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May 14, 2012

Dense Plasma Focus Fusion the road to net gain and then to commercialization

Getting to net gain over the next year or two

Focus Fusion Forum - Feasibility to become a net power producer fusing pB11 aneutronic fuel…. as outlined by Eric Lerner in the May 1st 2012 Agrion Webinar.

To gain higher yield and to attain “feasibility” the following steps are being done over the course of the next year (2012):

1) The “teeth that chew the sheath” tungsten crown to regularize the filaments - 10-100x yield
2) Full power output of Capacitors and to ‘Imitate’ the heavier mixture of pB11 by using Deuterium/Nitrogen.
3) Shorter Electrodes, slower run down, more fill gas.
4) New Raytheon switches for more Current from capacitors - 10x yield.
5) Switch to pB11 (incrementally higher percentage from the D/N mix) - 15x yield.
Goal: 30 kJ* gross fusion energy per shot proves feasibility of a positive net power output Generator using aneutronic fuel!
*A 5MW production reactor would have about 66 kJ gross fusion yield per shot*

From another comment about the Raytheon Switches (point 4)

FoFu-1 has been hampered by switch problems since its inception. The Raytheon switches, if they are the one I know of, will improve reliability dramatically. They are used on a 1 MA pulse power system that fires at 1 Hz and holds off 200 kV. Look up the linear transformer driver if you want to know more. I’m guessing these are the little brothers but they are good switches. They are talked about at many conferences. A few folks I know use them and they frequently comment on the high quality of the switches.

To my knowledge only a few groups operate their PF device at more than 1 Hz. The SRL group operated a PF using solid state up to 80 Hz at 260 kA. The NTU/NIE group in Singapore can operate two devices at up to 10 Hz. A few others operate at 1 Hz and above (~80 kA and ~300 kA) but they are rare. I’ve heard rumors of an Italian PF at 1 MA and 1 Hz but I haven’t come across any data. They were interested in radioisotope production so they would publish in journals I don’t frequent. I haven’t run across any talks at meetings I usually attend. The group I work in is using thyratron switches for 10 Hz, 60 kA and a type of spark gap for 0.25 MA, 1 Hz. Very few people have interests above ~10 Hz. The beauty of the PF and Z-pinches for most folks is the strong non-linear scaling in yield with current.

Technical Details and Applications about Dense Plasma Focus Fusion (2011)


After the net gain is proven the 100 person engineering problem ($30 million to solve three problems), (from 4:00 minutes to 10 minutes in the video)
1. How to get the waste heat out of the 5 MW device
2. Need 80% efficiency in the ion beam converter
3. Need high efficiency in the x-ray converter

Cannot go to thermal heat cycle. 80% of the costs for thermal are for the turbines etc.. So even if there was a free burner then by using the heat cycle you cannot get costs below 80%. Efficiency of conversion goes way down and it might make it impossible to reach breakeven.

The electrode gets the most wear and tear. They hope the electrode will last a month and get replace in a two hour maintenance procedure. The machine would last indefinitely and all of the parts are replaceable. The 5 megawatt size has great advantages to place it right next to the load. Put it at the substations.

Creating distribution infrastructure is cheaper than transmission structure.




Politics of Nuclear Fusion Research (2011)





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