scholarly journals Coupled Modeling and Simulation of Phase Transformation in Zircaloy-4 Fuel Cladding Under Loss-of-Coolant Accident Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenjun Lu ◽  
Libo Qian ◽  
Wenzhong Zhou
Keyword(s):  
Thermal Conductivity ◽  
Phase Transformation ◽  
Nuclear Fuel ◽  
Transformation Model ◽  
Fuel Cladding ◽  
Fuel Rod ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Accident Conditions ◽  
Enhanced Thermal Conductivity

Under loss-of-coolant conditions, the temperature on fuel cladding will increase rapidly (up to 1000–1500 K), which will not only cause a dramatic oxidation reaction of Zircaloy-4 and an increase in hydrogen concentration but also cause an allotropic phase transformation of Zircaloy-4 from hexagonal (α-pahse) to cubic (β-phase) crystal structure. As we all know, thermophysical properties have a close relationship with the microstructure of the material. Moreover, because of an important influence of the phase transformation on the creep resistance and the ductility of the fuel rod, studying the crystallographic phase transformation kinetics is pivotal for evaluating properties for fuel rod completeness. We coupled the phase transformation model together with the existing physical models for reactor fuel, gap, cladding, and coolant, based on the finite element analysis and simulation software COMSOL Multiphysics. The critical parameter for this transformation is the evolution of the volume fraction of the favored phase described by a function of time and temperature. Hence, we choose two different volume fractions (0 and 10%) of BeO for UO2-BeO enhanced thermal conductivity nuclear fuel and zircaloy cladding as objects of this study. In order to simulate loss-of-coolant accident conditions, five relevant parameters are studied, including the gap size between fuel and cladding, the temperature at the extremities of the fuel element, the coefficient of heat transfer, the linear power rate, and the coolant temperature, to see their influence on the behavior of phase transformation under non-isothermal conditions. The results show that the addition of 10vol%BeO in the UO2 fuel decreased the phase transformation effect a lot, and no significant phase transformation was observed in Zircaloy-4 cladding with UO2-BeO enhanced thermal conductivity nuclear fuel during existing loss-of-coolant accident conditions.

Rupture behaviour of nuclear fuel cladding during loss-of-coolant accident

2016 ◽  
Vol 307 ◽  
pp. 319-327 ◽  
Author(s):  
Siddharth Suman ◽  
Mohd. Kaleem Khan ◽  
Manabendra Pathak ◽  
R.N. Singh ◽  
J.K. Chakravartty
Keyword(s):  
Nuclear Fuel ◽  
Fuel Cladding ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Nuclear Fuel Cladding

scholarly journals EXPERIMENTAL STUDY OF DAMAGED CR-COATED FUEL CLADDING IN POST-ACCIDENT CONDITIONS

2020 ◽  
Vol 28 ◽  
pp. 1-7
Author(s):  
Petr Červenka ◽  
Jakub Krejčí ◽  
Ladislav Cvrček ◽  
Vojtěch Rozkošný ◽  
František Manoch ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Experimental Methodology ◽  
Fuel Cladding ◽  
Loss Of Coolant Accident ◽  
Ring Compression ◽  
Loss Of Coolant ◽  
Accident Conditions ◽  
Cr Coating ◽  
The Impact ◽  
Positive Effect

To enhance the safety of nuclear power, the focus of researchers all around the world has recently mainly objected on the development of Accident Tolerant Fuels. Especially the Chromium coating of current Zirconium based cladding has been widely suggested and discussed for its immense positive effect on overall cladding properties. Nevertheless, it was observed that during the first stage of the Loss of Coolant Accident, cracks appear in the Cr coating due to its inability to tolerate higher plastic strain. Therefore, experimental methodology used in this article focuses on testing fuel cladding with damaged Cr coating after the high-temperature transient. The impact of cracks on degradation of cladding mechanical properties was observed using optical microscopy, ring compression test, microhardness, and evaluating hydrogen content and weight gain.

scholarly journals Demonstration of Multi-Physics Evaluation of Fuel Rod Burst Probability With Burnup Extension Under LBLOCA Conditions

2020 ◽  
Author(s):  
Hongbin Zhang ◽  
Cole Blakely ◽  
Jianguo Yu
Keyword(s):  
Operating Time ◽  
Economic Benefits ◽  
Pressurized Water ◽  
Fuel Rod ◽  
Current Limit ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Water Reactors ◽  
Accident Conditions ◽  
Operating Cycles

Abstract Extending the fuel discharge burnup level, e.g., from the current limit of rod averaged discharge burnup limit of 62 GWD/MT to a proposed new limit of 75 GWD/MT, can provide significant economic benefits to the current fleet of operating light water reactors (LWRs). It allows for longer operating cycles and improved resource utilization. The major economic gain of longer operating cycles is attributable to the increased capacity factor resulting from decreased refueling time as a fraction of total operating time, as well as fewer assemblies to be discharged for a given amount of energy produced. The main licensing challenges for higher burnup fuel are to ensure fuel rod safety under design basis accident conditions, especially under large-break loss-of-coolant accident (LBLOCA) and reactivity insertion accident (RIA). In this work, two-year cycle core design for a typical 4-loop pressurized water reactor (PWR) is performed with enrichment increased up to 6% and burnup extended to 75 GWD/MT. The fuel rod burst potential evaluations under large-break loss-of-coolant accident (LBLOCA) conditions are subsequently performed using the multi-physics best estimate plus uncertainty analysis framework LOTUS (LOCA Toolkit for the U.S. LWRs) and the preliminary results are presented.

scholarly journals Development of Thermal Models and Analysis of UO2-BeO Fuel during a Loss of Coolant Accident

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Deepthi Chandramouli ◽  
Shripad T. Revankar
Keyword(s):  
Thermal Conductivity ◽  
Temperature Drop ◽  
Specific Enthalpy ◽  
Performance Parameters ◽  
Transient Conditions ◽  
Fuel Rod ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Gas Gap ◽  
Lower Temperature

Small fraction of high conductivity BeO in UO2 fuel significantly improves thermal conductivity and also affects the overall performance of the fuel during steady state operation and during transients. In this study, performance of UO2-BeO composite under transient conditions such as loss of coolant accident (LOCA), using FRAPTRAN (fuel rod analysis program transient), was carried out. The subroutines in FRAPTRAN code that calculate key thermophysical properties such as thermal conductivity, specific heat capacity, and specific enthalpy were modified to account for the presence of the BeO in UO2. The fuel performance parameters like gas gap pressure, energy stored in fuel, and temperature profiles were studied. The simulation results showed reductions in fuel centerline temperatures and lower temperature drop across fuel rod cross-section under normal fuel operations. It was observed that there was reduction in gas gap pressure and energy stored in fuel. Transient conditions involving cladding rupture were investigated and important performance parameters such as cladding strain were studied. During these transients, the addition of BeO to UO2 fuel seems beneficiary.

Behavior of plasma sprayed Cr coatings and FeCrAl coatings on Zr fuel cladding under loss-of-coolant accident conditions

2018 ◽  
Vol 344 ◽  
pp. 141-148 ◽  
Author(s):  
Yiding Wang ◽  
Wancheng Zhou ◽  
Qinlong Wen ◽  
Xingcui Ruan ◽  
Fa Luo ◽  
...  
Keyword(s):  
Fuel Cladding ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Accident Conditions ◽  
Plasma Sprayed
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