Offsite Power Supply Destroyed. What's Happens Next at Ukraine's Zaporizhzhia Nuclear Plant

"A vital offsite electricity supply to the Zaporizhzhia nuclear plant has been destroyed by shelling," the Guardian reported Friday, "and there is little likelihood a reliable supply will be re-established, the United Nations' nuclear watchdog chief has said."Rafael Grossi, the director general of the International Atomic Energy Agency (IAEA), said shelling had destroyed the switchyard of a nearby thermal power plant. The plant has supplied power to the nuclear facility each time its normal supply lines had been cut over the past three weeks. The thermal plant was also supplying the surrounding area, which was plunged into darkness. Local Ukrainian officials said work was under way to restore the connection, which has been cut multiple times this week.... When the thermal supply has been cut the plant has relied on its only remaining operating reactor for the power needed for cooling and other safety functions. This method is designed to provide power only for a few hours at a time. Diesel generators are used as a last resort. The constant destruction of thermal power supply has led Ukraine to consider shutting down the remaining operating reactor, said Grossi. Ukraine "no longer [has] confidence in the restoration of offsite power", he said. Grossi said that if Ukraine decided not to restore the offsite supply the entire power plant would be reliant on emergency diesel generators to ensure supplies for the nuclear safety and security functions. "As a consequence, the operator would not be able to restart the reactors unless offsite power was reliably re-established," he said. NPR provides some context:Normally, the plant holds a 10-day reserve of diesel fuel, the agency says, and currently has approximately 2,250 tonnes of fuel available. If that fuel is depleted, or the generators are damaged in further fighting, it could trigger a meltdown. But Steven Nesbit, a nuclear engineer and member of the American Nuclear Society's rapid response taskforce, which is tracking the current crisis, says that doesn't necessarily mean there would be a Chernobyl-like catastrophe. The meltdown at Chernobyl was due to a unique mix of design flaws and operator error that would be essentially impossible to replicate at Zaporizhzhia. And unlike the Fukushima nuclear disaster in 2011, some of the reactors at Zaporizhzhia have already been shut down for a while, allowing the nuclear fuel to cool somewhat, Nesbit says. Even in the worst case scenario, the reactors at Zaporizhzhia are a modern design surrounded by a heavy "containment" building, Nesbit says. "It's reinforced concrete, typically about three to four feet of that; it's designed to withstand very high internal pressures." That could allow it to hold in any radioactive material. But the world's nuclear agency doesn't want to test any of this. Meanwhile, the French international news agency AFP reports on what's been happening at the plant since it was captured by Russian troops in March:Russian forces controlling Ukraine's Zaporizhzhia nuclear power plant have killed two staff at the facility and detained and abused dozens of others, the head of Ukraine's nuclear energy agency told AFP on Friday. "We do not know where about ten people are now," Petro Kotin said. "They were taken (by the Russians) and after that we have no information about their whereabouts," Kotin said, adding about 200 people had been detained. He described the current situation at the plant as "very difficult," citing "torture" of staff and "beatings" of personnel. "The Russians look for pro-Ukrainian people and persecute them. People are psychologically broken," he said in an interview with AFP reporters in his office in Kyiv... "Two people on the territory of the plant were wounded during shelling - a woman and a man - on separate occasions," Kotin, clad in a military-style jacket, said. "But people understand that the nuclear safety of the plant depends on them, so the employees return to Energodar and continue working at the facility," he added.

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