Nuclear Disaster Averted After Ukraine Dam Break. But What Threats Remain?

This week, the head of the United Nations atomic watchdog, Rafael Mariano Grossi, was so concerned about a new risk at the Zaporizhzhia Nuclear Power Plant that he flew to Ukraine and crossed the front line in the country’s war with Russia to see the situation for himself.

Mr. Grossi had been to the plant before and had also expressed grave concerns about the potential for nuclear catastrophe, but this threat was different: The recent destruction of a dam on the Dnipro River had deprived…