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THE Nuclear Fusion Thread Pt. 3

Discussions of conventional and alternative energy production technologies.

Re: THE Nuclear Fusion Thread Pt. 3

Unread postby Tanada » Wed 10 Apr 2019, 15:30:01

Ready, set, go: Scientists evaluate novel technique for firing up fusion-reaction fuel



To capture and control on Earth the fusion reactions that drive the sun and stars, researchers must first turn room-temperature gas into the hot, charged plasma that fuels the reactions. At the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL), scientists have conducted an analysis that confirms the effectiveness of a novel, non-standard way for starting up plasma in future compact fusion facilities.

The innovative technique, known as "transient coaxial helical injection (CHI)," eliminates the central magnet, or solenoid, that launches the plasma inside tokamaks, the most widely used fusion facilities. Such elimination could facilitate constant, or steady state, fusion reactions and also free up valuable space in the center of compact spherical tokamaks, whose cored-apple shape has less room inside than conventional doughnut-shaped tokamaks that are more common.

Providing advantages

The freed-up space could provide advantages: It could be used to strengthen the magnetic field that confines the plasma and thereby improve its performance. Elimination of the solenoid could also simplify the design of compact tokamaks.

Fusion reactions fuse light elements in the form of plasma -- the hot, charged state of matter composed of free electrons and atomic nuclei that occurs naturally throughout the universe -- and thereby generate energy. Scientists are seeking to replicate fusion on Earth for a virtually inexhaustible supply of safe and clean power to generate electricity.

Solenoids run down the center of a tokamak and induce current in the uncharged gas that researchers inject into the facility. The current strips electrons from the atoms in the gas, turning it into a charged plasma -- a process called "ionization," or plasma breakdown. The current also creates a magnetic field that combines with the field produced by magnets that surround the tokamak to bottle up and control the plasma, enabling heating heating to produce fusion reactions.

Eliminating the solenoid

By contrast, the transient CHI process reported in Physics of Plasmas produces the crucial electric current with electrodes placed near the bottom or top of the tokamak, eliminating the space-eating solenoid. "What we primarily focused on was the beginning stage of forming the plasma," said physicist Kenneth Hammond of the Max Planck Institute of Plasma Physics, the lead author of the paper who did research on CHI as a Columbia University graduate student at PPPL and is joining the laboratory this summer. "This helped paint a fuller picture of how CHI discharges work."

Transient CHI -- so-called because the electrodes that produce the plasma-launching current run briefly rather than continuously -- was first developed in experiments on the small Helicity Injection Torus (HIT-II) at the University of Washington and the larger National Spherical Torus Experiment (NSTX) at PPPL prior to its upgrade; the process also had been modeled at PPPL. The experiments, which showed that transient CHI could be scaled up from smaller to larger machines, motivated the recent study, said Roger Raman, a University of Washington physicist on long-term assignment to PPPL and a coauthor of the paper.

The study found that the placement of CHI electrodes in the earlier experiments "could exhibit a severe weakness when scaled up to a reactor," Hammond said. He then analyzed an alternative electrode configuration similar to one presently used in QUEST, a spherical tokamak in Japan. The findings showed that the alternative configuration could scale up well in a future spherical tokamak-based fusion facility designed at PPPL. "The good news from this study is that the projections for startup in large-scale devices look promising," Hammond said.

Valuable potential

The CHI technique has valuable potential, concurred Tom Brown, a principal engineer at PPPL who helped design the concept of the future spherical facility. "If successful, CHI could provide space for interior components that could enhance the performance of spherical devices," Brown said. However, he added, "further engineering details need to be developed at the experimental level that also can work within a higher-level [demonstration] device and also in an eventual fusion power plant."

Researchers have thus far tested the CHI scaling in simulations conducted on the Tokamak Simulation Code, a computer program created by PPPL physicist Stephen Jardin that has modeled plasmas around the world. Jardin, a coauthor of the Physics of Plasmas report, worked with Raman to produce the simulation referred to in the paper. "Although CHI has never been tested on a large reactor-scale device," Hammond said, "we are optimistic that the same relationships will hold on the larger size with stronger magnetic fields."

Future experiments are scheduled on URANIA, a solenoid-free spherical tokamak at the University of Wisconsin-Madison. The new experiments will test the startup of plasma with two independently operated transient CHI electrodes -- a configuration that could produce greater flexibility for optimizing the promising system.


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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby EnergyUnlimited » Wed 10 Apr 2019, 16:28:43

@Tanada,
OK, lats say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby kublikhan » Wed 10 Apr 2019, 17:48:43

EnergyUnlimited wrote:@Tanada,
OK, lats say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.
This problem is going to be explored in the IFMIF project. IFMIF-DONES is currently in the engineering design phase.

The International Fusion Materials Irradiation Facility, also known as IFMIF, is a projected material testing facility in which candidate materials for the use in an energy producing fusion reactor can be fully qualified. IFMIF will be an accelerator-driven neutron source producing a high intensity fast neutron flux with a spectrum similar to that expected at the first wall of a fusion reactor using a deuterium-lithium nuclear reaction.

Background
The deuterium-tritium fusion reaction generates mono-energetic neutrons with an energy of 14.1 MeV. None of the commonly available neutron sources are adequate for fusion materials testing for various reasons. The construction of IFMIF is recommended in the European Roadmap for Research Infrastructures Report.
International Fusion Materials Irradiation Facility

The early construction of an 'Early DEMO' requires the accelerated construction of a neutron irradiation plant. This initial irradiation plant will have reduced specifications in terms of accumulated damage of the irradiated materials (30-40 dpa instead of 150 dpa). Thus, in the European framework it was decided to design and build a facility capable of producing the specified amount of damage as soon as possible. A discussion period was opened to determine the specifications of this so-called Early Neutron Source (ENS).

Following a proposal by the LNF, the design adopted for ENS is DONES (DEMO-Oriented Neutron Source), which basically consists of a simplification of IFMIF. Currently, the ENS is one of the EUROfusion Work Packages.

DONES will thus be similar to IFMIF but will only have one accelerator, and it will only include the irradiation modules required to test the structural materials, without a laboratory for the characterization of the irradiated samples. Based on these simplifications, both the cost and the time required for the design and construction of the facility will be significantly reduced. Also, DONES is being designed in such a way that it could eventually be upgraded in order to meet the full capabilities of IFMIF. The objective of the ENS project in the framework of EUROfusion (2015-2018) is the development of the R&D and the engineering activities required to start the construction of the facility before 2020.
IFMIF-DONES

In this paper, an overview and the present status of the IFMIF-DONES engineering design is presented for a generic site, making emphasis on the recent design evolution from previous phases.
The IFMIF-DONES project: preliminary engineering design

steps for implementation
EUROfusion and Fusion for Energy (F4E) started in 2015 a process to develop the engineering design of DONES and to identify possible EU sites to host the facility. In December 2017, F4E positively evaluated the joint Spain-Croatia proposal to site DONES in Granada. As the IFMIF-DONES enters the Roadmap 2018, it will be eligible for the Preparatory Phase grant by the EC and, simultaneously, will begin the Implementation Phase with the initial steps for the construction of the civil engineering infrastructure.
IFMIF-DONES
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby Tanada » Thu 11 Apr 2019, 02:20:25

EnergyUnlimited wrote:@Tanada,
OK, lets say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.


Personally I would line the walls with cadmium steel tanks and fill the tanks with asphalt, but it is not my project. Cadmium is a good neutron absorbent and asphalt has serious advantages over water as a neutron moderator. Its a solid at room temperature and doesn't boil until it gets above 500 C degrees so it acts as something of a heat sink if an emergency takes place.

Failing that you can always go with the old standby, heavy water using deuterium isotope of hydrogen like Canada uses in their fission reactor designs. You can also add a lot of boron to the water as was originally done in the emergency shutdown systems for fission reactors.
I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby EnergyUnlimited » Thu 11 Apr 2019, 15:00:15

Tanada wrote:
EnergyUnlimited wrote:@Tanada,
OK, lets say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.


Personally I would line the walls with cadmium steel tanks and fill the tanks with asphalt, but it is not my project. Cadmium is a good neutron absorbent and asphalt has serious advantages over water as a neutron moderator. Its a solid at room temperature and doesn't boil until it gets above 500 C degrees so it acts as something of a heat sink if an emergency takes place.

Failing that you can always go with the old standby, heavy water using deuterium isotope of hydrogen like Canada uses in their fission reactor designs. You can also add a lot of boron to the water as was originally done in the emergency shutdown systems for fission reactors.

These neutrons are needed to breed back trithium (from Li-6 lets say). You cannot afford to waste them. Another thing is that you need to make inner walls of reactor out of something. Any known solid materials are going to be eroded in no time at all. I don't think that cadmium steel would be an exception.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby StarvingLion » Wed 16 Oct 2019, 13:30:50

Cog's Bankrupt Navy has just SAVE US ALL....

Did US Navy patent a functional fusion device?

October 13, 2019

https://atomicinsights.com/did-us-navy- ... /#comments

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