Development of Local Heat Transfer Models for Safety Assessment of High Temperature Gas-Cooled Reactor Cores—Part I: Pebble Bed Reactors

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Richard Stainsby ◽  
Matthew Worsley ◽  
Andrew Grief ◽  
Frances Dawson ◽  
Mike Davies ◽  
...  
Keyword(s):  
High Temperature ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Normal Operation ◽  
Fuel Particle ◽  
Subsequent Paper ◽  
Pebble Bed ◽  
Transient Conditions ◽  
Pebble Bed Reactors ◽  
Reactor Cores

This and the subsequent paper present models developed for determining fuel particle and fuel element temperatures in normal operation and transient conditions in high temperature reactor cores. Multiscale modeling concepts are used to develop the models for both pebble bed and prismatic core types. This paper, Part I, presents the development of the model for pebble bed reactors. Comparison is made with finite element simulations of an idealized “two-dimensional” pebble in transient conditions, and with a steady-state analytical solution in a spherical pebble geometry. A method is presented for determining the fuel temperatures in the individual batches of a multibatch recycle refuelling regime. Implementation of the multiscale and multibatch fuel models in a whole-core computational fluid dynamics model is discussed together with the future intentions of the research program.

Development of Local Heat Transfer Models for Safety Assessment of Pebble Bed High Temperature Gas-Cooled Reactor Cores

2008 ◽  
Author(s):  
Richard Stainsby ◽  
Matthew Worsley ◽  
Andrew Grief ◽  
Ana Dennier ◽  
Frances Dawson ◽  
...  
Keyword(s):  
Steady State ◽  
Analytical Solution ◽  
Local Heat Transfer ◽  
Research Programme ◽  
Local Heat ◽  
Normal Operation ◽  
Fuel Particle ◽  
Transient Conditions ◽  
Multi Scale ◽  
The Individual

This paper presents a model developed for determining fuel particle and fuel pebble temperatures in normal operation and transient conditions based on multi-scale modelling techniques. This model is qualified by comparison with an analytical solution in a one-dimensional linear steady state test problem. Comparison is made with finite element simulations of an idealised “two-dimensional” pebble in transient conditions and with a steady state analytical solution in a spherical pebble geometry. A method is presented for determining the fuel temperatures in the individual batches of a multi-batch recycle refuelling regime. Implementation of the multi-scale and multibatch fuel models in a whole-core CFD model is discussed together with the future intentions of the research programme.

Deep Burn Strategy for Pure Reactor-Grade Plutonium in Pebble Bed High Temperature Gas-Cooled Reactors

2008 ◽  
Author(s):  
Eben Mulder ◽  
Dawid Serfontein ◽  
Eberhard Teuchert
Keyword(s):  
High Temperature ◽  
Fuel Cycle ◽  
Waste Incineration ◽  
Β Decay ◽  
Pebble Bed ◽  
Pebble Bed Reactors ◽  
Advanced Fuel ◽  
Very High ◽  
High Temperature Gas

In this article an advanced fuel cycle for pebble bed reactors is introduced that can safely and efficiently incinerate pure reactor-grade Pu [Pu(LWR)], thereby fulfilling the bulk of the GNEP waste incineration requirements. It is shown below that the very high fissile content of the Pu(LWR)-fuel enables it to convert practically all of the 240Pu to 241Pu and incinerate it. Since the fuel contains no 238U, no fresh 239Pu is produced. The 239Pu is reduced in-situ by 99.5% and the 240Pu by 97.6%. The only significant fissile isotope remaining is 241Pu, however, it will decay with a half life of 14.4 years to the fertile 241Am by β-decay.

Radiation Shielding Design of High Temperature Reactor Pebble-Bed Module (HTR-PM)

2016 ◽  
Author(s):  
Sida Sun ◽  
Sheng Fang ◽  
Hong Li
Keyword(s):  
High Temperature ◽  
Dose Calculation ◽  
Radiation Shielding ◽  
Source Analysis ◽  
Pebble Bed ◽  
Pebble Bed Reactors ◽  
Protection Strategies ◽  
Reduction Methods ◽  
High Temperature Reactor ◽  
Shielding Design

Radiation safety is an important concern in the design and licensing of the 200MWe High Temperature Reactor Pebble-bed Module (HTR-PM) demonstration power plant in China. To meet the requirement of the regulatory, various radiation protection strategies and methods are applied in the design process of systems and components of HTR-PM. In this study, the radiation shielding design of HTR-PM is reviewed, which includes the radiation source analysis, in-house dose calculation tool, shielding and dose reduction methods used for primary systems. The underlying conservative assumption is also discussed for correctly evaluating the dose calculation result. This summary provides a relatively systematic review of the radiation shielding methods in the design phase of HTR-PM, which may provide useful information and experiences for the radiation shielding design of future pebble-bed reactors.

Study on the Core Cooling Scheme After Accident Shutdown of the Pebble-Bed Modular High Temperature Gas-Cooled Reactor

2012 ◽  
Author(s):  
Yanhua Zheng ◽  
Lei Shi ◽  
Fubing Chen
Keyword(s):  
High Temperature ◽  
Temperature Distribution ◽  
Normal Operation ◽  
Helium Temperature ◽  
Fuel Temperature ◽  
Pebble Bed ◽  
Decay Heat ◽  
The Core ◽  
Core Cooling ◽  
High Temperature Gas

One of the most important properties of the modular high temperature gas-cooled reactor is that the decay heat in the core can be carried out solely by means of passive physical mechanism after shutdown due to accidents. The maximum fuel temperature is guaranteed not to exceed the design limitation, so as to the integrity of the fuel particles and the ability of retaining fission product will keep well. Nonetheless, the auxiliary active core cooling should be design to help removing the decay heat and keeping the reactor in an appropriate condition effectively and quickly in case of reactor scram due to any transient and the main helium blower or steam generator unusable. Based on the preliminary design of the 250 MW pebble-bed modular high temperature gas-cooled reactor, assuming that the core cooling will be started up 1 hour after the scram, different core cooling schemes are studied in this paper. After the reactor shutdown, a certain degree of natural convection will come into being in the core due to the non-uniform temperature distribution, which will accordingly change the core temperature distribution and in turn influence the outlet hot helium temperature. Different cooling flow rates are also analyzed, and the important parameters, such as the fuel temperature, outlet hot helium temperature and the pressure vessel temperature, are studied in detail. A feasible core cooling scheme, as well as the reasonable design parameters could be determined based on the analysis. It is suggested that, considering the temperature limitation of the structure material, the coolant flow direction should be same as that of the normal operation, and the flow rate could not be too large.

Gas-Cooled Modular Reactors With Spherical Fuel Elements — Their Inherent Safety and Applications Not Just for Power Generation

2014 ◽  
Author(s):  
Walter Jaeger ◽  
H. J. Hamel ◽  
Heinz Termuehlen
Keyword(s):  
Power Generation ◽  
High Temperature ◽  
Reactor Design ◽  
Inherent Safety ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Pebble Bed Reactors ◽  
Fuel Elements ◽  
High Temperature Gas

The gas-cooled reactor design with spherical fuel elements, referred to as high-temperature gas-cooled reactors (HTGR or HTR reactors) or pebble bed reactors has been already suggested by Farrington Daniels in the late 1940s; also referred to as Daniels’ pile reactor design. Under Rudolf Schulten the first pebble bed reactor, the 46MWth AVR Juelich reactor (Atom Versuchs-Reactor Jülich) was built in the late 1960s. It was in operation for 22 years and extensive testing confirmed its inherent safety.

Computational Fluid Dynamics Assessment of the Local Hot Core Temperature in a Pebble-Bed Type Very High Temperature Reactor

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee
Keyword(s):  
Nusselt Number ◽  
High Temperature ◽  
Pressure Drop ◽  
Core Temperature ◽  
Normal Operation ◽  
Face Centered Cubic ◽  
Pebble Bed ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Assessment of the local hot core temperature during normal operation in a pebble-bed type very high temperature reactor has been carried out by using the computational fluid dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are simple cubic (SC), body-centered cubic, and face-centered cubic. The results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and Nusselt number. Both results showed a similar tendency that the pressure drop and the Nusselt number increases as the porosity decreases but there were large differences in their absolute values. The benchmark calculation for the pressure drop of the packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal-fluid behavior in an ordered pebble arrangement.

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