High speed sliding pressure ventingplus(AREVA’s FCVS with enhanced organic iodine retention) design principles and qualification of severe accident equipment

2012 ◽  
Author(s):  
Norbert Losch ◽  
Sebastian Buhlmann ◽  
Christian Hutterer
Keyword(s):  
High Speed ◽  
Design Principles ◽  
Severe Accident ◽  
Organic Iodine ◽  
Sliding Pressure ◽  
Iodine Retention

Analyzing Droplet Size Distributions Inside a Self-Priming Venturi Scrubber for Filtered Containment Venting Systems

2018 ◽  
Author(s):  
P. Papadopoulos ◽  
T. Lind ◽  
H.-M. Prasser
Keyword(s):  
Droplet Size ◽  
High Speed ◽  
Nuclear Power ◽  
Power Plants ◽  
Gas Flow ◽  
Tube Bundle ◽  
Droplet Size Distribution ◽  
Severe Accident ◽  
Design Element ◽  
Venturi Scrubber

After the accident in the Fukushima Daiichi nuclear power plant, the interest of adding Filtered Containment Venting Systems (FCVS) on existing nuclear power plants to prevent radioactive releases to the environment during a severe accident has increased. Wet scrubbers are one possible design element which can be part of an FCVS system. The efficiency of this scrubber type is thereby depending, among others, on the thermal-hydraulic characteristics inside the scrubber. The flow structure is mainly established by the design of the gas inlet nozzle. The venturi geometry is one of the nozzle types that can be found in nowadays FCVS. It acts in two different steps on the removal process of the contaminants in the gas stream. Downstream the suction opening in the throat of the venturi, droplets are formed by atomization of the liquid film. The droplets are contributing to the capture of aerosols and volatile gases from the mixture coming from the containment. Studies state that the majority of the contaminants is scrubbed within this misty flow regime. At the top of the venturi, the gas stream is injected into the pool. The pressure drop at the nozzle exit leads to the formation of smaller bubbles, thus increasing the interfacial area concentration in the pool. In this work, the flow inside a full-scale venturi scrubber has been optically analyzed using shadowgraphy with a high-speed camera. The venturi nozzle was installed in the TRISTAN facility at PSI which was originally designed to investigate the flow dynamics of a tube rupture inside a full-length scale steam generator tube bundle. The data analysis was focused on evaluating the droplet size distribution and the Sauter mean diameter under different gas flow rates and operation modes. The scrubber was operated in two different ways, submerged and unsubmerged. The aim was to include the effect on the droplet sizes of using the nozzle in a submerged operation mode.

Development of Numerical Simulation for Jet Breakup Behavior in Complicated Structure of BWR Lower Plenum: (4) Multi-Channel Experimental Analysis by Detailed Two-Phase Analysis Code TPFIT

2014 ◽  
Author(s):  
Takayuki Suzuki ◽  
Hiroyuki Yoshida ◽  
Fumihisa Nagase ◽  
Yutaka Abe ◽  
Akiko Kaneko
Keyword(s):  
High Speed ◽  
Evaluation Method ◽  
Simulation Method ◽  
Severe Accident ◽  
Interface Tracking ◽  
Phase Flow ◽  
Complicated Structure ◽  
Two Phase ◽  
Support Plate ◽  
Multi Phase

In order to improve the safety of Boiling Water Reactor (BWR), it is required to know the behavior of the plant when an accident occurred as can be seen at Fukushima Daiichi nuclear power plant accident. Especially, it is important to estimate the behavior of molten core jet in the lower part of the reactor pressure vessel at a severe accident. In the BWR lower plenum, the flow characteristics of molten core jet are affected by many complicated structures, such as control rod guide tubes, instrument guide tubes and core support plate. However, it is difficult to evaluate these effects on molten core jet experimentally. Therefore, we considered that multi-phase computational fluid dynamics approach is the best way to estimate the effects on molten core jet by complicated structure. The objective of this study is to develop the evaluation method for the flow characteristic of molten core jet including the effects of the complicated structures in the lower plenum. So we are developing a simulation method to estimate the behavior of molten core jet falling down through the core support plate to the lower plenum of the BWR. The simulation method is based on interface tracking method code TPFIT (Two Phase Flow simulation code with Interface Tracking). To verify and validate the applicability of the developed method in detail, it is necessary to obtain the experimental data that can be compared with detailed numerical results by the TPFIT. Thus, the authors are carrying out experimental works by use of multi-phase flow visualization technique. In the experiments, time series of interface shapes are observed by high speed camera and velocity profiles in/out of the jet are measured by the PIV method. In this paper, we carried out analysis of the multi-channel experiment using the analytical method based on the TPFIT. Specifically, predicted results including interface shape and velocity profile in and out simulated molten material were compared with measured results. In the results, predicted results agreed with measured results qualitatively.

Development of Numerical Simulation for Jet Breakup Behavior in Complicated Structure of BWR Lower Plenum: 1 — Preliminary Analysis of Jet Breakup Behavior in Complicated Structure by TPFIT

2013 ◽  
Author(s):  
Takayuki Suzuki ◽  
Hiroyuki Yoshida ◽  
Fumihisa Nagase ◽  
Yutaka Abe ◽  
Akiko Kaneko
Keyword(s):  
High Speed ◽  
Measured Data ◽  
Severe Accident ◽  
Interface Tracking ◽  
Phase Flow ◽  
Complicated Structure ◽  
Support Plate ◽  
Jet Breakup ◽  
Multi Phase ◽  
Developing Method

In order to improve the safety of Boiling Water Reactor (BWR), it is required to know the behavior of the plant when an accident occurred as can be seen at Fukushima Daiichi nuclear power plant accident. Especially, it is important to estimate the behavior of molten core jet in the lower part of the containment vessel at severe accident. In the BWR lower plenum, the flow characteristics of molten core jet are affected by many complicated structures, such as control rod guide tubes, instrument guide tubes and core support plate. However, it is difficult to evaluate these effects on molten core jet experimentally. Therefore, we considered that multi-phase computational fluid dynamics approach is the best way to estimate the effects on molten core jet by complicated structure. The objective of this study is to develop the evaluation method for the flow characteristic of molten core jet including the effects of the complicated structures in the lower plenum. So we are developing a simulation method to estimate the behavior of molten core jet falling down through the core support plate to the lower plenum of the BWR. The method has been developed based on interface tracking method code TPFIT (Two Phase Flow simulation code with Interface Tracking). To verify and validate the applicability of the developed method in detail, it is necessary to obtain the experimental data that can be compared with detailed numerical results by the TPFIT. Thus, in this study, we are carrying out experimental works by use of multi-phase flow visualization technique. In the experiments, time series of interface shapes are observed by high speed camera and velocity profiles in/out of the jet will be measured by the PIV method. In this paper, the outline of the developing method based on the TPFIT was explained. And, the developing method was applied to preliminary experiment with/without modeled complicated structures. As the results, predicted interface shapes were almost agreed with measured data. However, predicted falling down velocity of the jet was lower than measured data. We considered causes of this underestimation and improved the method and simulation conditions to resolve this problem.

scholarly journals X-Ray Imaging Calibration for Fuel-Coolant Interaction Experimental Facilities

2021 ◽  
Vol 253 ◽  
pp. 06005
Author(s):  
Christophe Journeau ◽  
Michael Johnson ◽  
Shifali Singh ◽  
Fréderic Payot ◽  
Ken-ichi Matsuba ◽  
...  
Keyword(s):  
Test Section ◽  
High Speed ◽  
Limit Of Detection ◽  
Image Intensifier ◽  
Precise Determination ◽  
Severe Accident ◽  
X Ray ◽  
X Ray Imaging ◽  
Experimental Facilities ◽  
Lower Limits

During a severe accident in either sodium-cooled or water-cooled nuclear reactors, jets of molten nuclear fuel may impinge on the coolant resulting in fuel-coolant interactions (FCI). Experimental programs are being conducted to study this phenomenology and to support the development of severe accident models. Due to the optical opacity of the test section walls, sodium coolant, and the apparent optical opacity of water in the presence of intense ebullition, high-speed X-ray imaging is the preferred technique for FCI visualization. The configuration of these X-ray imaging systems, whereby the test section is installed between a fan-beam X-ray source and a scintillator-image intensifier projecting an image in the visual spectrum onto a high-speed camera, entails certain imaging artefacts and uncertainties. The X-ray imaging configuration requires precise calibration to enable detailed quantitative characterization of the FCI. To this end, ‘phantom’ models have been fabricated using polyethylene, either steel or hafnia powder, and empty cavities to represent sodium, molten fuel and sodium vapor phases respectively. A checkerboard configuration of the phantom enables calibration and correction for lens distortion artefacts which magnify features towards the edge of the field of view. Polydisperse steel ball configurations enable precise determination of the lower limit of detection and the estimation of parallax errors which introduce uncertainty in an object’s silhouette dimensions. Calibration experiments at the MELT facility determined lower limits of detection in the order of 4 mm for steel spheres, and 1.7-3.75 mm for vapor films around a molten jet.

scholarly journals Design Principles of Mold Powder for High Speed Continuous Casting

1994 ◽  
Vol 80 (3) ◽  
pp. 219-224 ◽  
Author(s):  
Masayuki KAWAMOTO ◽  
Keiji NAKAJIMA ◽  
Takashi KANAZAWA ◽  
Ken NAKAI
Keyword(s):  
Continuous Casting ◽  
High Speed ◽  
Design Principles ◽  
Mold Powder

scholarly journals Design Principles of Mold Powder for High Speed Continuous Casting.

1994 ◽  
Vol 34 (7) ◽  
pp. 593-598 ◽  
Author(s):  
Masayuki Kawamoto ◽  
Keiji Nakajima ◽  
Takashi Kanazawa ◽  
Ken Nakai
Keyword(s):  
Continuous Casting ◽  
High Speed ◽  
Design Principles ◽  
Mold Powder

Experimental Investigation Into Buckling Failure of Slender Metal Plates in Severe Accident Conditions

2014 ◽  
Author(s):  
Byeongnam Jo ◽  
Wataru Sagawa ◽  
Koji Okamoto
Keyword(s):  
High Speed ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Load ◽  
Severe Accident ◽  
Steel Columns ◽  
Wide Range ◽  
Buckling Failure ◽  
The Difference ◽  
Accident Conditions

Buckling failure load of stainless steel columns under compressive stress was experimentally measured in severe accident conditions, which addresses the accidents in Fukushima Daiichi nuclear power plants. Firstly, buckling failure load defined as load which causes failure of the column (plastic collapse) was measured in a wide range of temperatures from 25 °C up to 1200 °C. The load values measured in this study were compared to numerical estimations by eigenvalue simulations (for an ideal column) and by nonlinear simulations (for a column with initial bending). Two different methods for measurement of the buckling failure load were employed to examine the effect of thermal history on buckling failure. Different load values were obtained from two methods in high temperature conditions over 800 °C. The difference in the buckling failure load between two methods increased with temperature, which was explained by the effect of creep at high temperatures. Moreover, the influence of asymmetric temperature profiles along a plate column was also explored with regard to the failure mode and the buckling failure load. In present study, all of the buckling processes were visualized by a high speed camera.

SIMMER-III Code Assessment for Material Expansion Dynamics During Core Disruptive Accidents in Sodium-Cooled Fast Reactors

2014 ◽  
Author(s):  
Hidemasa Yamano ◽  
Yoshiharu Tobita
Keyword(s):  
High Speed ◽  
Phase 1 ◽  
Computer Code ◽  
Severe Accident ◽  
Phase 2 ◽  
Assessment Program ◽  
Multi Phase Flow ◽  
Integral Assessment ◽  
Multi Phase ◽  
Physical Phenomena

The sodium-cooled fast reactor (SFR) severe accident analysis computer code SIMMER-III has been developed and assessed comprehensively and systematically in a code assessment (verification and validation) program which consists of a two-step effort: Phase 1 for fundamental or separate-effect assessment of individual code models; and Phase 2 for integral assessment of key physical phenomena relevant to SFR safety. This paper describes the achievement of the code assessment on material expansion dynamics in the framework of the Phase 2 assessment program. Detailed descriptions are given for two representative experimental analyses (VECTORS and OMEGA), which are intended to validate high speed multi-phase flow dynamics in pin bundle structure and large vapor bubble expansion dynamics into a coolant pool, respectively. Through the assessment program, the SIMMER-III code has proved to be basically valid both numerically and physically, with current applicability to integral reactor safety calculations.

Sign in / Sign up

Export Citation Format

Share Document