A start-up thinks of achieving an exploitable nuclear fusion system within a year

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American start-up Zap Energy, created in 2017, is working on developing a nuclear fusion reactor that does not use magnets. Its latest prototype is almost ready for the first tests and the company claims that its fusion energy could be exploited within a year! While other reactor prototypes are still struggling to get the power they need, many scientists remain more than skeptical of this announcement.

Nuclear fusion is emerging as a solution of choice to produce energy without harming the environment. In fact, it does not use fossil fuels, does not emit CO2 and does not produce long-lived high-level radioactive waste. It is based on virtually inexhaustible fuels (deuterium and tritium, which are two isotopes of hydrogen) and poses no risk of runaway reaction (unlike fission reactions).

The fusion reaction consists of the assembly of two atomic nuclei to form a heavier nucleus. This requires bringing these fuels to an extremely high temperature (several million degrees) in a confined environment. To create this plasma, there are several approaches, in particular magnetic confinement fusion (on which tokamaks are based, including the ITER reactor under construction) and inertial confinement fusion, performed by laser or axial neck (also called Z pinch ). It is on this last option that Zap Energy’s experimental reactor is based.

A fusion reaction that doesn’t require magnets

Few initiatives currently rely on this approach – most experimental fusion reactors in existence today use magnetic fields. However, Z-pinch nuclear fusion can be more efficient, simpler, and more cost-effective. In fact, Z-pinch reactors do not need complex networks of magnetic coils, nor particularly expensive shielding materials.

They rely on an electromagnetic field generated in the plasma itself. This fixes the plasma inside a relatively short column (about 2 meters high) and “squeezes” it until it is hot and dense enough for nuclear fusion to occur. Using this technique, Zap Energy hopes to soon produce more energy than needed to trigger the fusion reaction – something no one has been able to do so far reliably and sustainably, regardless of technique.

Zap Energy hopes to commercialize nuclear fusion power through modular, garage-sized reactors. © Zap Energia

The Z-pinch technology was created in the 1950s, but it suffered from instability issues. The Zap Energy team decided to exploit what’s known as “clipped axial flow” to smooth out plasma flows and thereby remove distortions that were sources of instability – and that hampered previous Z-pinch fusion attempts.

Last week, the start-up marked a critical technical milestone, creating its first plasmas in its FuZE-Q reactor. ” We demonstrate through simulation and experimentation that shear fluxes can stabilize fusion plasmas and that this stability should extend to a commercially viable scale. said Uri Shumlak, Scientific Director at Zap Energy. To accelerate the pace of bringing its technology to market, the company also announced the closing of a $160 million Series C financing.

Soon reactors the size of a garage?

Compared to current fusion approaches, Zap Energy’s technology does not require superconducting magnets or high-powered lasers. Therefore, it is more likely to rapidly evolve into smaller, less complex, and more scalable systems that will actually harness the energy of fusion.

The greater the current used to reach the Z-pinch, the hotter and denser the plasma. Increasing the current intensity is therefore a key element in advancing Z-pinch nuclear fusion. After hitting 500 kA last fall, Zap Energy developed a new device that supports higher currents: the FuZE-Q. ” The FuZE-Q is the fourth-generation Z-pinch device we’ve built, and it’s arguably the most ambitious says Brian Nelson, chief technology officer.

Electric current is the main energy production factor in Z-pinch fusion. Zap Energy’s experiments are gradually advancing towards the energy gains necessary for the commercial exploitation of this energy. © Zap Energia

The FuZE-Q can theoretically support the intensities necessary to reach the point of energy balance. Modeling predicts the latter to be around 650 kA of current. Of course, it will be necessary to go far beyond this threshold before this energy can really be considered a practical source of energy. The team is also looking to develop mass fusion reactors “small enough to fit in a garage”. Each of these reactors would be able to power at least 8,000 homes, the company says.

Critics are complaining, however, arguing that we have just embarked on another round of ‘fusion energy fever’, reports the New York Times. ” The fact that these claims are widely accepted is solely due to the effective propaganda of the laboratory’s sponsors and spokespersons. Daniel Jassby, a retired plasma physicist at Princeton University, told the paper. In any case, Zap Energy still has a long way to go, and in particular, it must develop a power supply powerful enough to compress plasma.

Source: ZapEnergy

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