Comparative analysis of reactor pressure vessel failure using two thermo-fluid-structure coupling approaches

2020 ◽  
Vol 368 ◽  
pp. 110819
Author(s):  
Peng Yu ◽  
Weimin Ma
2020 ◽  
pp. 30-40
Author(s):  
O. Kotsuba ◽  
Yu. Vorobyov ◽  
O. Zhabin ◽  
D. Gumenyuk

An overview of the main improvements in updated version 2.1 of MELCOR computer code related to more representative mathematical modeling of complex thermohydraulic severe accident processes of core degradation, transfer of molten fragments to the bottom of the reactor, heating and failure of the bottom of the reactor pressure vessel is presented. The elements of WWER-1000 NPP computer model for the MELCOR 1.8.5 (control volumes, thermal structures and structures of the reactor core) that are reproduced for a reactor with the primary side, the secondary side and the containment are described. The changes implemented in WWER-1000 NPP model for MELCOR 1.8.5 to convert it to MELCOR 2.1 version that are mainly related to more detailed modeling of the reactor core and reactor pressure vessel bottom are provided. The paper presents the results of comparative analysis of severe accident scenario of total station blackout at WWER-1000 NPP with MELCOR 1.8.5 and 2.1. The comparison demonstrates good agreement between the main parameters’ results (pressure and temperature in hydraulic elements of the primary, secondary sides and the containment, temperature of core elements, the mass of the generated non-condensed gases and their concentration in the containment) obtained with these code versions for severe accident in-vessel phase. The identified differences in the time of core structures degradation and reactor vessel bottom failure are insignificantly affected by the behavior of the parameters in the primary side and the containment in the in-vessel phase of the severe accident and are related to more detailed modelling of the reactor core and bottom part of the reactor in MELCOR 2.1.


Author(s):  
Mingqian Zhang ◽  
Yuangang Duan ◽  
Xiaobing Ran ◽  
Yanwu Liu

In order to better understand the stresses to which the flow distribution device (FDD) is subjected for the pressure fluctuation, we need to improve our knowledge of the fluid flow inside the reactor pressure vessel (RPV). The flow field of the reactor lower plenum which is associated with a typical pressurized water reactor (PWR) is simulated by using ANSYS CFX code. Calculations have been carried out from reactor pressure vessel inlet to the core outlet. Grid sizes of million nodes with the k-epsilon turbulent model have been used with a porous zone approach for the reactor core space. Predictions of the steady-state pressure and velocity field have been made. The results are compared with the scaled experiment data in order to verify the accurate description of the fluid flow. Based on this verified turbulent model, a sub-domain is extracted from the lower plenum for the transient two-way Fluid-Structure Interaction (FSI) simulation which is limited by the computer capability and computing time. This transient analysis of fluid-structure coupling system is conducted by using CFX and ANSYS in numeric calculation of flow field and structure, with an exchanging platform MFX-ANSYS/CFX which can transfer fluid pressure and structure displacement between computational fluid dynamics (CFD) and computational structure dynamics (CSD) grid systems. The loose coupling method is used to investigate the transient dynamic response of the flow distribution device which is immerged in the bottom plenum. Dynamic stress and strain of the flow distribution device are given and discussed. This analysis practice can be guidance for the optimization design of reactor and improve our understanding of reactor components flow induced vibration phenomena.


2014 ◽  
Vol 10 (1) ◽  
pp. 123-127 ◽  
Author(s):  
Gyeong-Geun Lee ◽  
Yong-Bok Lee ◽  
Min-Chul Kim ◽  
Junhyun Kwon

2020 ◽  
Vol 110 ◽  
pp. 102798
Author(s):  
KaiTai Liu ◽  
Mei Huang ◽  
JunJie Lin ◽  
HaiPeng Jiang ◽  
BoXue Wang ◽  
...  

2021 ◽  
Vol 13 (10) ◽  
pp. 5498
Author(s):  
Alvaro Rodríguez-Prieto ◽  
Mariaenrica Frigione ◽  
John Kickhofel ◽  
Ana M. Camacho

The growth of green energy technologies within the frame of the 7th Sustainable Development Goal (SDG) along with the concern about climatic changes make nuclear energy an attractive choice for many countries to ensure energy security and sustainable development as well as to actively address environmental issues. Unlike nuclear equipment (immovable goods), which are often well-catalogued and analyzed, the design and manufacturing codes and their standardized materials specifications can be considered movable and intangible goods that have not been thoroughly studied based on a detailed evaluation of the scientific and technical literature on the reactor pressure vessel (RPV) materials behavior. The aim of this work is the analysis of historical advances in materials properties research and associated standardized design codes requirements. The analysis, based on the consolidated U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.99 Rev.2 model, enables determination of the best materials options, corresponding to some of the most widely used material specifications such as WWER 15Kh2MFAA (used from the 1970s and 1980s; already in operation), ASME SA-533 Grade B Cl.1 (used in pressurized water reactor-PWR 2nd–4th; already in operation), DIN 20MnMoNi55 and DIN 22NiMoCr37 (used in PWR 2nd–4th) as well as ASTM A-336 Grade F22V (current designs). Consequently, in view of the results obtained, it can be concluded that the best options correspond to recently developed or well-established specifications used in the design of pressurized water reactors. These assessments endorse the fact that nuclear technology is continually improving, with safety being its fundamental pillar. In the future, further research related to the technical heritage from the evolution of materials requirements for other clean and sustainable power generation technologies will be performed.


2021 ◽  
Vol 527 ◽  
pp. 167698
Author(s):  
Xuejiao Wang ◽  
Wenjiang Qiang ◽  
Guogang Shu ◽  
Junwei Qiao ◽  
Yucheng Wu

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