According to a letter sent by the US Department of Energy to Rosatom, Russia’s state owned nuclear energy company last month, the US has sensitive nuclear technologies at a nuclear plant in Ukraine. It warns Russia not to touch them.

Andrea Ferkile is the director of Energy Department’s Office of Nonproliferation Policy. In a letter dated 17 March 2023 and reviewed by CNN, she informs Rosatom’s director general, that the Zaporizhzhia Nuclear Power Plant located in Enerhodar, “contains US nuclear technical data which is controlled by the United States Government for export.”

US export controls apply to goods, software and technologies that could be used to undermine US national security.

The letter from the Energy Department comes at a time when Russian forces are still in control of the plant. It is the largest nuclear station in Europe, and it sits on a part in the Zaporizhzhia area that Russia occupied following its invasion of Ukraine in February last year. Due to Russian shelling, the plant has been frequently disconnected from Ukraine’s electricity grid. This has raised fears of a nuclear disaster across Europe.

Rosatom is in charge of the management and operation of the plant, even though it’s still operated by Ukrainian employees. In a letter, the Energy Department informed Rosatom that it was “illegal” for Russian citizens and entities to use US technology.

The letter states that it is illegal for Russian citizens or entities, as well as non-authorized individuals, such Rosatom, to access, possess or control such technology and technical data. They may also seize or review them, and re-export or ship them.

Rosatom may or may not have responded to the letter. In a CNN statement, the National Nuclear Security Administration of the Energy Department confirmed that this letter is genuine.

RBC Ukraine was the first to report on these letters.

Shayela Hassel, deputy director of Public Affairs for the National Nuclear Security Administration at the Department of Energy, confirmed that the letter was genuine.

She said: “The Secretary for Energy is responsible under law for authorizing transfers of civilian nuclear technology that has not been classified and providing assistance to foreign atomic power activities.” DOE does not comment upon regulatory activities.”

CNN reviewed a letter from Ferkile, dated October 24, 2020, to the Energy Department Inspector General. It outlines technology that the US exported to Ukraine to be used in the Zaporizhzhia Plant and confirms the fact that “there is no record of any authorization for the transfer of this technology and technical information to any Russian entity or national.”

On its website, the Office of Nuclear Energy of the Energy Department has made public the US’ support of the plant. In June 2021 it stated that “the United States assisted in implementing new maintenance procedures and operation at the reactor which should strengthen energy security in Ukraine”.