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Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Kahuna
Posts: 300
Joined: Sun Jul 26, 2009 12:17 pm
Location: CA

Post by Kahuna »

New Energy & Fuel Article on LPP Progress & Challenges:

http://newenergyandfuel.com/http:/newen ... one-to-go/

D Tibbets
Posts: 2775
Joined: Thu Jun 26, 2008 6:52 am

Post by D Tibbets »

Joseph Chikva wrote:
D Tibbets wrote:They speak of P-B11 because from a physics standpoint (their claims) it is both doable and desirable. While D-T may be more doable, it is less desirable, and quite possibly more expensive for these cash strapped research efforts.
Nobody argues that better to be healthy and at the same time to be rich. So, we all know what is desirable. But I have well stated doubts on viability. Once again: if double for them to lift 200 kg bar, let's they show their ability to lift 100 kg.
As I do not see their such ability.
The P-B11 of D-He3 reactions may be essential for the ff or FRC due to engineering issues (energy density). It is a trade off- more difficult physics, but much easier engineering.
You are wrong. The same physics with much complex engineering. And the second wrong point is that you talk about commercial reactor. Do you believe that their existing experimental device can produce net power? Or that is intended only to prove viability of concept?
I think that proving viability is maximum they need. Without any energy conversion into electricity.
Also why do you (and others) think that direct energy converter will be cheaper and easier than combination of first wall, blanket, heat transfer circuits, steam turbine, generator? Have you ever seen running direct energy converter? This a big extremely high current decelerator (negative accelerator) of charged particles. And unlike steam cycle that is well developed nobody around the world has not any experience in its design and building.

By the way, you in vain bothered on difficulties with processing of tritium. That is not so difficult and dangerous as you think. At least now even tritium sights for riffles are offered for hunters and also for militaries. And for one shots only fraction of gram are required. And one Canadian company sells tritium compressed in cylinders for laboratories. If they (LPP team) are so proud when get several millions neutrons per each shot, so they are not afraid neutrons, and so let they use DT mix and get on 7-8 orders higher yield. Certainly, if they can.
Gun sights with tritium in the paint is far different from handling gaseous tritium, and handling huge amounts in a Tokamak. The liquid lithium blanket on the lateral walls and bottom may be a modest engineering challenge, but on the top? Capturing the 17MeV neutrons in high enough efficiencies while also handling the deposited heat load for net gain tritium production will be a considerable challenge.
In a ff device, the damage from the high energy neutrons is much worse because of the fusion density in these small machines. The wall loading will be much greater than in much larger machines with much smaller wall loading issues- such as Tokamaks or even Polywells. A Tokamak or Polywell may survive D-T fusion long enough for economic profit. A dense plasma focus or FRC (?) will not.

So D-T fusion may be an option for bragging rights, but P-B11 or D-He3 burning are the only options for a working commercial DPF reactor, and some think even this will erode the electrodes (in part due to X-rays) too fast for successful utilization on a commercial basis.

Dan Tibbets
To error is human... and I'm very human.

Skipjack
Posts: 6051
Joined: Sun Sep 28, 2008 2:29 pm

Post by Skipjack »

A dense plasma focus or FRC (?) will not.
Actually John Slough of MSNW LLC and Helion has developed a viable solution for that.

Joseph Chikva
Posts: 2039
Joined: Sat Apr 02, 2011 4:30 am

Post by Joseph Chikva »

D Tibbets wrote:Gun sights with tritium in the paint is far different from handling gaseous tritium, and handling huge amounts in a Tokamak.
Huge ammounts?
Tritium nucleus weighs 5.01E-27 kg
Number density let's say 1E20 m^-3
Plasma volume 840 m^3
So, the single charge of tritium for ITER 4.2E-4 kg and this is only 0.42g
and for equimolar mix of DT fuel 0.42g of tritium and 0.28g deuterium
Total charge of fuel is 0.7g

D Tibbets
Posts: 2775
Joined: Thu Jun 26, 2008 6:52 am

Post by D Tibbets »

Joseph Chikva wrote:
D Tibbets wrote:Gun sights with tritium in the paint is far different from handling gaseous tritium, and handling huge amounts in a Tokamak.
Huge ammounts?
Tritium nucleus weighs 5.01E-27 kg
Number density let's say 1E20 m^-3
Plasma volume 840 m^3
So, the single charge of tritium for ITER 4.2E-4 kg and this is only 0.42g
and for equimolar mix of DT fuel 0.42g of tritium and 0.28g deuterium
Total charge of fuel is 0.7g
It depends on how you calculatethe numbers. A commercial Tokamak may generate 5-10 GW. . That would be ~ 10^22 fusions per second, or ~ 0.1 mole of tritium consumed (and needing replenishment from the lithium blanket and associated beryllium, lead/etc. magnifiers). This number is similar to yours.

The point is that this amount needs to be produced, and processed per second. In an hour this would add up to ~ over a Kg of tritium passing through the various production, collection and processing systems. Tiny leaks or separation inefficiencies could lead to major contamination issues, and of course further add to the burden of the already challenging tritium generation.

~ 20- 50 Kg of tritium may be produced per day. I don't think anyone would consider this a trivial amount.
I don't know what volume of water containing this much tritium would be dangerous, but I guess it would be a large lake.

Dan Tibbets
To error is human... and I'm very human.

Joseph Chikva
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Joined: Sat Apr 02, 2011 4:30 am

Post by Joseph Chikva »

D Tibbets wrote: but I guess
You are wrong.

Ivy Matt
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Joined: Sat May 01, 2010 6:43 am

Post by Ivy Matt »

There's a new video up on the LPP website, LPP director of business development Derek Shannon giving a presentation at the 15th Annual Mars Society Convention. It's half an hour long, though, and I didn't really hear anything new to me, except that LPP currently plans to start working with boron fuel this winter.
Temperature, density, confinement time: pick any two.

D Tibbets
Posts: 2775
Joined: Thu Jun 26, 2008 6:52 am

Post by D Tibbets »

Joseph Chikva wrote:
D Tibbets wrote: but I guess
You are wrong.
J C, your dismissal of my guess without any reference, has forced me to do a little research.

Normal tritium for commercial purposes is ~ 400 g per year. EPA standards for drinking watter is 20,000 picocuries per liter. At 9650 Curies per g of tritium, that would be ~ 9650x10^12 picocuries / 20,000 picocuries = 4.8 * 10^11 liters of water per gram of tritium.

That is ~500 billion liters of water contaminated with 1 gram of tritium would reach the upper limits of EPA safty limit.
Converting liters to cubic meters (1 M^3 / 1000 liters) gives ~ 500 million M^3 of contaminated water. Multiply that by thousands of grams of tritium produced and recycled through a large Tokamak and your back up to ~ 500 billion M^3 of contaminated water. In a lake ~ 100 meters deep that would be a surface area of ~ 5 billion M^2 or ~ 5,000 KM ^2.
I think this would qualify as a big lake!

Of course expectations would be that only a very tiny fraction of the tritium might escape. But still the possibilities need to be considered, and I GUESS the radiation hazards specifically from tritium from a commercial Tokamak would exceed a whole handfull of fission power plants. It cannot be ignored or dismissed. The tritium problem of D_T fusion cannot be neglected. The saving grace is the relative short half life of tritium. Confinement/ storage needs are only for a few hundreds of years, not the ~ 100,000 years for fission.

Note that D-D fusion also produces tritium and on large commercal scales it will add up to a lot. It has to be stored or used. Bussard has proposed burning tritium and helium 3 fusion products by feeding it back into a D-D Polywell. This improves gain, and also eliminates the tritium. Nothing is perfect and these issues need to be carefully considered what ever machine is considered.

In a tritium contamination accident. An earthquake or sunomi might breach a reactor and release the tritium in the system. The scale of this would be much larger in the Tokamak than a Polywell. The tritium produced per second or in the reaction space in the reactor may be a fraction of a gram, but the main problem is what could be released in the liquid lithium, etc materials that are undergoing processing for reuse.


http://www.nrc.gov/reading-rm/doc-colle ... on-fs.html
EPA set a maximum contaminant level of 20,000 picocuries per liter (pCi/L) for tritium. This level is assumed to yield a dose of 4 mrem per year.
http://ah-tritium.blogspot.com/
Commercial tritium demand is 400 grams/year . The current U.S. arsenal of 10,000 warheads requires approximately 2200 grams/year (at four grams of tritium/warhead) to offset decay.

The specific activity of 3H (Tritium) is 28.8 Ci/milliatom, or 9650 Curies per gram, or 357 Tera-Becquerels per gram, or as 28.7 Ci/mmol (Curies per millimole). Pure tritium gas (T2) has a specific activity just over 57,000 Curies/mol.

One Curie of tritium weighs about 0.0001036 grams. One Curie of tritium contains approximately 20,811,069,238,989,819,449 atoms = about 2.08 X 10^19 atoms. One atom of tritium weighs about 4.979 X 10^-24 grams (0.000 000 000 000 000 000 000 004 979 grams). Whether in the form of gaseous hydrogen or as water vapor, 1.85 x 10^12 Bq (50 Ci) of tritium occupies a volume of about 1/6 of a cup. One gram of T2 gas has a radioactivity of 3.59 X 10^14 Bq (9.7 X 10^3 Curies). There are about 359,000,000,000,000 (359 trillion) decays per second in one gram of tritium gas (T2).
Dan Tibbets
To error is human... and I'm very human.

Teemu
Posts: 92
Joined: Mon Oct 17, 2011 10:15 am

Post by Teemu »

So that would be Lake Erie pretty much exactly, volume 489 km3.

Joseph Chikva
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Joined: Sat Apr 02, 2011 4:30 am

Post by Joseph Chikva »

D Tibbets wrote:Normal tritium for commercial purposes is ~ 400 g per year.
The your sentense may meant "there is not more production" or "there is not more qualified consumption". I think the second. And you?

KitemanSA
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Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Post by KitemanSA »

See?

D.T. goes about proving his initial guess about a "large lake" and does the troll accede? No, it find some piqueun argument.

Please folks, don't feed the troll!

Joseph Chikva
Posts: 2039
Joined: Sat Apr 02, 2011 4:30 am

Post by Joseph Chikva »

KitemanSA wrote:D.T. goes about proving his initial guess about a "large lake"
Does not matter initial or final but guess on large lake is nonsense. As tritium is offered on the market in gaseous form and that is not as dangerous as you or Dan think. As I have shown you and others its application for e.g. military and hunter's sights.

303
Posts: 114
Joined: Thu Jan 12, 2012 11:18 am

Post by 303 »

http://www.physics.isu.edu/radinf/tritium.htm

Some rifles use tritium for in their front sight. They will use about 12 mCi of tritium dissolved in a phosphor liquid contained in a small glass vial.

The rifle sights contain 12 mCi of tritium. If all of its activity were ingested, the CEDE would be 768 mrem or roughly two years of dose from natural background.


so im guessing you wouldnt want to skinny dip in this lake of yours, anyone know more about how or why this vial is used in a gun sight ?

KitemanSA
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Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Post by KitemanSA »

Cuz it is still safer than the Radium they used to use?

Joseph Chikva
Posts: 2039
Joined: Sat Apr 02, 2011 4:30 am

Post by Joseph Chikva »

303 wrote:anyone know more about how or why this vial is used in a gun sight ?
Imagine that at nighttime you can see the target as that is illuminated by some sources - e.g. illumination mortar bomb but you yourself are in darkness and can not see your rifle’s sights - both: front and rear as well. But if your sights have the lighting dots, you can easily combine them with target and so can engage that.

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