scholarly journals A Multi-Physics Adaptive Time Step Coupling Algorithm for Light-Water Reactor Core Transient and Accident Simulation

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6374
Author(s):  
Alexey Cherezov ◽  
Jinsu Park ◽  
Hanjoo Kim ◽  
Jiwon Choe ◽  
Deokjung Lee
Keyword(s):  
Heat Transfer ◽  
Reactor Core ◽  
Light Water Reactor ◽  
Time Step ◽  
Light Water ◽  
Water Reactor ◽  
Adaptive Time Step ◽  
Accident Simulation ◽  
Adaptive Time ◽  
Coupling Algorithm

A new reactor core multi-physics system addresses the pellet-to-cladding heat transfer modeling to improve full-core operational transient and accident simulation used for assessment of reactor core nuclear safety. The rigorous modeling of the heat transfer phenomena involves strong interaction between neutron kinetics, thermal-hydraulics and nuclear fuel performance, as well as consideration of the pellet-to-cladding mechanical contact leading to dramatic increase in the gap thermal conductance coefficient. In contrast to core depletion where parameters smoothly depend on fuel burn-up, the core transient is driven by stiff equation associated with rapid variation in the solution and vulnerable to numerical instability for large time step sizes. Therefore, the coupling algorithm dedicated for multi-physics transient must implement adaptive time step and restart capability to achieve prescribed tolerance and to maintain stability of numerical simulation. This requirement is met in the MPCORE (Multi-Physics Core) multi-physics system employing external loose coupling approach to facilitate the coupling procedure due to little modification of constituent modules and due to high transparency of coupling interfaces. The paper investigates the coupling algorithm performance and evaluates the pellet-to-cladding heat transfer effect for the rod ejection accident of a light water reactor core benchmark.

Properties of Light Water Reactor Core Melts

1977 ◽  
Vol 32 (3) ◽  
pp. 239-246 ◽  
Author(s):  
S. Nazaré ◽  
G. Ondracek ◽  
B. Schulz
Keyword(s):  
Reactor Core ◽  
Light Water Reactor ◽  
Light Water ◽  
Water Reactor

Chemical Reactions between Light Water Reactor Core Melt and Concrete

1979 ◽  
Vol 46 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Alfred Skokan ◽  
Helmut Holleck ◽  
Martin Peehs
Keyword(s):  
Chemical Reactions ◽  
Reactor Core ◽  
Light Water Reactor ◽  
Light Water ◽  
Water Reactor

A Large-Scale Numerical Simulation on Bubbly and Liquid Film Flows in Narrow Fuel Channels

2005 ◽  
Author(s):  
K. Takase ◽  
H. Yoshida ◽  
Y. Ose ◽  
H. Akimoto
Keyword(s):  
Large Scale ◽  
Two Phase Flow ◽  
Reactor Core ◽  
Light Water Reactor ◽  
Phase Flow ◽  
Analysis Method ◽  
Two Phase ◽  
Light Water ◽  
Water Reactor ◽  
Fuel Bundle

In order to predict the water-vapor two-phase flow structure in a fuel bundle of an advanced light-water reactor, large-scale numerical simulations were carried out using a newly developed two-phase flow analysis method and a highly parallel-vector supercomputer. Conventional analysis methods such as subchannel codes need composition equations based on many experimental data. Therefore, it is difficult to obtain highly prediction accuracy on the thermal design of the advanced light-water reactor core if the experimental data are insufficient. Then, a new analysis method using the large-scale direct numerical simulation of water-vapor two-phase flow was proposed. The coalescence and fragmentation of small bubbles were investigated numerically and the bubbly flow dynamics in narrow fuel channels were clarified. Moreover, the liquid film flow inside a tight-lattice fuel bundle which is used to the advanced light-water reactor core was analyzed and the water and vapor distributions around fuel rods and a spacer were estimated quantitatively.

Investigation of Activity Release During Light Water Reactor Core Meltdown

1978 ◽  
Vol 40 (3) ◽  
pp. 278-283 ◽  
Author(s):  
H. Albrecht ◽  
V. Matschoss ◽  
H. Wild
Keyword(s):  
Reactor Core ◽  
Light Water Reactor ◽  
Light Water ◽  
Water Reactor ◽  
Core Meltdown

scholarly journals Evaluation of PBMR-400 Core Design Steady State Condition with Serpent and AGREE

2021 ◽  
Vol 2048 (1) ◽  
pp. 012024
Author(s):  
H Ardiansyah ◽  
V Seker ◽  
T Downar ◽  
S Skutnik ◽  
W Wieselquist
Keyword(s):  
Monte Carlo ◽  
Cross Sections ◽  
Reactor Core ◽  
Light Water Reactor ◽  
Steady State Condition ◽  
Light Water ◽  
Water Reactor ◽  
The Core ◽  
Core Simulation ◽  
Full Core

Abstract The significant recent advances in computer speed and memory have made possible an increasing fidelity and accuracy in reactor core simulation with minimal increase in the computational burden. This has been important for modeling some of the smaller advanced reactor designs for which simplified approximations such as few groups homogenized diffusion theory are not as accurate as they were for large light water reactor cores. For narrow cylindrical cores with large surface to volume ratios such the Ped Bed Modular Reactor (PBMR), neutron leakage from the core can be significant, particularly with the harder neutron spectrum and longer mean free path than a light water reactor. In this paper the core from the OECD PBMR-400 benchmark was analyzed using multigroup Monte Carlo cross sections in the HTR reactor core simulation code AGREE. Homogenized cross sections were generated for each of the discrete regions of the AGREE model using a full core SERPENT Monte Carlo model. The cross sections were generated for a variety of group structures in AGREE to assess the importance of finer group discretization on the accuracy of the core eigenvalue and flux predictions compared to the SERPENT full core Monte Carlo solution. A significant increase in the accuracy was observed by increasing the number of energy groups, with as much as a 530 pcm improvement in the eigenvalue calculation when increasing the number of energy groups from 2 to 14. Significant improvements were also observed in the AGREE neutron flux distributions compared to the SERPENT full core calculation.

Inspection and Evaluation Guidelines for Light Water Reactor Core Internals in Japan

2002 ◽  
Author(s):  
Kimihito Takeuchi ◽  
Naoto Iizuka ◽  
Masashi Kameyama ◽  
Haruo Fujimori ◽  
Yuichi Motora ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Structural Integrity ◽  
Reactor Core ◽  
Light Water Reactor ◽  
Light Water ◽  
Water Reactor ◽  
Integrity Assessment ◽  
Engineering Society ◽  
Safety Function ◽  
Internal Component

There have been many cracking experiences of light water reactor (LWR) core internals worldwide in the past. Thermal and Nuclear Power Engineering Society in Japan (TENPES) has organized a committee to prepare technically reasonable and appropriate inspection and evaluation guidelines (I&E guidelines) for core internals. This committee consists of scholars and representatives from electric utilities and nuclear plant vendors in Japan. I&E guidelines, which cover a rational inspection plan, structural integrity assessment and repair methods, have been developed considering nuclear safety function and structural strength of each core internal component. For BWR reactors, the development of I&E guidelines cover major core internal components like shroud support, core shroud, top guide, core plate, ICM and CRD housing, core spray piping and sparger, jet pump etc. For PWR reactors, the development of I&E guidelines cover baffle former bolts, barrel former bolts, core barrel weld, bottom mounted instrumentation, etc. The I&E guidelines will be completed by the end of March 2002. The basic concept of the guidelines, and a guideline for shroud support of a BWR as an example, are shown in this paper.

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