Investigation of Thermal Coupling in Condensation Process at COSMEA Facility with ATHLET Code

in Reactor engineering (2018, October)

CFD Simulations of Adiabatic Boiling in Different Riser Geometries

Poster (2018)

SIMULATION OF CONDENSATION IN A SLIGHTLY INCLINED TUBE AT COSMEA FACILITY WITH ATHLET CODE

Scientific Conference (2017, September 06)

Safety is an essential topic in the development process of nuclear power plant. Several Generation III reactor designs contain passive safety system to control accident without the need for external power ... [more ▼]

Safety is an essential topic in the development process of nuclear power plant. Several Generation III reactor designs contain passive safety system to control accident without the need for external power supply. An example for such passive systems is the Emergency Condenser (EC) of the KERENA reactor design. The system removes heat from the Reactor Pressure Vessel in the case of design basis accidents. The experimental facility COSMEA at Helmhotz Zentrum Dresden Rossendorf (HZDR) was set up to investigate the flow morphology and heat transfer structure of condensation processes. The test rig consists of a 3 m long condenser pipe which is 0.76° inclined with inner diameter 43.3 mm. On the shell side active cooling is performed using the TOPFLOW facility infrastructure. According to the Emergency Condenser Reference design, the experiments of COSMEA are conducted in different pressure levels (5, 15, 25, 45 and 65 bar) with steam mass flow rates up to 1 kg/s. An inlet mixing system was developed to operate the experiment in a stepwise method due to the scale of the test rig. Condensation rates, pressure, temperature and flow rate for different steam fraction are measured. In addition, an x-ray tomography is installed to study the details of the resulting stratified flow structures. Extra heat flux probes are assembled to detect the azimuthal distribution of the heat flux. In this work, COSMEA was simulated the thermal hydraulic system codes ATHLET. The performance of the ATHLET heat transfer models were identified. Primarily, the steady-state model was developed and the simulation results were compared to the experiment. The thermal coupling which considers the heat exchange between outside and inside of the pipe during the condensation was analyzed. Posteriorly the case of modeling transient condensation process was simulated. The influence on thermal coupling parameters, particularly heat transfer coefficient due to pressure drop inside the pipe was predicted and the feasibility and limitation of the system codes were evaluated. [less ▲]

Full scale BWR containment loca response test at the INKA test facility

in International Conference on Nuclear Engineering, Proceedings, ICONE (2015), 2015-January

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify ... [more ▼]

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify the functionality and performance of the KERENA safety concept required for the transient and accident management, the test facility "Integral Teststand Karlstein" (INKA) was built at Karlstein (Germany). It is a mock-up of the KERENA boiling water reactor containment, with integrated pressure suppression system. The complete chain of passive safety components is available. The passive components and the levels are represented in full scale. The volume scaling of the containment compartments is approximately 1:24. The reactor pressure vessel (RPV) is simulated via the steam accumulator of the Karlstein Large Valve Test Facility. This vessel provides an energy storage capacity of approximately 1/6 of the KERENA RPV and is supplied by a Benson boiler with a thermal power of 22 MW. With respect to the available power supply, the containment- and system-sizing of the facility is by far the largest one of its kind worldwide. From 2009 to 2012, several single component tests were conducted (Emergency Condenser, Containment Cooling Condenser, Core Flooding System etc.). On March 21st, 2013, the worldwide first large-scale only passively managed integral accident test of a boiling water reactor was simulated at INKA. The integral test measured the combined response of the KERENA passive safety systems to the postulated initiating event was the "Main Steam Line Break" (MSLB) inside the Containment with decay heat simulation. The results of the performed integral test (MSLB) showed that the passive safety systems alone are capable to bring the plant to stable conditions meeting all required safety targets with sufficient margins. Therefore the test verified the function of those components and the interplay between them as response to an anticipated accident scenario. The test provided evidence that the INKA is worldwide the first large scale test facility to perform integral verification tests of passive safety concepts under plant-like scaling and thermodynamic conditions. Hence, the test facility also shows that it is capable to perform containment response tests for existing Generation II BWRs (with active safety systems) and advanced (passive) reactor designs besides KERENA. These test results can be used to strengthen existing containment codes with regard to heat transfer, natural circulation, gas- and temperature stratification and others. Copyright © 2015 by JSME. [less ▲]

Effizienz der Pi Theorem Methodik

in Dimensionshomogenität (2015)

Dimensionshomogenität: Erkenntnis ohne Wissen?

Book published by Springer-Verlag (2015)

Pi-Theorem

in Dimensionshomogenität (2015)

Passive integral LOCA accident testing at Karlstein test facility

in International Congress on Advances in Nuclear Power Plants, ICAPP 2014 (2014), 3

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA . In order to verify the functionality and performance of the concept required for the ... [more ▼]

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA . In order to verify the functionality and performance of the concept required for the transient and accident management, the test facility "Integral Teststand Karlstein" (INKA) was built in Karlstein (Germany). It is a mockup of the KERENA boiling water reactor containment, with integrated pressure suppression system. The complete chain of passive safety components is available. While the scaling of the passive components and the levels match the original values, the volume scaling of the containment compartments is approximately 1:24. The reactor pressure vessel (RPV) is simulated via the steam accumulator of the Karlstein Large Valve Test Facility (GAP). This vessel provides an energy storage capacity of approximately 1/6 of the KERENA RPV and is supplied by a Benson boiler with a thermal power of 22 MW. With respect to the available power supply, the containment- and system-sizing of the facility is by far the largest one of its kind worldwide. On March 21, 2013 the worldwide first large-scale, only passively managed, integral accident test of a boiling water reactor was simulated at INKA. The integral test measured the combined response of the KERENA passive safety systems to the postulated initiating event "Main Steam Line Break" (MSLB) inside the Containment with decay heat simulation. The main goals were to show the performance and the interaction of the KERENA passive safety systems, the ability to keep the core covered, to discharge the decay heat via the appropriate pathway under all circumstances and to maintain the containment within defined limits, i.e. to bring the plant to a controlled state. The performed integral test (MSLB) was being initiated via the opening of the leak at original RPV boundary conditions (75 bar reactor pressure). The leak causes a mass and energy flow from the reactor pressure vessel into the containment. The resulting drop in the RPV water level activates the Emergency Condenser, so that an additional path for energy transfer out of the RPV in parallel to the leak is opened. The pressure increase in the containment is limited via the containment pressure suppression system (short term) and the containment cooling condensers (long term). The results of the test showed that the passive safety systems alone are capable to bring the plant to stable conditions meeting all required safety targets with sufficient margins. Therefore the test verified the function of those components and the interplay between them as response to an anticipated accident scenario. The test provided evidence that the INKA is worldwide the first large scale test facility to perform integral verification tests of passive safety concepts under plant-like scaling and thermodynamic conditions. [less ▲]

Condensation in horizontal heat exchanger tubes

in International Congress on Advances in Nuclear Power Plants 2012, ICAPP 2012 (2012), 4

Many innovative reactor concepts for Generation III nuclear power plants use passive safety equipment for residual heat removal. These systems use two phase natural circulation. Heat transfer to the ... [more ▼]

Many innovative reactor concepts for Generation III nuclear power plants use passive safety equipment for residual heat removal. These systems use two phase natural circulation. Heat transfer to the coolant results in a density difference providing the driving head for the required mass flow. By balancing the pressure drop the system finds its operational mode. Therefore the systems depend on a strong link between heat transfer and pressure drop determining the mass flow through the system. In order to be able to analyze these kind of systems with the help of state of the art computer codes the implemented numerical models for heat transfer, pressure drop or two phase flow structure must be able to predict the system performance in a wide parameter range. Goal of the program is to optimize the numerical models and therefore the performance of computer codes analyzing passive systems. Within the project the heat transfer capacity of a heat exchanger tube will be investigated. Therefore the tube will be equipped with detectors, both temperature and pressure, in several directions perpendicular to the tube axis to be able to resolve the angular heat transfer. In parallel the flow structure of a two phase flow inside and along the tube will be detected with the help of x-ray tomography. The water cooling outside of the tube will be realized by forced convection. It will be possible to combine the flow structure measurement with an angular resolved heat transfer for a wide parameter range. The test rig is set up at the TOPLFOW facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), so that it will be possible to vary the pressure between 5 and 70 bar. The steam mass content will be varied between 0 and 100 percent. The results will be compared to the large scaled Emergency Condenser Tests performed at the INKA test facility in Karlstein (Germany). The paper will explain the test setup and the status of the project will be presented. [less ▲]

The integral test facility karlstein

in Science and Technology of Nuclear Installations (2011), 2012