of which $38,874,000 shall remain available until September 30, 2020: Provided , That not to exceed $7,180 shall be for official reception and representation expenses. Procurement, construction, and improvements For necessary expenses of the Federal Law Enforcement Training Centers for procurement, construction, and improvements, including the planning, operational development, engineering, and purchases prior to sustainment and for information technology-related procurement, construction, and improvements, including non-tangible assets of the Federal Law Enforcement Training Centers, $85,577,000, to remain available until September 30, 2023. Science and technology directorate Operations and support For necessary expenses of the Science and Technology Directorate for operations and support, including the purchase or lease of not to exceed 5 vehicles, $308,520,000, of which $170,462,000 shall remain available until September 30, 2020: Provided , That not to exceed $20,000 shall be for official reception and representation expenses. Research and development For necessary expenses of the Science and Technology Directorate for research and development, $504,596,000, to remain available until September 30, 2021. domestic nuclear detection office Operations and support For necessary expenses of the Domestic Nuclear Detection Office for operations and support, $54,664,000: Provided , That not to exceed $335,440 shall be for official reception and representation expenses. Procurement, construction, and improvements For necessary expenses of the Domestic Nuclear Detection Office for procurement, construction, and improvements, $89,096,000, to remain available until September 30, 2021. Research and development For necessary expenses of the Domestic Nuclear Detection Office for research and development, $145,661,000, to remain available until September 30, 2021. Federal assistance For necessary expenses of the Domestic Nuclear Detection Office for Federal assistance through grants, contracts, cooperative agreements, and