UoB_Chris_Hutton

Sums! 15J per day is 1.74x10^-4 Watts. (small!) Density of diamond 3.51g/cm-3 so 1cm3 would be 0.0006W. You would need 167000cm3 to make 100W, which is 0.67 cubic meters.

Sure, it's not a lot of power per unit vol!

Remember these are best used for low-powered devices like sensors rather than a light bulb!

Also, C-14 isn't actually in a spent fuel rod, it's in the graphite moderator which makes up most of the core in a Magnox and AGR reactor.

Standard alkaline AA batteries are designed for short timeframe discharge: one battery weighing about 20g has an energy storage rating of 700J/g. If operated continuously, this would run out in 24 hours.
In comparison, a diamond beta-battery would be designed to last longer. The actual amount of C14 in each battery has yet to be decided but as a rough guide, one battery, containing 1g of C14 will deliver 15J per day (based on calculations extrapolated from Ni63 prototype). On the face of it, this is less than an AA battery. However, it will continue to produce this level of output for 5,730 years, so its total energy storage rating is very high (2.7TeraJ aka million million Joules).

We hope it will grow into commercial uses, as well as dealing with some of the UK's radioactive waste.

Hope that answers your question!

Well just like in a standard battery, we can join several diamond battery systems together in either series or parallel to make more. As our research gathers pace we expect to see the power available increasing as our devices become more efficient. Hopefully we would be able to power lots of devices, but these would be especially useful where it is difficult to replace the battery (5730 year half life) such as remote locations.

I think the idea of using it to power deep space probes would be great - wouldn't it be amazing to be still receiving signals after thousands of years!

Yes, the lifetime comes from the half-life of carbon-14 which is 5730 years. And that radioactivity is locked up in the diamond structure so it can't escape into the environment.

We're keen to make use of all types of applications actually; we know about several scientific applications but are also keen to use it in more widespread applications. We had a member of the public suggest that powering tyre pressure gauges would be a really good application, so definitely applicable widely.