Research on Improved Simplified SCWR Assembly and Core Design

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Yao Lei ◽  
Xia Bangyang ◽  
Lu Di ◽  
Wang Lianjie
Keyword(s):  
Surface Temperature ◽  
Electric Power ◽  
Heat Generation ◽  
Supercritical Water ◽  
Complex Structure ◽  
Heat Generation Rate ◽  
Safety Criterion ◽  
New Type ◽  
Full Power ◽  
Supercritical Water Cooled Reactor

Abstract A new type of simplified assembly without “water rod” or solid moderator is identified to simplify China Supercritical Water-cooled Reactor with the rated electric power of 1000 MWel (CSR1000) core structure. A study on the properties of this new assembly has been carried out. Under the condition of heat full power, maximum cladding surface temperature (MCST) is 658 °C, very close to safety criterion 650 °C, and maximum linear heat generation rate (MLHGR) is 40.0 kW/m, slightly higher than safety criterion 39 kW/m. Considering rod stuck criterion, the maximum keff is 0.9833, lower than safety criterion 0.99. The discharge burn-up reduced to 21368 MWd/t, a sharp decreasing of 31.1%. This simplified assembly provides a new idea for solving the problem of complex structure of supercritical water-cooled reactor (SCWR).

A novel heat generation acquisition method of cylindrical battery based on core and surface temperature measurements

2021 ◽  
pp. 1-17
Author(s):  
Xiaoli Yu ◽  
Qichao Wu ◽  
Rui Huang ◽  
Xiaoping Chen
Keyword(s):  
Surface Temperature ◽  
Heat Generation ◽  
Discharge Rate ◽  
Total Heat ◽  
Temperature Measurements ◽  
Generation Rate ◽  
Air Cooling ◽  
Heat Generation Rate ◽  
Environmental Chamber ◽  
Average Heat

Abstract Heat generation measurements of the lithium-ion battery are crucial for the design of the battery thermal management system. Most previous work uses the accelerating rate calorimeter (ARC) to test heat generation of batteries. However, utilizing ARC can only obtain heat generation of the battery operating under the adiabatic condition, deviating from common operation scenarios with heat dissipation. Besides, using ARC is difficult to measure heat generation of the high-rate operating battery because the battery temperature easily exceeds the maximum safety limit. To address these problems, we propose a novel method to obtain heat generation of cylindrical battery based on core and surface temperature measurements and select the 21700 cylindrical battery as the research object. Based on the method, total heat generation at 1C discharge rate under the natural convection air cooling condition in the environmental chamber is about 3.2 kJ, and the average heat generation rate is about 0.9 W. While these two results measured by ARC are about 2.2 kJ and 0.6 W. This gap also reflects that different battery temperature histories have significant impacts on heat generation. In addition, using our approach, total heat generation at 2C discharge rate measured in the environmental chamber is about 5.0 kJ, with the average heat generation rate being about 2.8 W. Heat generation results obtained by our method are approximate to the actual battery operation and have advantages in future applications.

Coupled Three-Dimensional Neutronics and Thermal-Hydraulics Analysis for SCWR Core Typical Transients

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Wang Lianjie ◽  
Lu Di ◽  
Zhao Wenbo
Keyword(s):  
Electric Power ◽  
Supercritical Water ◽  
Transient Analysis ◽  
Three Dimensional ◽  
Thermal Hydraulics ◽  
Water Density ◽  
Fuel Temperature ◽  
Control Rod ◽  
Reactor Protection System ◽  
Supercritical Water Cooled Reactor

Transient performance of China supercritical water-cooled reactor (SCWR) with the rated electric power of 1000 MWel (CSR1000) core during some typical transients, such as control rod (CR) ejection and uncontrolled CR withdrawal, is analyzed and evaluated with the coupled three-dimensional neutronics and thermal-hydraulics SCWR transient analysis code. The 3D transient analysis shows that the maximum cladding surface temperature (MCST) retains lower than safety criteria 1260 °C during the process of CR ejection accident, and the MCST retains lower than safety criteria 850 °C during the process of uncontrolled CR withdrawal transient. The safety of CSR1000 core can be ensured during the typical transients under the salient fuel temperature and water density reactivity feedback and the essential reactor protection system.

Transient Heat Transfer for Carbon Dioxide Flowing Over a Horizontal Plate With Exponentially Increasing Heat Input

2008 ◽  
Author(s):  
Makoto Shibahara ◽  
Qiusheng Liu ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Generation Rate ◽  
Transient Heat Transfer ◽  
Horizontal Plate ◽  
Heat Generation Rate ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Transient heat transfer coefficients for carbon-dioxide gas flowing over a horizontal plate (ribbon) at various periods of exponentially increasing heat input was experimentally and theoretically studied. In the experimental studies, transient heat transfer coefficients were measured under various velocities and periods. The platinum plate with a thickness of 0.1 mm was used as test heater and heated by electric current. The heat generation rate was exponentially increased with a function of Q0exp(t/τ). The gas flow velocities ranged from 1 to 3 m/s, the gas temperatures ranged from 313 K to 353 K, and the periods of heat generation rate ranged from 46 ms to 17 s. The surface temperature and heat flux increase exponentially as the heat generation rate increases with the exponential function. It was clarified that the heat transfer coefficient approaches the quasi-steady-state one for the period longer than about 1 s, and it becomes higher for the period shorter than around 1 s. In the theoretical study, forced convection transient heat transfer was numerically solved based on a conventional turbulent flow model. The temperature within the boundary layer around the heater increases with the increase of the surface temperature. It is understood that the gradient of the temperature distribution near the wall of the plate is higher at a higher surface temperature difference. The values of numerical solutions for the heat fluxes agree well with the experimental data, though the numerical solutions for surface temperatures show some differences with the experimental data.

Use of Geometrically-Accurate Models to Predict Spent Nuclear Fuel Cladding Temperatures Within a Truck Cask Under Normal and Fire Accident Conditions

2010 ◽  
Author(s):  
Krishna Kumar Kamichetty ◽  
Miles Greiner ◽  
Venkata V. R. Venigalla
Keyword(s):  
Surface Temperature ◽  
Heat Generation ◽  
Spent Nuclear Fuel ◽  
Thermal Dissipation ◽  
Heat Generation Rate ◽  
Fuel Cladding ◽  
Cfd Simulations ◽  
Nuclear Fuel Cladding ◽  
Accident Conditions ◽  
Fire Accident

The temperature of spent nuclear fuel cladding within transport casks must be determined for both normal conditions of transport and hypothetical fire accident conditions to assure that it does not exceed certain limit conditions. In the current work a two-dimensional finite-element thermal model of a legal-weight truck cask is constructed that accurately models the geometry of the fuel rods and cover gas. Computational fluid dynamics (CFD) simulations are performed that include buoyancy induced motion in, and radiation and natural convection heat transfer across the cover gas, as well as conduction in all solid components. Separate simulations are performed using helium or nitrogen cover gas. Stagnant-gas CFD (SCFD) simulations are preformed and compared to CFD simulations to determine the effect of gas motion. For normal conditions of transport, the peak clad temperature is determined for a range of fuel heat generation rates to determine the thermal dissipation capacity based on peak cladding and surface temperature, QC and QS. These are respectively, the fuel heat generation rates that bring the peak cladding temperature to 400°C, or the peak surface temperature to 85°C (their allowed limits for normal transport). Transient fire/post fire simulations are then performed for a range of fire durations to determine the critical durations for cladding Creep Deformation or Burst Rupture, DCD or DBR. These are the fire durations that bring the cladding temperature to 570°C or 750°C, respectively. When the cladding temperature is used to select the fuel heat generation rate, the thermal dissipation capacity is 3265 W/assembly when helium is the cover gas, which is 30% higher when nitrogen is used (due to helium’s higher thermal conductivity). When nitrogen is the cover gas, the critical fire durations for creep deformation and burst rupture are, respectively, 3.3 and 7.2 hours. These durations are 18% and 14% shorter for helium (because the allowed fuel heat generation rate is higher for helium). When the fuel heat generation is chosen based on the package surface temperature, for helium, the thermal dissipation capacity is 1040 W/assembly, and the critical fire durations for creed deformation and burst rupture are, respectively, 4.7 and 11.6 hours. The values for nitrogen are all within 4% of these values. The CFD and SCFD simulations give essentially the same results. This indicates that gas motion does not significantly affect the cladding temperature, and the future calculations may not need to incur the increased computation expense required to model that motion.

Quantification of thermal energy generation in annular hyperbolic porous-finned heat sinks using inverse optimization

2021 ◽  
pp. 095440892110243
Author(s):  
Sagnik Pal ◽  
Ranjan Das
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Heat Generation ◽  
Thermal Energy ◽  
Inverse Method ◽  
Golden Section ◽  
Energy Generation ◽  
Heat Sinks ◽  
Search Technique ◽  
Golden Section Search

The present paper introduces an accurate numerical procedure to assess the internal thermal energy generation in an annular porous-finned heat sink from the sole assessment of surface temperature profile using the golden section search technique. All possible heat transfer modes and temperature dependence of all thermal parameters are accounted for in the present nonlinear model. At first, the direct problem is numerically solved using the Runge–Kutta method, whereas for predicting the prevailing heat generation within a given generalized fin domain an inverse method is used with the aid of the golden section search technique. After simplifications, the proposed scheme is credibly verified with other methodologies reported in the existing literature. Numerical predictions are performed under different levels of Gaussian noise from which accurate reconstructions are observed for measurement error up to 20%. The sensitivity study deciphers that the surface temperature field in itself is a strong function of the surface porosity, and the same is controlled through a joint trade-off among heat generation and other thermo-geometrical parameters. The present results acquired from the golden section search technique-assisted inverse method are proposed to be suitable for designing effective and robust porous fin heat sinks in order to deliver safe and enhanced heat transfer along with significant weight reduction with respect to the conventionally used systems. The present inverse estimation technique is proposed to be robust as it can be easily tailored to analyse all possible geometries manufactured from any material in a more accurate manner by taking into account all feasible heat transfer modes.

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