((a)) ** In general** Except as provided in subsection (b), amounts appropriated pursuant to a DOE national security authorization for operation and maintenance or for plant projects may, when so specified in an appropriations Act, remain available until expended.

((b)) ** Exception for program direction funds** Amounts appropriated for program direction pursuant to a DOE national security authorization for a fiscal year shall remain available to be obligated only until the end of that fiscal year.