When it selected Intel to help build a $500 million supercomputer last year, the Energy Department bet that computer chips made in the United States could help counter a technology challenge from China.

Officials at the department's Argonne National Laboratory told us that the  Aurora super computer to be installed at facilities near Chicago in 2021, would be the first US system to reach a technical pinnacle known as exascale computing.

Intel pledged to supply three kinds of chips for the system from its factories in Oregon, Arizona and New Mexico. But a technology delay by the Silicon Valley giant has thrown a wrench into that plan, the latest sign of headwinds facing government and industry efforts to reverse America's dependence on foreign-made semiconductors. It was also an indication of the challenges ahead for US hopes to regain a lead in critical semiconductor manufacturing technology.

When Robert Swan, its chief executive, warned last month that the next production advance would be 12 months late he suggested that some chips for Aurora might be made outside Intel factories.

Shifting a key component to foreign factories would undermine company and government hopes of an all-American design.