Tag Archives: nuclear

3D-printed components are now in use at US nuclear plant

At the US Department of Energy’s (DOE) Manufacturing Demonstration Facility at Oak Ridge National Laboratory (ORNL), two unusual components were assembled — and by assembled, I mean 3D-printed. The two channel fasteners are now in use at the Tennessee Valley Authority’s Browns Ferry Nuclear Plant Unit 2 in Athens, Alabama.

ORNL used novel additive manufacturing techniques to 3D print channel fasteners for Framatome’s boiling water reactor fuel assembly. Four components, like the one shown here, were installed at the TVA Browns Ferry nuclear plant. Credit: Framatome

Not too long ago, 3D-printing was an innovative but still new technology that promised to change the world — at some point in the future. Well, that point in the future has come. Not only is the technology mature enough to be used, but it’s mature enough to be used in a crucial system where failure is simply not acceptable.

“Deploying 3D-printed components in a reactor application is a great milestone,” said ORNL’s Ben Betzler in a recent press release. “It shows that it is possible to deliver qualified components in a highly regulated environment. This program bridges basic and applied science and technology to deliver tangible solutions that show how advanced manufacturing can transform reactor technology and components.”

“ORNL offers everything under one roof: state-of-the-art printing capabilities, world-class expertise in machining, next-generation digital manufacturing technologies, plus comprehensive characterization and testing equipment,” said Ryan Dehoff, ORNL section head for Secure and Digital Manufacturing.

The components are a good fit for the task. The channel fasteners have a relatively simple geometry, which works excellently with an additive manufacturing application (which is what “3D printing” commonly refers to). Fuel channel fasteners have been used for many years in boiling water nuclear reactors. They attach the external fuel channel to the fuel assembly, ensuring that the coolant is restrained around each fuel assembly.

[Also Read: The first ever 3D-printed steel bridge opens in Amsterdam]

Growing up

3D printing has matured dramatically in recent years, and the fact that the nuclear industry is increasingly looking towards it speaks volumes about that.

The components were developed in collaboration with the Tennessee Valley Authority, French nuclear reactor Framatome, and the DOE Office of Nuclear Energy. This was funded by the Transformational Challenge Reactor, or TCR, program based at ORNL.

Currently, the TCR aims to further mature and implement innovative technologies (and algorithms such as artificial intelligence) to its components and projects.

“Collaborating with TVA and ORNL allows us to deploy innovative technologies and explore emerging 3D printing markets that will benefit the nuclear energy industry,” said John Strumpell, manager of North America Fuel R&D at Framatome. “This project provides the foundation for designing and manufacturing a variety of 3D-printed parts that will contribute to creating a clean energy future.”

The change has been made for a couple of months now, and operations at the Browns Ferry plant resumed on April 22, 2021. The components appear to operate as intended, and they will remain in the reactor for six years with regular inspections during this period.

This is just one example of the projects that involve 3D printing for nuclear reactors. ORNL are looking at ways to extend the viability and operations of nuclear plants, while also deploying new components that would make plants more efficient and robust.

3D printing is reshaping what’s possible with nuclear energy, and could very well have an important part to play in our transition towards a sustainable, low-carbon future. At the very least, it’s bound to make nuclear energy cheaper and more competitive with fossil fuels.

“There is a tremendous opportunity for savings,” said John Strumpell, manager of U.S. fuel research and development at Framatome, in a previous press release earlier this year. Indeed, 3D printing seems ready to enter the market.

A startup proposes using autonomous microreactors fueled by nuclear waste to produce energy

Nuclear reactors are definitely powerful, but they also produce quite a lot of problematic, radioactive waste. A new Silicon Valley startup plans to change that through the introduction of small-scale reactors that run on waste from their conventional peers.

Rendering of the Aurora powerhouse, a concept developed by Oklo to test their reactor design currently ongoing in Idaho. Image credits Gensler / Wikimedia.

The startup Oklo plans to give us a reliable and cost-effective source of power while also solving the issue of radioactive waste, which needs to be stored and managed in particular conditions for hundreds of thousands of years. Their solution is to reuse the waste in autonomous reactors that don’t try to slow down the nuclear decay of the material. Effectively, such a reactor would be able to extract more power from fuel that has already been spent, giving us a use for the processes that happen naturally in a radioactive fuel dump, instead of letting them waste away as radioactive pollution.

No wasting power

“What we’ve done is take waste that you have to think about managing for 100,000 or a million years … and now changed it into a form where you think about it for a few hundred, maybe thousands of years,” Oklo’s co-founder Jacob DeWitte told CNBC.

If you’ve read our piece about nuclear reactors, you’ll know that their main purpose is to draw out the physical processes taking place within them as much as possible. This prevents the fuel from turning into a bomb — very nice — but also limits how much power can be extracted from it — not so nice.

Oklo’s plan is to use small-scale reactors that don’t use water or any other medium around the reaction chamber, mediums which work to slow down the neutrons released from the fuel. This would make them overall more efficient and allow the reactors to extract energy even from spent fuel rods. This approach wouldn’t work in a traditional reactor, however, because fresh fuel is too energetic, and would explode.

In order to keep everything cost-effective, the startup envisions their design to be autonomous, require no human supervision, and be quite small-scale. They would not provide nearly as much energy as a traditional reactor, but would still be enough to power an industrial site, a campus, or a whole company.

Their project started in 2013, with the company spending the last seven years trying to get access to nuclear waste to demonstrate their technology. Oklo was established in 2013 and spent the next seven years getting access to nuclear waste to demonstrate its technology. In 2019, the startup unveiled its plans for its microreactor with integrated solar panels, churning out 1.5 megawatts (MW) of power. Each one, it says, can be built in a year’s time.

The reactors run on spent fuel that’s meant for disposal, and each batch of radioactive waste can power the small-scale reactor for 20 years, according to the startup. In the end, the material they output is still radioactive, but to a much lesser extent than what goes in. This double-spent material will then be vitrified (turned to glass) and buried underground, just like typical nuclear waste.

Oklo is still awaiting a license to build its first microreactor, but the idea of an unsupervised nuclear device is definitely not something regulators will be keen on, no matter how cost-efficient it might be. Exactly where this story will go is still quite undecided, but it is exciting that we have this technology on hand.

Even if the microreactors don’t end up the way Oklo envisaged them initially, they could provide a great way for us to handle nuclear waste going forward. We could significantly slash the radiation our waste produces and the time it remains active after churning it through such a microreactor, and we’d get some energy out of it to boot.

Even a localized nuclear war can alter the world’s climate

A nuclear exchange could lead to global climate instability for several years, a new paper reports. Surprisingly, however, the effects depend in no small measure on where bombs fall and what happens after detonation — not on the weapons themselves. Their severity could range from minimal to significant cooling of the climate.

Atmospheric black carbon (soot) levels one month (left), six months (middle), and 12 months after the nuclear exchange. Image credits Lawrence Livermore National Laboratory.

We don’t talk about nuclear weapons too much today. It’s pretty interesting when you consider that our weapons have only become stronger and faster since the Cold War, and back then, the threat of nukes was always looming. In order to understand what their use would mean for the planet, a research team from the Lawrence Livermore National Laboratory (LLNL) looked at the climate consequences of a regional nuclear weapon exchange. The scenario involved 100 15-kiloton nuclear weapons being launched between India and Pakistan.

The scenario was run through two high-fidelity models taking a wide range of factors into account, the team explains.

Bombing the climate

“One of the new aspects of our work is that we examined the dependence of the climate effects on different amounts of fuel available at the location of the detonation and subsequent fire,” said LLNL mechanical engineer Katie Lundquist, the leader of the study and a co-author of the team’s paper.

The team focused their analysis on the fires such weapons would ignite, They considered factors such as available fuel at the site of the fires and the characteristics of the plume such as smoke composition and aerosol properties. All these allowed the team to simulate the effect such fires would have on global climate through their emission products. If the fires started by these bombs are large enough, they can block incoming sunlight and thus influence global climate.

All in all, if smoke and soot from these fires remain in the lower troposphere they will be quickly degraded and have a negligible effect. If they can reach all the way to the upper troposphere or higher (due to the rising heat of particularly strong fires) they will push through to the stratosphere. Here, smoke can deflect much more of the incoming light, enough to cool the surface down.

“Our simulations show that the smoke from 100 simultaneous firestorms would block sunlight for about four years, instead of the eight to 15 years predicted in other models,” the Livermore researchers wrote.

In the example given above, they write, global surface temperatures would likely drop by 1 to 1.5 degrees Celsius.

However, if the weapons only start fires in suburban areas, there would be little to no climate effect. Fires in dense urban areas are the most problematic, they explain, as they contain a lot of varied types of fuel in a small area (high fuel density). All this material can produce enough heat and particles to influence the climate. Such fires could produce a cooling effect three times that of the 1991 eruption of the Mount Pinatubo volcano in the Philippines.

The study comes to show just how important local factors are in determining the climate impact of such an exchange. It also helps showcase the full extent a local nuclear war could have.

The paper “Examining the climate effects of a regional nuclear weapons exchange using a multiscale atmospheric modeling approach” has been published in the Journal of Geophysical Research: Atmospheres.

North Korea’s 2017 nuclear test dwarfs that of Hiroshima

North Korean leader Kim Jong Un watches a missile test in a photo provided on July 26, 2019 (Korean Central News Agency/Korea News Service via AP)

On September 3, 2017, North Korea did what was always said to be jokingly impossible. They found a way to move mountains. Literally.

That day, the country conducted a nuclear test so powerful that it lifted an entire mountain off the ground. Almost 17 times more powerful than the bomb dropped on Hiroshima by the United States — known as “Little Boy” — in 1945, North Korea’s blast released energy equivalent to 245 and 271 kilotons of TNT. Little Boy had a yield of 15 kilotonnes.

According to research recently published in the Geophysical Journal International — a publication of the Royal Astronomical Society — the explosion was calculated by using satellite data to augment measurements of tests on the ground.  

Using data from the Japanese ALOS-2 satellite and a technique called Synthetic Aperture Radar Interferometry (InSAR), scientists led by Dr K. M. Sreejith of the Space Applications Centre of the Indian Space Research Organisation (ISRO), measured the changes on the surface above the test chamber. The 2017 explosion was sited at Mount Mantap in the northeast of North Korea. InSAR uses multiple radar images to create maps of deformation over time, allowing direct study of the sub-surface processes from space. This is the first time satellite data has been used to measure the strength of bomb tests.

Simulation of The Advanced Land Observing Satellite-2 (Japan Aerospace Exploration Agency)

The new data suggests that the explosion was powerful enough to shift the surface of the mountain above the detonation point by a few meters, and the flank of the peak moved by up to half a meter. Analyzing the InSAR readings in detail reveals that the explosion took place about 540 meters below the summit, about 2.5 kilometers (1.55 miles) north of the entrance of the tunnel used to access the test chamber.

“Satellite based radars are very powerful tools to gauge changes in earth surface, and allow us to estimate the location and yield of underground nuclear tests,” said K. M. Sreejith of the Space Applications Centre, lead author of the study, in a statement. “In conventional seismology by contrast, the estimations are indirect and depend on the availability of seismic monitoring stations.”

North Korea kick-started its nuclear program after it withdrew from the Treaty on the Non-Proliferation of Nuclear Weapons in 2003. Three years later, they conducted their first series of tests, eventually culminating in the 2017 test which experts suspect was a hydrogen bomb.

In 2017, Newsweek determined the number of casualties of 15-kiloton and 150-kiloton bombs were they to hit Newsweek’s New York office — 174,640 deaths and 477,470 deaths, respectively.

Were a 271-kiloton bomb to hit New York City and land in lower Manhattan, it would cause close to a million deaths.

Fukushima Daiichi.

Devastated Fukushima nuclear plant will run out of storage space for radioactive water in three years

The utility company that operates the tsunami-crippled Fukushima’s nuclear power plant will run out of space to store its contaminated water in three years.

Fukushima Daiichi.

Two IAEA experts examine recovery work on top of Unit 4 of TEPCO’s Fukushima Daiichi Nuclear Power Station on 17 April 2013 as part of a mission to review Japan’s plans to decommission the facility.
Image credits Greg Webb / IAEA via Flickr / IAEA Imagebank.

Fukushima Daiichi suffered extensive meltdowns (in three of its reactors) due to a massive 2011 earthquake and tsunami that devastated northeastern Japan. In a bid to contain the radioactive fallout, TEPCO (Tokyo Electric Power Company Holdings Inc.) has installed some 1,000 tanks to hold the treated — but still radioactive — water used to keep the reactors cool.

The tanks hold over 1 million tons of the dirty water. While experts recommend that it is released into the sea in a controlled manner, locals vehemently oppose the plan. However, there is growing pressure to resolve the issue: TEPCO reports it will run out of storage room for this water in three years, according to The Japan Times.

Running out of tanks

Immediately after the tsunami, the Fukushima Daiichi nuclear plant’s reactors were leaking water with radioactive isotopes into the ocean. In an effort to contain these atoms, 960 tanks were built at the site to siphon the runoff. These tanks can hold roughly 1.15 million tons of water. TEPCO expects to secure enough extra tanks to hold 1.37 million tons in total by the end of 2020.

But, with an average 170 tons of contaminated water produced each day during fiscal 2018, those tanks are going to fill up fast. TEPCO aims to reduce the volume to 150 per day next year — but even that should only be enough for the next three years or so. Even at that reduced level, the tanks would reach full capacity in either the summer or fall of 2022, the company estimates.

TEPCO installed equipment to decontaminate the water, but it still contains tritium, a radioactive hydrogen isotope that also occurs in minute amounts in nature. A panel commissioned by the Ministry of Economy, Trade and Industry considered diluting and releasing the water into the ocean.

“Releasing tritium-tainted water into the sea in a controlled manner is common practice at nuclear power plants around the world, and it was generally considered the most viable option as it could be done quickly and would cost the least,” writes Kazuaki Nagata for The Japan Times.

“But people in Fukushima, especially fishermen, fear it will damage the region’s reputation.”

However, with the 2020 Summer Olympics in Tokyo fast approaching, the government doesn’t want to rock the boat too much and is delaying a decision. Prime Minister Shinzo Abe told the International Olympic Committee in his final pitch to secure the Games six years ago that the situation at Fukushima was “under control,” according to Reuters,

Clean-up plans are due for completion in 2021. The tanks pose flooding and radiation risks that will hamper efforts, however.


What are the different types of energy

Energy — we need it to stay alive. But what exactly is it, and what ‘flavors’ does it come in? Let’s find out.


Chemical energy turned into electric energy turned into kinetic energy turned into thermal energy and electromagnetic energy in a single photo. Fitting.
Image via Pixabay.

Just as there are many different ways to do work, there are also many types of energy. As a general guideline, we split it up into two major types and several subtypes. Physicists measure energy in joules, although a more familiar unit of measure might be the calorie. With that crash introduction, let’s take a look at:

Potential and Kinetic energy

The two slices of the energy pie (in how we interpret it, at least) are kinetic and potential energy. Every type of energy we’ll be discussing today is a particular form of either of these two. Kinetic energy is energy actively performing work right now (such as moving an object or heating it up) while potential energy is what is currently ‘in storage’, which can be released if the right circumstances are met.

Energy cannot be created or destroyed, but it can be transformed. If you, for example, lift an apple over your head, you’re transforming kinetic (motion) energy into potential energy (the apple wants to go down and will do so if you let it go). As it falls, all the potential energy you’ve stored inside the fruit is turned back into kinetic energy. Alternatively, a battery holds chemical (potential) energy. It can be turned into electrical energy, then into light and heat in your smartphone (both types of kinetic energy).

So let’s start by looking at one of the most fascinating, in my eyes, types of energy:

Thermal energy


Infrared photograph of a group of people.
Image credits Nevit Dilmen / Wikimedia.

As a rule of thumb, all energy bends the knee to the principle of energy transformation except thermal energy. Please note at this time that what we perceive as heat isn’t thermal energy per se, but the transfer of thermal energy. Something that feels warm to the touch has more thermal energy than you — and you’re receiving it. Something that feels cold draws energy from you. The energy flow is what you perceive as ‘hot’ or ‘cold’.

Temperature, then, is how densely-packed thermal energy is in an object.

Thermal energy itself is the disorderly movement of particles inside an object. It is the sum of the kinetic and potential energy of molecules moving, rotating, or vibrating in a random manner. Thermal energy is randomly distributed among these particles or atoms, and as such is a measure of entropy — a physical’s system lack of order or predictability. The second law of thermodynamics says that the entropy of an isolated system never decreases. In plain ‘ol English, this second law basically says that you can’t take a hot object (high entropy state) and cool it down (low entropy state) without draining that energy somewhere else.

In a roundabout way, that also means thermal energy can’t be transformed, only transferred. There’s nothing wrong with thermal energy, but it is so disorderly that we can’t effectively channel it to transform it. Thermal energy also wants to even out as much as possible over as wide a volume as possible (ideally, across the whole Universe, in its book). This, alongside its workless nature, is why thermal energy is often seen as a ‘residual’ type of energy that all other energy degrades into.

The interplay between thermal energy and physical work are enshrined in the first law of thermodynamics. This law also shows us how heat, i.e. thermal energy imbalances, can be used to perform work. In short, it says that the energy state of a closed system is the difference between changes in heat (gains in energy) and work performed (energy expenditure).

Thermal energy itself can’t perform work, but an imbalance and subsequent transfer of thermal energy can. A hot oven is more energetic than a cool oven, but neither move by themselves. The fires bellowing in a steam locomotive’s furnaces don’t directly drive the thing forward. They heat up water, however, which then expands into steam, and this (heat-induced) change in state and volume is converted into motion. If you want to get all physical about it, the motions of individual water particles can get so hectic that it turns to steam; the motions of these steam molecules then get transferred (via impact) to the various pistons they drive in the engine, effectively converting thermal energy flow into motion.

So, to sum it up, thermal energy is the hipster of energies. By itself, it cannot be converted into other types of energies. Only differences in thermal energy can be transformed/used to perform work. The efficiency of such processes will never be 100% — you will never be able to recover all the energy in heat.

Mechanical energy

Steam engine.

An old steam engine used to drain water from mine shafts somewhere in Germany.
Image via Pixabay.

Mechanical energy is the total potential and kinetic energy resulting from the movement, or current location, of physical objects.

Kinetic mechanical energy characterizes physical bodies in motion and is half the product between its mass and the square of its velocity. The heavier something is, and the faster it moves, the harder it is to stop (i.e. the more kinetic energy it has). Potential mechanical energy depends on the body’s position relative to other bodies.

Potential mechanical energy is often associated with forces that apply work against the field of a conservative force. Conservative forces are forces independent of the path of motion, such as gravity or electrostatic interactions between particles. The easiest way to illustrate potential mechanical energy is by imagining you’re carrying a bucket of water up a flight of stairs. If you then dump the water, it will flow down to the ground. You stored potential energy in the water by acting against the gravitational field (i.e. you lifted the water). When you released it from the bucket, that water expended its potential energy as kinetic energy under the action of gravity.

An interesting property of mechanical energy is that in an isolated, ideal system, it is constant. In real systems, however, non-conservative forces (such as friction or air drag) will eventually sap mechanical energy, turning it into heat.

Chemical energy

Do you know what has a lot of chemical energy? Chocolate. But, if you want something with a lot of chemical energy, you need dynamite.

Diet Coke Mentos.

Or dynamite’s much-feared bigger brother: the diet coke and Mentos.
Image via Wikipedia.

Chemical energy is potential energy stored inside a substance’s chemical bonds. Our bodies break open bonds during cellular respiration to obtain this type of energy. Chemical energy is also released when we blow up a stick of dynamite, when feeding wood into a fireplace, when pressing the gas pedal, and as the battery in your smartphone generates electricity.

If a substance can react with another to undergo a transformation through a chemical reaction, it has chemical energy. That energy is equal to the difference between the energy content of the products and the reactants (if the temperature remains constant). It doesn’t much matter what, exactly, that change is — it can be a change in how a molecule’s atoms are arranged; it can involve the breakdown and creation of new products. As long as a chemical change takes place, it will either generate or absorb energy.

Combustion, that merry thing keeping the world going, is a superb example of chemical energy being released. Fire is what happens when oxygen molecules bind to various compounds, releasing the energy in their bonds.

Electrical energy

This type of energy is the result of the flow of electric charge through a conductor due to electrical attraction or repulsion between charged particles. Electrical energy can be potential (static electricity) or kinetic (when the charges are in motion, i.e. electrical current).

It is generated from differences in electrical potential between two or more objects in a given system. It can also be generated by kinetic force, though the movement of a copper wire loop or disk around the poles of a magnet. Generally speaking, this works because the electrons in the copper wire are free to move about as they please.


Very large copper wires and very big magnets. This is the rotor and stator for a generator at the Vargöns hydroelectric power plant in Sweeden. The outer diameter is of 11,4 m.
Image credits Tekniska museet.

Each electron is negatively charged, so it will be attracted to positively-charged particles and pushed away by other negatively-charged particles. You can also see this as the electron attracting certain particles while repulsing others — in other words, each charged particle has a tiny electric field around it that can exert a force on other particles, causing them to move (force over distance is physical work). Generators function by supplying force to move these charged particles around, causing them to move other charged particles, in turn, generating electricity.

A moving charged particle will always generate a magnetic field. A moving magnetic field always induces an electric current in a conductor. That’s why these two are usually clumped together under the banner of ‘electromagnetism‘.

Nuclear energy

Nuclear energy is released (or absorbed, mind you) whenever a nuclear reaction, or radioactive decay, occurs. It is the product of differences in the nuclear binding energy of the first and final state of these transmissions. The nuclear binding energy of an atom is defined as the minimum energy needed to break it apart.

In essence, all atoms are made up of particles and the forces holding these particles together. Different types of atoms need different amounts of force to keep them together. When an atom undergoes change, or when it is split, this energy is released. Nuclear energy, therefore, is potential energy.

In any exothermic (net-energy-positive) nuclear process, nuclear mass might ultimately be converted to thermal energy, and given off as heat. Fission and fusion are the best-known nuclear transformations that release energy. The Sun and all other stars are directly powered by nuclear fusion.

Depending on how technical you want to go with the classifications, you could draw up other types of energy. Elastic energy describes how stretchy things revert to their shape when you let go, for example. However, I tried my hardest to give you the overarching ‘flavors’ of energy, ones that can reasonably fit all other subtypes (elastic energy is a form of mechanical energy). But, if you feel I left something interesting out, perform some physical work on your keyboard and let me know in the comments below!

Physical, encryption-like method could help the world finally get rid of nukes

MIT researchers have devised a method that could allow states to prove they’re disposing of nuclear weapons without giving away any of their technical details — which are considered state secrets.

Mark 5.

Open nose cavity US Mark 5 nuclear bomb showing the ‘pit’.
Image credits Scott Carson / US Atomic Energy Commission.

Nuclear disarmament negotiations (particularly those between the U.S. and Russia) always hit a patch of rough ground when verification processes come up. The main point of these talks is to promote nuclear non-proliferation — the understanding that the fewer nukes there are in the world at any one time, and the fewer actors there are with access to them, the easier it will be for humanity not to blast itself back to an irradiated stone age. However, every reliable verification process that the two parties could agree on as trustworthy (i.e. visually identifying the warheads) would give away technical data pertaining to the weapons.

This would never fly. For starters, governments don’t like other people to know how their nukes work — especially the people they’re generally aiming said nukes at. Secondly, such measures would risk disseminating technical details to third-parties, thereby defeating the whole purpose of disarmament efforts. Visual confirmation, then, became a no-go.

To spot a warhead

Now, an MIT research team reports developing a novel method of confirmation that could help promote nuclear disarmament without disseminating any state secrets. The method, similar to a physics-based version of cryptographic encryption systems, can be applied in two different versions — just in case one is found to have drawbacks by any government. The findings were published in two different papers.

Lacking a reliable tool to identify nuclear weapons, and thus bereft of a way to enforce their destruction, past agreements have focused on decommissioning of delivery systems. It makes sense, as it’s far harder to ‘fake’ a plane or a ballistic missile, whereas nuclear bombs are basically spheres of plutonium. Such measures have worked reasonably well up to now, but lead author Areg Danagoulian believes that it only skirted the real issue: to avoid such weapons falling into the hands of terrorist or rogue states, we need to dispose of the actual warheads — which means we need a reliable way to identify them or spot fakes, one to which governments will agree.

“How do you verify what’s in a black box without looking inside? People have tried many different concepts,” Danagoulian says. “But these efforts tend to suffer from the same problem: If they reveal enough information to be effective, they reveal too much to be politically acceptable.”

Their solution draws inspiration from digital data encryption methods, which alter data using a set of large numbers, which form the key. Without this key, the encrypted data is a hodge-podge of characters. However, while it may be illegible, it is still possible to tell if it is identical to another set of encrypted data — if they use the same key, the datasets would be the same hodge-podge. Danagoulian and his team applied the same principle for their warhead verification system — “not through computation but through physics,” he explains. “You can hack electronics, but you can’t hack physics.”

The method analyzes both of a warhead’s essential parts: the sphere of radioactive elements that supply its nuclear ‘gunpowder’, and the dimension of the hollow sphere called a pit that serves as a ‘detonator’ — details pertaining to both elements are considered state secrets. Because of this, they couldn’t simply probe the weapons’ internal characteristics, and they couldn’t tell a fake apart just by measuring emitted radiation.

Negative filter

So what the team did was to introduce a physical key, created from a mix of the same isotopes used in the weapon, but in a ratio unknown to the inspection crew. Similarly to a filter applied to a photo, the key will scramble information about the weapon itself. In keeping with that analogy, the physical key is like a complementary color filter (a picture’s negative) that will cancel out all of the weapon’s emissions when lined up properly. If the investigated object has a different emission pattern (i.e. it’s a fake), it will bleed through the filter, alerting the investigation crew.

Nuclear verification.

(Top) diagram showing the configuration that could be used to verify that a nuclear warhead is real. (Bottom left) measurement without the reciprocal. (Bottom right) measurement with the reciprocal.
Image credits Areg Danagoulian.

This filter — called a cryptographic reciprocal or a cryptographic foil — will be produced by the same country that made the warheads, thereby keeping their secrets safe. The weapon can be hidden in a black box to prevent visual inspection, lined up with the foil, then get blasted with a beam of neutrons. A detector will then analyze the output and render it as a color image — if the warhead is genuine, the image will be blank. The second variant of this process substitutes a photon beam for the neutron one.

These tests are based on the requirements of a Zero Knowledge Proof — where the honest prover can demonstrate compliance, without revealing anything more. It also benefits from a built-in disincentive to lie. Because the template is the perfect complement of the weapon itself, when superimposed over a dummy it will actually reveal information about the warhead’s composition and configuration — the very things states don’t want others to know about.

It’s a neat concept; the only issue I have with it right now is that it only works if all parties involved are genuine, and do actually create the right reciprocals for their warheads. Still, if the system does someday get adopted and helps bring about significant reductions in the number of nuclear weapons in the world, Danagoulian says, “everyone will be better off.”

“There will be less of this waiting around, waiting to be stolen, accidentally dropped or smuggled somewhere. We hope this will make a dent in the problem.”

The papers “Experimental demonstration of an isotope-sensitive warhead verification technique using nuclear resonance fluorescence” has been published in the journal Proceedings of the National Academy of Sciences; “Nuclear disarmament verification via resonant phenomena” has been published in the journal Nature Communications.

Europeans don’t believe climate change deniers and want governments to take action, huge poll reveals

Europeans say that the effects of shifting climate can already be felt and show strong support in favor of economic policy measures to cope with and mitigate climate change, a major polling study reveals.

Image credits David Mark.

A big part of ‘doubt-mongering‘ is to push the narrative that a particular subject is still open for debate: “the science isn’t in yet”, “people don’t agree,” or “it’s a matter of personal choice”. We’ve seen it with tobacco, the food industry, and most recently the energy industry — with politicians and paid scientific papers perpetuating bogus data to polarize public opinion towards internal arguments rather than action.

But there isn’t as much of a debate as some would like you to believe, at least not in Europe, a new poll study has found. Citizens of four major cities don’t view climate change as a future problem, saying that its effects can already be felt in severe floods or storms. There’s also huge support for action against climate change, such as subsidizing clean energy and imposing financial penalties on nations that refuse to honor the Paris climate deal signed in 2015 — and the US might be on that list.

The poll is the first in-depth measurement of the perception of climate change in countries throughout the EU, and involved more than 1,000 people each in UK, Germany, France, and Norway, with the results weighted to be nationally representative.

Most people agreed on one point: that climate change is caused at least in part by human activity, particularly through the burning of fossil fuels. Some 60% of respondents further consider that its effects can already be felt. Two-thirds of respondents supported their country’s commitment to the Paris deal and a similar percentage said that countries who did not honor the agreement should be penalized, for example through the border carbon taxes some French officials have suggested.

Old world, new energy

Windmills at Denmark’s Bønnerup Strand helped the country run exclusively on wind power on several occasions.
Image credits Dirk Goldhahn.


Renewables also enjoyed a lot of support and were viewed very positively by the public, with 70% of people expressing support for using public money to subsidize clean industries the UK and Germany, 75% in France, and 87% in Norway. Fracking and nuclear power didn’t enjoy the same popularity, with just 20% of people expressing a positive view of fracking in the UK, 15% in Germany, and 9% in France, while nuclear power was only seen with favorable eyes by 23% of Frenchmen — although it supplies the lion’s share of the country’s electrical energy.

“It is encouraging to see that most people in this very large study recognise that climate change is happening, and that support for the need to tackle it remains high amongst the people we surveyed,” said Prof Nick Pidgeon at Cardiff University, who led the international project.

This solid public backing could be monumental in light of political uncertainties throughout the world, with some leaders, such as the US president Donald Trump, openly opposing climate action.

“With the recently shifting political mood in some countries, climate policy is now entering a critical phase. It is therefore even more important that the public’s clear support for the Paris agreement is carried through by policymakers across Europe and worldwide.”

“People see that if there are free riders, that is not a very good thing,” he added.

Still, there remain some differences of opinion between the countries. A proposal to increase taxes levied on fossil fuels saw support in Norway, an even split in the UK, and a two-to-one opposition in France and Germany. Another was in the public’s trust in the EU, national, and local governments to shift energy systems towards cleaner sources. Germans were generally positive, while people in the UK were loath to trust in any of the institutions.

One worrying find is that while people have formed something of a consensus on these issues, the effect of doubt-mongering is very visible — while climate change is for all intents and purposes a scientific consensus by now, people believe that only about a third of scientists agree it’s happening.

The polling took place in June 2016, before the Brexit referendum. The full report is available online here.


Cooking nuclear waste into glass and ceramic materials could provide safe, efficient containment

Containing radioactive waste in glass and other ceramic materials might be the key to protect people — and the environment — from their harmful effects.

Image via Pexels / Public Domain.

Nuclear power is awesome. Splitting the atom can yield huge amounts of energy for no greenhouse gas emissions. The downside, however, is that you’re left with piles of radioactive by-product (waste) that is really, really harmful for people, animals, plants, pretty much everything. The good news is that radioactivity naturally decays over time — usually a few million years.

The bad news is that the waste is chemically mobile in water (it gets carried around by rain or rivers) and in air — so you have to keep it well isolated and locked up until that time passes. Which is quite a hassle. The way we go about it now is geological disposal — a fancy way of saying “we bury it really deep” — in disused mines, ocean floor disposal, or (planned) specialized deep-storage.

Rutgers University researcher and assistant professor in the Department of Materials Science and Engineering Ashutosh Goel thinks he’s found a better way to go about it, by immobilizing radioactive waste in glass and ceramic materials. Goel is the principal investigator (PI) or co-PI for six glass or glass-related waste containment projects. His work may help to one-day safely dispose of highly radioactive waste, now stored at commercial nuclear power plants.

“Glass is a perfect material for immobilizing the radioactive wastes with excellent chemical durability,” said Goel.

One of his projects involves mass-producing apatite glasses to immobilize iodine-129 atoms in a chemically-stable form. This isotope of iodine has a half-life of 15.7 million years and is highly mobile in water and air according to the EPA. Exposure to iodine-129 affects the thyroid gland and increases the risk of cancer. Another one of his projects developed a way to synthesize apatite minerals from silver iodide particles. Goel is also studying how to capture sodium and aluminum atoms from highly radioactive wastes in borosilicate glasses which resist crystallization.

Containing waste in glass might provide us with a safe way to dispose of them in the future. And it will look like this.
Image credits Albert Kruger / U.S. Department of Energy.

Among Goel’s major founders is the U.S. Department of Energy (DOE), which currently oversees one of the most wide-scale nuclear cleanup programs in the world, following the U.S.’s 45 year-long nuclear weapon development and production program. This project once included 16 major facilities throughout Idaho, Nevada, South Carolina, Tennessee and Washington state, according to the DOE. The site in Washington state, Hanford, is one of the biggest clean-up challenges the department faces. This complex manufactured more than 20 million pieces of uranium metal fuel, processing around 110,000 tons of fuel from nine reactors on the Columbia River.

Around 56 million gallons of radioactive waste from the Hanford plants went to underground storage in 177 tanks. It’s estimated that 67 of these tanks — more than a third — have leaked part of the waste, the DOE says. In 1989, clean-up efforts started at the site. The liquids have been pumped out of the tanks, leaving behind mostly-dry waste. Work began on a radioactive liquid waste treatment plant in 1999, which is nearing completion.

“What we’re talking about here is highly complex, multicomponent radioactive waste which contains almost everything in the periodic table,” Goel said. “What we’re focusing on is underground and has to be immobilized.”

The DOE hopes to start churning out radioactive-waste-glass by 2022 or 2023 at Hanford, Goel said.

“The implications of our research will be much more visible by that time.”

“[The process] depends on its [the waste material’s] composition, how complex it is and what it contains,” Goel added. “If we know the chemical composition of the nuclear waste coming out from those plants, we can definitely work on it.”

The full paper “Can radioactive waste be immobilized in glass for millions of years?” is still awaiting publication. Materials provided by Rutgers University can be found here.

Ken Buesseler, oceanographer, answers questions about Fukushima’s impact on the oceans

Ken Buesseler studies marine radioactivity. He uses radioactive elements such as thorium that are naturally occurring in the ocean as a technique to study the ocean’s carbon cycle, as well as fallout from atmospheric nuclear weapons testing and recently, the sources of radionuclides from Fukushima Dai-ichi in 2011. Following the 2011 earthquake in Japan and the subsequent tsunami, the Fukushima Dai-ichi nuclear power plant was severely affected, with massive quantities of radioactive material spilling into the oceans.

Buesseler took the time to answer some questions on Reddit as part of an AMA (Ask Me Anything). Here are some of his most interesting insights, you can read all of it here.

What is the estimated scale of radiation released into the ocean, from Fukushima, in terminology, or comparison, a layman might understand?

Total levels and scales vary depending upon the mix of contaminants, but if we pick just one, cesium-137, there was about 10 times more cesium-137 released during nuclear testing globally, than Chernobyl. And for cesium-137, Chernobyl was 2-5 times greater than Fukushima, but then again most of the Chernobyl fallout fell on land, not in the ocean.

Can you give any insight on how long it took for the ocean to return to normal after the atomic tests, and perhaps compare it to the Fukushima leak?

In the 1960, immediately after the end of testing on the Pacific atolls, the concentration of radioactive cesium in the Pacific off the coast of Japan was about 50 Becquerels per cubic meter (Bq/m3) and 10 Bq/m3 off California. By 2011 immediately before the earthquake and tsunami, that had fallen throughout the Pacific to about 2 Bq/m3 as a result of radioactive decay. Today, the highest we have seen off the coast of North America is 6 Bq/m3. Off the coast of Japan after the accident, (aside from the extremely high levels detected at the source of release from the reactors) we recorded a high of 4,500 Bq/m3. You can see more about pre-Fukushima levels worldwide here:

Living in San Francisco during and the the years after Fukushima, I heard about people taking iodine tablets as a precautionary measure against radiation poisoning. Was I right in ignoring this as an overreaction since Japan is half a world away?

The California Coastal Commission had a report in 2014, that if you were in California in 2011 and drank tap water at the highest levels found and breathed in the air at its peak level- both for an entire year- your dose or net health impact would be about 5 micro Sieverts or about the same exposure as a single dental X ray. This is not zero, but a very low dose indeed. And no need to be taking iodine tablets, though remember at that time it was less certain what was going on and if it was going to get worse

I live in Osaka, Japan. How safe would you say is the seafood caught off the coast of western Honshu?

Off Japan today, except for those in the vicinity of the reactors, seafood and other products taken from the Pacific are currently below strict limits set by the Japanese for human consumption. Tens of thousands of fish have been and are being tested off Japan. If fish are found above the limits, commercial fishing remains closed. In 2011 about half the fish caught near Fukushima were above Japan’s limit (100 Bq/kg). In 2014 that had dropped to 1%. BTW, none of the fish caught on “our side” of the Pacific have been found to be above any of the limits set by Japan or higher limits in US/Canada.

What was the most unexpected things about your findings?

Sampling off Japan in 2011, we were more worried about hitting debris and harming our research vessel, than the levels of radioactivity which we were measuring with hand held devices as we sampled.
Another thing, maybe not unexpected but disappointing is the fact that no US Federal agency takes responsibility for ocean radioactivity studies

I teach middle school science. What is one major misconception about oceanic radioactivity that I (and the Internet) should clear up immediately?

The danger is in the dose, so while we should be concerned about any level of exposure to radioactivity, there is a huge difference in the levels, in this case in cesium from Fukushima, which ranged from 2 to 50 million in the units we use. That is like the difference in the temperature on earth and the temperature on the center of the sun. There’s already radioactive forms of cesium in the ocean. So it is a good question how much more radioactive cesium did Fukushima add, but we need to be aware that since the testing of atomic weapons there are many radionuclides we can measure in the ocean and on land.

(1) To what extent do radionuclides generally bioaccumulate (increase in concentration in an individual organism/population)?
(2) To what extent do radionuclides generally biomagnify (increase in concentration with trophic level)?
(3) Do the specific radionuclides released from Fukushima Dai-ichi differ in terms of their potential for bioaccumulation/biomagnification from other naturally occurring radionuclides in the ocean, e.g., Cesium?

Different radionuclides do not behave the same in all marine organisms, just as for other non-radioactive contaminants. For example cesium, which behaves like a salt, will accumulate in fish by a factor of 50 to 100 times the levels in water, but as a salt, it will also flush out of organisms quickly, about half in 2 months, through normal bodily functions and therefore does not bioaccumulate at higher levels. Strontium however behaves more similarly to calcium in humans and animals and is taken up and concentrated in bones where it remains with a biological half life of a couple years.
Think of it this way. If a cesium-137 contaminated fish were to be canned, it would take 30 years (the radiological half-life) for 50% of the cesium-137 to disappear. In contrast, if that same fish were to swim to cleaner waters, it would lose 50% of its radioactive cesium burden in just two months.


Move over, toys: scientists create LEGO replica of a nuclear spectrometer

A new model of a spectrometer was unveiled by Australian national nuclear research and development organisation (ANSTO); but this one is made of LEGOs.

Image via ANSTO.

Bbuilt by John Burfoot of Macquarie  ICT Innovations Centre (MacICT), the replica is absolutely stunning, and one of the goals is to get kids more interested in science.Burfoot, a science and robotics facilitator at MacICT, spent the model over several weeks. He said:

“About a third of the time went on the design, another third on building it and the final third on the programming,” said Burfoot, who has designed many robots for school education previously but not a scientific instrument until now. He described the experience as exciting, inspiring and a little bit scary. “It recaptured the flow or synergy you feel during the creative process—something that children who build robotic models can also experience.” When he encountered technical problems, he consulted with student engineers at Macquarie University to find solutions.

It’s also another reminder that LEGOs aren’t just toys – they’re educational tools as well. Six local school kids whose parents work at ANSTO will construct another Taipan model themselves, adding their own improvements and refinements.

Instrument Scientist, Kirrily Rule, who operates Taipan (the spectrometer) is very enthusiastic about this new resource:

”It’s very different than the LEGO I used as a kid. Much more than a toy, education officers can use the model to demonstrate physics to children and hopefully stimulate their interest in science,” said Rule. Like the original instrument, it has moving parts. “You can control how it moves, just like our Taipan, which bends like a snake,” said Rule.

Taipan is a triple-axis spectrometer developed for the study of collective motions of atoms in solids – and the replica mimics it almost exactly (with the obvious limitations of LEGO pieces). It even has a small glass prism used as a sample.

“We are using the prism to split the white light into the colours of the rainbow – which each have different wavelengths (and energies) – to show how the neutron’s energy can change during the interaction with the sample,” said Rule.“So instead of thermal neutrons in the LEGO model, we are using light. The concept is very similar.”

Instrument scientist Kirrily Rule (second from right) explains how ANSTO’s real triple axis spectrometer Taipan works to kids who have an interest in LEGO robotics. Image via ANSTO.

They also used a mirror-like material for the model to reflect the light from the prism.

“We used offcuts from the silicon panels that came from our Emu instrument, which brings another level of accuracy to the model,” explained Rule.

Dr Damien Kee, an education technology expert said that creations such as this encourage kids to think more creatively and to actively engage in scientific activities.

Now, ANSTO plans to build even more instruments from LEGOs – and personally, I think this is a great initiative.

A haunting view of Chernobyl, captured by aerial drones

For a 60 Minutes report that aired earlier this month, filmmaker Danny Cooke spent a week exploring abandoned cities Chernobyl and nearby Pripyat. Pripyat was just preparing to open a new amusement park just days before the nuclear meltdown happened at Chernobyl.

Now, Cooke has posted a a compilation entitled “Postcards from Pripyat, Chernobyl” — a mix of drone footage and traditional cinematography. According to The Guardian, this is the first time we’ve seen footage of the area from the air. There’s something incredibly emotional, yet disturbing about the area, as Cooke himself says:

“There was something serene, yet highly disturbing about this place. Time has stood still and there are memories of past happenings floating around us.”

Chernobyl was the site of a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine, then officially the Ukrainian SSR, part of the Soviet Union. It was the worst worst nuclear power plant accident in history in terms of cost and casualties. The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles (18 billion $USD), but the long term effect of cancer and deformations are still accounted for.

Dodgem cars at the abandoned Pripyat amusement park near Chernobyl. Photograph: Timothy Swope/Alamy

You can also watch the full 60 minutes report here.

Radiation Level at Fukushima nuclear plant is 1000 times over accepted level after earthquake

The damage caused by the 8.9 earthquake in Japan is far from being over – asa matter of fact, unfortunately, it may very well just be starting. The earthquake and the tsunamis it created cut down power supply throughout a major part of Japan, and so the cooling system of several power plants was unable to do its job.

As a result, the radiation level at the Fukishima power plant is about 1000 times bigger than the accepted level, and technicians are desperately trying to figure out ways to prevent a meltdown, which would have catastrophic results; one way to do this would be to release steam that has been vaporized by heat from the nuclear core, which would lower the pressure, and thus, the temperature.

“It’s possible that radioactive material in the reactor vessel could leak outside but the amount is expected to be small and the wind blowing towards the sea will be considered,” Chief Cabinet Secretary Yukio Edano told a news conference.

The earthquake which shook Japan to its very core caused all sorts of issues, and this latest nuclear problem is extremely hard to tackle. The good news however, is that eleven reactors close to the epicenter shut themselves down when they sensed the earthquake.

“Reactors shut themselves down automatically when something called ‘ground acceleration’ is registered at a certain point, which is usually quite small. It will instantly drop control rods into the [nuclear] core,” Professor Tim Albram, a nuclear fuel engineer at the University of Manchester in the U.K., explained to the press.

How this whole situation will be handled remains to be seen, but things seem pretty dire at the moment; hopefully though, there will be no further complications, as Japan has already seen too many during these two days.

Bikini corals are recovering from atomic blast


Bikini Atoll (also known as Pikinni Atoll) is an uninhabited 2.3-square-mile (6.0 km²) atoll in one of the Micronesian Islands in the Pacific Ocean. Its historical importance lies in the fact that along with more than 20 nuclear weapons tests between 1946 and 1958, the world’s first test of a practical dry fuel hydrogen bomb took place.Now, more than 50 years later, after the devastating earth shattering nuclear blast, the corals are flourishing again. Some coral species, however, appear to be locally extinct. These extraordinary results were developed by an international team of scientists from Australia, Germany, Italy, Hawaii and the Marshall Islands. This is really surprising, as the Bravo Bomb that blew up there is the most powerful bomb ever exploded, a thousand times more powerful than the Hiroshima bomb; it raised temperatures to 55,000 degrees, shook islands 200 kilometers away and left a crater 2km wide and 73m deep as well as virtually destroyed a couple of islands.

Here’s what Zoe Richards of the ARC Centre of Excellence for Coral Reef Studies and James Cook University had to say:

“I didn’t know what to expect – some kind of moonscape perhaps. But it was incredible, huge matrices of branching Porites coral (up to 8 meters high) had established, creating thriving coral reef habitat. Throughout other parts of the lagoon it was awesome to see coral cover as high as 80 per cent and large tree-like branching coral formations with trunks 30cm thick. It was fascinating – I’ve never seen corals growing like trees outside of the Marshall Islands. The healthy condition of the coral at Bikini atoll today is proof of their resilience and ability to bounce back from massive disturbances, that is, if the reef is left undisturbed and there are healthy nearby reefs to source the recovery.”

However, it’s not all fun and games. A disturbingly significant number of species has dissapeared: 42.

“The missing corals are fragile lagoonal specialists – slender branching or leafy forms that you only find in the sheltered waters of a lagoon,” Zoe explains.

Because of its extraordinary situation, the Bikini Atoll is now part of a larger project to have northern Marshall Island Atolls World Heritage listed.