Space reactor fuel element testing in upgraded TREAT

Abstract

The testing of candidate fuel elements at prototypic operating conditions with respect to temperature, power density, hydrogen coolant flow rate, etc., is a crucial component in the development and qualification of nuclear rocket engines based on the Particle Bed Reactor (PBR), NERVA-derivative, and other concepts. Such testing may be performed at existing reactors, or at new facilities. A seoping study has been performed to assess the feasibility of testing PBR based fuel elements at the TREAT reactor. Initial results surest that full-scale PBR elements could be tested at an average energy deposition of -60-80 Ma, V-s/L in the current TREAT reactor. If the TREAT reacltor was upgraded to include fuel elements with a higher temperature limit, average energy deposition of~100 MW/L may be achievable. INTRQDUCTIONA critical component in the development of nuclear rocket propulsion engines for Space Exploration Initiative (SEI) missions is a highly robust fuel element which can operate at high temperatures in a hydrogen environment. Fuel elements require extensive in-pile and out-of-pile testing at prototypic operating temperatures, power distribution, power density, gaseous coolant flow rate, pressure, and operatir.g time to determine operating capability and safety margins. The design, construction, and operation of a specific multiple fuel element testing reactor for space reac,or fuel elements would require considerable time and resources in today's environment. Rapid and early testing of single fuel elements whether they be Particle Bed Reactor (PBR) or NERVA based fuel elements is essential to determine the optimum approach for the design of SEI mission nuclear rocket engines. It is proposed to modify existing Department of Energy reactors such as TREAT which is operated by the Argonne National Laboratory at the Idaho National Engineering Laboratory (INEL) site to conduct full = scale, single element tests of PBR or NERVA-derivative fuel at close to prototypic operating conditions and environments, as weil as construct new facilities at other possible sites.

Options for Subscale Maturation of Advanced Reactor Technologies Testing for Nuclear Thermal Propulsion

“…The PRIME tests will include exposure to flowing hydrogen during irradiation. TREAT was also considered as an option to test PBR fuel elements under the SNTP program, but not pursued beyond a preliminary assessment [Todosow et al 1993]. • Able to create experimental transient that exceed startup times.…”