revenues estimated to total $96,000,000 in fiscal year 2019 may be retained and used for operating expenses within this account, as authorized by section 201 of Public Law 95–238 , notwithstanding the provisions of 31 U.S.C. 3302: Provided further , That the sum herein appropriated shall be reduced as collections are received during the fiscal year so as to result in a final fiscal year 2019 appropriation from the general fund estimated at not more than $170,000,000. Office of the inspector general For expenses necessary for the Office of the Inspector General in carrying out the provisions of the Inspector General Act of 1978, $51,330,000, to remain available until September 30, 2020. Atomic energy defense activities National nuclear security administration Weapons Activities For Department of Energy expenses, including the purchase, construction, and acquisition of plant and capital equipment and other incidental expenses necessary for atomic energy defense weapons activities in carrying out the purposes of the Department of Energy Organization Act ( 42 U.S.C. 7101 et seq.), including the acquisition or condemnation of any real property or any facility or for plant or facility acquisition, construction, or expansion, $10,850,000,000, to remain available until expended: Provided , That of such amount, $102,022,000 shall be available until September 30, 2020, for program direction. Defense nuclear nonproliferation For Department of Energy expenses, including the purchase, construction, and acquisition of plant and capital equipment and other incidental expenses necessary for defense nuclear nonproliferation activities, in carrying out the purposes of the Department of Energy Organization Act ( 42 U.S.C. 7101 et seq.), including the acquisition or condemnation of any real property or any facility or for plant or facility acquisition, construction, or expansion, $1,902,000,000, to remain available until expended. Naval reactors For Department of Energy expenses necessary for naval reactors activities to carry out