nuclear-news

Nuclear disasters–in–waiting

RICHARD STONE, Science 4 Jan 24

Having taken a heavy toll on Ukraine’s ecosystems and water resources, the war with Russia threatens to create a another environmental disaster: damage to the region’s extensive nuclear infrastructure—including 15 power reactors and three research reactors.

“There continues to be a highly precarious nuclear safety and security situation across Ukraine,” International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi said in a statement after explosions were heard near the Khmelnitsky Nuclear Power Plant and its two Soviet-era reactors on 28 November 2023—the second near-miss in a single month at the site. “All of Ukraine’s nuclear facilities remain vulnerable, either directly if hit by a missile or indirectly if their off-site power supplies are disrupted.”

Russia’s assault on Ukrainian nuclear sites began on the very first day of the full-scale invasion. On 24 February 2022, troops overran the Chornobyl Nuclear Power Plant, infamous for the explosion and fire there in 1986 that sent a plume of radioactive smoke into Western Europe. During 5 weeks of occupation, Russian soldiers ransacked labs and kicked up radioactive soil and dust as they dug trenches and slogged through contaminated forests in the exclusion zone around the defunct plant. To the east that spring, Russian troops frequently shelled the Kharkiv Institute of Physics and Technology, damaging a hall containing a subcritical nuclear reactor.

Shelling has also flared up repeatedly around the Zaporizhzhia Nuclear Power Station, a complex of six reactors that constitutes Europe’s largest nuclear power plant. Russia captured the plant in March 2022 and the reactors were shut down 6 months later, eliminating the risk of a core meltdown. Still, a prodigious amount of nuclear material remains there: The reactor halls hold 1380 tons of fresh and spent uranium oxide fuel, and two repositories store an additional 2100 tons of spent fuel laced with nasty long-lived radionuclides—the ingredients, many Ukrainians fear, of a “dirty bomb” that would use conventional explosives to spread radioactive isotopes……………………………………….

The presence of IAEA observers at the Zaporizhzhia station since September 2022 has deterred the theft of dirty-bomb ingredients. But a major missile strike on one of its spent fuel repositories could turn the plant itself into a dirty bomb, spreading radioactive contamination in a radius of up to 30 kilometers, says Volodymyr Borysenko, a nuclear engineer with the National Academy of Sciences of Ukraine’s Institute for Safety Problems of Nuclear Power Plants (ISPNPP).

Even a smaller strike could contaminate the reactor complex. And the spent fuel is also at risk from repeated electricity blackouts that have struck the plant, the latest in early December 2023. Diesel-fueled generators can supply power for up to 10 days, but a prolonged outage could be dangerous, as power is needed to pump cooling water into the plant’s uranium reactor cores and pools holding spent fuel.

A lesser known radioactive risk is situated about 150 kilometers upstream from the Zaporizhzhia plant on the Dnipro River. During the Cold War, the Prydniprovsky Chemical Plant was one of Europe’s largest uranium ore processing facilities. The complex accumulated some 40 million tons of tailings—leftovers of milling uranium—and other foul residues before it closed in 1992. By early 2022, Ukraine, with help from the European Union, had fenced off highly contaminated areas. But a missile or artillery strike on a tainted building or dump could disperse radioactive dust over the nearby city of Kamianske.

One relative bright spot is Chornobyl, where Ukrainian scientists are restoring labs damaged early in the war. But large parts of the exclusion zone remain off limits because of the threat of mines and unexploded ordinance, says ISPNPP Director Anatolii Nosovskiy. Complicating matters for radiation monitoring, he says, the Ukrainian army has built defensive fortifications in the zone, near the border with Belarus…………………. https://www.science.org/doi/10.1126/science.adn7987 

January 7, 2024 - Posted by Christina Macpherson | safety, Ukraine