Effect of packing fraction variations on the multiplication factor in pebble-bed nuclear reactors

Kerntechnik ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. 208-213 ◽  
Author(s):  
L. Snoj ◽  
M. Ravnik
Keyword(s):  
Nuclear Reactors ◽  
Packing Fraction ◽  
Multiplication Factor ◽  
Pebble Bed

Numerical Simulation of Accident Scenario in High Temperature Gas Cooled (Pebble Bed) Nuclear Reactors

2012 ◽  
Author(s):  
Geoffrey J. Peter
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Boundary Conditions ◽  
Nuclear Reactors ◽  
Numerical Study ◽  
Packed Bed ◽  
Pebble Bed ◽  
Accident Scenario ◽  
Set Up ◽  
High Temperature Gas

The accident scenario resulting from blockages due to the retention of dust in the coolant gas or from the rupture of one or more fuel particles used in the High Temperature Gas Cooled (Pebble Bed) Nuclear Reactors considered for the next generation of Advanced High Temperature Reactors (AHTR), for nuclear power production, and for high-temperature hydrogen production using nuclear reactors to reduce the carbon footprint is examined in this paper. Blockages can cause local variations in flow and heat transfer that may lead to hot spots within the bed that could compromise reactor safety. Therefore, it is important to know the void fraction distribution and the interstitial velocity field in the packed bed. The blockage for this numerical study simulated a region with significantly lower void than that in the rest of the bed. Finite difference technique solved the simplified continuity, momentum, and energy equations. Any meaningful outcome of the solution depended largely upon the validity of the boundary conditions. Among them, the inlet and outlet velocity profiles required special attention. Thus, a close approximation to these profiles obtained from an experimental set-up established the boundary conditions. This paper presents the development of the elliptic-partial differential equation for a bed of pebbles, and the solution procedure. The paper also discusses velocity and temperature profiles obtained from both numerical and experimental setup, with and without effect of blockage. In addition, the paper compares the results obtained from the experimental set-up with numerical simulation using a commercially available code that uses finite element techniques.

scholarly journals Caution Is Needed in Operating and Managing the Waste of New Pebble-Bed Nuclear Reactors

Joule ◽  
2018 ◽  
Vol 2 (10) ◽  
pp. 1911-1914 ◽  
Author(s):  
Rainer Moormann ◽  
R. Scott Kemp ◽  
Ju Li
Keyword(s):  
Nuclear Reactors ◽  
Pebble Bed

Replacement Zircaloy for Silicon Carbide as Fuel Cladding Material in PWR – A Neutronic Evaluation

2015 ◽  
Vol 1769 ◽  
Author(s):  
Rochkhudson B. de Faria ◽  
Felipe Torres ◽  
Fabiana B. A. Monteiro ◽  
Claubia Pereira
Keyword(s):  
Silicon Carbide ◽  
Nuclear Reactors ◽  
Temperature Tolerance ◽  
Multiplication Factor ◽  
Pressurized Water Reactor ◽  
Fuel Cladding ◽  
Pressurized Water ◽  
High Temperature Tolerance ◽  
Literature Reviews ◽  
Cladding Material

ABSTRACTSilicon carbide (SiC) has a potential to replacement zircaloy as fuel cladding material due to its high temperature tolerance, chemical stability and low neutron affinity. These characteristics may improve the economic and safety of nuclear reactors. Previous work has examined the possible use of SiC as a fuel cladding material in a PWR (Pressurized Water Reactor) environment. However, the advantage thermo mechanical and neutronic analysis replacement zircaloy cladding is not clear. Literature reviews has been done to predict the thermo mechanical behavior of SiC in high temperatures. The neutronic analysis was made using the SCALE 6.0 (Standardized Computer Analysis for Licensing Evaluation) code. This codes system is widely accepted and used worldwide for safety analysis and criticality of nuclear reactors has been utilized to model a typical fuel element of a PWR. It was used the CSAS6 and TRITON modules. The goals are to evaluate the behavior of the infinite multiplication factor (kinf) and neutron flux using SiC as a fuel cladding material.

Effects of random pebble distribution on the multiplication factor in HTR pebble bed reactors

2010 ◽  
Vol 37 (8) ◽  
pp. 1056-1066 ◽  
Author(s):  
G.J. Auwerda ◽  
J.L. Kloosterman ◽  
D. Lathouwers ◽  
T.H.J.J. van der Hagen
Keyword(s):  
Multiplication Factor ◽  
Pebble Bed ◽  
Pebble Bed Reactors

Granular flow in pebble-bed nuclear reactors: Scaling, dust generation, and stress

2013 ◽  
Vol 265 ◽  
pp. 69-84 ◽  
Author(s):  
Chris H. Rycroft ◽  
Abdel Dehbi ◽  
Terttaliisa Lind ◽  
Salih Güntay
Keyword(s):  
Granular Flow ◽  
Nuclear Reactors ◽  
Pebble Bed ◽  
Dust Generation

scholarly journals Axial Shuffling on Pebble Bed Reactor using PRAKTIK 3D-HTR

2021 ◽  
Vol 927 (1) ◽  
pp. 012012
Author(s):  
Muhammad Rizki Oktavian ◽  
Ganjar Putro Indratoro
Keyword(s):  
Critical Condition ◽  
Axial Direction ◽  
Reactor Power ◽  
Movement Speed ◽  
Diffusion Method ◽  
Thermal Reactor ◽  
Multiplication Factor ◽  
Pebble Bed ◽  
Core Diameter ◽  
Pebble Bed Reactor

Abstract With moving fuel, the pebble bed reactor (PBR) provides flexibility in the fuel management process due to the capability of online fuel refueling. This capability allows the reactor to operate at any given time without the need to shut down for refueling. The complexity of the depletion and burnup analysis requires the problem to be solved with sophisticated and robust computer codes that can handle the fuel shuffling. Since the fuel refueling is conducted from top to bottom, the shuffling and fuel movement in the axial direction should be modeled with acceptable accuracy. The purpose of the simulation is to obtain the equilibrium or even a critical condition of the reactor. The model used is based on the simplified pebble bed reactor with 200 MWt of thermal reactor power, 3 meters of core diameter, and 10 meters of core height. To model the axial shuffling on the reactor, a neutronic computer code called PRAKTIK 3D-HTR is used. The code utilizes the diffusion method in a three-dimensional cylindrical geometry to model the neutronic phenomena in the reactor. Moreover, PRAKTIK 3D-HTR is equipped with the burnup calculation and depletion analysis to be able to handle fuel movement. Finally, the axial shuffling mechanism is implemented using the once-through-then-out (OTTO) method. Implementing this method to the reactor, an equilibrium condition can be obtained. In this condition, the reactor condition in terms of criticality and flux shape is relatively constant. The critical condition can also be searched using PRAKTIK 3D-HTR to obtain the condition when the multiplication factor is equal to unity. The criticality search is conducted by changing the fuel movement speed. If the multiplication factor is less than 1, then the shuffling speed needs to be increased. Otherwise, if it is more than 1, the shuffling speed will be decreased.

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