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Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
J. Hardy, Jr., J. J. Volpe, D. Klein
Nuclear Science and Engineering | Volume 55 | Number 4 | December 1974 | Pages 401-417
Technical Paper | doi.org/10.13182/NSE74-2
Articles are hosted by Taylor and Francis Online.
Parameter measurements and calculations in two D2O-moderated thorium-uranium critical assemblies are described in detail. The first, designated ETA-I, contained 6.7 wt% 235UO2-ThO2 fuel rods 0.66 cm in diameter, clad in aluminum. The second assembly, ETA-II, contained 3.0 wt% 233UO2-ThO2 fuel rods 1.09 cm in diameter, clad in Zircaloy-2. A relatively hard spectrum was obtained in both lattices. Because leakage was small and the central flux spectra were closely asymptotic, these assemblies provided a cleanly analyzable test of important reaction cross sections. Parameters measured in ETA-I were 232Th fission/235U fission (δ02), 232Th capture/235U fission (CR*), and epithermal/thermal-neutron ratios for 235U fission (δ25) and 232Th capture (p02). Corresponding measurements with 233U were made in ETA-II; δ02 was measured directly in fuel and ThO2 pellets by observing specific fission product gamma rays with a high resolution Ge(Li) detector. With this system, 232Th capture gamma-ray activity was also measured directly in a fuel pellet. The epithermal/thermal-neutron ratios were measured by the thermal-neutron subtraction technique relative to 164Dy, and CR* was measured relative to its thermal-neutron value in a very soft spectrum. A three-dimensional adjoint Monte Carlo program was used to calculate foil flux perturbations and cadmium cutoff energies. Supplemental fast/epithermal-neutron spectrum comparisons were made between the ETA assemblies and the 4/1 TRX critical assembly by means of the following activation detectors: 197Au(n,γ), 55Mn(n,γ), 235U(n,f), 238U(n,f), 27Al(n,α), and 96Zr(n, γ). The lattices were analyzed explicitly with a full energy range Monte Carlo program having a detailed cross-section description. ENDF/B Version 2 and light-water breeder reactor (LWBR) cross-section sets were used. On the whole, agreement with experiment was very good.
