Meet the Inventor of the Nuclear Waste-Powered Diamond Battery

Meet the Inventor of the Nuclear Waste-Powered Diamond Battery

By Kyle Gracey

In December, we reported on the “diamond battery“, an artificial diamond that can convert gamma rays given off by nuclear waste into electricity. PreScouter Global Scholar, Nicole Percy, recently spoke to one of its creators, Dr. Tom Scott, University of Bristol Professor of Materials: Geochemistry and Metallurgy of Uranium. Dr. Scott gave us an in-depth look at his team’s research and the progress and challenges to commercialization.

Q: What’s the status of your current research of this battery?

A: We’re about nine months into our program, which is a three year program to generate further more advanced prototypes of the diamond battery technology. That technology is actually two technologies that can be used independently or they could be used side by side in a hybrid device.

The one technology that is most new is what we call a gammavoltaic but it’s essentially, you’d say, a version of the photovoltaic, the solar panel.  But instead of it converting energy from sunlight or visible light, it converts gamma energy into electrical energy.

The applications for that would be in niche environments.  For example, you could use them in nuclear waste stores where they power sensory devices and the ambient radiation field coming from the radioactive waste powers the device.

As long as there’s radiation around, then the device will be powered.  In that respect, a little bit like a pedman’s handle.

The other opportunity for the technology is in fusion power, where fusion there is a neutron that is produced, you also produce a hard gamma.  In the current concept of fusion reaction is they’re really looking at converting the heat into electricity by essentially the same way a normal power plant works, heating water, running a turbine, etc.

But now, some of the fusion guys have become aware of this technology and they’re quite keen to make an assessment of it.  So, they need to use a gammavoltaic for converting the radioactive energy part of what’s being produced by a fusion reactor to put that to electricity as well and thereby you’d increase the output of a reactor.

Q: I did a little bit of reading and I read that these kind of batteries are powering something, like a smaller device, but sorry, to clarify, do you mean there is a potential for them to power larger devices in the home?

A: For a gammavoltaic, if you put that next to something that’s really radioactive like a vitrified nuclear waste, then actually, as it functions with time, you can generate quite a lot of electricity.

What we’re working on with the technology at the moment: We have a prototype that we’ve been testing and we’re developing second and third generations, which is about refining the structure of the device such that we get the most efficient energy generation.

I can’t go into too much detail about that because it’s likely we’ll be patenting. I’ll answer that very shortly.

Q: So, are you in the process of filing a patent?

A: Yes, exactly. We’re in the process of doing various… Entering a round of testing new devices at the moment, which we’re doing on relatively small scale devices.

Once we’ve nailed that in terms of the structure, we’ll be looking to upscale that so we can make larger panels.

You can imagine, if you had a vitrified nuclear waste chemist, then you might have a shroud of these diamond gammavoltaics which you drop around the outside, and they sit there and they feed of the gamma field that’s coming off the waste package.  Basically, you have a table coming away from that which is carrying away the electricity that’s been generated.

Q: Wow, interesting! I also read, for example, about pacemakers. There is some potential for smaller versions, correct?

A: Yes.  That’s the second technology.  I’ve talked to you so far about gammavoltaics.

The second technology, which we also have prototypes for, but again what we’re doing over the next two and a half years is developing more and more efficient ones which have higher power outputs, higher voltage outputs.  They’re what we call betavoltaics. These are the ones which most people understand the concept of.

They’ve got a radioactive B to emit it in the diamond structure and the diamond structure itself basically then converts it’s beta decay into a cascade of lower energy electrons and that becomes the power supply.

We have a device which is small and lightweight.  There’s no detectable radiation on the outside and it provides a constant trickle of electrical current.  It’s not like a chemical battery. It’s more like a power cell in that respect.

The way you make that technology work is you link it with a ceramic capacitor and you have a very low voltage monitoring circuit, which basically monitors, they don’t use much power, how full the ceramic capacitor.  And when that capacitor is full, it then discharges into a working circuit, which could be lots of different things. It could be different senses, it could be a tracking device, you name it in terms of the Internet of Things, and that’s what would it enable.

That’s the main focus of what we’re doing.  Certain manufacturing companies have said, “If you can adopt these commercially, we would have ordered four billion of these last year.”  That’s where we’re seeking to… Whilst we’re developing better and better prototypes, we’re also now starting to think about how do we produce these things, where’s the best place to produce these things and where’s the best place to get a hold of materials from, and the lowest possible cost?

Q: Is it fair to say you’re a bit further along in the development of these betavoltaic devices?

A: Yes, it is.  There’s a couple we’ll be able to tell you about soon but I’m not allowed to at the moment. Again, there are more patents being generated at the moment.

To make the radioactive diamond battery devices, the betavoltaics, we have now three different methods or routes for manufacturing them.  We have new ways of making them. We can make them of different strength power output, depending on which way we make them.

That’s very useful because it means that, technologically in terms of prototype, we may use one route because it’s very quick, but for mass production we may use a different route because it lends itself to that production better, for example.

One of the things I can tell you that we’re doing is we are putting some of our diamond, which is radioactive initially, into nuclear reactor cores, and we’re activating some of the diamond.  We’re taking it back from the reactor and growing more non-radioactive diamond on the outside of it in order to shield it and to produce the layer which converts the beta particles into electricity.

That’s a much quicker way of us getting more and more prototypes created than the other ways, which is growing from highly radioactive gases.

Q: What do you think are some of main barriers to commercializing this product?

A: That’s a really good question.  It comes down to where we choose to make them and also, depending on which markets we go into, what the regulator thinks is acceptable.

If you think about most, in the UK certainly but probably Canada as well, most houses will have a fire alarm in every room.  And, in those fire alarms, you have small amounts of americium.

Americium is a well regarded radioactive material.  It’s beta and gamma coming from it. It’s perfectly acceptable to a regulator to have that in your house.

Where our biggest hurdle will be is to get regulatory acceptance and approval to make these devices for a mainstream consumer market.

Q: Relating back to–

A: We have to demonstrate safety for those devices.

Q: Yes. I read a little bit about how they work and it’s a diamond which is radiated and then there’s another layer of diamond on top of that.  Sorry, I’m pretty basic on my science here, but diamond is the hardest substance, so what do you think is the easiest way to explain the safety?

A: You have your hand in the middle of a ham sandwich.  A diamond battery would be the ham to the radioactive part and then outside of that you have a combination of the butter and the bread, and your bread, depending on the sandwich and reference, the bread is a bit thicker.  It might be white bread or brown bread.

In terms of our research, really what we’re actually doing is a lot of work on optimizing what the bread is like as opposed to what the ham is like.  We’ve got the ham bit sorted but it’s a significant flavor of the bread, if you take that as the analogy, it will depend on how efficient your device is.  It will also control the voltage that you get from it. We’re aiming to get approximately two volts output from it.

Q: One question that occurred to me is if you’re putting this in a pacemaker, and usually after people pass away they remove the pacemaker but in disposing…  Is there going to be a difficulty in disposing or recycling? Because they have such a long term potential, they could probably never run out of power, do you think there will be any kind of complications with that kind of issue?

A: It will highly depend on exactly which beta emitting I suppose we choose to use inside the diamond structure.  There are three specific isotopes that we are interested in that today, unfortunately, I won’t talk you through what those three are.

But one of them is Carbon-14. The other two are shorter, half life, and therefore if you were going to use it in a pacemaker, you wouldn’t bother because of the half life is short compared to Carbon-14.

A Carbon-14 device, yes, you’d want to recover it because it’s just too valuable to not recover it, if that makes sense.  A human being will live, if you’re lucky, 100 years but the device will still be working after several thousand years perfectly happily.  It’s like why would you waste all of that energy? Yes, you would, I think, choose to recover that and choose to reuse.

Where it really has great applications is in things like long distance space flights.  If you think about the satellite, well they’re not really satellites.

Q: Probe?

A: More in (name of a spacecraft) which has left the solar system. When you get really far from the sun, the photovoltaic panels don’t work anymore.  Exploring the edges of our solar system is a problem if you’ve got a spacecraft which has got photovoltaics.

But if you’ve got a betavoltaic embedded inside it, first of all, it’s a lot lighter to put into space because it’s only carbon compared to a plutonium based RTG.  It’s also less hazardous and less expensive than those equivalents as well.

It still gives you energy for thousands and thousands of years.  It’s exactly the kind of thing that you want in terms of, for the most part.

For example, if you send a spacecraft to go and look at the rings of Saturn, it’s going to take 13 years to get there.  What you do once your spacecraft is pointed in the right direction and is boosted off, you put almost all of your electronics into sleep apart from core electronics which are kept alive for the duration of the space flight, because you need something there to restart everything when it’s pointed to do so.

The betavoltaics would be really well suited to exactly that application because the device itself is extremely radiating hard and radiating tolerant that the cosmic grace, for example, wouldn’t be damaged due to the function of time, whereas other types of devices might well get damaged.

Q: That makes sense.  Going back to the disposal or retrieval.  I think I’m mainly curious to would it be harmful in any way or bad for the environment, etc., if these were negligently disposed of?

A: It would be quite difficult to negligently dispose of it because, first of all, you’ve got the non-radioactive on the outside, there’s no radiation on the outside.  And also because these devices have a very thinned cross section, even if you might stack them in lots of cells, the individual cross section is very thick.

If you snapped one in half, you wouldn’t get any appreciable radioactivity on the cross section you just created.  Does that make sense?

Q: Yes.

A: The only way that you would inadvertently release the radioactors inside is if you incinerate it at about 1000 degrees C, which for most things that contain radioactive materials, that’s pretty much always going to resolve in release.

What you wouldn’t want to do is with someone who has one of these fitted as a pacemaker, you wouldn’t want to (cremate) them or what would happen is you get a puff of radioactive gas out of the chimney, but almost immediately we’d arrest the atmosphere and it wouldn’t be harmful.

Q: They tend to avoid doing that anyways because the metal from the pacemaker damages the chamber or something like that. Right?

A: Yes, exactly.  But Carbon-14 and most of them are produced in the upper atmosphere.  It’s something which is naturally occurring. If there was an inadvertent release, you wouldn’t be able to detect it.  Most of it is what the natural background of Carbon-14 is anyway after dilution.

We’re talking freak device, we’re talking a gram of quantity or less.

Q: Going back to main barriers to putting these things on the market.  Do you think that cost is going to be a big one? You talked a little bit about trying to find some way to manufacture it and you’re looking for a way to do that best and cheaply, but how accessible do you imagine this technology being?

A: We have an industrial advisory board which includes companies like Toshiba, Siemens, ARM, EDF Energy, Sellafield, The National Nuclear Lab.

We have the right people involved with advice about how we commercialize and they’ve been really important in terms of shaping our thinking of what demand of the device looks like but also visibly which markets we would hit, in which order.

The current thinking is we go to the highest value market, the markets that would be prepared to pay the most for a device and for many, income is generated from something in that market.  We spend that on reducing the cost of the device so we can hit the next market down in terms of cost. And you go down and down and down. That’s the route we’re going to try and take.

The markets which would be willing to pay top dollar for devices, for example, would be, like we talked about, space application and military surveillance and security.  That would be the first market that you’d hit. Then you could go down and go to things like medical devices, and then you could go down and go towards things like the Internet of Things, car tire pressure monitors; Those kind of things where you’d want millions of devices per year but that are a very low cost.

Actually you can understand there’s a cascade of different markets where the Internet of Things market, you might only be paying $10 or $20 dollars for a device on things like that, where for military application or space application, they might be at room to pay thousands or tens of thousands of dollars for a device.

That’s the route that we hope to be able to take in terms of taking any income that we generate to drawing down the cost, increase output and to keep getting that over several stages.

Q: It would take, I guess, a great many years before these things start showing up in our iPhones. Correct?

A: Yes.  Somewhere between, I’d say, I would expect…  When you see them coming up domestically, they will have already been well exploited in other sections, let’s say.  But I would hope between 6 and 10 years before you start to see an iPhone that never needs recharging.

Q: So 8 to 10 years?  Interesting.

A: On the side of the device which is all about the low power electronics, the isolaic capacitor, the monitoring circuit, we’ve done an awful lot of work and we have good prototypes on that side.  That’ll be a key part of the technology keeping forward, delivering the right electronics alongside the device.

What will be an interesting thing to watch is obviously there’s a lot of emphasis at the moment with Internet of Things and mobile phone devices, into making them more efficient and lower power consumption.  That plays into our hands because we’re working from the other end. We’ve got really small power outputs and we’re working hard to increase the power output and maximize it.

You can see those two technological drives are pushing towards a meeting of minds and meeting of technology whereby in six years time, my iPhone might be twice as efficient as it is now, which might mean I can have a smaller, cheaper diamond battery device that would power it constantly.

Q: Do you know of anyone else who’s working on a similar idea, is of competition of concern right now?

A: At the moment, we don’t have any competition but that’s not to say it’s not going to be coming up quite soon.  We do know there are several international groups extremely interested in what we’re doing. One of them is Element Six, who are the diamond device company owned by De Beer, who we’ve kind of collaborated with for some time, a decade or more.  But they’re keeping a very close eye on this, as are other organizations internationally.

What we would hope is that the strength of the patents we are filing is enough to keep other rivals at bay so that we’ve got most of the core stuff down so that nobody else can make these things apart from us.  That’s probably quite naive based on other countries don’t really respect patent law at all.

There will be an element of what we do where we patent some of the stuff but some of the know-how, we don’t advertise what it is.  It would be very difficult to reinvent that wheel. We have a vacant IP technology team at Bristol and they are involved in all of these types of discussions all the time.

Q: I’m just curious because when you described the whole moving from a specialties markets down to a consumer market, by that time you’ll probably have all of your patents sorted out so that there isn’t really an issue with competition. Right?

A: Yes.  Our best bid in this case is based on one whereby we are paid by people who own radioactive graphite and they pay us to get rid of it, or to make it less radioactive, and in doing so we produce Carbon-14 that we can use to make diamond battery betavoltaics, which we can then sell and we get paid for those.

We kind of get paid twice and that makes it more viable. In fact, we could pass on cost savings in terms of getting paid to process the graphite, we could pass that on to make the cost of the diamond battery not so significant for a consumer.

In that way, we’d get a good PR in terms of helping to solve the international nuclear waste problem, not that we fully solve that problem but we can do a bit to change public perception about nuclear energy and at the same time we’re being very efficient in terms of recycling things that are useful for secondary use in the economy in areas where there is high value for it.

Q: Yes, definitely. It’s almost like every part of the animal.

A: Yes, exactly, absolutely that.

Q: I think I’ve covered most of my bases here but I just wanted to clarify.  If it’ll take eight to 10 years to hit the consumer market and you’re creating these higher prototypes, when do you really expect it to hit the specialty market?  What’s your timeline?

A: We would hope to start hitting the specialist market within three years.

Q: And you mentioned that the main barriers for that are just regulation and manufacturing?

A: Yes.  Manufacturing for mass production.  We would certainly, within three years, be able to make hundreds of devices where we are now and members of the team, members of the industrial advisory board will have prototypes which they would have out and be using in the real world for different things, just to test things out and to demonstrate technology.

In terms of the mass production.  The bit about regulation is partly about…  If you’re going to mass produce these things, you’re going to produce hundreds of thousands of devices a day.  You have to think about having on-site, wherever you’re making these things, the radioactive feedstock to make them, which means that you have to have permission to hold quite a lot of radioactive material in one place.

That’s part and parcel of the problem and so that’s why we would never be able to mass produce diamond batteries at the university because the environment agency wouldn’t allow the university to hold that much radioactive Carbon-14.

Q: In that case?

A: In the long run, we’d have to make these devices at a place where we do have regulatory approval to hold the feedstock material.  Obviously one individual device doesn’t have that much radioactive material in it, relatively speaking, but when you have all of the feedstock material together, then that’s quite a lot of radioactivity.

Q: Where do you expect that might be approved first?

A: It’s a really interesting one.  How do I phrase this? I’m very encouraged that the UK government has just decided to fund a facility at Culham Centre for Fusion Energy, which is in Oxfordshire, which is a facility that is specifically designed to extract tritium and other beta-emitting radioactives from waste irradiated graphite.  They’re putting something like 35 million into that facility.

That’s an example of a site where they can hold a significant inventory of beta emitting isotopes, which are exactly the ones we’d want to use for our devices.

In the future, it would be sites just like that where we’d want to make the case to have a manufacturing facility for the batteries.

Q: Apologies if this is an ignorant question but I want to know.  The regulation of manufacturing is one but would regulation of distributing also be another barrier?  Are those two separate barriers or in getting approval for one, say you got approval to manufacture in the UK, would you almost by default have the approval to distribute and sell?

A: If you think about the approvals behind making detectives with americium is exactly the same kind of case that you’d have to make for the diamond battery.

To make all of those smoke detectors at one site, you’d have to have an awful lot of material in one place, which is exactly the same as for us.  But then you have to have a separate but linked approval that says you’re allowed to sell these to domestic markets because they have a safety value but they’re not dangerous to anyone.

In terms of making the devices, we have to prove that they’re safe. We will have to do lots of tests that show there’s no detectable radiation on the outside if we break these. Is there any release of radioactive material? We’d have to prove that there’s not.

We’d have to prove through a series of specified tests, let’s say, by the regulators.  We’d have to show the risks posed by these devices and we’d have to show that it was sufficiently low that these could be allowed out into mainstream use everywhere.  And we’re confident that we could do that.

Q: I think that’s mainly what I want to know but is there anything else that you can see preventing these devices from being produced, aside from those two main barriers?

A: The upscaling the manufacturing is not a trivial thing.  It’s really not trivial at all. Please don’t think for a minute that we’ve got everything fully covered in terms of the technology development.  We’re working really hard at it and we know what the technical barriers are and we think we know how to overcome them. It’s not something that’s immediately done overnight and it’s not foolproof that we’ll easily be able to mass produce these things.

We’ll be able to make them in good numbers but to produce millions a year, that’s going to take a lot of further in the development to get to that size.  It probably means the configuration of the device will be different to what it currently looks like. It’ll be very exciting to do that but there’s still that technological barrier that we are part way to overcome it.  Part of that is the upscale of the manufacturing.

Q: Your timeline is creating more prototypes, and in doing so, testing them and showing that they’re safe. Correct?

A: Yes.

Q: Also, getting the patents and the regulatory approvals and then perfecting the manufacturing process…right?

A: Exactly.

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