Development Work for a Borax Internal Core-Catcher for a Gas-Cooled Fast Reactor

1978 ◽  
Vol 39 (2) ◽  
pp. 138-154 ◽  
Author(s):  
M. Dalle Donne ◽  
S. Dorner ◽  
G. Schumacher
Keyword(s):  
Fast Reactor ◽  
Development Work ◽  
Core Catcher ◽  
Internal Core

scholarly journals Severe Accidents in Sodium-Cooled Fast Reactors: CFD Sensitivity Studies on the Thermal Ablation of Core-Catcher

2021 ◽  
Author(s):  
Olivier A. Czarny ◽  
Adrien Collin de l'Hortet ◽  
Nicolas Goreaud
Keyword(s):  
Thermal Ablation ◽  
Solid Material ◽  
Ablation Process ◽  
Fast Reactors ◽  
Severe Accidents ◽  
Core Catcher ◽  
Show Evidence ◽  
Internal Core ◽  
Sensitivity Studies

Abstract The present work aims at testing the CFD capabilities to simulate erosion of materials which interact with a corium mass. The main foreseen applications are the design of external/internal core catchers or in-vessel retentions devices used to mitigate severe accidents for Sodium-cooled Fast Reactors (SFR). 2D axisymmetric simulations of a corium jet impinging a sacrificial solid material show evidence of a pool-effect, previously observed in experiments, which contributes to limit the ablation process. Complementary sensitivities assess the influence of jet diameter, temperature and velocity.

COOLABILITY EVALUATION OF DEBRIS BED ON CORE CATCHER IN A SODIUM-COOLED FAST REACTOR

2019 ◽  
Vol 2019.27 (0) ◽  
pp. 1292
Author(s):  
Eiji Matsuo ◽  
Kyohei Sasa ◽  
Kazuya Koyama ◽  
Hidemasa Yamano ◽  
Shigenobu Kubo ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Core Catcher

scholarly journals Numerical Investigation of Corium Coolability in Core Catcher: Sensitivity to Modeling Parameters

2018 ◽  
Author(s):  
Liancheng Guo ◽  
Andrei Rineiski
Keyword(s):  
Fast Reactor ◽  
Large Scale ◽  
Mass Transfer Process ◽  
Severe Accident ◽  
Liquid Sodium ◽  
Numerical Experience ◽  
The Core ◽  
Sodium Fast Reactor ◽  
Core Catcher ◽  
Fuel Pin

To avoid settling of molten materials directly on the vessel wall in severe accident sequences, the implementation of a ‘core catcher’ device in the lower plenum of sodium fast reactor designs is considered. The device is to collect, retain and cool the debris, created when the corium falls down and accumulates in the core catcher, while interacting with surrounding coolant. This Fuel-Coolant Interaction (FCI) leads to a potentially energetic heat and mass transfer process which may threaten the vessel integrity. For simulations of severe accidents, including FCI, the SIMMER code family is employed at KIT. SIMMER-III and SIMMER-IV are advanced tools for the core disruptive accidents (CDA) analysis of liquid-metal fast reactors (LMFRs) and other GEN-IV systems. They are 2D/3D multi-velocity-field, multiphase, multicomponent, Eulerian, fluid dynamics codes coupled with a fuel-pin model and a space- and energy-dependent neutron kinetics model. However, the experience of SIMMER application to simulation of corium relocation and related FCI is limited. It should be mentioned that the SIMMER code was not firstly developed for the FCI simulation. However, the related models show its basic capability in such complicate multiphase phenomena. The objective of the study was to preliminarily apply this code in a large-scale simulation. An in-vessel model based on European Sodium Fast Reactor (ESFR) was established and calculated by the SIMMER code. In addition, a sensitivity analysis on some modeling parameters is also conducted to examine their impacts. The characteristics of the debris in the core catcher region, such as debris mass and composition are compared. Besides that, the pressure history in this region, the mass of generated sodium vapor and average temperature of liquid sodium, which can be considered as FCI quantitative parameters, are also discussed. It is expected that the present study can provide some numerical experience of the SIMMER code in plant-scale corium relocation and related FCI simulation.

scholarly journals New Reactor Safety Measures for the European Sodium Fast Reactor. Part II: Preliminary Assessment

2021 ◽  
Author(s):  
Joel Guidez ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Enrico Girardi ◽  
Jeremy Bittan ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Heat Removal ◽  
Reactor Safety ◽  
Preliminary Assessment ◽  
Safety Measures ◽  
Decay Heat ◽  
European Project ◽  
Sodium Fast Reactor ◽  
Core Catcher ◽  
Gen Iv

Abstract The European project ESFR SMART offers innovative options of a sodium fast reactor to improve its safety. This paper explains the results of preliminary calculations made of the main options to verify the big lines of their feasibility. Design propositions and calculations are here provided of following innovative options: removal of the safety vessel, innovative decay heat removal systems, core catcher, thermal pumps and secondary loops. In conclusion, all these options seem able to fulfil the big lines of new safety rules for GEN-IV reactors. A status of the R&D necessary to validate these new options is also proposed.

scholarly journals ESFR SMART PROJECT CONCEPTUAL DESIGN OF IN-VESSEL CORE CATCHER

2021 ◽  
Vol 247 ◽  
pp. 01002
Author(s):  
Joel Guidez ◽  
Antoine Gerschenfeld ◽  
Janos Bodi ◽  
Konstantin Mikityuk ◽  
Francisco Alvarez-Velarde ◽  
...  
Keyword(s):  
Natural Convection ◽  
Fast Reactor ◽  
Passive Control ◽  
Mitigation Strategies ◽  
Severe Accident ◽  
Fukushima Accident ◽  
The Core ◽  
Core Catcher ◽  
Thermal Calculations ◽  
Core Meltdown

Even before Fukushima accident occurred, the safety authorities have required that new power plant designs must take into account beyond design-basis accidents including possible core meltdown. Among the mitigation strategies, the corium retention must be ensured, so a core catcher is implemented in the design of the Generation IV Sodium-cooled Fast Reactor. An internal core catcher within the vessel (in-vessel retention) is the option chosen for the European Sodium-cooled Fast Reactor investigated in the H2020 ESFR-SMART project. The new core investigated in ESFR SMART with lower void effect has a better behavior in case of severe accident. The use of passive control rods is also an improvement for prevention of severe accident. Moreover, we have in the ESFR SMART core dedicated tubes for corium discharge that should allow discharging quickly the melted materials and should help to prevent large criticality. Calculations show that after several seconds, these discharge tubes begin to open, and the corium arrives by this preferential way on the core catcher, quicker and in limited quantities at the beginning of the accident. However, the core catcher is designed to be able to retain the whole core meltdown. Its design allows good possibilities of cooling by natural convection of sodium. Some thermal calculations were provided with a multi-layer concept but the global mechanical conception seems difficult. So a one layer core catcher in molybdenum, material compatible with sodium and used on the core catcher of the last SFR, started in 2016: BN 800, is investigated. Explanations are given on the choice of this material proposed for the catcher and used for thermal calculations. With the proposed design, the corium is spread on the core catcher and the residual power of the corium can be dispelled by natural convection by the sodium circulating around and above the core catcher without boiling of sodium if the melted core is less than about 25% of whole core. In case of bigger quantities of melted core, boiling of sodium could appear under the core catcher. Further less conservative calculations would be necessary to better know the limit.

Numerical and Experimental Model Studies on Thermal Hydraulic Behavior of FBR Internal Core Catcher Assembly

2006 ◽  
Author(s):  
Sanjay Kumar Das ◽  
Anil Kumar Sharma ◽  
A. Jasmin Sudha ◽  
G. Punitha ◽  
G. Lydia ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Maximum Temperature ◽  
Model Studies ◽  
The Core ◽  
Core Catcher ◽  
Internal Core ◽  
Series Of Experiments ◽  
Retention Device ◽  
Good Agreement

Core Catcher is provided as an in-vessel core debris retention device to collect, support, cool and maintain in sub-critical configuration, the generated core debris from fuel melting due to certain postulated Beyond Design Basis Events (BDBE) for Fast Breeder Reactor (FBR). This also acts as a barrier to prevent settling of debris on main vessel and keeps its maximum temperature within acceptable creep range. Heat transfer by natural convection in the core catcher assembly has been assessed numerically and through water experiments using geometrically similar configuration. Resistive heating elements are used in experiment as heat source to simulate debris decay heat on core catcher. Series of experiments were carried out for two configurations referred as geometry A and geometry B. The later configuration showed enhanced natural convective heat transfer from the lower plenum of the vessel. Temperatures were monitored at critical positions and compared with numerical evaluation. Numerically evaluated flow fields and isotherms are compared with experimental data for specific steady state temperatures on heat source plate. Numerical results are found to be in good agreement with that obtained from experiments. The combined efforts of numerical and experimental work conclude core catcher assembly with geometry B to be more suitable.

Preliminary Analysis of In-Vessel Corium Confinement and Cooling in a Large Sodium Fast Reactor

2012 ◽  
Author(s):  
Franco Polidoro ◽  
Flavio Parozzi
Keyword(s):  
Fast Reactor ◽  
Preliminary Analysis ◽  
Structural Integrity ◽  
Mechanical Energy ◽  
Severe Accident ◽  
Sodium Fast Reactor ◽  
Safety Margins ◽  
Core Catcher ◽  
Core Meltdown ◽  
Accident Conditions

Considering a reasonable range of core meltdown accidents that can be postulated for GenIV sodium fast reactors, good safety margins exist for corium confinement and cooling inside the reactor vessel. Coolable conditions can be reached with the adoption of an ad-hoc device in the lower plenum, i.e. core catcher, capable to intercept the downward motion of the molten material and assure its cooling. Such device has to be designed to withstand to extreme thermal-mechanical conditions that rise as consequence of the large mechanical energy release and high temperature of molten corium. As this study has been carried out in the frame of the Collaborative Project on European Sodium Fast Reactor (CP ESFR) of the 7th Framework Programme Euratom, on the basis of the postulated accident conditions assumed for a reference 1500 MWe pool-type sodium fast reactor, the present work provides a preliminary analysis of the thermal response of a possible core catcher placed within the vessel. The dynamic thermal behaviour of the corium-structure-coolant system is analyzed with the computer code CORIUM-2D, an original simulation tool developed by RSE - Ricerca Sul Sistema Energetico, with the aim to assess the thermal interaction among corium, structures and coolant under severe accident conditions in both Light Water Reactors (LWRs) and Liquid Metal Fast Breeder Reactors (LMFBRs). The results of the numerical simulations show that the steady-state coolable configuration of core debris and the structural integrity of main containment structures can be reached in a number of partial core meltdown situations.

Electron Microscopy of Bacteriophage T7 Internal Head Proteins

1975 ◽  
Vol 33 ◽  
pp. 638-639
Author(s):  
P. Serwer
Keyword(s):  
Electron Microscopy ◽  
Bacteriophage T7 ◽  
Specimen Preparation ◽  
Dna Molecule ◽  
The Core ◽  
Internal Core ◽  
Phage T7 ◽  
T7 Phage ◽  
Preparation Techniques ◽  
Internal Head

The genome of bacteriophage T7 is a duplex DNA molecule packaged in a space whose volume has been measured to be 2.2 x the volume of the B form of T7 DNA. To help determine the mechanism for packaging this DNA, the configuration of proteins inside the phage head has been investigated by electron microscopy. A core which is roughly cylindrical in outline has been observed inside the head of phage T7 using three different specimen preparation techniques.When T7 phage are treated with glutaraldehyde, DNA is ejected from the head often revealing an internal core (dark arrows in Fig. 1). When both the core and tail are present in a particle, the core appears to be coaxial with the tail. Core-tail complexes sometimes dislodge from their normal location and appear attached to the outside of a phage head (light arrow in Fig. 1).

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