[en] The feasibility of improving the neutronic characteristics of boiling water reactors (BWR) by using U-Zr hydride fuel is studied. Several modified BWR fuel assembly designs are considered. These include designs in which hydride fuel rods replace water rods only, replace water rods and a fraction of the oxide fuel rods, replace oxide fuel in the upper half of all the fuel rods, and replace all the oxide fuel in the assembly. It is found that replacement of at least half of the oxide fuel rods in the fuel assembly by U-ZrH_1.6 fuel might simultaneously improve the performance of BWR in three ways: (a) Increasing the energy extracted per fuel assembly and the cycle length by up to ∼10%. (b) Reducing the uranium ore and SWU requirements by approximately 10%. (c) Reducing the negative void coefficient of reactivity by, at least, 50%. It is also found that replacement of all the oxide fuel by hydride fuel opens interesting new options for the design of BWR fuel assemblies. The net result might be simplified assembly designs that can generate significantly more energy while featuring small negative void coefficient of reactivity. U-ThH₂ fuel appears to be even more promising than U-ZrH_1.6. For the potential benefits from hydride fuel to be realized, a clad material that is not permeable to hydrogen and is not as neutron absorbing as stainless steel needs to be developed

[en] Highlights: • We used the weighted least square with nonlinear regression method to fit experimental nuclear data. • The FITWR code has been successful applied for both light and heavy nuclei with many resonance points. • More improvements will be applied in the future, by including a new methods for nuclear data fitting. - Abstract: A computer program named FITWR has been developed and applied to the experimental total cross sections for MEV incident energy particles such as neutron and proton. The computer program FITWR adapted the weighted least square method with weighted mathematical models with nonlinear regression applied to high order fitting polynomial, in order to meet the growing demands of the experimental nuclear data. The computer program FITWR deals with variance and covariance data provided along with experimental data and yields those for the evaluated ones

[en] The author describes the theoretical models of coupling MCNP and OPRGEN--MCBurn. A PWR pin cell benchmark burn-up calculation problem of 3 burn-up cases is used to verify MCBurn. It is concluded that the results of MCBurn on reactivity and isotopic compositions are in good agreement with those obtained from measurement and/or calculated by other codes. Moreover, MCBurn is superior to the similar codes such as MOCUP or Monte-burns as far as some of calculating results, the parameter choice and determination as well as the program automatic run are concerned

[en] A new continuous representation of the ACE format thermal neutron scattering data was released in 2007, this representation gives more accurate description for the secondary neutron energies, but was not widely known. In this paper, the continuous representation was introduced and compared with the traditional discrete one, the continuous thermal neutron scattering data processing capability was also developed in RMC code. The capability was validated by a set of benchmarks, of the 63 testing cases, only 2 cases show difference a bit more than 3σ for the discrete representation and the continuous representation. Results show that a change from the traditional discrete representation to the continuous one does not produce noticeable changes for the eigenvalues when calculating critical experiments. (author)

[en] Using the Fully Ceramic Microencapsulated (FCM) fuel in light water reactors has multiple advantages, as it is accident tolerant because of; no hydrogen generation due to the cladding interaction with steam at high temperature, better retention of fission fragments and proliferation resistant due to very small production of transuranic elements during the burnup as compared to the standard UO2 fuel. In this study neutronics analysis of AT-FCM fuel consisting of TRISO particles embedded in SiC matrix is performed for replacement in existing VVER-1000 reactors. Standard VVER-1000 fuel assembly is transformed to Accident Tolerant Fully Ceramic Microencapsulated (AT-FCM) fuel assembly based on hydraulic diameter of the VVER-1000 assembly, the number of fuel pins are decreased with increased diameter and enrichment to conserve the initial fissile loading in AT-FCM assembly. Fuel centerline temperature of the AT-FCM assembly is found to be lower than the reference UO2 fuel assembly at the same total power produced because of the much higher thermal conductivity. FCM-TRISO fuel assembly namely Array 15 with 169 pins is proposed and analyzed. Pin cell, assembly level and full core calculations have been performed with SERPENT code using implicit and explicit models. VVER-1000 full core is modelled using the transformed FCM assembly. The embedded TRISO particles in a SiC matrix and the use of FeCrAl cladding turns out to be the perfect case for accident tolerance. High burnup of AT-FCM core in terms of MWd/kgHM for the same number of EFPDs is observed as compared to reference UO2 core due to the small breeding of transuranic elements Pu-239, Pu-240 and Pu-241. Appreciable quantity of the power is produced due to the fission of transuranic elements in reference UO₂ assembly so the burnup in MWd/kgHM remains smaller than the AT-FCM fuel. Comparatively more softening of spectrum is found in AT-FCM fuel cells and assemblies towards the middle of the cycle (MOC) and End of the Cycle (EOC), this softening of spectrum tends to increase the rate of U-235 depletion. Very small quantities of plutonium isotopes are produced in AT-FCM as compared to the reference UO₂ assembly because of small loading of U-238 at the BOC. The neutronics performance of AT-FCM core with burnable poison consisting of Gd₂O₃ and Er₂O₃ turn out to be better than reference UO₂ assembly as it exhibits smooth burnup. Fuel Temperature Coefficient (FTC) and Moderator Temperature Coefficient (MTC) of the AT-FCM assembly is negative for most part of the cycle however, towards the end of cycle it becomes less negative due to small quantities of resonance absorbers, softening of thermal flux and increased rate of fission absorption in UO₂.

[en] This paper reconsiders the 'curse of resources' hypothesis for the case of China, and distinguishes between resource abundance, resource rents, and resource dependence. Resource abundance and resource rents are shown to be approximately equivalent, and their association with resource dependence varies with institutional quality. Resource abundance/rents has a positive impact on economic growth, while resource dependence has a negative impact. The impact of the 'West China Development Drive' policy, started in 2000, is substantial, and this is investigated through a comparative analysis based on cross-section samples, and through a panel-data timevarying coefficient approach for West and East provinces. Resource effects do change after the policy shock.

[en] Breakdown in ablative pulsed plasma thrusters (APPTs) must be studied in order to design new types of APPTs and measure particular parameters. In this paper, we studied a parallel-plate ablative pulsed plasma thruster that used a coaxial semiconductor spark plug. By operating the APPT about 500 times with various capacitor voltages and electrode gaps, we measured and analyzed the voltage of the spark plug, the voltage between the electrodes, and the discharge current. These experiments revealed a time delay (∼1–10 μs) between spark plug ignition and capacitor discharge, which may affect the performance of high-pulsing-rate (>10 kHz) and double-discharge APPTs, and the measurements of some of the APPT parameters. The delay time decreased as the capacitor voltage increased, and it increased with an increasing electrode gap and increasing number of ignitions. We explain our results through a simple theoretical analysis

[en] In this paper, we use the instantaneous Bethe–Salpeter method to calculate the semi-leptonic and non-leptonic production of the orbitally excited scalar D${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}{\text{—<!-- ??? -->}}_0$ in B meson decays. When the final state is 1P state D${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}{\text{—<!-- ??? -->}}_0$(2400), our theoretical decay rate is consistent with experimental data. For D${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}{\text{—<!-- ??? -->}}_J$(3000) final state, which was observed by LHCb collaboration recently and here treated as the orbitally excited scalar D${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}{\text{—<!-- ??? -->}}_0$(2P), its rate is in the order of 10${}^{-<!--\; ???\; -->4}$∼10${}^{-<!--\; ???\; -->6}$. We find the special node structure of D${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}{\text{—<!-- ??? -->}}_0$(2P) wave function possibly results in the suppression of its branching ratio and the abnormal uncertainty. The 3P states production rate is in the order of 10${}^{-<!--\; ???\; -->5}$.

[en] Optical sensors, such as fiber interferometers transmit along light paths and perform measurements based on optical path difference. These types of sensors can reduce device volume and improve sensing performance using optical multiplexing. A beam splitter for optical path multiplexing in an optical fiber ring is proposed. A photonic crystal was used to design the beam splitter. By optimizing and improving the photonic crystal microstructure, the beam splitting function can be realized while taking into account the cycling capability. Therefore, the light can recirculate multiple times in the fiber ring to realize light path multiplexing. The finite difference time domain method is used to analyze and evaluate the performance of the beam splitter.

[en] The interactions of V with Cr₂O₃(0001) films and Cr with V₂O₃(0001) films at room temperature are studied using x-ray photoelectron spectroscopy and low-energy-electron diffraction. The results show that the deposited V is oxidized and the Cr₂O₃(0001) surface is reduced at the initial coverage due to the interaction of V with the Cr₂O₃ substrate; V becomes metallic at V coverage greater than 5 monolayer equivalent. Full oxidization of the deposited vanadium cannot be achieved by O₂ exposure at room temperature for 20 min. However, V₂O₃(0001) films have been observed after heating the sample to 600-700 K in oxygen ambient at 1x10^-7 mbar. Similar results have been obtained for the Cr/V₂O₃(0001)/Re(0001) system. (author)