TerraPower LLC, a nuclear energy venture chaired by Microsoft Corp co-founder Bill Gates, is seeking a new partner for early-stage trials of its technology after new US rules forced it to abandon an agreement with China, company officials told the Wall Street Journal.

TerraPower reached an agreement with state-owned China National Nuclear Corp in 2017 to build an experimental nuclear reactor south of Beijing. But Gates wrote in an essay published late last week that TerraPower is unlikley to follow through on its plans in the face of new US restrictions on technology deals with China.

The Bellevue, Washington-based company is now unsure which country it will work with to conduct trials of its technology, which is desgined to use depleted uranium as fuel for nuclear reactors in a bid to to improve safety and costs, company officials told the Journal.

“We’re regrouping,” Chief Executive Chris Levesque told the Journal in an interview. “Maybe we can find another partner.”

The US Department of Energy in October announced new restrictions on nuclear deals with China, in keeping with a broader plan by the Trump administration to limit China’s ability to access US made technologies it considers to be of strategic importance.

Gates, who co-founded TerraPower, said in his essay that regulations in the United States are currently too restrictive to allow the reactor prototype to be built domestically.