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NRC looks to leverage previous approvals for large LWRs
During this time of resurging interest in nuclear power, many conversations have centered on one fundamental problem: Electricity is needed now, but nuclear projects (in recent decades) have taken many years to get permitted and built.
In the past few years, a bevy of new strategies have been pursued to fix this problem. Workforce programs that seek to laterally transition skilled people from other industries, plans to reuse the transmission infrastructure at shuttered coal sites, efforts to restart plants like Palisades or Duane Arnold, new reactor designs that build on the legacy of research done in the early days of atomic power—all of these plans share a common throughline: leveraging work already done instead of starting over from square one to get new plants designed and built.
Thomas Elevant, Hans E. Brelén, Per G. Lindén, Jan Scheffel
Fusion Science and Technology | Volume 32 | Number 2 | September 1997 | Pages 304-318
Technical Paper | Experimental Device | doi.org/10.13182/FST97-A19900
Articles are hosted by Taylor and Francis Online.
In the next generation of magnetic fusion experiments, such as the International Thermonuclear Experimental Reactor (ITER), information on ion temperature profiles will be needed for burn optimization and transport studies. The feasibility of obtaining these profiles for the core plasma (r < 0.75 of minor radius) directly from the width of measured 14-MeV neutron energy spectra is demonstrated for Maxwellian ion distributions. Neutron energy spectra are calculated using the Monte Carlo technique. Reaction kinematics and velocity distribution of the reacting ions are taken into account, which enables the resulting neutron flux and energy distribution entering a defined collimator to be calculated. Energy spectra of neutrons emitted along a line of sight (LOS) are obtained by adding the contributions from a large number of subvolumes. The associated correction factor (peak temperature over LOS measured temperature) depends on the ion temperature and on the shapes of the temperature and density profiles. The resulting accuracy in the evaluated ion temperature profiles is expected to be better than ± 10%. However, this can be improved to ±5% provided that the ion density profile shape is known. The relative accuracy is estimated to be better than ±5%. Features of several spectrometer candidates are briefly described in relation to ITER conditions and measurement requirements. A time-of-flight (TOF) neutron spectrometer is outlined. Experiments with a test device confirm the calculated energy resolution and separation of neutron from gamma events. The spectrometer is shown to be applicable to ITER under both ohmically heated and ignited conditions. A feedback system will be used to control the detector count rate at high neutron flux levels to accommodate the large dynamic neutron flux range from 5 × 106 to 5 × 1010 n/(cm2 · s). An array of five to nine TOF spectrometers provides ion temperature profiles that satisfy ITER measurement requirements, i.e., Ti ≥ 2.5 keV; 10% accuracy; and spatial and temporal resolutions of 30 cm and 100 ms, respectively.
