The Energy Blog

Largest Laser Beam in the World to Create Fusion

This video is about the National Ignition Facility, more details in previous post, at Lawrence Livermore National Laboratory, employing the largest bank of laser beams in the world, to be used in an experiment designed to create fusion ignition, a potential clean energy source for the 21st century. The $3.5 billion complex is under construction and expected to start full operations in 2009.

Scientists are creating a system to replicate fusion by using lasers to create the high heat and pressure needed for fusion. At the center of the project is a gold cylinder the size of a dime. This gold cylinder, called the hohlraum, houses a capsule containing the hydrogen isotopes – the fuel for the fusion reaction. NIF scientists will blast the hohlraum with 192 laser beams simultaneously (containing a total of 1.8 million joules of energy, about 500 trillion watts) for a few billionths of a second. The cylinder will produce x-rays that compress and heat the capsule resulting in a nuclear fusion reaction.

This experiment is not a continuous fusion reactor, it is an experimental device designed to determine whether scientists can create a fusion reaction for an instant of time, using this method. It does not produce any continuous output as ITER is designed to, It is one of the first major steps designed to see if lasers can be used to create fusion.

The ITER Tokamak, a $13 billion magnetic containment device, is based on totally different technology and would be the first fusion device to produce thermal energy at levels equivalent to conventional electricity power plants.

Several other containment devices are being tested throughout the world, in an attempt to develop a device that is superior to that used in ITER. The technology used in ITER is the most advanced and thus was selected for use in that ground breaking experiment.

Thanks to Lauren Sommer of KQED for the tip

Helically Symmetric eXperiment (HSX) at UW More Efficient than Previous Stellarators

A research team, headed by electrical and computer engineering Professor David Anderson and research assistant John Canik at the University of Wisconsin-Madison, recently proved that the Helically Symmetric eXperiment (HSX) can overcome a major barrier in plasma research: Previous stellarators lost too much energy to reach the high temperatures needed for fusion.

Results show that the the odd-looking magnetic plasma chamber design of the HSX in fact loses less energy than previous stellarators, meaning that fusion in this type of stellarator could be possible.

Current plasma research builds on two types of magnetic plasma confinement devices, tokamaks and stellarators. The HSX aims to merge the best properties of both by giving a more stable stellarator the confinement of a more energetically efficient tokamak. "The slower energy comes out, the less power you have to put in, and the more economical the reactor is," says Canik.

Nuclear Fusion Edge Instability Problem Tackled

A possible way to prevent super-hot gases in fusion reactors from damaging the containment vessel has been discovered, which could make fusion a more viable energy solution.  Fusion reactors generate power by heating hydrogen plasma to 100 million degrees Celsius. This causes hydrogen isotopes to fuse together and release energy. But the blistering plasma has to be contained within a vessel using a donut-shaped magnetic field, created using several powerful superconducting magnets. Over time, the reactor's plasma-containing vessel will inevitably be damaged by instabilities known as "edge-localized modes" (ELMs)¹ that occur when hot plasma bursts out of the magnetic field.

Unless these ELMs can be controlled, expensive components need to be replaced regularly. Researchers at General Atomics discovered that by using a separate magnetic coil to induce small perturbations in the reactor's main magnetic field, they found that they could bleed off enough of the plasma particles to prevent the ELMs from bursting out.

Laser Fusion Milestone Achieved

A major milestone was reached recently when scientists at Lawrence Livermore National Laboratory in California reported that they had demonstrated that laser pulses shot into a cavity can produce the conditions required to trigger nuclear fusion reactions.  The finding was a crucial test of principle for Livermore's National Ignition Facility (NIF), the $3.5 billion complex now under construction and expected to start full operations in 2009.

When completed NIF will be, by far, the world’s largest and most energetic laser and a major international scientific resource. Designed to study the physics of matter at extreme densities, pressures, and temperatures, NIF will use 192 laser beams to compress fusion targets to conditions required for thermonuclear ignition and burn. In the process, more energy will be liberated than is used to initiate the fusion reactions.

About Focus Fusion

Developers, led by Eric J. Lerner, are developing Focus Fusion, a fusion process to generate electricity that is expected to be relatively cheap, highly efficient, and small enough to fit into a garage.  The process which channels hydrogen-boron fuel through a plasma focusing device, uses a smaller, more elegant approach than is currently being pursued by conventional fusion researchers.  This device could be fired up and shut off with the flip of a switch, with no damaging radiation, no threat of meltdown, and no possibility of explosions

Focus Fusion reactors are small and decentralized, ideally suited for distributed power generation. Focus Fusion reactors can fit into a garage.  Lawrenceville Plasma Physics (LPP) Focus Fusion project aims at developing an electric generator with a projected output of about 5 MW, sufficient for a small community.  The Focus Fusion process can produce electricity directly without the need to generate steam, use a turbine or use a rotating generator. The reactors are extremely compact and economical, with expected costs of $300,000 apiece. As the fuel is an insignificant cost, electric power production is estimated at about one tenth of a cent per kWh, fifty times cheaper than current costs.  Because it can be shut off and turned on so easily, a bank of these could easily accommodate whatever surges and ebbs are faced by the grid on a given day, without wasting unused energy from non-peak times into the environment, which is the case with much of the grid’s energy at present.  On-site personnel are not needed on a daily basis, maintenance would be rare.  One technician could operate a dozen facilities by themselves.

Fusion - The ITER Project

June 28 - Fusion took a giant step closer to becoming a commercial reality today, as France was selected to host a $13 billion experimental nuclear fusion project that scientists hope will eventually produce a clean, safe and endless energy resource and help phase out polluting fossil fuels.  An experimental device called the "International Thermonuclear Experimental Reactor (ITER)" will be built in France. ITER is hopefully the step that will bridge the gap between today’s studies of plasma physics and tomorrow's electricity-producing fusion power plants. The goal of the project is to demonstrate methods of extracting the power of nuclear fusion.  Fusion is the same process that goes on in the center of the sun in which energy is produced when the hydrogen isotopes deuterium and tritium are fused together to form helium, while releasing huge quantities of heat.

The ITER Tokamak, a magnetic containment device, would be the first fusion device to produce thermal energy at levels equivalent to conventional electricity power plants, and would demonstrate the technology necessary for the first prototype commercial fusion power plant. It is based around a hydrogen plasma torus operating at over 100 million °C, and will produce 500 MW of fusion power.  It would work by heating isotopes of hydrogen to hundreds of millions of degrees, creating a plasma of charged particles.