scholarly journals Investigation of Natural Circulation Instability and Transients in Passively Safe Small Modular Reactors

2016 ◽  
Author(s):  
Mamoru Ishii
Keyword(s):  
Natural Circulation ◽  
Small Modular Reactors ◽  
Passively Safe

scholarly journals Numerical Study on the Effects of Relative Diameters on the Performance of Small Modular Reactors Driven by Natural Circulation

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5881
Author(s):  
Young Jin Kim ◽  
Byung Jin Lee ◽  
Kunwoo Yi ◽  
Yoon Jae Choe ◽  
Min Chul Lee
Keyword(s):  
Temperature Distribution ◽  
Steam Generator ◽  
Flow Rate ◽  
Numerical Study ◽  
Natural Circulation ◽  
Hydraulic Parameters ◽  
Small Modular Reactors ◽  
Velocity Changes ◽  
Energy Equations ◽  
Tube Pitch

Most of the small modular reactors (SMRs) under development worldwide present the same components: an integral reactor vessel with a low-positioned core as the heat source and a high-positioned steam generator as the heat sink. Moreover, some SMRs are being designed to be driven by natural circulation during normal power generation. This work focused on such designs and on their performance, considering the changes generated by the geometric and hydraulic parameters of the system. Numerical simulations using mass, momentum, and energy equations that considered buoyancy forces were performed to determine the effects of various geometric and hydraulic parameters, such as diameters and flow resistances, on the reactor’s performance. It was found that nonuniform diameters promote velocity changes that affect the natural circulation flow rate. Moreover, the reactor’s temperature distribution depends on the steam generator tube pitch. Therefore, the hydraulic diameters of the reactor’s coolant passages should be maintained as uniform as possible to obtain a more uniform temperature distribution and a larger mass flow rate in SMRs.

scholarly journals Autonomous Load Following and Operational Aspects of the Star-LM HLMC Natural Convection Reactor

2002 ◽  
Author(s):  
James J. Sienicki ◽  
Plamen V. Petkov
Keyword(s):  
Natural Circulation ◽  
Reactor Core ◽  
Heat Removal ◽  
Computer Code ◽  
Primary Coolant ◽  
Load Following ◽  
Autonomous Operation ◽  
Nitride Fuel ◽  
Passively Safe ◽  
Operational Aspects

STAR-LM is a 300 to 400 MWt class modular, fully transportable, proliferation resistant, and passively safe reactor system that offers developing nations and power producers nearly autonomous operation for very long term. Autonomous load following is the ability of the reactor core power to adjust itself to match the heat removal as a consequence of inherent physical phenomena. STAR-LM achieves autonomous load following through the utilization of a fast neutron spectrum core, inert lead-bismuth eutectic primary coolant, high thermal conductivity transuranic nitride fuel, and 100+% natural circulation heat transport of the primary coolant. To investigate and demonstrate autonomous operation as well as other operational aspects, representative operational transients are analyzed for the 300 MWt STAR-LM design using a coupled thermal hydraulics-neutron kinetics plant dynamics analysis computer code. Autonomous load following without reactivity effects from control rods is demonstrated for decrease-in-turbine load and increase-in-turbine load transients. For initial startup, startup from hot standby, and normal shutdown transients effected by withdrawal or insertion of shutdown rods, the reactor transitions stably to the desired steady state.

Experimental studies and computational benchmark on heavy liquid metal natural circulation in a full height-scale test loop for small modular reactors

2017 ◽  
Vol 316 ◽  
pp. 26-37 ◽  
Author(s):  
Yong-Hoon Shin ◽  
Jaehyun Cho ◽  
Jueun Lee ◽  
Heejae Ju ◽  
Sungjune Sohn ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Natural Circulation ◽  
Experimental Studies ◽  
Heavy Liquid ◽  
Small Modular Reactors ◽  
Test Loop ◽  
Height Scale ◽  
Scale Test ◽  
Full Height

STEADY-STATE FLOW DISTRIBUTION ANALYSIS OF NATURAL CIRCULATION IN WATER TUBE BOILER

2020 ◽  
Vol 12 (3) ◽  
pp. 275-288
Author(s):  
Atul M. Elgandelwar ◽  
R. S. Jha ◽  
Mandar M. Lele
Keyword(s):  
Steady State ◽  
Natural Circulation ◽  
Flow Distribution ◽  
Distribution Analysis ◽  
Steady State Flow ◽  
State Flow ◽  
Water Tube

AN ANALYSIS OF THE STEADY STATE AND STABILITY CHARACTERISTICS OF A NATURAL CIRCULATION BOILING CHANNEL

2019 ◽  
Author(s):  
C. L. Spigt ◽  
Fred J.M. Dijkman ◽  
J. F. Tummers ◽  
M. Bogaardt
Keyword(s):  
Steady State ◽  
Natural Circulation
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