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Discuss ways to make polywell research more widely known or better understood. Includes education and outreach.

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A new post is up.

Post by mattman »


A new post is up.

http://thepolywellblog.blogspot.com/201 ... ation.html

Over 15,600 pageviews. Wow.

Post Summary:

This post has two parts: a business analysis and an engineering analysis that supports it. The business analysis forecast machine price point, durability, ideal environments and break in markets. The feasibility debate is framed as hinging on if there is a plasma structure in the center or not, and data is called for. Bussards’ 1994 Navy report outlining an IEC power plant is mentioned. A price point of 91 cents and 16 cents a kilowatt-hour for a 1% efficient machine, fusing DD and PB11 respectively, is estimated. These cores are estimated to get about the same neutron flux as current pressurized water reactor fission cores, without a moderator. Market segments such as mobile generators, renewables, and isolated generation stations are mentioned. An emerging or high tech economy which is not dominated culturally, politically and economically by oil, gas, and coal is discussed as a launching environment. This is argued to be most fusion friendly.

The US Army is identified as a first adopter. It has the personal, resources and the unbiased outlook to support efforts. Generators for bases need fuel. This represents vulnerable supply lines, price fluctuations and 70% of battlefield tonnage and could be changed. The city of Sana’a in Yemen is identified as a first adopter. The city of 2.1 million needs water, is not connected to the oil industry, is the national capital and has an existing pipeline to the sea. A fusion powered desalination project could be supported by the government. Mumbai India is discussed; the city has a technology, entertainment, and financial based economy, has nuclear research institutions and needs water. The steel and copper mining industries are discussed - steel because it benefits from a drop in coal prices. Implementation means an onsite reactor owned and serviced by a contractor.

The engineering analysis estimates ion collision energy, price, ring construction, reactor durability and method of particle injection. Fuels each have ideal voltages, cross sections and energy generated, which supports the idea that the reactor is tunable. This is enumerated for DT, PB11 and two DD reactions. Using these, twelve price points are calculated, for a worst, (20% fuel conversion, 1% energy capture) better (35% fuel conversion, 5% energy capture) and best (45% fuel conversion, 12% energy capture) case scenarios. From this - tritium is prohibitively expensive - even in unreasonable conditions (99.999% fuel conversion, 90% energy capture) the price would be ~60 dollars a kilowatt hour. Pure deuterium is recommended and Boron is preferred for long term durability.

Material selection for the rings is discussed: graphite, 316 steel, neodymium, molybdenum, tungsten-carbide, silicon carbide, boron, Teflon and aluminum are all considered. Based on relative magnetic permeability, neutron activation, melting point, thermal conductivity, price and electrical conductivity – the case for stainless steel or tungsten-carbide is made. Reactor burnout due to embrittlement, transmutation and thermal stress is outlined. A basic analysis of neutron bombardment using the displacements per atom (dpa) equation is presented. Material cracking is a problem at 1 dpa. To apply this equation, cross section data for specific byproducts, materials and energies was recovered from the Los Alamos’s nuclear information service. Data was incomplete, so only the neutron data was used (a worst case analysis). Cross sections are estimated by constituent material proportions. Dpa rates predicted, range from 0.0006 to 8.61 (a 1300 MW PWR fission core experiences 0 to 90 dpa). This analysis is very limited by not considering thermal stress, local chemistry and materials processing.

The time for electron fill up is estimated. Electron guns are modeled based on off the shelf products. The time is calculated based on the fuel, the voltage predicted, the ion to electron ratio and the number of guns. The machine is treated like it pulses for 100 microseconds up five minutes. A review of Nevins paper is called for – which argues pulsing, will not work. The ion injection analysis is unneeded.

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