An electrical outage at Ukraine鈥檚 Chernobyl Nuclear Power Plant has taken spent fuel cooling systems offline, leading to a potential risk of overheating and the release of dangerous levels of radiation 鈥� but due to the age of the fuel, it should be safe until power is restored.

The International Atomic Energy Agency (IAEA) reports that several Ukrainian electrical substations have been hit by Russian military strikes, causing power outages at Chernobyl. 鈥淭he IAEA is actively following developments in order to assess impact on nuclear safety,鈥� wrote IAEA director general Rafael Grossi .

Spent nuclear fuel from reactors continues to emit radiation for years, creating heat that must be shed, or else the fuel can melt and emit a spike of dangerous radiation. The fuel from Chernobyl鈥檚 former reactors is stored in a large cooling pond that is constantly replenished with fresh, cold water to keep its temperature down.

But without an electricity supply 鈥� which the IAEA says the site now lacks 鈥� this cooling has stopped, which will allow the water temperature to rise and increase the rate of evaporation.

鈥淲hen the fuel comes out of a reactor, it will be hot for a while, because there will be fission products and there will be radioactive and giving off gammas and betas and alphas 鈥� just emitting energy, which needs to be removed, otherwise it will eventually melt,鈥� says at the University of Cambridge.

Working in Chernobyl鈥檚 favour, however, is that its stored fuel is older and therefore has already had time to emit much of its radioactive energy and cool down. The risk now is lower than the risk was in 2022, for example, when 快猫短视频 reported on similar power outages at Chernobyl.

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鈥淚t is always a worry when a nuclear site loses power, but worry about nuclear risks is often several orders of magnitude above the risks associated with other events with similar consequences,鈥� says , also at Cambridge.

Chernobyl鈥檚 reactor 4 exploded in 1986, but reactor 2 was shut down in 1991, reactor 1 ceased generating power in 1996 and reactor 3 鈥� the final one at the site 鈥� was decommissioned in 2000.

The exact specifications of the storage pools that contain the fuel left over from those reactors at Chernobyl are kept classified, says Cosgrove. But he is aware of an inspection by regulators in 2022, which found that the risk of spent fuel overheating in the case of a power outage was low. 鈥淭his fuel has been sat in there for 20 years, so it will have decayed. More and more of that energy will be gone,鈥� he says.

Electrical supply to Chernobyl 鈥� and indeed much of Ukraine 鈥� has been up and down since Russia鈥檚 full-scale invasion. But in recent months, Russia has increased its attacks on Ukrainian infrastructure.

The loss of power at Chernobyl is the latest in a string of Russian actions that have compromised nuclear safety, including occupying Chernobyl for several weeks and disrupting staff from maintaining it properly, taking over the Zaporizhzhia Nuclear Power Plant in a similar but long-running manner, and striking the New Safe Confinement building, which covers the ruins of Chernobyl鈥檚 reactor 4 disaster, with a drone in February last year.

Chinese researchers have developed an extremely energy efficient and low-cost technology for extracting uranium from seawater, a potential boon to the country鈥檚 nuclear power ambitions. China currently leads the world in building new nuclear power plants, and shoring up its supply of uranium will help these efforts.

The world鈥檚 oceans hold an estimated 4.5 billion tonnes of uranium 鈥� more than 1000 times that available to mining 鈥� but it is extremely dilute. Previous experimental efforts have harvested uranium from seawater by physically soaking it up with artificial sponges or a polymer material inspired by blood vessel patterns, or by the more efficient and more expensive electrochemical method of trapping uranium atoms with electric fields.

at Hunan University in China and his colleagues have developed an upgraded electrochemical technique that is cheaper and requires less energy than any other for use with seawater. Unlike typical electrochemical systems, which only pull uranium atoms from water at the positive electrode, their device contains two copper electrodes, one positive and one negative, that can both gather uranium.

This approach was able to extract 100 per cent of the uranium atoms from a salty seawater-like solution within 40 minutes. By comparison, some physical adsorption methods extract less than 10 per cent of the available uranium.

The system is 鈥渧ery innovative鈥� and 鈥渁 significant step forward compared to鈥� existing uranium extraction methods鈥�, says at the University of North Texas, who wasn鈥檛 involved in the new research.

When tested with small amounts of natural seawater 鈥� about 1 litre running through the system at any time 鈥� the new method was able to extract 100 per cent of uranium from East China Sea water and 85 per cent from South China Sea water. In the latter case, the researchers also achieved 100 per cent extraction with larger electrodes.

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The experiments also showed the energy required was more than 1000-fold less than other electrochemical methods. The whole process cost about $83 per kilogram of extracted uranium. That is twice as cheap as physical adsorption methods, which cost about $205 per kilogram, and four times as cheap as previous electrochemical methods, which cost $360 per kilogram.

Scaling up the size and volume of the new devices 鈥� along with potentially stacking or connecting them together 鈥� could lead to 鈥渋ndustrialisation of uranium extraction from seawater in the future鈥�, the researchers wrote. Given a 58-hour test in 100 litres of seawater, their largest experimental array extracted more than 90 per cent of the available uranium.

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One of the most successful previous demonstrations of harvesting uranium from seawater came in the 1990s, when the Japan Atomic Energy Agency extracted a kilogram of the element from the ocean using a physical adsorption method. That set a milestone that has inspired Chinese academic and industry researchers ever since.

In 2019, a Chinese state-owned nuclear company teamed up with research institutes to form the Seawater Uranium Extraction Technology Innovation Alliance. This organisation aims to build a demonstration plant by 2035 and achieve ongoing industrial production by 2050, according to the .

鈥淔rom an engineering perspective, there is still a long way to go before implementing this method and any electrochemical-based method for large-scale uranium extraction from seawater,鈥� says Ma.

Half of the nuclear reactor projects currently under construction are in China. The country is on track to surpass the US and the European Union in total installed nuclear power capacity by 2030, according to the .

But China鈥檚 nuclear industry also imports most of the uranium that it uses. So any it can economically extract from seawater will be more than welcome.

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