Half a million volt fusor... Am I crazy?

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deuteriumhusky
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Half a million volt fusor... Am I crazy?

Post by deuteriumhusky »

I've been given the chance to build my dream fusor. My new power supply is rated for 125 kV at 100 mA in pulsed mode and i'm working with an EE to build a voltage quadrupler so I can operate at 500kV at 25 mA. I can't say now much however i'm moving my fusor to a more industrial setting that has a rated hydrogen sniffer and it is rated to provide the necessary amperage. I'm moving it out of a residential zone and into one that's zoned for industrial use and one that can provide the necessary amperage. I'm going to jacket the inside with 2"-4" of lead (the chamber is a 13" diameter cylinder). For low power operation (3.6 kW) i'm using a 30 A variac however for high power operation I'm going to need to find a variable input transformer that can provide ~110A. The chamber walls are already thick at 1/4" stainless steel. I'm going to experiment with several solid targets as well as a few new grid designs as well as an online irradiation port.
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Adam Szendrey
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Re: Half a million volt fusor... Am I crazy?

Post by Adam Szendrey »

I'm sure I don't need to say this , but it can't be stressed enough...The voltages you put forward along with the potential power capability of your proposed power supply is an absolutely, instant kill combination, and a major fire hazard, not to mention the shine from the reactor (x-rays). Shielding against the latter is one thing (and pretty much the simplest), but I strongly suggest an interlock system for the HV part...put the fusor in a metal cage with a door that, if opened, immediately shuts off the supply and grounds it's output. You'll also need a massive feedthrough to pull this off, some sort of current limiting, etc. I'd say forget about the "voltage quadrupler" and just use your 125 kV supply, as is....You don't gain much above that voltage anyway, and a "voltage quadrupler" will just add stored energy to the mix, capacitors, making it all the more deadly.... Even at that voltage it'll take some serious planning and a very careful assembly, to do this at least somewhat safely, and without a lot of arcing, and corona discharging (you'll need plenty of clearance, and to carefully design the HV lead, proper grounding, etc). Extra care needs to be taken so no lines/connections going to the reactor (be it a gas line, or cooling, or control, sensors, etc) can "float", and the HV can't arc to them either. ONLY do this if you have the proper know how and experience with high voltage, high power. I might be a bit "over-protective", but damn, such high voltages at those currents can do some crazy stuff...Good luck.
Tom McCarthy
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Re: Half a million volt fusor... Am I crazy?

Post by Tom McCarthy »

Adam is by no means being "over protective."

Even for a 60kV (Half of your supply's voltage without the quadrupler) supply like I have, the electrical engineer has made me move my Fusor into a third-level institution for supervision under their EE department. As Adam suggested, there's going to be an interlock system too...When you first hear about all the safety precautions it can seem like a lot of exaggeration and hyperbole, but the reality is that electricity is the most dangerous thing you're going to be working with in a Fusor, miles ahead of any other danger. Make sure the guy you're working with knows what he's doing and get a second opinion, otherwise deuterium husky becomes medium-rare husky.

Also, I can't get it now, but there's a curve showing that above ~80kV (from memory) your gain from raising voltage flattens to almost nothing, it's just a big waste of energy.

Tom
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Bob Reite
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Re: Half a million volt fusor... Am I crazy?

Post by Bob Reite »

According to a chart that I have at hand, at 100 KV, the cross secion for D-D fusion is 100 Millibarns. The curve maxes out at around 200 give or take for 700 KV or so, 500 KV comes pretty close. Is a mere doubling worth all the hassle of dealing with 500 KV? You are going to need a large space in order to have the clearances you need to keep things from arcing over to where they shouldn't. Corona will be a major headache.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Andrew Robinson
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Re: Half a million volt fusor... Am I crazy?

Post by Andrew Robinson »

It's easy for people on this forum to scale these numbers... 20Kv, 40Kv, 400Kv... Its just a number right haha. Only those that have extensive experience with these types of high voltages truly understand the challenges at hand. I would be VERY careful!!! Let me rephrase. You cant just scale up and expect your high voltage system to behave the same. I really hope you have enough experience with high voltage to know what you're getting yourself into. Best of luck and BE SAFE!
I can wire anything directly into anything! I'm the professor!
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Richard Hull
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Re: Half a million volt fusor... Am I crazy?

Post by Richard Hull »

I would go along with all the rest here.

For the average amateur, it is a struggle to get 40kv at usable currents. Several of our best folks have hit 60kv. There is little to no operating experience above this level here....at least with successful, ever increasing fusion numbers. All the best and be safe.

The classic, amateur fusor operates in a very tight zone of glow discharge with hyper tight regulation of pressure,voltage and current by a trained and experienced user needed to make successful runs. Increasing the voltage and or the pressure, to seek increased fusion, will force currents often to the point of damaging or melting the grid. Usually, long before this happens, a current limiting safety circuit foils the electron emission "runaway", shutting down the supply. Melting occurs when there are no automatic safeguards in place or when the operator is inattentive or inexperienced.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Jim Kovalchick
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Re: Half a million volt fusor... Am I crazy?

Post by Jim Kovalchick »

The University of Wisconsin has pushed some pretty high voltages, and I would start by looking at their work.

Just the feedthrough would make most of us broke.
Brian_Neumeyer
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Re: Half a million volt fusor... Am I crazy?

Post by Brian_Neumeyer »

What order of magnitude did Wisconsin get? Additionally, where would one look at their work?
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Rich Feldman
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Re: Half a million volt fusor... Am I crazy?

Post by Rich Feldman »

Let me Google that for you. Second question first:
Department of Engineering Physics.
439 Engineering Research Building
1500 Engineering Drive
University of Wisconsin-Madison
Madison, WI 53706

The answer to the first question impressed me, and can be found just as easily. STFI.
All models are wrong; some models are useful. -- George Box
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