Twenty-eight years after its Chernobyl nuclear plant exploded, Ukraine confronts a nuclear specter of a different kind: the possibility that the country's reactors could become military targets in the event of a Russian invasion.

Speaking at the Nuclear Security Summit in The Hague in March, Andrii Deshchytsia, Ukraine's acting foreign minister, cited the "potential threat to many nuclear facilities" should events deteriorate into open warfare.

Earlier in the month, Ihor Prokopchuk, Ukraine's ambassador to the International Atomic Energy Agency, circulated a letter to the organization's board of governors warning that an invasion could bring a "threat of radiation contamination on the territory of Ukraine and the territory of neighboring states." In Kiev, Ukraine's parliament responded by calling for international monitors to help protect the plants as the cash-strapped government attempts to boost its own efforts.