The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
T. Gelain - One of the best experts on this subject based on the ideXlab platform.
-
Lumped-parameter simulations of wall condensation and sump evaporation under typical thermal-hydraulic conditions of nuclear Reactor Containment severe accident
Progress in Nuclear Energy, 2014Co-Authors: J. Malet, T. GelainAbstract:During the course of a severe accident in a Pressurized Water Reactor, pressurization of the Containment occurs and hydrogen can be produced by the Reactor core oxidation and distributed in the Containment according to natural, mixed and forced convection flows induced by break flow, wall condensation and spray systems used in some Reactors' Containment to prevent overpressure. Because of these phenomena, water can be collected in the sump Containment, inducing further heat and mass exchanges between the sump surface and the atmosphere. Considering the large volume of the Reactor Containment, LP (0D) codes are preferred to CFD calculations, which still remain a very challenging task to compute. The French IRSN has tested different tools for Containment studies with lumped-parameter codes and the reference code is now ASTEC/CPA, so that mainly results of this code will be presented here. This paper focuses mainly on several IRSN tests especially developed for Containment studies and the above mentioned thermal-hydraulical phenomena. The objective of this paper is to present the validations performed with LP codes on these different experimental tests. Experiments on the TOSQAN facility are considered. © 2014 Elsevier Ltd. All rights reserved.
-
lumped parameter simulations of wall condensation and sump evaporation under typical thermal hydraulic conditions of nuclear Reactor Containment severe accident
Progress in Nuclear Energy, 2014Co-Authors: J. Malet, T. GelainAbstract:Abstract During the course of a severe accident in a Pressurized Water Reactor, pressurization of the Containment occurs and hydrogen can be produced by the Reactor core oxidation and distributed in the Containment according to natural, mixed and forced convection flows induced by break flow, wall condensation and spray systems used in some Reactors' Containment to prevent overpressure. Because of these phenomena, water can be collected in the sump Containment, inducing further heat and mass exchanges between the sump surface and the atmosphere. Considering the large volume of the Reactor Containment, LP (0D) codes are preferred to CFD calculations, which still remain a very challenging task to compute. The French IRSN has tested different tools for Containment studies with lumped-parameter codes and the reference code is now ASTEC/CPA, so that mainly results of this code will be presented here. This paper focuses mainly on several IRSN tests especially developed for Containment studies and the above mentioned thermal-hydraulical phenomena. The objective of this paper is to present the validations performed with LP codes on these different experimental tests. Experiments on the TOSQAN facility are considered.
Mikael Oxfall - One of the best experts on this subject based on the ideXlab platform.
-
long term hygrothermal performance of nuclear Reactor concrete Containments laboratory evaluations of measurement setup in situ sampling and moisture flux calculations
Cement & Concrete Composites, 2016Co-Authors: Mikael Oxfall, Peter Johansson, Manouchehr HassanzadehAbstract:Abstract A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear Reactor Containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear Reactor Containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the Reactor Containment have a noticeable effect on the environmental conditions in the Containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.
-
Long-term hygrothermal performance of nuclear Reactor concrete Containments – Laboratory evaluations of measurement setup, in situ sampling, and moisture flux calculations
Cement and Concrete Composites, 2016Co-Authors: Mikael Oxfall, Peter Johansson, Manouchehr HassanzadehAbstract:Abstract A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear Reactor Containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear Reactor Containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the Reactor Containment have a noticeable effect on the environmental conditions in the Containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.
-
Climatic conditions inside nuclear Reactor Containments - Monitoring campaign
2013Co-Authors: Mikael OxfallAbstract:The Reactor Containment is one of the most important buildings at a nuclear power plant. In case of an accident the Containment wall is the final protection against radioactive leakage to the surrounding environment. A Reactor Containment contains different types of concrete structures. They can be grouped as external structures constituting a barrier between the inside of the Containment and the outside environment, and internal structures e.g. to sectionalize the internal space of the Containment and the biological shield. Concrete structures in Reactor Containments are e.g. used as load bearing structures, protection of the steel liner from e.g. corrosion and to adsorb radioactive nuclides. During operation the climatic conditions inside the Reactor Containment can be harsh, with temperatures over 50 °C and low relative humidities (RH). Knowledge about the condition in the Containment and in the concrete structures is thereby important in order to evaluate the condition of the Reactor Containment and possible changes over time. The objective of this dissertation is to present a measurement setup suitable for long term measurements in concrete and investigate how the climatic conditions inside the Reactor Containments affect the concrete structures and vice versa. The project is divided into three parts in which the first part contains a material study of concrete from one nuclear Reactor Containment. The results from the material study showed that no clear variation of moisture transport properties over the depth of a structure could bee observed. The findings will be of great value in the continuation of the PhD project which will follow this Licentiate project, in which a model to predict future and past moisture conditions in the concrete will be developed. In the second part an accuracy evaluation of a measurement setup is presented. The setup was used to measure the RH and temperature onsite. In the accuracy evaluation the effects of both leakage through the setup and temperature were evaluated. The results showed that measured RH was influenced by the temperature changes as expected. Furthermore, the results indicated leakage through the setup. The leakage may have influenced the measurements of the devices placed closed to the surface of the structure. However, it is concluded that the setup is suitable for long term measurements. An supplementary accuracy evaluation will be presented in the upcoming doctoral thesis. The third part presents result from three monitoring campaigns conducted at different nuclear Reactor Containments in Sweden. The monitoring campaigns were conducted during one operational year. The campaigns included measurements in different zones of ambient RH and temperature and measurements, on different depth, inside the concrete. The results showed that measurements on shallow depth were critical but if properly installed there were no indication of leakage. In all zones a clear moisture profile was observed which indicates that the concrete within the Reactor Containment are still drying after about 30 years of exposure to high temperatures and low RH. (Less)
J. Malet - One of the best experts on this subject based on the ideXlab platform.
-
Lumped-parameter simulations of wall condensation and sump evaporation under typical thermal-hydraulic conditions of nuclear Reactor Containment severe accident
Progress in Nuclear Energy, 2014Co-Authors: J. Malet, T. GelainAbstract:During the course of a severe accident in a Pressurized Water Reactor, pressurization of the Containment occurs and hydrogen can be produced by the Reactor core oxidation and distributed in the Containment according to natural, mixed and forced convection flows induced by break flow, wall condensation and spray systems used in some Reactors' Containment to prevent overpressure. Because of these phenomena, water can be collected in the sump Containment, inducing further heat and mass exchanges between the sump surface and the atmosphere. Considering the large volume of the Reactor Containment, LP (0D) codes are preferred to CFD calculations, which still remain a very challenging task to compute. The French IRSN has tested different tools for Containment studies with lumped-parameter codes and the reference code is now ASTEC/CPA, so that mainly results of this code will be presented here. This paper focuses mainly on several IRSN tests especially developed for Containment studies and the above mentioned thermal-hydraulical phenomena. The objective of this paper is to present the validations performed with LP codes on these different experimental tests. Experiments on the TOSQAN facility are considered. © 2014 Elsevier Ltd. All rights reserved.
-
lumped parameter simulations of wall condensation and sump evaporation under typical thermal hydraulic conditions of nuclear Reactor Containment severe accident
Progress in Nuclear Energy, 2014Co-Authors: J. Malet, T. GelainAbstract:Abstract During the course of a severe accident in a Pressurized Water Reactor, pressurization of the Containment occurs and hydrogen can be produced by the Reactor core oxidation and distributed in the Containment according to natural, mixed and forced convection flows induced by break flow, wall condensation and spray systems used in some Reactors' Containment to prevent overpressure. Because of these phenomena, water can be collected in the sump Containment, inducing further heat and mass exchanges between the sump surface and the atmosphere. Considering the large volume of the Reactor Containment, LP (0D) codes are preferred to CFD calculations, which still remain a very challenging task to compute. The French IRSN has tested different tools for Containment studies with lumped-parameter codes and the reference code is now ASTEC/CPA, so that mainly results of this code will be presented here. This paper focuses mainly on several IRSN tests especially developed for Containment studies and the above mentioned thermal-hydraulical phenomena. The objective of this paper is to present the validations performed with LP codes on these different experimental tests. Experiments on the TOSQAN facility are considered.
Manouchehr Hassanzadeh - One of the best experts on this subject based on the ideXlab platform.
-
Long-term hygrothermal performance of nuclear Reactor concrete Containments – Laboratory evaluations of measurement setup, in situ sampling, and moisture flux calculations
Cement and Concrete Composites, 2016Co-Authors: Mikael Oxfall, Peter Johansson, Manouchehr HassanzadehAbstract:Abstract A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear Reactor Containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear Reactor Containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the Reactor Containment have a noticeable effect on the environmental conditions in the Containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.
-
long term hygrothermal performance of nuclear Reactor concrete Containments laboratory evaluations of measurement setup in situ sampling and moisture flux calculations
Cement & Concrete Composites, 2016Co-Authors: Mikael Oxfall, Peter Johansson, Manouchehr HassanzadehAbstract:Abstract A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear Reactor Containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear Reactor Containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the Reactor Containment have a noticeable effect on the environmental conditions in the Containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.
Peter Johansson - One of the best experts on this subject based on the ideXlab platform.
-
Long-term hygrothermal performance of nuclear Reactor concrete Containments – Laboratory evaluations of measurement setup, in situ sampling, and moisture flux calculations
Cement and Concrete Composites, 2016Co-Authors: Mikael Oxfall, Peter Johansson, Manouchehr HassanzadehAbstract:Abstract A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear Reactor Containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear Reactor Containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the Reactor Containment have a noticeable effect on the environmental conditions in the Containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.
-
long term hygrothermal performance of nuclear Reactor concrete Containments laboratory evaluations of measurement setup in situ sampling and moisture flux calculations
Cement & Concrete Composites, 2016Co-Authors: Mikael Oxfall, Peter Johansson, Manouchehr HassanzadehAbstract:Abstract A measurement setup for in situ sampling of internal relative humidity and temperature in concrete structures was developed. The setup was used to evaluate the moisture conditions and to determine whether drying of the concrete components within a nuclear Reactor Containment contributes to the moisture conditions. The measurement setup was tested for accuracy and thereafter installed in Swedish nuclear Reactor Containments for in situ monitoring. Results from the measurements confirmed that the setup is suitable, especially for long-term measurements at depths of 50 mm or more. Complementary moisture transport calculations showed that the moisture flux from the concrete to the interior of the Reactor Containment have a noticeable effect on the environmental conditions in the Containments. The calculations of the moisture condition in the concrete show that 15–30% of the evaporable water in the concrete has been dried out during the 30 years of operation.