[en] The real-time hybrid reactor simulation (HRS) capability of the Penn State TRIGA reactor has been expanded for boiling water reactor (BWR) out-of-phase behavior. During BWR out-of-phase oscillation half of the core can significantly oscillate out of phase with the other half, while the average power reported by the neutronic instrumentation may show a much lower amplitude for the oscillations. A description of the new HRS is given; three computers are employed to handle all the computations required, including real-time data processing and graph generation. BWR out-of-phase oscillation was successfully simulated. By adjusting the reactivity feedback gains from boiling channels to the TRIGA reactor and to the first harmonic mode power simulation, limit cycle can be generated with both reactor power and the simulated first harmonic power. A 3-D display of spatial power distributions of fundamental mode, first harmonic, and total powers over the reactor cross section is shown

[en] Hybrid reactor simulation (HRS) of boiling water reactor (BWR) instabilities, including in-phase and out-of-phase (OOP) oscillations, has been implemented on The Pennsylvania State University TRIGA reactor. The TRIGA reactor's power response is used to simulate reactor neutron dynamics for in-phase oscillation or the fundamental mode of the reactor modal kinetics for OOP oscillations. The reactor power signal drives a real-time boiling channel simulation, and the calculated reactivity feedback is in turn fed into the TRIGA reactor via an experimental changeable reactivity device. The thermal-hydraulic dynamics, together with first harmonic mode power dynamics, is digitally simulated in the real-time environment. The real-time digital simulation of boiling channel thermal hydraulics is performed by solving constitutive equations for different regions in the channel and is realized by a high-performance personal computer. The nonlinearity of the thermal-hydraulic model ensures the capability to simulate the oscillation phenomena, limit cycle and OOP oscillation, in BWR nuclear power plants. By adjusting reactivity feedback gains for both modes, various oscillation combinations can be realized in the experiment. The dynamics of axially lumped power distribution over the core is displayed in three-dimensional graphs. The HRS reactor power response mimics the BWR core-wide power stability phenomena. In the OOP oscillation HRS, the combination of reactor response and the simulated first harmonic power using shaping functions mimics BWR regional power oscillations. With this HRS testbed, a monitoring and/or control system designed for BWR power oscillations can be experimentally tested and verified

[en] With the specialized construction of nuclear power project, the EPC mode has been rapidly promoted in China, which has become a trend of project management. Zhangzhou nuclear power project adopts China's independent innovation of HPR1000 third-generation nuclear power technology. The HPR1000 demonstration project is still under construction. There is no mature, standardized and effective pricing mode for the general contract of domestic nuclear power project. In order to effectively solve the problem, this paper will analyzes and study the pricing mode of the general contract for Zhangzhou nuclear power project, by analyzing the problems existing in the construction mode of nuclear power projects at home and abroad, and the cost management of as-built nuclear power projects, combined with the pricing experience of the general contract at the present stage and in the past. This paper puts forward the pricing principles and risk control measures for the general contract of Zhangzhou project, so as to provide some reference for subsequent nuclear power projects. (author)

[en] The article describes the nuclear power project construction mode and the existing problems of the pricing mechanism in the construction of nuclear power plant. Combining the former contract pricing experience, the AP1000 nuclear power project pricing mechanism under EPC mode will be studied to propose that AP1000 nuclear power project under EPC mode should comply the market rules with the combination of responsibility, right, profit as the principle and the price of general contract should work in the mechanism of fixed price for partial items and flexible price for the whole project. The proposal will be the reference for following new-built AP1000 nuclear power project. (authors)

[en] The fluctuation conductivity as a function of temperature Δσ(T) of Bi_1.6Pb_0.4 · Sr₂Ca₂Cu₃O_y bulk polycrystal superconductors and YBa₂Cu₃O_7-δ superconducting single crystal films was measured experimentally. The coherence length ξ was calculated from that experimental data and energy gap Δ was derived from ξ and V_F. This energy gap Δ agrees roughly with that measured by other methods. Besides, the experimental Δσ(T) curves of BiPdbSrCaCuO were compared with the curves calculated from Aslamazov-Larkin theory and the agreement between two is good

[en] The real-time hybrid reactor simulation (HRS) capability of the Penn State TRIGA reactor has been recently expanded for BWR out-of-phase behavior. Out-of-phase oscillation is a phenomenon that occurs at BWRs. During this kind of event, half of the core can significantly oscillate out of phase with the other half, while the average power reported by the neutronic instrumentation may show a much lower amplitude for the oscillations. The HRS will be used for development and validation of stability monitoring and control techniques as part of an ongoing U.S. Department of Energy Nuclear Engineering Education and Research grant. The Penn State TRIGA reactor is used to simulate BWR fundamental mode power dynamics. The first harmonic mode power, together with detailed thermal hydraulics of boiling channels of both fundamental mode and first harmonic mode, is simulated digitally in real time with a computer. Simulations of boiling channels provide reactivity feedback to the TRIGA reactor, and the TRIGA reactor's power response is in turn fed into the channel simulations and the first harmonic mode power simulation. The combination of reactor power response and the simulated first harmonic power response with spatial distribution functions thus mimics the stability phenomena actually encountered in BWRs. The digital simulations of the boiling channels are performed by solving conservation equations for different regions in the channel with C-MEX S-functions. A fast three-dimensional (3-D) reactor power display of modal BWR power distribution was implemented using MATLAB graphics capability. Fundamental mode, first harmonic, together with the total power distribution over the reactor cross section, are displayed. Because of the large amount of computation for BWR boiling channel simulation and real-time data processing and graph generation, one computer is not sufficient to handle these jobs in the hybrid reactor simulation environment. A new three-computer setup has been identified that can efficiently address these requirements and is shown in Fig. 1. The host computer and target computer work cooperatively under the MATLAB Real-Time Workshop environment. The principal user interaction takes place on the host computer where parameter adjustments are initiated and some elementary information displays are presented. The hybrid BWR-simulation application code is generated in the host computer with SIMULINK and is downloaded to the xPC target option of the Real-Time Workshop (target computer). The target computer performs boiling channel thermal-hydraulic simulation and control of the experimental changeable reactivity device (ECRD) in the TRIGA reactor. The target computer is connected to the reactor through a DA/AD card. The TRIGA reactor power is measured, and a control signal is sent to the ECRD drive mechanism to simulate the BWR reactivity feedback. Desired hybrid simulation of BWR behavior is controlled by adjusting parameters in the host computer. The graph computer retrieves measured reactor power, which serves as the fundamental mode power of the BWR, and the simulated first harmonic power from the target computer. Spatial power distribution is calculated from these data, and the reactor physics model in the graph computer and 3-D display of BWR power of the two modes together with the total power is displayed there. BWR out-of-phase oscillation is successfully simulated with the new HRS setup. By adjusting the reactivity feedback gains from boiling channels to the TRIGA reactor and to the first harmonic mode power simulation, limit cycle can be generated with both reactor power and the simulated first harmonic power. Shown in Fig. 2 is the 3-D display of spatial power distributions of fundamental mode, first harmonic, and total powers over the reactor cross section at a certain time in an instability event. (authors)

[en] A sliding mode controller is designed for an ABWR nuclear power plant turbine throttle pressure regulation. To avoid chattering problem, which is common to conventional sliding mode controllers, and estimation of uncertainties and disturbances, the recursive-form sliding mode control algorithm is developed. To apply the sliding mode control technique, the original plant's 11.-order dynamics model is first transformed to a canonical form differential equation of a relative order of 2 for turbine throttle pressure's dynamics. Simulation results show that the design objectives are achieved and the resulting controller is superior to the existing PI controller in many aspects, including settling time, overshoot/undershoot in response to setpoint step input and fluctuation amplitude in the presence of external disturbances. (authors)

[en] A stability monitor for a boiling reactor is implemented and evaluated with the Penn State Hybrid Reactor System. The stability monitor is based on an extended Kalman filter which employs a reduced-order BWR reactor model. The filter uses measured power signal and estimates the void reactivity feedback gain and the decay ratio. The hybrid reactor system is a system combining a simulation module of BWR thermal hydraulics and the Penn State TRIGA reactor. A description of the hybrid system is also presented. (authors)

[en] Highlights: • Hepatotoxicity of TBBPA and Cd aerosol co-exposure was evaluated in CD-1 male mice. • Hepatic changes include focal necrosis, increased organ weight, and elevated enzymes. • TBBPA group exhibited highest hepatic toxicity followed by co-exposure and Cd groups. • We did not observe any synergistic effect of hepatic toxicity between TBBPA and Cd. • TBBPA/Cd suppressed antioxidant defensive mechanisms and increased oxidative stress. - Abstract: Cadmium (Cd) and tetrabromobisphenol A (TBBPA) are two prevalent contaminants in e-waste recycling facilities. However, the potential adversely health effect of co-exposure to these two types of pollutants in an occupational setting is unknown. In this study, we investigated co-exposure of these two pollutants on hepatic toxicity in CD-1 male mice through a whole-body aerosol inhalation route. Specifically, mice were exposed to solvent control (5% DMSO), Cd (8 μg/m"3), TBBPA (16 μg/m"3) and Cd/TBBPA mixture for 8 h/day and 6 days a week for 60 days. Hepatic changes include increased organ weight, focal necrosis, and elevated levels of liver enzymes in serum. These changes were most severe in mice exposed to TBBPA, followed by Cd/TBBPA mixture and Cd. These chemicals also led to suppressed antioxidant defensive mechanisms and increased oxidative stress. Further, these chemicals induced gene expression of apoptosis-related genes, activated genes encoding for phase I detoxification enzymes and inhibited genes encoding for phase II detoxification enzymes. These findings indicate that the hepatic damages induced by subchronic aerosol exposure of Cd and TBBPA may result from the oxidative damages caused by excessive ROS production when these chemicals were metabolized in the liver.

[en] Investigation of microbial communities of soils contaminated by antimony (Sb) and arsenic (As) is necessary to obtain knowledge for their bioremediation. However, little is known about the depth profiles of microbial community composition and structure in Sb and As contaminated soils. Our previous studies have suggested that historical factors (i.e., soil and sediment) play important roles in governing microbial community structure and composition. Here, we selected two different types of soil (flooded paddy soil versus dry corn field soil) with co-contamination of Sb and As to study interactions between these metalloids, geochemical parameters and the soil microbiota as well as microbial metabolism in response to Sb and As contamination. Comprehensive geochemical analyses and 16S rRNA amplicon sequencing were used to shed light on the interactions of the microbial communities with their environments. A wide diversity of taxonomical groups was present in both soil cores, and many were significantly correlated with geochemical parameters. Canonical correspondence analysis (CCA) and co-occurrence networks further elucidated the impact of geochemical parameters (including Sb and As contamination fractions and sulfate, TOC, Eh, and pH) on vertical distribution of soil microbial communities. Metagenomes predicted from the 16S data using PICRUSt included arsenic metabolism genes such as arsenate reductase (ArsC), arsenite oxidase small subunit (AoxA and AoxB), and arsenite transporter (ArsA and ACR3). In addition, predicted abundances of arsenate reductase (ArsC) and arsenite oxidase (AoxA and AoxB) genes were significantly correlated with Sb contamination fractions, These results suggest potential As biogeochemical cycling in both soil cores and potentially dynamic Sb biogeochemical cycling as well. - Highlights: • Two contrasting soil vertical profiles were selected. • All vertical profiles were contaminated by antimony and arsenic. • The contamination fractions shaped the innate soil microbiota. • Metabolic potentials in soil microbiota indicated arsenic metabolism. - Microbial communities were investigated in two contrasting soil vertical profiles.