Iran has been producing heavy water since it built its Tehran Research Reactor, but says that the reactor is only used for research and development.  Iran agreed to redesign the reactor to minimize plutonium production and avoid weapons-grade plutonium production.  On 14 January 2016, Iran stated that the core of the reactor had been removed and would be filled with concrete.

Iran also agreed to export all spent fuel within one year of its removal from the reactor.  The US purchased 32 tons of heavy water last April, in an effort designed to help Iran follow through with that aspect of the deal.

In his July 13 report for The Hill, Devin Henry states that, “Republicans say the purchases are tantamount to the U.S. underwriting the country’s nuclear program.”

In a debate on the floor Wednesday, Ed Royce (R-Calif.) declared, “Purchases like this only subsidize and incentivize Iran’s continued production of this sensitive material that plays a central roll in the production of weapons-grade plutonium,” said Rep. during a floor debate on Wednesday. 

Many Democrats were opposed to the bill, fearing that it would impact the United States’ influence over Iran’s nuclear program.  “This bill is far too broad,” said Rep. Eliot Engel (D-N.Y.).

The bill from Rep. Mike Pompeo (R-Kan.) will stop the federal government from purchases like the one it made in April. The bill passed 249-176.