s national security to consider, said Plant. “Governments will be keeping it somewhere safe in case they want to reuse it or in case a terrorist tried to get hold of it.”

That’s why a third option has become more popular in recent years: partial disassembly.

After all, unless the bomb is detonated, the nuclear material inside is in a steady and contained state — partial disassembly keeps it there while removing the opportunity for the bomb to be used. “If you remover the trigger, then what’s left can’t be used as a bomb,” said Rosner.

But partial disassembly is reversible; the trigger can be put back in and the warhead can therefore be reactivated. “You couldn’t put it back in a matter of hours so they can’t be on standby. You’re talking about weeks to do it,” said Rosner.

If North Korea should ever agree to denuclearize, it has a few options to consider — none of them are perfect and all of them come with long-term strings attached, but when nuclear powers work together to control their arsenals, the world is a safer place, said Plant.

[This article originally appeared on InsideScience.org.]

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Ecology

What if a jolt of electricity could make you happy?

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Scientists found a way to literally spark joy using joly of electricity. (Credit: icon99/shutterstock)

Scientists found a way to literally spark joy using jolts of electricity. (Credit: icon99/shutterstock)

People all around the world (or at least where Netflix is available) have been exhausting themselves of late trying to “spark joy” in their lives. The urge comes from cleaning guru Marie Kondo, whose philosophy rests on the principle that we should rid our homes and minds of things that don’t inspire bursts of pleasure.

The message resonates, in part, because it ties positivity to the world of material things. Happiness is in our minds. So having a tangible mechanism for producing joy is understandably comforting.

But there’s a simpler way to spark joy, if we really want to get literal about it. Any emotion we feel has a physical cause inside our brains. Electrical charges pass from neuron to neuron, spreading ripples of thought and feeling. What we call happiness is just electricity. And now researchers say they’ve found a remarkably specific means of triggering the electrical fireworks that add up to happiness in our brains. By electrically stimulating a brain region known as the cingulum, scientists created spontaneous laughter and a sense of calm and joy in three different patients.

The find could lead to treatments for anxiety and depression, and it hints at insights into the very roots of our emotions themselves.

An artist's illustration shows how an electrode tapped into the cingulum. (Credit: From Bijanki et al, J. Clin. Invest. (2019). Courtesy of American Society for Clinical Investigation)

An artist’s illustration shows how an electrode tapped into the cingulum. (Courtesy of American Society for Clinical Investigation)

Unexpected Bliss

The young woman is clad in hospital garb, sitting upright in a bed. A white hospital cap mushrooms above her head, wires splay from its rear. She’s due for brain surgery in a few days to treat a difficult, disruptive kind of epilepsy. She’s been worried and anxious.

She breaks into a radiant smile, laughter flowing uninhibited.

“I’m kind of like smiling because I can’t help it,” she says. A bit later, “Sorry, that’s just a really good feeling. That’s awesome.”

Neuroscientists just administered a tiny jolt of electricity to wires threaded through her skull and into her brain. The wires are there to guide surgeons to the source of her seizures. But before the procedure, she’s agreed to play guinea pig to a team of Emory University researchers.

Patients like her offer an unprecedented opportunity for researchers to test the workings of various brain regions with unparalleled specificity. By delivering targeted bursts of electricity through the electrodes, they can watch what happens when specific neural circuits are activated.

The team was sending small bursts of electricity to her cingulum, a horseshoe of brain matter that links to regions associated with emotion, self-assessment, social interaction and motivation, among other things. It’s also known to regulate anxiety and depression.

This kind of research, though hardly common, is not new. The patient’s reaction is.

“It was really exciting,” says Kelly Bijanki, a neuroscientist at Emory University who studies behavioral neuromodulation. She was one of the scientists working with the young woman, whose name was not given for privacy reasons, that day. She says the kind of spontaneous joy she saw was unprecedented.

Experiments with brain stimulation have elicited laughter and smiles before. But those responses seemed mechanical. Bijanki says the patients usually described it as a purely motor response. “Their body has laughed, but there’s no content to it.”

This case was different. There was real warmth behind the laughter; true happiness in her voice. At one point, the patient reported she was “so happy she could cry,” the researchers write in their paper.

“The way she was laughing was really infectious,” Bijanki says. “The whole room felt different: she was laughing, she was having a good time, and not afraid. Just that social, emotional contagion took over.”

Further tests confirmed the response. They conducted sham trials, telling the patient that they were providing stimulation when they weren’t. She didn’t react. They tested various levels of stimulation and saw that the more electricity they delivered, the stronger the joyous reaction was. The pattern remained the same: An initial burst of exultation faded into a state of happy relaxation after several seconds.

The researchers found no drawbacks to the treatment, either, they report in a paper in the Journal of Clinical Investigation. Her language skills and memory remained perfectly intact, and they saw no ill aftereffects of the stimulation.

In a screengrab from the scientists' experiment, the patient feels overwhelming joy even while pondering her dog dying. (Credit:)

In a screengrab from the scientists’ experiment, the patient feels overwhelming joy even while pondering her dog dying. (Credit: Bijanki et al, Journal of Clinical Investigation)

Put to the Test

The woman’s impending surgery would require her to remain awake while surgeons probed inside her skull. Their goal was to cut out the tissue responsible for her epilepsy, but it’s a game of millimeters. Doctors must remove enough to ensure that seizures don’t recur, but without causing permanent harm. The patient’s seizures appeared to emanate from a region near to language processing centers. Her job was to stay awake while surgeons worked, reading and talking to ensure they wouldn’t excise anything important.

The brain stimulation turned out to work so well that doctors were able to cut out completely the drugs used to manage anxiety during this type of brain surgery. Those medications can make patients sleepy and unresponsive, so the anesthesiologist decided to stop them midway through. The young woman, her skull opened to surgical tools, breezed through.

“During the surgery … she was telling me jokes about her dad, where prior to turning on the stimulation she had been crying and hyperventilating and right on the edge of panic,” Bijanki says.

To confirm their findings, the researchers performed the same tests with two more epilepsy patients with electrodes similarly implanted in their skulls. They got the same results. Jabs of electricity literally sparking joy inside their heads.

Putting Happiness to Work

It’s too simplistic to say the researchers have stumbled upon the place where joy hides within us. The brain is complex, and emotions well up from more than just a single place. Multiple brain regions are involved, and each contributes a facet to the emotion that we come to know as happiness.

In fact, researchers have found joy in another place in the brain as well. Sameer Sheth, a neurosurgeon at the Baylor College of Medicine, says that he’s had patients report feelings of euphoria during the course of his own work with brain stimulation as well. He was working with the ventral striatum, a region separate from the cingulum, though the two are tightly connected.

Stimulation to the ventral striatum has also produced the same sort of laughter and mood elevation that Bijanki saw, Sheth says.

But just because emotions are neurologically complex doesn’t mean there’s no value to understanding their origins.

“The more we understand this circuitry, the more we can fine tune how to harness that capability within an individual and the better we’ll be able to treat patients with mood disorders,” Sheth says.

Bijanki sees a range of applications for brain stimulation aimed at specific targets, beginning with the kind of surgeries the young epileptic was undergoing. By precluding the use of sedatives, the find might give brain surgeons new options when performing the kind of procedures the young woman went through. Allowing patients to give more feedback could make brain surgeries more targeted. It might also expand the scope of neurosurgery.

“The definition of what is an inoperable tumor is in some circumstances related to what is the surgeon reasonably comfortable with removing that isn’t going to ruin the patients life,” Bijanki says. “If the surgeon could know that in real time, then the surgery could proceed a little bit differently.”

More broadly, it could also find use as a treatment for mental disorders like depression, anxiety and PTSD. Bijanki imagines electrodes powered by a pacemaker battery delivering continuous, low-grade stimulation to patients with depressive disorders.

In the future, we may not even need wires to spark such emotions. Scientists are developing means of activating brain regions with pulses of light, or with ultrasound. Flashes and vibrations could one day deliver ease to the afflicted.

There are drugs that accomplish similar things today, of course, but those often have side effects, and the treatment isn’t always as direct. Brain stimulation could offer a better path.

Banish the Sadness

Bijanki was also struck by an odd side-effect of the stimulation. Though patients had no trouble recalling sad memories during treatment, the recollections were wholly powerless to make them feel unhappy.

“I remember my dog dying, and I remember that it was a sad memory, but I don’t feel sad about it right now,” the young woman said, as reported by the researchers in their paper. Another patient concurred, unable to recollect a tragic memory without smiling. The effect is slightly jarring, but it could provide a shield of sorts to those overcoming trauma.

Those suffering from PTSD often go through what’s called exposure therapy, where they are asked to repeatedly sift through memories of a traumatic event. The goal is to drain those memories of their fearsome power over time, but it is difficult, frightening work.

Paired with temporary brain stimulation that elides sadness, Bijanki thinks PTSD patients might be far better equipped to tread through painful memories.

Finding Balance

Ultimately, however, the goal of therapies involving brain stimulation isn’t to wipe out negative emotions.

Anger, sadness and fear are not without their merits, and banishing them could have unintended consequences. Sadness sits at the other end of the spectrum from happiness, for example. Taking away any of our emotions would be removing an aspect of our humanity. What’s more, we have emotions for a reason.

“Our emotions exist for a very specific purpose, to help us understand our world, and they’ve evolved to help us have a cognitive shortcut for what’s good for us and what’s bad for us,” Bijanki says.

That’s not the goal here, of course, though discussions about the ethical use of such technologies in the future is certainly warranted. Bijanki says that we’d need to be careful about applying things like brain stimulation that could be abused.

But, she’s not very worried about electrodes and electric shocks becoming the next designer drug. It’s just too technically demanding, she says. And the potential benefits for those with depression and other conditions are great.

Sometimes the bad can outweigh the good. In those cases, sparking a little joy might be what we need.

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NASA Picks Science Experiments to Send to the Moon This Year

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Virgin Galactic’s SpaceShipTwo Just Made its Second Trip to Space

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SpaceShipTwo under rocket power

SpaceShipTwo is carried into the air on the back of a plane, but then takes off into space under its own power. (Credit: Virgin Galactic)

On Friday, Virgin Galactic’s SpaceShipTwo flew in space for the second time, taking off from Mojave, California after days of weather delay. SpaceShipTwo took off at 8:07 a.m. PST carrying two pilots, a crewmember, and a nearly full weight of science projects from NASA.

Unlike most spaceflights that fire rockets from the ground, SpaceShipTwo is carried on the belly of a plane named WhiteKnightTwo before being released to propel itself into the upper atmosphere. After being carried 45,000 feet into the air, SpaceShipTwo successfully fired its rocket engine and reached suborbital space at approximately 8:55 a.m. PST. It coasted there for only a few minutes before heading back toward the ground, where it landed much like any other plane, roughly an hour after takeoff. Like all of SpaceShipTwo’s planned flights, this one was suborbital, meaning it does not reach orbit, and attains weightlessness for only a few minutes during its trip.

SpaceShipTwo made its maiden space voyage in December 2018, and today was its fifth powered flight in total. Unlike other private spaceflight companies like SpaceX, Virgin Galactic has made their main goal ferrying private citizens into space, and have been taking reservations for years.

The third crewmember today was Virgin Galactic’s Chief Astronaut Instructor and cabin evaluation lead. Her job today was to see how SpaceShipTwo feels from the cabin. Eventually, Virgin Galactic hopes to seat six passengers in place of the science payloads – or alongside them.

The spacecraft today also carried research projects from NASA’s Flight Opportunities program, which pairs research institutions with private companies who can fly their projects into space. The combined weight of the payloads put SpaceShipTwo at close to, but just under, the requirements for the commercial launch weight that NASA has specified. One of Virgin Galactic’s goals during this flight was testing how the vehicle flies with a greater weight distribution. Details will likely come later, but the flight was successful, which bodes well for the craft’s future in ferrying cargo as well as passengers.

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