Scientists Turn Nuclear Waste Into Diamond Batteries (newatlas.com)

Scientists at the University of Bristol have found a way to convert thousands of tons of nuclear waste into man-made diamond batteries that can generate a small electric current for thousands of years. New Atlas reports: How to dispose of nuclear waste is one of the great technical challenges of the 21st century. The trouble is, it usually turns out not to be so much a question of disposal as long-term storage. Disposal, therefore is more often a matter of keeping waste safe, but being able to get at it later when needed. One unexpected example of this is the Bristol team's work on a major source of nuclear waste from Britain's aging Magnox reactors, which are now being decommissioned after over half a century of service. These first generation reactors used graphite blocks as moderators to slow down neutrons to keep the nuclear fission process running, but decades of exposure have left the UK with 104,720 tons of graphite blocks that are now classed as nuclear waste because the radiation in the reactors changes some of the inert carbon in the blocks into radioactive carbon-14. Carbon-14 is a low-yield beta particle emitter that can't penetrate even a few centimeters of air, but it's still too dangerous to allow into the environment. Instead of burying it, the Bristol team's solution is to remove most of the c-14 from the graphite blocks and turn it into electricity-generating diamonds. The nuclear diamond battery is based on the fact that when a man-made diamond is exposed to radiation, it produces a small electric current. According to the researchers, this makes it possible to build a battery that has no moving parts, gives off no emissions, and is maintenance-free. The Bristol researchers found that the carbon-14 wasn't uniformly distributed in the Magnox blocks, but is concentrated in the side closest to the uranium fuel rods. To produce the batteries, the blocks are heated to drive out the carbon-14 from the radioactive end, leaving the blocks much less radioactive than before. c-14 gas is then collected and using low pressures and high temperatures is turned into man-made diamonds. Once formed, the beta particles emitted by the c-14 interact with the diamond's crystal lattice, throwing off electrons and generating electricity. The diamonds themselves are radioactive, so they are given a second non-radioactive diamond coating to act as a radiation shield.

Comments

Long range space probes?

[Sasayaki]

Seems like this kind of technology would be very useful for long duration space probes.

Re:Long range space probes?

[AmiMoJo]

1g of carbon apparently produces 15 Joules per day, which if you work it out is only going to deliver tens of microamperes. Enough for timekeeping and maybe running a simple LCD, perhaps even the odd very short very low power very low range radio broadcast for a sensor.

I suppose if they includes a fairly large amount of the stuff it might generate enough energy to be useful in a space probe, but I don't think the power/weight ratio is there. You would want to use something a bit more potent if you were spending that much money, as they did with various nuclear powered probes.

Where it will shine is for sensors. There was a plan to install sensors on water pipes before they were buried using nuclear batteries, for example. Stress sensors in buildings and on bridges. All sorts of areas where replacing the sensor is difficult and expensive so you want decades of battery life and the basic sensor isn't going to change much in that time.

Re:Long range space probes?

[DanielRavenNest]

> Putting something radioactive on the launch pad and having it detonate in the atmosphere would be terrible too (Which is why we don't send nuclear materials into the sun.)

That's not why we don't do it. I worked on a "Space Disposal of Nuclear Waste" study at Boeing, under contract to the DOE. The risk reduction (about two cancer deaths a year on a statistical basis) was simply not worth the extra cost (about double that of burying it underground). Also, the Sun is not the safest place to dispose of it. If your rocket fails and leaves it crossing the orbit of Venus or Mercury, they could send it back to Earth by accident. The lowest risk is to place it in an orbit halfway between Venus and Earth (0.85 AU), and that also takes much less delta-V than hitting the Sun.

The nuclear waste was assumed to be glassified into coke-can sized segments, then formed into 2-meter "waste balls" surrounded by 20 cm thick steel alloy, which in turn was surrounded by heat shield tiles. The worst case accident is no on the launch pad, which is merely a lot of fire. The worst case is the rocket failing just before reaching orbit, where the payload kinetic energy is twice that of the best rocket fuel. So the heat shield enabled surviving re-entry, and the thick steel shell enabled surviving a terminal-velocity ground impact. It was also a corrosion-resistant alloy, because most launch failures end up dropping the payload in the ocean. We assumed a 2% launch failure rate.

The waste balls were so damage-resistant, that the study manager would have been happy to take one home and put it in the basement to keep the house warm in the winter (they generate 2 kW from radioactive decay heat). House fires, natural gas explosions, earthquakes, none of those would do any damage to it.

Energy input.

[Anonymous Coward]

What is the energy input required to create this vs the energy it will output?

Re:Brilliant research

[AHuxley]

The UK had very different needs that just power from its reactors.
After the US stopped sharing nuclear projects with the UK, the need for mil and public nuclear research was fully funded.
"Information sharing ceases" https://en.wikipedia.org/wiki/...
"End of American cooperation" https://en.wikipedia.org/wiki/...
That has led the UK with some very different and unique production lines e.g. Sellafield/Windscale/Calder Hall, later Magnox reactors, the need for tritium production. A nice big military plutonium stockpile was created.
Most of the UK nuclear work is now to look after old sites, keep the staff ready to build new nuclear submarine servicing in England if the other UK sites won't stay open.

Re:Fine, power your bitcoin asic ...

[jcochran]

You gotta remember that you're dealing with idiots who tremble at even a hint of an idea that radiation is near them. In fact, there's a little device in your car (assuming it's powered by gasoline) where it's name was determined due to the fear of radiation. The "catalytic converter" has that name because of idiots who fear the concept of radiation. The correct proper name for that device is "catalytic reactor". But the word reactor is used in nuclear reactors so "obviously" a "catalytic reactor" is dangerously radioactive and should never ever be placed in a car because it might spread radiation all over the place and don't even think about what would happen in an accident. Because of that fear, engineers call that little device a "catalytic converter" because that doesn't have the dangerous radiation inducing effects that the word "reactor" has.

Remember your audience and compensate for their ignorance and/or stupidity.

Energy density

[lorinc]

What's the recoverable energy density of this? I mean, how many watts of electricity can I get out of on of these, for how long, per cm^3?