Multiphysics Analysis of Thorium-Based Fuel Performance Under Reactor Steady-State and Transient Accident

2020 ◽  
Author(s):  
Chenjie Qiu ◽  
Rong Liu ◽  
Wenzhong Zhou
Keyword(s):  
Steady State ◽  
Safety Margin ◽  
Operating Conditions ◽  
Fuel Performance ◽  
Transient Conditions ◽  
Normal Operating ◽  
Accident Conditions ◽  
Behavior Models ◽  
Line Temperature ◽  
Thermal Physical Properties

Abstract The ThO2 fuel has higher thermal conductivity and melting boiling point than the UO2 fuel, which is beneficial to the fast removal of heat and the improvement of fuel melt margin. In this paper, the material properties and thermodynamic behaviors of thorium-based fuel were firstly reviewed. And then the thermal physical properties and the fuel behavior models of Th0.923U0.077O2 fuel and Th0.923Pu0.077O2 fuel have been implemented in fuel performance analysis code FRAPCON and FRAPTRAN. Finally, the performances of Th0.923U0.077O2 fuel, Th0.923Pu0.077O2 fuel and UO2 fuel under both normal operating conditions and transient conditions (RIA and LOCA) are analyzed and compared. The Th0.923U0.077O2 fuel is found to have lower fuel center-line temperature and the thorium-based fuels are observed to have a delayed pellet-cladding mechanical interaction (PCMI) under steady state. Furthermore, the fission gas release, cladding strain and internal fuel energy under transient conditions are found to be lower too. Lastly, the cladding displacement and temperature under transient conditions are also compared. The thorium-based fuel was found to have a higher safety margin and accident resistance than conventional UO2 fuel under both normal operating conditions and accident conditions.

Extending the application range of a fuel performance code from normal operating to design basis accident conditions

2008 ◽  
Vol 383 (1-2) ◽  
pp. 137-143 ◽  
Author(s):  
P. Van Uffelen ◽  
C. Győri ◽  
A. Schubert ◽  
J. van de Laar ◽  
Z. Hózer ◽  
...  
Keyword(s):  
Fuel Performance ◽  
Application Range ◽  
Normal Operating ◽  
Design Basis ◽  
Design Basis Accident ◽  
Accident Conditions

Numerical Techniques Applied to Hydraulic Turbines: A Perspective Review

2016 ◽  
Vol 68 (1) ◽  
Author(s):  
Chirag Trivedi ◽  
Michel J. Cervantes ◽  
Ole Gunnar Dahlhaug
Keyword(s):  
Steady State ◽  
Numerical Models ◽  
Guide Vane ◽  
Numerical Technique ◽  
Fluid Dynamic ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Numerical Techniques ◽  
Transient Conditions ◽  
Hydraulic Turbines

Applications of computational fluid dynamic (CFD) techniques to hydropower have increased rapidly in the last three decades. The majority of the experimental investigations of hydraulic turbines were supported by numerical studies and this has become a standard practice. In the paper, applied numerical techniques and flow modeling approaches to simulate the hydraulic turbines are discussed. Both steady-state and transient operating conditions of the turbines are considered for the review. The steady-state conditions include the best efficiency point (BEP), high load (HL), and part load (PL). The transient conditions include load variation, startup, shutdown, and total load rejection. The performance of the applied numerical models and turbulence modeling with respect to the operating conditions are discussed. The recently developed numerical technique (transient blade row modeling) using the Fourier transformation (FT) method is discussed. This technique allows guide vane and blade passages to be modeled with the pitch ratio other than unity. Numerical modeling and simulation of hydraulic turbines during the transient operating conditions is one of the most challenging tasks because guide vanes' angular movement is time-dependent and mesh should be dynamic/moving. Different approaches applied to simulate the transient conditions and their limitations are discussed. Overall, this review summarizes the role of numerical techniques, advantages, limitations, and upcoming challenges within hydropower.

scholarly journals Multiphysics Modeling of Thorium-Based Fuel Performance With Cr-Coated SiC/SiC Composite Under Normal and Accident Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengyu Liu ◽  
Rong Liu ◽  
Chengjie Qiu ◽  
Wenzhong Zhou
Keyword(s):  
Failure Time ◽  
Mechanical Performance ◽  
Hoop Strain ◽  
Fuel Performance ◽  
Multiphysics Modeling ◽  
Normal Operating ◽  
Loss Of Coolant Accident ◽  
Accident Conditions ◽  
Work First ◽  
Centerline Temperature

Using the finite element multiphysics modeling method, the performance of the thorium-based fuel with Cr-coated SiC/SiC composite cladding under both normal operating and accident conditions was investigated in this work. First, the material properties of SiC/SiC composite and chromium were reviewed. Then, the implemented model was simulated, and the results were compared with those of the FRAPTRAN code to verify the correctness of the model used in this work. Finally, the fuel performance of the Th0.923U0.077O2 fuel, Th0.923Pu0.077O2 fuel, and UO2 fuel combined with the Cr-coated SiC/SiC composite cladding and Zircaloy cladding, respectively, was investigated and compared under both normal operating and accident conditions. Compared with the UO2 fuel, the Th0.923U0.077O2 and Th0.923Pu0.077O2 fuels were found to increase the fuel centerline temperature under both normal operating and reactivity-initiated accident (RIA) conditions, but decrease the fuel centerline temperature under loss-of-coolant accident (LOCA) condition. Moreover, compared to the UO2 fuel with the Zircaloy cladding, thorium-based fuels with Cr-coated SiC/SiC composite cladding were found to show better mechanical performance such as delaying the failure time by about 3 s of the Cr-coated SiC/SiC composite cladding under LOCA condition, and reducing the plenum pressure by about 0.4 MPa at the peak value in the fuel rod and the hoop strain of the cladding by about 16% under RIA condition.

Experimental Study of the Effect of Hydrogen Inflow on Passive Core Cooling System With Natural Circulation Flow

2020 ◽  
Author(s):  
Yasunori Yamamoto ◽  
Masayoshi Mori ◽  
Kosuke Ono ◽  
Tetsuya Takada
Keyword(s):  
Steady State ◽  
Cooling System ◽  
Natural Circulation ◽  
Operating Conditions ◽  
Quasi Steady State ◽  
Circulation Flow ◽  
Term Operation ◽  
Accident Conditions ◽  
Core Cooling

Abstract Isolation Condenser (IC) is one of the passive core cooling systems with natural circulation flow, which is effective for safety measures against station black out. Once core uncover occurs, hydrogen generated in the core affects operating condition of ICs. To use ICs as an important safety measure not only for transient conditions but also for accident conditions, robustness of ICs against hydrogen inflow must be understood well. In this study, experiments with high pressure steam were conducted using experimental setup simulating IC, where helium was injected to simulate hydrogen effects. When the pressure in an accumulator increased high enough, natural circulation flow generated in the experimental loop. After the long-term operation, the pressure and the natural circulation flow rate achieved nearly constant. The pressure at quasi-steady state increased with increasing the helium injection amount. The pressure difference in a section including outlet side of a vertical pipe was slightly increased when helium was injected which may have indicated that the helium accumulated in the section and caused increment of the pressure loss. The startup pressure of the IC simulator also increased when helium was injected, where the driving force by the water head difference also decreased. Though long-term operations were performed after helium injection, the effect of injected helium on operating conditions of the IC remained for quasi-steady state conditions.

scholarly journals Thermal behavior analysis of PWR fuel during RIA at various fuel burnups using modified theatre code

2016 ◽  
Vol 31 (4) ◽  
pp. 307-317
Author(s):  
Amjad Nawaz ◽  
Yoshikawa Hidekazu ◽  
Ming Yang ◽  
Anwar Hussain
Keyword(s):  
Steady State ◽  
Thermal Performance ◽  
Pulse Width ◽  
Pulse Height ◽  
Operating Conditions ◽  
Reactor Safety ◽  
Transient Conditions ◽  
Power Pulse ◽  
Fuel Rod ◽  
Fuel Failure

The fuel irradiation and burnup causes geometrical and dimensional changes in the fuel rod which affects its thermal resistance and ultimately affects the fuel rod behavior during steady-state and transient conditions. The consistent analysis of fuel rod thermal performance is essential for precise evaluation of reactor safety in operational transients and accidents. In this work, analysis of PWR fuel rod thermal performance is carried out under steady-state and transient conditions at different fuel burnups. The analysis is performed by using thermal hydraulic code, THEATRe. The code is modified by adding burnup dependent fuel rod behavior models. The original code uses as-fabricated fuel rod dimensions during steady-state and transient conditions which can be modified to perform more consistent reactor safety analysis. AP1000 reactor is considered as a reference reactor for this analysis. The effect of burnup on steady-state fuel rod parameters has been investigated. For transient analysis, hypothetical reactivity initiated accident was simulated by considering a triangular power pulse of variable pulse height (relative to the full power reactor operating conditions) and pulse width at different fuel burnups which corresponds to fresh fuel, low and medium burnup fuels. The effect of power pulse height, pulse width and fuel burnup on fuel rod temperatures has been investigated. The results of reactivity initiated accident analysis show that the fuel failure mechanisms are different for fresh fuel and fuel at different burnup levels. The fuel failure in fresh fuel is expected due to fuel melting as fuel temperature increases with increase in pulse energy (pulse height). However, at relatively higher burnups, the fuel failure is expected due to cladding failure caused by strong pellet clad mechanical interaction, where, the contact pressure increases beyond the cladding yield strength.

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