In an integral pressurized water reactor(IPWR), the primary coolant system components and the loop system equipment are housed in the reactor pressure vessel, and the pipe lines connecting between those components are...
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In an integral pressurized water reactor(IPWR), the primary coolant system components and the loop system equipment are housed in the reactor pressure vessel, and the pipe lines connecting between those components are eliminated because of the requirement of compact layout in-vessel. The compactness and inherent safety of the system are enhanced with the concise structure. Thus, this design scheme is suitable for the medium or small size nuclear power plants or ships nuclear systems in the economic and technological aspects. According to the thermal- hydraulic characteristics of the IPWR,a reasonable description of the system mathematical and physical model is established, including core model, simplified pump model, once-through steam generator (OTSG) model, flow friction and heat transfer models. Meanwhile, all possible flow and heat transfer conditions are considered and the corresponding optional models are presented. In addition, the Gear method is used for the numerical solution of transient equations. The full pressure startup method is simulated with this model. Because of the adoption of modular programming techniques, both of the steady and transient state analysis codes can be applied easily to other thermal-hydraulic analysis of special reactors and special cases by modifying and updating the corresponding function modules.
In the present study, a thermal-hydraulic safety analysis code for AP1000 named RETAC (REactor Transient Analysis Code) has been developed using FORTRAN 90 language. A point reactor neutron kinetics model with six gro...
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In the present study, a thermal-hydraulic safety analysis code for AP1000 named RETAC (REactor Transient Analysis Code) has been developed using FORTRAN 90 language. A point reactor neutron kinetics model with six groups of delayed neutrons was adopted to describe the core thermal power transient. A distribute parameter model with two-phase drift flux model was used in the U-tube steam generator simulation. In the pressurizer simulation, a multi-region non-equilibrium model was adopted. Similar to current large commercial codes such as RELAP5 and RETRAN series, the four-quadrant analogy curves were used for the solution of the transient behaviors of the main coolant pumps. In this paper, a new and reasonable model for the passive residual heat removal heat exchanger (PRHR HX) was proposed based on basic equations of mass, momentum and energy. Gear method and Adams predictor-corrector method were adopted alternately for a better solution to ill-condition differential equations corresponding to detail processes. The PRHR HX inadvertent operation accident was chosen in the transient accident analysis. Furthermore, the simulation results obtained by RETAC were compared with that by Westinghouse-developed LOFTRAN code. The comparison results showed a good agreement and thus proved the accuracy and reliability of the RETAC code. With the adoption of modular programming techniques, the RETAC code can be easily modified and applied to higher power passive safety reactors in the future.
A pebble bed water cooled reactor (PBWR) is one of the renewed reactor designs in nuclear power generation. It is currently under consideration and development worldwide in the conceptual design of high temperature ga...
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A pebble bed water cooled reactor (PBWR) is one of the renewed reactor designs in nuclear power generation. It is currently under consideration and development worldwide in the conceptual design of high temperature gas-cooled reactor and supercritical water-cooled reactor. In this study, the different geometrical models of the PBWR were built in which the thermal- hydraulic characteristics of the coolant were analyzed and compared. The results indicate that with the same physical parameters and boundary conditions, the packing form of body-centered cubic is the best choice to the actual case.
The steam generator secondary passive emergency feedwater system is a new design for traditional generation II + reactor CPR1000. The passive emergency feedwater system is designed to supply water to the SG shell side...
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The steam generator secondary passive emergency feedwater system is a new design for traditional generation II + reactor CPR1000. The passive emergency feedwater system is designed to supply water to the SG shell side and improve the safety and reliability of CPR1000 by completely or partially replacing traditional emergency water cooling system in the event of the feed line break (FLB) or loss of heat sink accident. The passive emergency feedwater system consists of steam generator (SG), heat exchanger (HX), air cooling tower, emergency makeup tank (EMT), and corresponding pipes and valves for air cooling condition. In order to improve the safety and reliability of CPR1000, the model of the primary loop system and the passive emergency feedwater system was developed to investigate residual heat removal capability of the passive emergency feedwater system and the transient characteristics of the primary loop system affected by the passive emergency feedwater system using RELAP5/MOD3.4. The transient characteristics of the primary loop system and the passive emergency feedwater system were calculated in the event of feed line break accident. Sensitivity studies of the passive emergency feedwater system were also conducted to investigate the response of the primary loop and the passive emergency feedwater system on the main parameters of the passive emergency feedwater system. The passive emergency feedwater system could supply water to the SG shell side from the EMT successfully. The calculation results showed that the passive emergency feedwater system could take away the decay heat from the primary loop effectively for air cooling condition, and that the single-phase and two-phase natural circulations were established in the primary loop and passive emergency feedwater system loop, respectively.
Pt-Ni bimetallic catalysts and their corresponding monometallic catalysts supported on active carbon were prepared by incipient wetness impregnation or chelating formaldehyde reduction. The effect of feed/catalyst rat...
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α-Fe2O3 nanorod arrays were fabricated by a low-temperature aqueous chemical growth (ACG) technique and followed by an annealing process. For the surface doping of α-Fe2O3 nanorods, β-FeOOH nanorods obtained via AC...
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α-Fe2O3 nanorod arrays were fabricated by a low-temperature aqueous chemical growth (ACG) technique and followed by an annealing process. For the surface doping of α-Fe2O3 nanorods, β-FeOOH nanorods obtained via ACG were coated with a thin layer of Cr3+ precursor solution by spin coating, and then underwent the annealing treatment in air. Conducting polymer polypyrrole (PPy) decorated α-Fe2O3 nanorods were prepared by electrodeposition method using malic acid contained pyrrole aqueous solution. Primary results showed that the photocurrents of α-Fe2O3 nanorod array photoanodes were greatly enhanced by surface doping of Cr3+, as well as PPy decoration. This might be due to the retarded charge recombination and promoted surface reaction rate of photogenerated holes with water. Further investigation on surface modification of α-Fe2O3 nanorod array photoanodes is currently conducted in our group.
The effects of three factors on combustion performance of petroleum coke, Herin Coal and Shenmu Coal have been studied, including the ratio of primary air, excess air factor, and the swirling intensity of outer second...
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The effects of three factors on combustion performance of petroleum coke, Herin Coal and Shenmu Coal have been studied, including the ratio of primary air, excess air factor, and the swirling intensity of outer secondary air. The experiments were carried out on a one-dimensional furnace with dual channel swirling burner, in which temperature of center furnace, emission of air pollutants, and burn-out rate of fuel were measured. The results provide the optimal ratio of primary air, excess air factor and swirling intensity of outer secondary air for the fuels. The combustion performance of petroleum coke B is much better than petroleum coke A, but worse than Hejin coal and Shenmu coal. In addition, the burn-out rate of petroleum coke depends much more on the temperature in terminal stage of combustion than in the early stage of combustion.
A method for synthesizing of 2-nitrobenzaldehyde from 2-nitrobenzyl alcohol using ionic liquids (ILs) has been developed. The conversion of 2-nitrobenzyl alcohol and the selectivity of 2-nitrobenzaldehyde in the ionic...
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