COLUMBIA, S.C. AP – The Department of Energy should halt construction on a nuclear waste reprocessing facility in South Carolina after an internal investigation found several safety flaws, the head of a nuclear nonproliferation group said Monday.

A report issued by the department’s inspector general late last month found that a piece of steel broke during construction of a plant that is supposed to dispose of 34 metric tons of nuclear waste by converting it to fuel for commercial reactors. The report also discovered the agency used inadequate steel bars to build another facility that “could have resulted in a spill of up to 15,000 gallons of high-level radioactive waste,” Gregory Friedman, the Energy Department’s inspector general, wrote in the report.