Now that summer is coming to a close I think it’s time to get the project moving. I can’t really afford it but with some modest expenditure I think I can get the vacuum chamber up and running.

It occurs to me that the project needs some sort of aim. Although ultimately I’m just playing at this, there should be some point to the experiments.

The big fusion experiments – NIF and ITER – are likely to succeed in generating net power at some point in the near-ish future. Then what? You can be sure that domestic electricity bills won’t go down. The power companies will simply claim that new fusion power stations require huge capital expenditure to justify keeping bills high (or even increasing them). One way or another the status quo will remain the same.

More importantly, these giant power stations will not help developing nations which cannot afford to build huge national delivery grids (which in any case suffer from transmission losses). In some, particularly mountainous, places it is simply impractical to build pylons and power lines.

Fuel cell technology may yet develop to the point where it becomes a realistic method of powering vehicles. The problem is that fuel cells run on hydrogen and hydrogen is currently produced in volume by cracking methane using steam. This requires large amounts of power and generates CO2; not good for the planet.

Thomas Edison’s vision for power delivery was to have neighbourhood power stations. He was wildly wrong in one respect – he wanted to use DC voltage. Thank god for Nikola Tesla who realised that high voltage AC was the more efficient method of delivery. Still, local production of high voltage AC power offers an intriguing prospect.

If fusion is really going to deliver on its promise then it needs to be delivered in a more democratic way. While ITER and NIF can press ahead with multi-megawatt reactor designs I want the aim of this project to deliver a small, portable reactor. I know that realistically I don’t have a chance but I want this to guide the experiments I do.

Imagine if you could build a small scale fusion reactor about the size of a modern car engine, delivering say 50KW. Every home would have one the wall next to the boiler. There would be no transmission losses and power generation would be taken out of the hands of a few big corporates. It would be simple to roll such devices out to every village in the developing world bringing power to everybody equally. If it were light enough you could put it in a car and solve the problems of fossil fuels overnight. It’s a bold vision but a democratising and highly disruptive one.

So this is the goal of the project – to build a small 50KW reactor (luckily one that fits inside the vacuum chamber I have). It may not be possible at all but it’s worth pursuing and you can be sure that no big corporation or research project is looking at it.

There are some big challenges with a small scale reactor. The first of these is heat. Much of the energy of a fusion reaction is releases in the kinetic energy of the reaction products. This means heat. Trying to recover the heat output of 20 kettles quietly, in a small space is a problem. Not an insurmountable though.

Another problem is the reaction products themselves. The cheapest and most plentiful fuel is deuterium but D-D reactions produce high energy neutrons. These cause problems with energy recovery, shielding and their effect on the reactor components. Nobody wants a highly radioactive box on their kitchen wall. The answer, then, lies in advanced aneutronic reactions such as proton-Boron11 but then these require much higher temperatures.

Tough problems!

Another Break

Here’s where I am at the moment…

Vacuum Chamber - Nearly There

Vacuum Chamber – Nearly There

The vacuum chamber is nearly complete. I have the ion tube for the flange on the arm although I don’t have the cables to connect it and the thermocouple sensor to the controller. The big 12″ flange on the top is about 2mm too big and will need to be replaced. I’ve connected the pumps and spun them up to check that they work.

The Polywell experiment is sat on top of the chamber. It’s nearly ready.

Unfortunately I’m unemployed at the moment so, until I’ve got some more money coming in, that’s going to have to be it for now.

I’m going to press on when I can. In the meantime I’ll try and gather some thoughts about the likelyhood of getting the polywell to work and also about other approaches such as muon catalysed fusion which I think may show more promise.

Vacuum Chamber Grief

I now have all the bits I need for the vacuum chamber apart from the sensor cables. I’ve spent the morning putting it all together. I finally took the big 12″ CF flange off the top of the chamber ready to fit the seals and bolt it down for the first vacuum test. Guess what. The flange, which I bought with the chamber is about 2mm too big. As a result the knife edges don’t match and the bolt holes don’t align properly. For fuck’s sake.

Now I’ll have to try and work out what size the flange actually is. My best guess is DN250CF but the DN250CF viton seal that I have doesn’t look like it fits either. The correct flange will likely cost around £300 and will take weeks to come. I got the original one from the US with the chamber so I don’t see much chance of getting any money back on it.

It seems like I’m still stuck at square one even after 3 months and about £5000. Not in a good mood.

Update Feb 2014

The project has been on a bit of a hiatus for the last couple of months while I waited for the fittings for the vacuum chamber to arrive. Today they arrived! I’ve started fitting them but I realise that I’ve missed a couple of minor things. Grrr! Fortunately the parts are ex-stock so next week I should be able to start getting the vacuum chamber up and running – at last.

The only problem I have now is cables for my ancient Varian Muti-Guage. It’s so ancient that the sensor cables are hard to find. If I can’t find any I can at least get the thermocouple up and running.

Jupiter 2M

I now have a turbo and backing pump in hand. The chamber is clearing customs and I’m waiting for a quote for all the flanges and other kit to come back. It will soon be time to do some real experiments.

In the meantime I was reading this article about electrostatic/magmentic confinement:

One of the criticisms I’ve read about the Bussard Polywell is that electrons leak out of the edges and cusps too quickly. I had already thought about putting a wire cage inside the polywell to plug the gaps in the electrostatically. As usual, somebody else has thought of it first.

A Ukrainian team has been working on a series of IEC devices which operate in a similar way to the polywell (they are IEC devices) but differ by plugging the magnetic field with a series of negatively charged electrodes. The team report good confinement times with their “Jupiter 2M” device. They are also linear devices which makes construction simpler. I’ll give some thought to building one of these, possibly first.


Progress Update

Things are a little quiet at the moment while I gather kit together. The vacuum chamber is en route from the US, I’ve bought a Leybold Turbovac TMP 50 turbomolecular pump and I’m bidding on a backing pump for the turbo. Everything should arrive in the next couple of weeks.

In the meantime I came across this…

Cold fusion – I’m yet to be convinced,

First coil

This is my first attempt at winding a coil. It turns out that the 2.0mm wire is much harder to work with than I expected. It’s quite springy and the holes I put on the bobbin to allow the wire out are perpendicular. The wire doesn’t like bending 90 degrees!

First attempt at winding a coil

First attempt at winding a coil

It wasn’t possible to get the turns to lie in neat rows. This is going to be really important if I want  a symmetrical magnetic field. I need to tweak the bobbin design and perhaps revisit building a winding machine.


The makerbeam parts that I ordered arrived yesterday.

Some offcuts of makerbeam showing the profile. Each beam is 10mm sqaure.

Some offcuts of makerbeam showing the profile. Each beam is 10mm sqaure.


After a quick trip to the Brighton Hackspace to cut the beam lengths to size, here is the basic frame for the experiment…

This is the basic frame for the experiment.

This is the basic frame for the experiment.

Ion Gun

The standard polywell “puffs” the fuel gas (deuterium to start with) into the core of the polywell from one of the corners. The idea is that the circulating electrons ionize the fuel which is then accelerated towards the core by the electric field generated by the electrons confined in the core. This doesn’t seem like a very efficient method of getting fuel ions into the core. As I’m injecting electrons using and electron gun I’m proposing to use the same principle to inject fuel – an ion gun.

This is my first stab at an ion gun…

A basic ion gun

A basic ion gun

Starting from the right, the small cube represents a tungsten filament. This emits electrons which are accelerated by the first cylinder (an anode) towards the half cylinder (this is another anode at higher potential). The fuel gas is injected via the small cylinder at the top. The electrons move across the stream of gas at high speed which ionises it. The lower, perpendicular cylinder, is a cathode which accelerates the ions towards the centre of the polywell.

The final ion gun will be a block of some description which will have these components mounted inside it. This ensures that the fuel gas only has one path to follow and doesn’t drift off in the vacuum chamber.