scholarly journals Study on Effect of Local Power Distribution of Fuel Assembly on Critical Power of Reduced-Moderation Water Reactor (RMWR)

2010 ◽  
Vol 9 (2) ◽  
pp. 139-149
Author(s):  
Toru NAKATSUKA ◽  
Yoshihiro NAKANO ◽  
Tsutomu OKUBO
Author(s):  
Xuming Wang ◽  
Cenxi Yuan ◽  
Chen Ye

Taishan European Pressurized Water Reactor (EPR) is a third generation advanced pressurized water reactor (PWR), which adopts the third generation advanced fuel assembly (AFA-3G-LE) from AREVA for the first time. As suggested by American Electric Power Research Institute (EPRI), an EPRI level III crud risk assessment is necessary for new type of plants. Because crud induced power offset (CIPS) and crud induced local corrosion (CILC) can lead to axial offset anomaly (AOA) and fuel cladding failure, respectively. A EPRI level III CIPS/CILC risk assessment for Taishan EPR is performed with a new framework of simulation by using sub-channel code FLICA, crud code BOA, and Monte Carlo transport code Tripoli-4. Such framework enables a self-consistent calculation, including a detailed description on neutronics contributed by boron. The validation of present work is confirmed because of the good agreement with the experienced data of EPRI. The results show that AFA-3G-LE has a good performance on crud risk assessment. Even in the worst case, the boron-10 deposition (2.6 g) and the maximum thickness of crud (59 μm) are lower than the low risk threshold, 31.33 g and 75 μm, respectively. Hence, It is expected that Taishan EPR has a very low risk on CIPS and CILC.


Author(s):  
Zhixiong Tan ◽  
Jiejin Cai

After Fukushima Daiichi Nuclear Power Plant accident, alternative fuel-design to enhance tolerance for severe accident conditions becomes particularly important. Silicon carbide (SiC) cladding fuel assembly gain more safety margin as novel accident tolerant fuel. This paper focuses on the neutron properties of SiC cladding fuel assembly in pressurized water reactors. Annular fuel pellet was adopted in this paper. Two types of silicon carbide assemblies were evaluated via using lattice calculation code “dragon”. Type one was consisted of 0.057cm SiC cladding and conventional fuel. Type two was consisted of 0.089cm SiC cladding and BeO/UO2 fuel. Compared the results of SiC cladding fuel assembly neutronic parameters with conventional Zircaloy cladding fuel assembly, this paper analyzed the safety of neutronic parameters performance. Results demonstrate that assembly-level reactivity coefficient is kept negative, meanwhile, the numerical value got a relatively decrease. Other parameters are conformed to the design-limiting requirement. SiC kinds cladding show more flat power distribution. SiC cases also show the ability of reducing the enrichment of fuel pellets even though it has higher xenon concentration. These types of assembly have broadly agreement neutron performance with the conventional cladding fuel, which confirmed the acceptability of SiC cladding in the way of neutron physics analysis.


Author(s):  
Pablo E. Araya Go´mez ◽  
Miles Greiner

Two-dimensional simulations of steady natural convection and radiation heat transfer for a 14×14 pressurized water reactor (PWR) spent nuclear fuel assembly within a square basket tube of a typical transport package were conducted using a commercial computational fluid dynamics package. The assembly is composed of 176 heat generating fuel rods and 5 larger guide tubes. The maximum cladding temperature was determined for a range of assembly heat generation rates and uniform basket wall temperatures, with both helium and nitrogen backfill gases. The results are compared with those from earlier simulations of a 7×7 boiling water reactor (BWR). Natural convection/radiation simulations exhibited measurably lower cladding temperatures only when nitrogen is the backfill gas and the wall temperature is below 100°C. The reduction in temperature is larger for the PWR assembly than it was for the BWR. For nitrogen backfill, a ten percent increase in the cladding emissivity (whose value is not well characterized) causes a 4.7% reduction in the maximum cladding to wall temperature difference in the PWR, compared to 4.3% in the BWR at a basket wall temperature of 400°C. Helium backfill exhibits reductions of 2.8% and 3.1% for PWR and BWR respectively. Simulations were performed in which each guide tube was replaced with four heat generating fuel rods, to give a homogeneous array. They show that the maximum cladding to wall temperature difference versus total heat generation within the assembly is not sensitive to this geometric variation.


2017 ◽  
Vol 792 ◽  
pp. 012051
Author(s):  
S J Castillo ◽  
G A Vargas ◽  
E del Valle Gallegos

2021 ◽  
Vol 31 (1) ◽  
pp. 60-71
Author(s):  
Leonardo Acosta Martínez ◽  
Carlos Rafael García Hernández ◽  
Jesus Rosales García ◽  
Annie Ortiz Puentes

One of the challenges of future nuclear power is the development of safer and more efficient nuclear reactor designs. The AP1000 reactor based on the PWR concept of generation III + has several advantages, which can be summarized as: a modular construction, which facilitates its manufacture in series reducing the total construction time, simplification of the different systems, reduction of the initial capital investment and improvement of safety through the implementation of passive emergency systems. Being a novel design it is important to study the thermohydraulic behavior of the core applying the most modern tools. To determine the thermohydraulic behavior of a typical AP1000 fuel assembly, a computational model based on CFD was developed. A coupled neutronic-thermohydraulic calculation was performed, allowing to obtain the axial power distribution in the typical fuel assembly. The geometric model built used the certified dimensions for this type of installation that appear in the corresponding manuals. The thermohydraulic study used the CFD-based program ANSYS-CFX, considering an eighth of the fuel assembly. The neutronic calculation was performed with the program MCNPX version 2.6e. The work shows the results that illustrate the behavior of the temperature and the heat transfer in different zones of the fuel assembly. The results obtained agree with the data reported in the literature, which allowed the verification of the consistency of the developed model.


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