The detailed designs of a nuclear reactor must be preceded by expensive experimental work. In many cases, nuclear test facility construction and operation costs represent a major portion of the total program budget. Also, training in nuclear engineering is not complete without laboratory experience. Since the nuclear industry is highly regulated for product safety, educational and research institutions will need to obtain the necessary licenses from the NRC. This process may take longer than is planned, which could negatively affect their prospects. In nuclear engineering, important services are based on the use of nuclear reactor simulators. However, their application is essentially limited to providing general response characteristics of selected reactor systems.
A proposed test facility can be used for many specific purposes such as a new reactor design, safety evaluation, licensing or student training. In this approach, the fuel element simulators have the same configuration and dimensions as the reactor’s fuel assemblies. The fuel channels are filled with a neutron absorber and depleted fuel, which can be in the form of particles, annular pellets or liquid. Several detector packs, each includes Th-232, U-235 and uncoated devices are distributed through a plane in the core. A source of neutrons moves along the various channels to simulate the core nuclear characteristics, including the reactor’s critical mass and neutron flux distribution. DC or RF heaters can be used to simulate the core thermal characteristics.
A miniaturized fission chamber and a loop filled by helium simulate delayed-neutron emitter diffusion and feedback system performance. Measurements of noble gas, halogen and bromide elements living fuel at fission chamber versus gas or steam flow will be performed. The volatile and gas fission products (mainly krypton and xenon, as well as delayed iodine and bromine) are continually transported into the external purifier.
The measurements of delayed neutrons emitted from the fission chambers with main fuel isotopes – 233U, 235U, 239Pu or 238U fuel will be made using the pulsed target-distributed accelerator. Delayed neutrons will be registered in the time intervals between the neutron pulses by detector comprising of 3He-counters. The experiment will be done at different pulse time and with different time intervals between the neutron pulses. Advantage of this set-up is that the neutron flux distribution and detection of the delayed neutron activities will be done at the same location without fissionable materials.
A reference design would be largely based on Russian testing systems designed for nuclear-pumped lasers, gaseous fuel and VVER-440 reactors. A prototype of the Armenian Nuclear Power Plant Unit #2 in-core monitoring system was built and many experiments with calorimetric gamma-ray detectors were conducted at the research facilities of the Ukrainian Academy of Sciences.