; or (B) a fusion reactor. . 3. Versatile neutron source Section 955(c) of the Energy Policy Act of 2005 ( 42 U.S.C. 16275(c) ) is amended to read as follows: (c) Versatile neutron source (1) In general In order to advance the research and development of domestic advanced, affordable, secure, and clean nuclear energy, the Secretary shall construct a versatile reactor-based fast neutron source, which shall operate as a national user facility. The Secretary shall consult with the private sector, universities, National Laboratories, and relevant Federal agencies to ensure that such facility is capable of meeting Federal research needs for neutron irradiation services. (2) Facility capabilities (A) Capabilities The Secretary shall ensure that the facility described in paragraph (1) will provide, at a minimum, the following capabilities: (i) Fast neutron spectrum irradiation capability. (ii) Capacity for upgrades to accommodate new or expanded research needs. (B) Considerations In carrying out subparagraph (A), the Secretary shall consider the following: (i) Capabilities that support experimental high-temperature testing. (ii) Providing a source of fast neutrons, at a neutron flux higher than that at which existing research facilities operate, sufficient to enable research for an optimal base of prospective users. (iii) Maximizing irradiation flexibility and irradiation volume to accommodate as many concurrent users as possible. (iv) Capabilities for irradiation with neutrons of a lower energy spectrum. (v) Multiple loops for fuels and materials testing of different coolants. (vi) Additional pre-irradiation and post-irradiation examination capabilities. (vii) Lifetime operating costs and lifecycle costs. (3) Start of operations The Secretary shall, to the maximum extent practicable, ensure that the start of full operations of the facility described in paragraph (1) occurs before December 31, 2026. (4) Reporting The Secretary shall include in the annual budget request of the Department an explanation for any delay in