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The narrow field of options for safely managing Ukraine’s Zaporizhzhia Nuclear Power Plant

By Mark Hibbs | March 10, 2023 Bulletin of the Atomic Scientists,

One year after Russia’s assault and takeover of the Zaporizhzhia plant, Russians and Ukrainians face decisions about the operation status of the six reactors that will significantly impact nuclear safety and security. Decision makers might mothball the reactors, or instead elect one or more of a range of modes for operating them, on a scale from cold shutdown to resumed criticality and low-power operation…………………………………………………………………………………………..

 the safest option for the Zaporizhzhia nuclear power plant would be to shut all reactors down, depressurize the circuits, and remove their fuel until the end of the war. As an IAEA peer reviewer in one European country with similar reactors said: “There would be no heat, no pressure, no radioactivity, and no severe accident.”

But the plant’s fuel inventory is another key consideration in decisions about how or if the Zaporizhzhia reactors are to be run. If removed from reactor cores, hot, highly radioactive fuel must be safely stored and contained. 

Ukraine regulations require that the spent fuel storage pool at each reactor accommodate a full core of fuel in an emergency. As part of EU post-Fukushima upgrades, Zaporizhzhia reactors were outfitted with portable equipment to supply water in an emergency to spent fuel pools and to reactor cores. But moving a core of fuel into a pool would significantly increase the heat load, and safe storage margins might be limited following previous re-racking to pack more fuel in the pools.

Safety authorities may ultimately decide that the fuel would be better protected if left in the reactors, since they were designed to protect and cool the fuel including in an emergency. Separately, the owner/operator may not want to undertake prolonged outages of de-fueled reactors in the interest of limiting restart authorization requirements………………………………… https://thebulletin.org/2023/03/the-narrow-field-of-options-for-safely-managing-ukraines-zaporizhzhia-nuclear-power-plant/

March 10, 2023 - Posted by Christina Macpherson | safety, Ukraine