The report says the site's Eisenhower-era "H-Canyon" processing facility is believed to be safe. But necessary health and environmental studies have been delayed by up to two years because the site doesn't have the staff to complete them. That problem and other challenges could lead to delays and cost overruns.
The Energy Department had planned until 2004 to shut down the H-Canyon by 2007 but now plans to continue processing spent fuel there until 2019. The plan is expected to cost $4.3 billion to $4.6 billion.
The audit, released Friday, was done by the Government Accountability Office.