Focus Fusion: hot; $80k raised; Oxford lecture; safety

Posted by Sterling D. Allan
Pure Energy Systems News

Here’s an exerpt from an update from Focus Fusion

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LPP Focus Fusion Report

May 27, 2014

Summary:

  • Research news: High electron temperatures confirm FF-1 is hot;
  • Iran collaborators cut erosion
  • Crowdfunding launched; Gizmag coverage, $80 k raised so far
  • Lerner speaks at Oxford University
  • New cosmology research stirs debate
  • New information on Focus Fusion Safety

High electron temperatures confirm that FF-1 is hot

While LPPFusion’s experimental device, FF-1, remains inactive awaiting its new electrodes, a re-analysis of last year’s data shows that the electrons in the tiny plasmoid are just as hot as the ions—billions of degrees. This new analysis is important confirmation of the record 1.8 billion- degree ion temperatures published in 2012 and overcomes a limitation of that earlier data.In that earlier paper, the mean ion energy was measured.  But the measurement technique could not distinguish between ions moving as bulk motion around in a circle—trapped within the plasmoid—and random motion.  It is the random motion that produces the collisions needed for fusion reactions. By analogy it is the difference between the ordered motion of cars circling a race track and the random motion of a pile-up. Collisions are bad in traffic—but good in fusion.

The new electron temperature analysis overcomes that limitation. The measurement is based on x-rays emitted when electrons collide with ions. So it only measures random, collision-generating motion. If the electrons have that much random motion, as these measurements show, then that confirms that the ion energy is also mostly random—good for producing fusion.

The x-ray data was obtained last year by filtering one detector with 3 mm of copper and another with 6 mm of copper. The more energetic the x-rays, the more would penetrate the full 6mm. So the energy of the x-rays could be measured by comparing the amount detected through the thick shield compared with those simultaneously detected through the thin shield. The more energetic the x-rays, the more energetic-hotter the electrons that produced them.

Thanks to programming by our team’s Electrical Engineer Fred Van Roessel, we now have a program that automatically detects the x-ray peaks and lines them up in the two detectors (tricky because of the spikiness of the data). For 28 shots with clear matching of the peaks, the electron temperatures range from 90-160 keV (1.0 to 1.8 billion degrees K), just the same range as for the ion temperatures. Better yet, the electron temperature is correlated with the total fusion yield, as shown in Fig. 1. That indicates that we’re looking at the same plasmoid with both the x-ray and neutron detectors.

may2014_scatter-plot
Figure 1. Fusion yield in billions of neutrons (from our deuterium experimental gas) is plotted against electron mean energy. The correlation indicates that both hot x-rays from the electrons and neutrons from fusion reactions are coming from the plasmoid and confirms the multi-billion-degree temperatures first reported in 2012. (100 keV energy is equivalent to 1.1 billion degrees K)
More work needs to be done before these results can be published. The ion and electron temperatures for individual shots must be compared as well as the times of the peak temperatures. But this work-in-progress is another piece of evidence that FF-1 has already achieved the temperatures needed for burning aneutronic fusion fuels

Iran Collaborators Pressure

Erosion Down

In preparing for FF-1’s new experiments, the key objective is to eliminate as much as possible erosion – vaporization of the electrodes into the plasma, which creates impurities and interferes with achieving high density. The new tungsten electrodes will cut way down on several main mechanisms for this vaporization, but the LPP Fusion team identified a mechanism that the tungsten by itself won’t stop – runaway electrons. Now, experiments performed by LPP Fusion collaborators at the Plasma Physics Research Center in Tehran have shown that simply increasing the pressure of the gas in the vacuum chamber can stop the runaways, as theoretical calculations had predicted. This gives assurance that this source of erosion too can be stopped in the new FF-1 tests.Runaway electrons occur at the start of the current pulse, when high electric fields break down the resistance of the neutral gas, stripping electrons off of atoms and creating a plasma that can carry the current. The high fields accelerate some electrons to such high energy that they smash into the anode, the inner electrode, vaporizing a ring of material, as described in the LPP Fusion Feb. 27 report. Increased pressure should slow the electrons down with more collisions, thus preventing the vaporization.

That’s exactly what the PPRC team found.  When they ran their small 2 kJ plasma focus device with 0.2 torr of nitrogen, heavy erosion of the anode occurred. But when they lifted the pressure to 1 torr, the erosion was too small to be measured. These results confirm the hypothesis that runaway electrons are doing the erosion and show that they can be stopped.

In the meantime, the FF-1 team has implemented a second way to stop the runaways with pre-ionization. Here a small pulse of electricity smoothes the way for the much larger flow, getting rid of the high fields that lead to runaways. So we’ll have defense in depth with two complementary methods when experiments re-start.

Crowdfunding Launched on IndieGoGo, Gizmag Coverage, $80 K Raised

Just half way through our Indiegogo crowdfunding campaign, with 20 days to go, we’ve gotten 800 contributions totaling over $80,000. We got a big boost in news coverage from Gizmag, bringing in a wave of contributions. On the Indiegogo site, we are just we are just a few slots shy of being on their front page, which should give us another big boost when we arrive, possibly this week. So, even though we are at 40% of our goal half-way through the campaign, we still have great hopes of reaching our goal. In fact all 12 of the campaigns currently on the front page have already reached their goals.But we’ll need more publicity and our LPP Fusion team, Focus Fusion Society volunteers and our great campaign staffers are working hard letting the world know about clean fusion energy research. Thanks to all those who have given generously. We need your contributions, no matter what size, if you have not already given go for it now! Our special thanks to our top givers: Robert Beigler, Peter Crabb, Andrew Kursar and Walter Rowntree at $5,000 each and Jay Arena, Victoria Fash, Sami Lehesaari, Russell Robles , Greg Sanders and three anonymous donors at $1,000 each. Onwards to our goal!

Lerner Speaks at Oxford University

Oxford University societies hosted two presentations by LPPFusion President and Chief Scientist Eric Lerner in May. The Oxford University Scientific Society invited Lerner to tell them about our Focus Fusion project and the crowdfunding campaign. The presentation, a full description of where we are and the implications of our project are available here. The Oxford University Space and Astronomy Society also invited Lerner to speak about his and his colleagues’ new paper on the non-expansion of the universe. Thanks to our hosts Avi Roy, Leon Kong and Ryan MacDonald for the invitations.

New Information on Focus Fusion Safety

In the course of online discussion coming from our crowdfunding campaigns, some wildly inaccurate claims have been made by others about the production of radioactive waste in a focus fusion generator. We’ve replied online, but it is important to set the record straight in a document available on our own website, which we are doing here .First, LPPFusion has always said that a Focus Fusion generator would produce no “radioactive waste” NOT “no radioactivity”. Just about everything has some radioactivity – including human beings. But radioactive waste has radioactivity at dangerous levels. For example Class A waste, the least dangerous, has a radioactive level of 3.5 microcuries/cc.

While the main reaction in a pB11 generator is aneutronic, meaning it produces no neutrons, there are secondary reactions that produce about one neutron for every 200 aneutronic reactions. This neutron can produce tiny amounts of radioactivity in pure beryllium electrodes in two ways. First, about one in every 24,000 neutrons will be absorbed by a Be9 nucleus to create Be10, a radioactive isotope. After a month in a generator (about as long as we think the electrodes can last before they are eroded out of shape) the electrodes will have about 1 nanocurie/cc from this source which is 3,000 times less than the least radioactive waste.

Second, about 1 in 400 neutrons will break apart the Be9 nucleus, forming Li6 and He4. Neither of these is radioactive, but in a month’s time, about one in 26,000 Li6 nuclei will absorb a neutron, producing another He4 nucleus and a tritium nucleus. Tritium is a radioactive isotope of hydrogen, with a 12.6 year half-life. At the 800 C temperatures of the electrodes in the generator, the tritium will almost all escape into the chamber or the cooling helium gas. The tritium within the chamber will eventually be exhausted with the product of the main pB11 reaction, which is also helium.

If the tritium produced by a single 5 MW Focus fusion generator is simply diluted by a flow of 1000 gallons a day of water ( less than three US households’ use) the amount of radioactivity  will be below US safety limits for drinking water. The tiny amount of tritium trapped inside the electrodes will have radioactivity about 4,000 times less than the least dangerous radioactive waste.

Thus, NO radioactive waste is produced.

Detailed calculation and references are available here.

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