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.

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.

(Pub. L. 107–314, div. D, title XLVII, § 4709, formerly div. C, title XXXVI, § 3628, Dec. 2, 2002, 116 Stat. 2760; renumbered div. D, title XLVII, § 4709, by Pub. L. 108–136, div. C, title XXXI, § 3141(j)(2)(A)–(C), Nov. 24, 2003, 117 Stat. 1781; Pub. L. 113–291, div. C, title XXXI, § 3142(p), Dec. 19, 2014, 128 Stat. 3901.)