Remote handling strategy and prototype tooling of the ITER vacuum vessel pressure suppression system bleed line valve assembly and rupture disk assembly

The Vacuum Vessel Pressure Suppression System (VVPSS), a key safety system of the ITER plant, is designed to protect the Vacuum Vessel (VV) from over pressure occurring in the case of LOCA (Loss Of Coolant Accident) or other pressurizing accidents such as LOVA (Loss Of Vacuum Accident). The steam condensation in the Suppression Tanks (main elements of the VVPSS system), occurs at sub-atmospheric pressure. The steam condensation, at pressures equal or greater than the atmospheric, has been numerically analyzed and experimentally investigated in the past in order to optimize the design of the pressure suppression system of boiling water nuclear reactors. However, very limited experimental data is available concerning the steam condensation in a water tank at sub-atmospheric pressure. In order to analyze the steam condensation in these operating conditions, an experimental study, funded by ITER Organization, is conducted at the Department of Civil and Industrial Engineering (DICI) of University of Pisa. The tests analyze the condensation of saturated or superheated steam at sub-atmospheric pressures (4.2 kPa and slightly above the water vapour saturation pressure), and pool temperature up to 50°C at several heights of water head. The experimental facility, to perform this study, has been set up with a significant scaling factor regarding the full size installation at ITER. In this paper the experimental rig, the conditions of the experiments, and the test matrix are presented. The temperature and pressure measurements with details of the data acquisition system are described. The tests were performed at different patterns of the sparger exit holes (1, 3 and 9) and for three steam mass flow rates per one hole. The results show very high efficiency of condensation for all examined conditions. Finally, a comparison between the condensation regimen at sub-atmospheric and at atmospheric pressure is discussed.

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Experimental results of functional performance of a vacuum vessel pressure suppression system in ITER

Fusion Engineering and Design ◽

10.1016/s0920-3796(02)00242-9 ◽

2002 ◽

Vol 63-64 ◽

pp. 217-222 ◽

Cited By ~ 4

Author(s):

Mitsuhiko Shibata ◽

Kazuyuki Takase ◽

Hironori Watanabe ◽

Hajime Akimoto

Keyword(s):

Functional Performance ◽

Experimental Results ◽

Vacuum Vessel ◽

Suppression System

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Experimental investigation of functional performance of a vacuum vessel pressure suppression system of ITER

Fusion Engineering and Design ◽

10.1016/j.fusengdes.2017.09.010 ◽

2017 ◽

Vol 122 ◽

pp. 42-46 ◽

Cited By ~ 11

Author(s):

R. Lo Frano ◽

D. Mazed ◽

D. Aquaro ◽

D. Del Serra ◽

F. Orlandi

Keyword(s):

Experimental Investigation ◽

Functional Performance ◽

Vacuum Vessel ◽

Suppression System

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CFD Thermal Analysis of ITER Pressure Suppression Tanks

Volume 9: Student Paper Competition ◽

10.1115/icone26-82550 ◽

2018 ◽

Author(s):

Lorenzo Basili ◽

Rosa Lo Frano ◽

Marco Olcese ◽

Igor Sekachev ◽

Donato Aquaro

Keyword(s):

Thermal Insulation ◽

Fusion Reactor ◽

Thermal Conditions ◽

Vacuum Vessel ◽

Bottom Part ◽

Optimum Configuration ◽

Computational Fluid Dynamics Cfd ◽

Tank Pressure ◽

Important System ◽

Suppression System

The aim of the paper is to investigate the thermal conditions (temperature distribution, heat losses) in the support system of the Vapour Suppression Tank (VST) of the Vacuum Vessel Pressure Suppression System (VVPSS), a safety important system of ITER fusion reactor, protecting the Vacuum Vessel (VV) against overpressures. The VVPSS includes four VSTs of identical volume and mounted as two stacked assemblies. The study focuses on the optimization of the design of the thermal insulation of the bottom part of the VST, connecting each two-tank stack to the basement, and also on the identification of the thermal loads at the interface between the tank support and the tank pressure boundary. A Computational Fluid Dynamics (CFD) analysis of the VST has been performed for four different insulation configurations and considering both steady state and transient loads following accidental conditions. The results of the analysis are used to provide recommendation on the optimum configuration of the thermal insulation. Measures for minimization of the thermal gradient in the critical area of the joint between the tank hemispherical head and support skirt to limit the thermal fatigue on the welds are also suggested.

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Concept Design of Computer Monitoring System for ITER Transfer Cask System

18th International Conference on Nuclear Engineering: Volume 6 ◽

10.1115/icone18-29086 ◽

2010 ◽

Author(s):

Haitian Wang ◽

Ge Li ◽

Lei Cao

Keyword(s):

Control System ◽

Fusion Energy ◽

Vacuum Vessel ◽

Concept Design ◽

Industrial Control ◽

Collaborative Project ◽

Experimental Physics ◽

Experiment System ◽

Remote Handling ◽

Set Up

The ITER (International Thermonuclear Experimental Reactor) is an international collaborative project, and its object is aiming at demonstrating the scientific and technological feasibility of fusion energy for peaceful purposes. In the ITER, the four important engineering challenges are the first wall of the blank model, the remote handling (RH), the heating of the plasma, and the superconducting technology. The RH control system is very complexity, and the total number of the control nodes is 15378, which consists of the control nodes in the Tokamak equipment, the hot cell equipment and the control room equipment. Only the number of the control nodes of the transfer cask system (TCS) is up to 2580. The TCS is one sub system of ITER RH system, which provides the means for the remote transfer of (clean/activated/contaminated) in-vessel components and remote handling equipment between hot cell facility and vacuum vessel through dedicated galleries and lift in the ITER buildings. Due to the experimental facility with a very long timeline, the control software on the ITER is better suited using an open source solution as compared to a commercial solution. According to market share and proven record, command control and data acquisition and communication (CODAC) group chooses the EPICS (Experimental Physics and Industrial Control System) as the preferred solution. China takes part in the ITER, and wishes to grasp the RH technology, which is one of the four key technologies related to the future fusion reactors for electric power generation. According to the CODAC system configuration with EPICS component, the concept control architecture of the TCS is presented in this paper. The control system consists of the file network, the interlock network, the safety network, real-time network, RH control network and visual supervising network etc. Then, the paper analyses each part corresponding requirement function. As a result, a development service platform concept is set up. Finally, the experiment system of the leg of the TCS has been constructed.

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Prevention of hydrogen accumulation inside the vacuum vessel pressure suppression system of the ITER facility by means of passive auto-catalytic recombiners

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2018.07.039 ◽

2019 ◽

Vol 44 (17) ◽

pp. 8971-8980 ◽

Cited By ~ 5

Author(s):

P.-M. Steffen ◽

E.-A. Reinecke ◽

S. Kelm ◽

A. Bentaib ◽

N. Chaumeix ◽

...

Keyword(s):

Vacuum Vessel ◽

Hydrogen Accumulation ◽

Suppression System

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Computational Fluid Dynamics Thermal Analysis of ITER Pressure Suppression Tanks

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4048007 ◽

2020 ◽

Vol 7 (1) ◽

Author(s):

Lorenzo Basili ◽

Rosa Lo Frano ◽

Marco Olcese ◽

Igor Sekachev ◽

Donato Aquaro

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Thermal Insulation ◽

Thermal Conditions ◽

Vacuum Vessel ◽

Optimum Configuration ◽

Computational Fluid Dynamics Cfd ◽

Tank Pressure ◽

Important System ◽

Suppression System

Abstract The aim of the paper is to present the results of the investigation of the thermal conditions (temperature distribution, heat losses) in the support system of the vapor suppression tank (VST) of the vacuum vessel pressure suppression system (VVPSS), a safety important system of ITER fusion reactor, protecting the vacuum vessel (VV) against overpressures. The VVPSS includes four VSTs of identical volume and installed as two stacked assemblies. The study focuses on the optimization of the design of the thermal insulation at the bottom of the VSTs, interfacing with the basement and also on the identification of the thermal loads at the interface between the tank support and the tank pressure boundary. A computational fluid dynamics (CFD) analysis of the VST has been performed for four different insulation configurations and considering both steady-state and transient loads following accidental conditions. The results of the analysis are used to provide recommendation on the optimum configuration of the thermal insulation. Measures for minimization of the thermal gradient in the critical area of the joint between the tank hemispherical head and support skirt to limit the thermal fatigue on the welds are also suggested.

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