WASHINGTON (Reuters) - A Chinese-American nuclear engineer pleaded guilty on Friday to conspiring to produce “special nuclear material” in China in violation of the U.S. Atomic Energy Act, the Department of Justice (DOJ) said.

Allen Ho, a naturalized U.S. citizen, and a Chinese state-owned nuclear power firm, the China General Nuclear Power Company (CGNPC), were indicted in April last year on charges of conspiracy.

The DOJ said Ho had pleaded guilty “to conspiracy to unlawfully engage or participate in the production or development of special nuclear material outside the U.S., without the required authorization from the U.S. Department of Energy (DOE) in violation of the Atomic Energy Act.”

A DOJ official said Ho and an associate, Ching Ning Guey -- who pleaded guilty to the same charge in 2015 -- were the first to be charged for violation of the 1946 act, a Cold-War era statute aimed at preventing nuclear proliferation.

The DOJ statement said Ho had been employed as a consultant by CGNPC and was also the owner of Energy Technology International (ETI), a Delaware corporation.

It said Ho assisted CGNPC in procuring U.S.-based nuclear engineers to assist in the design and manufacture of components for nuclear reactors more quickly.

It said Ho identified, recruited and executed contracts with U.S.-based experts from the civil nuclear industry who provided technical help for the development and production of special nuclear material for CGNPC.

Ho and CGNPC also facilitated travel to China and payments to the U.S.-based experts in exchange for their services, the DOJ said.

The United States defines special nuclear material as plutonium, uranium-233, or uranium enriched in the isotopes uranium-233 or uranium-235.

It says special nuclear material is only mildly radioactive, but includes fissile isotopes — uranium-233, uranium-235, and plutonium-239 — that, in concentrated form, could be used as the primary ingredients of nuclear explosives.

The Department of Justice did not say what sort of special nuclear material was involved and whether it included such “strategic special nuclear material.”

The Justice Department said Ho faced a maximum sentence of 10 years in prison and a $250,000 fine. It said sentencing had been set for May 17 in the U.S. District Court in Knoxville, Tennessee. Guey has yet to be sentenced.