a federal investigation is on after the computer system of at least one u.s. nuclear power plant was hacked. the cause of the breach is still unknown. this coming right on the heels of the men massive ransomware attack wreaking havoc on agencies and companies across the globe yesterday. chris trace gallagher is live wh more. acknowledging that a number of countries have been hit by this petya ransomware, but so far, dhs has not released any information about u.s. sites being hacked, although any news which covers the u.s. energy sector is starting u.s. officials who named and unnamed american nuclear power plant was hit by some type of cyber attack this year. it is unclear exactly when. apparently, they have acted not affect any sensitive operating systems and it did not raise alarm bells with the nuclear regulatory commission, but u.s. officials reportedly say that it is a ongoing matter that is being investigated.