Isegoria

Tri Alpha Energy has been working on nuclear fusion technology for nearly two decades and has just hit a milestone:

On Monday, the company announced that it started up a new nuclear fusion reactor that can achieve the high temperatures needed to continue to validate its technology plans. The reactor, named Norman — after the late company founder and professor, Norman Rostoker — can operate at temperatures between 50 million and 70 million degrees centigrade, which is in the temperature range of the core of the sun.

Commercial-scale nuclear fusion will likely have to operate in the range of a billion degrees centigrade. So Norman, which is the company’s fifth reactor, is just a step along the way.

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Norman, which is 100 feet in length and 45 feet wide, is housed at the company’s Foot Hill Ranch facility in Southern California. It can consume a whopping 750 megawatts of power in a short burst when it’s holding the plasma that is needed to create a nuclear fusion reaction.

Because of the high energy needs, the facility has an array of batteries and flywheels on standby that store the needed energy to get the reactor running. Norman achieved what’s called “first plasma” (i.e., it generated plasma in its core) in June.

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Unlike the tokamak’s donuts, Tri Alpha Energy is using a design that shoots beams of plasma into a vessel where it’s held in place, spinning, by a magnetic field. The design shares some properties with particle accelerators.

Norman cost $100 million to build, and can fit five times more plasma in it than the previous reactor. At the same time, it can still be housed at the facility that held the previous reactor.

Pliny the Elder, in his Natural History, described Rome’s concrete as “impregnable to the waves and every day stronger” — which, it turns out, was literally true:

Writing in the journal American Mineralogist, Jackson and colleagues describe how they analysed concrete cores from Roman piers, breakwaters and harbours.

Previous work had revealed lime particles within the cores that surprisingly contained the mineral aluminous tobermorite — a rare substance that is hard to make.

The mineral, said Jackson, formed early in the history of the concrete, as the lime, seawater and volcanic ash of the mortar reacted together in a way that generated heat.

But now Jackson and the team have made another discovery. “I went back to the concrete and found abundant tobermorite growing through the fabric of the concrete, often in association with phillipsite [another mineral],” she said.

She said this revealed another process that was also at play. Over time, seawater that seeped through the concrete dissolved the volcanic crystals and glasses, with aluminous tobermorite and phillipsite crystallising in their place.

These minerals, say the authors, helped to reinforce the concrete, preventing cracks from growing, with structures becoming stronger over time as the minerals grew.

By contrast, modern concrete, based on Portland cement, is not supposed to change after it hardens — meaning any reactions with the material cause damage.

A floating tidal turbine off the Orkney Islands generated 18 MWh over a 24-hour period, matching the generation capacity of offshore wind turbines:

The turbine is composed of a floating hull, with two turbines on the lower half of the body which sit just below the sea surface, the prime position for harnessing the energy of tidal flows. The turbines are also designed to fold upwards into the hull of the generator, which reduces transportation costs.

The machine has been designed to perform in areas with fast tidal flows, such as Scotland and Canada, but can be calibrated to perform in areas with softer breaks.

The SR2000 in numbers

Weight: 500 tonnes
Length: 64 metres
Rotor Diameter: 16 meters
Rotor Speed: 16 rpm
Rated Power: 2 MW

So far, no one has built a fusion reactor that generates more energy than it consumes, but researchers funded by NASA are developing small fusion rockets:

The large fusion reactors under development today, such as the International Thermonuclear Experimental Reactor (ITER), usually strive to generate hundreds of megawatts of power. In contrast, Paluszek and his colleagues at Princeton Satellite Systems are designing reactors meant to produce only a dozen megawatts or so. This humbler goal results in a smaller, lighter reactor that is easier to build and launch into space “for practical robotic and human missions,” Paluszek said.

In addition, these small fusion reactors are much cheaper than larger devices. Paluszek noted that, whereas modern fusion experiments might cost $20 billion, a prototype fusion rocket the researchers plan to develop should cost just $20 million. So far, they have received three NASA grants to fund the project, he said.

The aim for the fusion drives is to get about 1 kilowatt of power per 2.2 lbs. (1 kilogram) of mass. A 10-megawatt fusion rocket would therefore weigh about 11 tons (10 metric tons).

“It would probably be 1.5 meters [4.9 feet] in diameter and 4 to 8 meters [13 to 26 feet] long,” Paluszek said.

Nuclear fusion requires extremely high temperatures and pressures to force atoms to fuse, a process that converts some of the mass of the atoms into energy. The fusion reactors that Princeton Satellite Systems is developing uses low-frequency radio waves to heat a mix of deuterium and helium-3, and magnetic fields to confine the resulting plasma in a ring. (Deuterium is made of hydrogen atoms that each have an extra neutron; helium-3 is made of helium atoms, each of which is missing a neutron; and plasma is the state of matter found in stars, lightning bolts and neon lights.)

As this plasma rotates in a ring, some of it can spiral out and get directed from the fusion rocket’s nozzle for thrust. “We can get very high exhaust velocities of up to about 25,000 kilometers per second [55.9 million mph],” Paluszek said.

The large amounts of thrust this fusion rocket may deliver compared to its mass could enable very fast spacecraft. For instance, whereas round-trip crewed missions to Mars are estimated to take more than two years using current technology, the researchers estimated that six 5-megawatt fusion rockets could accomplish such missions in 310 days. This extra speed would reduce the risks of radiation that astronauts might experience from the sun or deep space, as well as dramatically cut the amount of food, water and other supplies they would need to bring with them.

In addition, the fusion reactors could also help generate ample electricity for scientific instruments and communications devices. For instance, whereas NASA’s New Horizons mission took more than nine years to get to Pluto and had little more than 200 watts of power to work with once it arrived, broadcasting about 1,000 bits of data back per second, a 1-megawatt fusion rocket could get a robotic mission to Pluto in four years, supply 2 million watts of power and broadcast more than 1 million bits of data back per second, Paluszek said. Such a mission could also carry a lander to Pluto and power it by beaming down energy, he added.

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Previous research suggested this kind of fusion rocket in the 1960s, but the designs proposed for them would not stably confine the plasmas, Paluszek said. About 10 years ago, reactor designer Sam Cohen figured out a magnetic-field design “that could make stable plasmas,” Paluszek explained.

One drawback of the kind of nuclear reactor that Princeton Satellite Systems is developing is that radio waves do not penetrate deeply into plasma. “We’re limited to something like 10 meters [33 feet] in diameter,” Paluszek said. To generate large amounts of power with this strategy, the researchers have to rely on multiple reactors.

Another pitfall is that, while this fusion reactor generates less deadly neutron radiation than most fusion reactors under development, it still does produce some neutrons, as well as X-rays. “Radiation shielding is key,” Paluszek said.

In addition, helium-3 is rare on Earth. Still, it is possible to generate helium-3 using nuclear reactors, Paluszek said.

Princeton Satellite Systems is not alone in pursuing small fusion reactors. For instance, Paluszek noted that Helion Energy in Redmond, Washington, also intends to fuse deuterium and helium-3, while Tri Alpha Energy in Foothill Ranch, California, aims to fuse boron and protons.

Stratolaunch’s carrier plane has rolled out for the first time:

The Stratolaunch carrier plane is designed to launch rockets into orbit from an altitude of 30,000 feet (9,100 meters). Initially, the plane will carry a single Pegasus XL rocket built by Orbital ATK, but the craft will eventually be able to carry up to three of those boosters simultaneously, Floyd said.

Stratolaunch Systems has been quietly designing and building the rocket-toting plane over the last few years.

“Over the past few weeks, we have removed the fabrication infrastructure, including the three-story scaffolding surrounding the aircraft, and rested the aircraft’s full weight on its 28 wheels for the first time,” Floyd said. “This was a crucial step in preparing the aircraft for ground testing, engine runs, taxi tests and, ultimately, first flight.”

The e-booster eliminates turbo lag:

It’s driven by electricity, so it spins up to 70,000 rpm in just three-tenths of a second, providing a boost until the turbocharger gets up to speed. BorgWarner says the cantaloupe-sized device, combined with a standard turbocharger, improves torque by 85 percent at 1,500 rpm, and by 55 percent at 2,000 rpm.

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BorgWarner first toyed with this idea in the late 1990s, but decided the e-booster needed too much power, says Verrier. But the recent development of 48-volt electrical systems changed the picture. Providing four times the power of a traditional 12-volt system allows the adoption of all kinds of new technologies: active ride control, electric water pumps, heated seats, and so on. The e-booster requires 5 or 6 kilowatts, something a 48-volt system can supply.