Commissariat A l'Energie Atomique Research Articles

Modeling of Pipe Whip Phenomenon Induced by Fast Transients Based on Fluid–Structure Interaction Method Using a Coupled 1D/3D Modeling Approach

The sudden increase in the operating pressure of nuclear power plants (NPPs) is due to the water hammer phenomenon, which tends to produce a whipping effect that causes serious damage to the pipes and their surroundings. The mechanical response of these pipelines under the influence of such fast fluid transients can be estimated using the fluid–structure interaction (FSI) method. The computational time and expense are predominantly dependent on the number of finite elements developed in the model. Hence, an effective modeling technique with limited and efficient nodes and elements is desired to obtain the closest possible results. A coupled 1D/3D finite element modeling approach using the FSI method is proposed to determine the influence of fast transients on the mechanical pipe whipping behavior of gas pipelines in NPPs. The geometric coupled modeling approach utilizes the presence of both the 3D solid elements and the 1D beam elements sharing a local conjunction. The computational model is modelled for a pipe-to-wall impact test scenario taken from the previously conducted French Commissariat a l’Energie Atomique (CEA) pipe whip experiments. The results of displacement, stresses, and impact velocity at the 3D section featuring the elbow are compared for the change in the 3D solid length varied at the juncture of the elbow. The computed results from the Ansys FSI coupling method using the Fluent and Transient Structural modules provides fair validation with the previously conducted experimental results and correlates with the CEA pipe whip tests on pipe-to-wall impact models. Thus, the 1D/3D coupled modeling approach, which minimizes the area of the solid region by constricting it to the impact area with appropriate contact modeling at the junctures, can be considered in the future for decreasing the computational time and the creation of finite elements.

Surface Tension and Density of Cr–Mn–Ni Steels with Transformation Induced Plasticity Effect

Thermophysical properties of liquid metal alloys play a crucial role in the variety of processes. Present work reports experimental investigations of two new transformation induced plasticity (TRIP) steels. A classical maximum bubble pressure technique is successfully used to measure surface tension and density of the liquid TRIP‐steel samples in the temperatures range of 1500–1800 °C. Experiments are performed in two different measurement cells from TU Freiberg and Commissariat a l'Energie Atomique (CEA), Cadarache. Capillaries are made of zirconia partially stabilized with yttrium oxide, and the samples are molten in Al2O3 crucibles. Measurements are conducted under the argon atmosphere. Surface tension of the investigated samples rises up to 1700 °C and further remains the same. Density of the new steels obtained in this study is in good agreement with the previously reported values for Fe–Cr alloys with similar Cr content. Density of the alloy is estimated as 875 488–11 885 × T (±218.85 kg m−3) for a 15%Cr alloy and 796 042–06 897 × T (±199 kg m−3) for a 19%Cr alloy.

Fast High-Energy X-Ray Imaging for Severe Accidents Experiments on the Future PLINIUS-2 Platform

The future PLINIUS-2 platform of the Commissariat a l’Energie Atomique (CEA) of Cadarache will be dedicated to the study of corium interactions in severe nuclear accidents, and will host innovative large-scale experiments. The nuclear measurement laboratory of CEA Cadarache is in charge of real-time high-energy X-ray imaging setups, for the study of the corium–water and corium–sodium interaction, and of the corium stratification process. Imaging such large and high-density objects requires a 15 MeV linear electron accelerator coupled to a tungsten target creating a high-energy bremsstrahlung X-ray flux, with corresponding dose rate about 100 Gy/min at 1 m. The signal is detected by phosphor screens coupled to high-framerate scientific CMOS cameras. The imaging setup is established using an experimentally validated home-made simulation software High-Energy MODeling for RAdiography and TOmography (MODHERATO). The code computes quantitative radiographic signals from the description of the source, object geometry and composition, detector, and geometrical configuration (magnification factor, etc.). It accounts for several noise sources (photonic and electronic noises, and swank and readout noise), and for image blur due to the source spot-size and to the detector unsharpness. In a view to PLINIUS-2, the simulation has been improved to account for the scattered flux, which is expected to be significant. This paper presents the scattered flux calculation using the Monte-Carlo N-particle transport code, and its integration into the MODHERATO simulation. Then, the validation of the improved simulation is presented, through confrontation to real measurement images taken on a small-scale equivalent setup on the PLINIUS platform. Excellent agreement is achieved. This improved simulation is therefore being used to design the PLINIUS-2 imaging setups (source, detectors, and cameras). Simulation will be presented for different configurations, as well as preliminary tests of alternative detectors considered for PLINIUS-2.

Absolute earthquake locations using 3-D versus 1-D velocity models below a local seismic network: example from the Pyrenees

This study was initiated during an ATER (attach´e temporaire d’enseignement et de recherche) position funded by the University Paul Sabatier III (Toulouse, France) at the Institut de Recherche en Astrophysique et Plan´etologie (IRAP, UMR5277) part of the Observatoire Midi-Pyr´en´ees (OMP). This work was funded by EDF (Electricit´e de France) under the SIGMA (Seismic Ground Motion Assessment) project. This work was included in the work package 1 (WP1), The seismic source in hazard models. We acknowledge Kevin Manchuel, leader of WP1. We also acknowledge people involved in the TOPO-IBERIA and PYROPE projects for providing us with the high quality data from these temporary seismic deployments.We want also to acknowledge the institutions responsible for the maintenance of the different permanent seismic networks contributing data to this study: Instituto Geogr´afico Nacional of Spain (IGN), Catalonian Geological Institute (IGC), Commissariat `a l’Energie Atomique (CEA), French Broad-band network (RLBP) and RAP French strong motion network provided by RESIF - R´eseau Sismologique et g´eod´esique Franc¸ais.Seismic Network.doi:10.15778/RESIF.FR. RESIF is a national Research Infrastructure, recognised as such by the French Ministry of Higher Education and Research. RESIF is managed by the RESIF Consortium, composed of 18 Research Institutions and Universities in France. RESIF additionally supported by a public grant overseen by the French National Research Agency (ANR) as part of the ‘Investissements d’Avenir’ program (reference: ANR-11-EQPX- 0040) and the French Ministry of Ecology, Sustainable Development and Energy. We acknowledge Thomas Bardainne (CGG - Microseismic) and Mario Ruiz Fernandez (Institute of Earth Sciences Jaume Almera of the Spanish Scientific Research Council (ICTJA-CSIC)) for providing us access to traveltime picks and velocity models from temporary seismic experiments. We acknowledge Robert Sarda (IMERYS) for giving information about blasts at the Luzenac quarry. Thanks to Leo Zijerveld for his suggestions and help with the English. Authors thank Prof Egill Hauksson, editor and two anonymous reviewers for their constructive reviews and careful handling of the manuscript.

Thermal modelling of the calorimeter used for energy measurement of LMJ laser pulse

In this work, a 3D thermal model of the LMJ calorimeter is developed usingComsol multiphysics. The unknown thermal properties of the system are identified by comparing the model results with the measured temperature. Several model's applications, such as comparing deposition modes (electrical and optical) or defining calibration procedure, are presented. The Laser Integration Line (LIL) at Commissariat a l'Energie Atomique (CEA) near Bordeaux (France) is a prototype beam line, built to demonstrate the technology and performance of the French Laser Megajoule (LMJ) ignition facility (1). Electrically calibrated laser calorimeters are considered as the most suitable tools to perform laser energy measurements. REC calorimeter has been especially manufactured to accurately quantify the energy of laser pulses of the LIL. REC consists of an absorbing glass which is attached to an aluminium plate. The response of the calorimeter is the time dependent temperature profile measured on the rear face of the aluminium plate using an array of Peltier cells. Moreover, electrical heaters are attached to the aluminium rear face to perform electrical calibration. (cf. figure 1). The energy deposited inside the calorimeter is dissipated into the thermal mass. Obviously, modelling and analysis of the calorimeter thermal behaviour are very important issues. In this study, a three-dimensional model is developed with COMSOL Multiphysics to analyze the calorimeter response.

Modelling the corrosion-induced cracking of reinforced concrete structures exposed to the atmosphere

The prediction of concrete cracking due to corrosion in atmospheric/carbonated conditions is a major issue for the evaluation of the durability of structures and the choice of maintenance policies. Because of the complexity of the phenomenon, a fully predictive approach is still missing. The proposed work can be considered as one step in this direction. It deals with a modelling study achieved at the Commissariat a l'Energie Atomique (CEA) with the CAST3M finite elements software. Model is constituted of three components: (1) concrete hydric behaviour, (2) rebar corrosion and (3) mechanical consequences on concrete (mainly concrete cracking). Actual developments consider analogies between rebar corrosion mechanisms and atmospheric corrosion ones, assuming that corrosion processes are influenced by the relative humidity evolution of atmosphere and/or of concrete.

MODELING BIO-OIL GASIFICATION BY A PLASMA PROCESS

Gasification is a thermochemical path that makes it possible to convert biomass into gases. The main requirements for the transformation process are both a high mass rate transformation and a low content of organic impurities (tars) in the produced gas (syngas). An allothermal process of gasification, based on the use of thermal plasma to supply the energy for bio-oil conversion is being studied at the CEA (Commissariat a l'Energie Atomique) Cadarache, bio-oil being produced by a pre-processing of biomass by flash pyrolysis. The purpose of this study is to demonstrate the feasibility and cost-effectiveness of the gasification of bio-oil by a thermal plasma process. Indeed, it is expected that the high level of temperature and presence of oxygenated active species in the plasma flow may help to reduce the tar content below 0.1 mg/Nm3, a required value for the Fischer Tropsch post-process and increase the mass yield. The first step of the work consists in developing a model that takes into account the plasma flow inside the reactor and the liquid material treatment in order to increase the understanding of the process and determine the optimal operating parameters of the plasma reactor. The bio-oil injected under the form of a liquid jet is subjected to fragmentation, evaporation and chemical reactions in the plasma jet. The modeling work presented in this paper is focused on the break up of the droplets formed by the disintegration of the liquid jet. It uses the Computational Fluid Dynamics (CFD) code Fluent 6.3. Numerical predictions are compared with experimental data obtained with a shadowgraphy system.

Nonlinear fluid–structure interaction calculation of the leakage behaviour of cracked concrete walls

In the case of severe accidents in nuclear power plants, containments are the last barrier to prevent the release of environmentally hazardous substances. Therefore, the leaktightness of the containment is of decisive importance for the safety and protection of the environment in case of an accident. A numerical model based on the Finite Element Method has been developed to calculate the leakage behaviour of reinforced concrete walls. Leakage flow and structural response are solved iteratively. For the calculation of the leakage flow a fluid model has been used which takes into account the condensation of the steam part within the air–steam mixture. Both, the release of the latent heat in the case of condensation and the following two-phase flow of air and water have been considered, too. Tests with the SIMIBE Experimental facility [Caroli, C., Coulon, N., Renson, C., 1995. Steam leakage through concrete cracks: parametric study with SIMIBE experiment and interpretation of the results. Tech. Rep. Commissariat A L’Energie Atomique (CEA)] are used for verification of the condensation and two-phase flow models.

Cold Tests of the Superconducting Coils for the Stellarator W7-X

rdquoA new plasma fusion experiment, Wendelstein 7-X (W7-X), is built in the Max-Planck Institute for Plasma Physics in Greifswald (IPP), Germany. This experiment employs superconducting coils, allowing for plasma discharges up to 30 minutes duration. W7-X will be an optimized stellarator with respect to plasma transport and stability. The W7-X magnet consists of 70 individual coils in a toroidal arrangement. Each coil of W7-X is thoroughly tested before installation in a cryogenic test facility at the Commissariat a l'Energie Atomique (CEA) in Saclay, France. The tests are essential, because no access is foreseen to the magnetic system during the entire operation period of W7-X. The test procedure will be described briefly, and some test results will be presented.

Sound field modelling using SimulUS

The motivation behind developing the SimulUS beam model was as a tool for the rapid visualisation of ultrasonic fields generated by phased array transducers (both linear and matrix). However, it is possible to model single crystal transducers by defining a 1 by 1 matrix. The present work was carried out using the version released in December of 2005 and was part of a larger validation programme in TWI involving other models. The core of the model is based on Huygen’s discretisation method of evaluating the free field ahead of the sound radiator (Section 2). SimulUS operates principally in the continuous wave (1) mode but a pulse wave expression is incorporated. The model is primarily designed for rapid visualisations of the sound field but it can be used as a pulse wave modelling package. The computing requirements are less intensive when the input waveform is of a single frequency (continuous wave). Hence, in this paper, the evaluation of the performance of SimulUS in its primary continuous wave mode is presented. SimulUS was envisioned for use in applications such as: q Technique development – such that the operator can rapidly evaluate the suitability of a particular setup for the inspection task. q Probe design – confident design of, in particular, phased array probes such that the designer can ensure that the parameters are correctly specified to achieve optimised field properties for the application. q Training – allowing students to understand the basics of phased array ultrasonics and conventional ultrasonics through an interactive learning approach; where the effects of varying the crystal size, pitch, frequency etc on the ultrasonic field generated by the transducer can be understood and even the effects of failed elements modelled. 2. Principles of ultrasonic field models Ultrasonic field models have been developed utilising various different theories. In essence, they are all required to evaluate the sound pressure field ahead of a transducer. As well as SimulUS, two other successful models will be described to illustrate the different approaches that have been taken in the past; both models are well established and have been extensively validated within industry and by research organisations. The models developed in the Non-Destructive Testing Applications Centre (NDTAC) of the Central Electricity Generating Board (CEGB) were based on an analytical approximation to the pressure distribution over the sound radiator. The CIVA model, developed by Commissariat a l’energie Atomique (CEA), is a semi-analytical model using a theory for electromagnetic wave propagation that was adapted for simulating the elastodynamic propagation of sound waves (2) . The sound field ahead of the probe face can be described using Huygen’s principle, which uses elementary waves of the same frequency which originate at discrete points on the radiating surface (3) . These waves then undergo interference effects in front of the radiating surface and their summation, as derived by Fresnel, gives the strength of the field at any point ahead of the probe. The solution depends on noting that at any given point ahead of the radiator, Huygens’ elementary waves from discrete points have taken different paths. Since the sound pressure has an inverse relationship to actual distance travelled from the origin, the path difference dictates actual pressure contributions from each elementary wave at the point of interest. This method of evaluating the resultant pressure contribution is known as zone construction. For each elementary contribution, the path difference is converted to an angular measurement along with the change in pressure at the given distance; vector addition is used to evaluate the pressure and phase at any given point ahead of the radiator. This method can be used effectively for evaluating the pressure values along the beam axis and off axis with modifications to the element configuration. This forms the basis of the SimulUS model where the contribution of wavelets from sources on the transducer is summed on the calculation plane. The NDTAC beam model is an analytical model that was developed to form part of a larger systematic approach to the modelling of ultrasonic inspections. The model was designed to generate the sound fields created by single crystal probes. It is a modified version of the simple piston oscillator model of a single crystal. The Fresnel integral approach to evaluate pressure values at a general point ahead of the probe face is computationally intensive. The NDTAC model was envisaged as a module in a systematic approach to evaluating defect interaction; since the beam model needed to be run several times, it needed to be computationally less intensive while providing sufficient accuracy in the prediction of pressure values ahead of the probe. Hence, the NDTAC model suggests an approximation for the amplitude profile over the radiating face such that the evaluation of the field ahead can be performed analytically as opposed to resorting to numerical methods (4)

Improving High-Temperature Measurements in Nuclear Reactors with Mo/Nb Thermocouples

Many irradiation experiments performed in research reactors are used to assess the effects of nuclear radiations on material or fuel sample properties, and are therefore a crucial stage in most qualification and innovation studies regarding nuclear technologies. However, monitoring these experiments requires accurate and reliable instrumentation. Among all measurement systems implemented in irradiation devices, temperature—and more particularly high-temperature (above 1000°C)—is a major parameter for future experiments related, for example, to the Generation IV International Forum (GIF) Program or the International Thermonuclear Experimental Reactor (ITER) Project. In this context, the French Commissariat a l’Energie Atomique (CEA) develops and qualifies innovative in-pile instrumentation for its irradiation experiments in current and future research reactors. Logically, a significant part of these research and development programs concerns the improvement of in-pile high-temperature measurements. This article describes the development and qualification of innovative high-temperature thermocouples specifically designed for in-pile applications. This key study has been achieved with technical contributions from the Thermocoax Company. This new kind of thermocouple is based on molybdenum and niobium thermoelements, which remain nearly unchanged by thermal neutron flux even under harsh nuclear environments, whereas typical high-temperature thermocouples such as Type C or Type S are altered by significant drifts caused by material transmutations under the same conditions. This improvement has a significant impact on the temperature measurement capabilities for future irradiation experiments. Details of the successive stages of this development are given, including the results of prototype qualification tests and the manufacturing process.

A Case for Small Modular Fast Reactor

This paper describes a 50MWe Small Modular Fast Reactor (SMFR) design that has been developed jointly by Argonne National Laboratory (ANL), Commissariat a l'Energie Atomique (CEA), and Japan Atomic Energy Agency (JAEA) as an international collaborative effort. Key design innovations include a metallic fueled core with 30-year lifetime and supercritical carbon dioxide Brayton cycle.

A Case for Small Modular Fast Reactor

This paper describes a 50MWe Small Modular Fast Reactor (SMFR) design that has been developed jointly by Argonne National Laboratory (ANL), Commissariat a l'Energie Atomique (CEA), and Japan Atomic Energy Agency (JAEA) as an international collaborative effort. Key design innovations include a metallic fueled core with 30-year lifetime and supercritical carbon dioxide Brayton cycle.

New Apparatus for Thermal Diffusivity and Specific Heat Measurements at Very High Temperature

The thermal characterization of a material under its conditions of use (temperature, pressure, etc.) is an essential step to check its adequacy with regard to a specific application and to predict its behavior. For needs of material characterization, Commissariat a l’Energie Atomique (CEA) has developed with Laboratoire National de Metrologie et d’Essais (LNE) a new apparatus to study thermophysical properties of solid materials in the range from 300 to 3300 K. This setup allows measurements of either the thermal diffusivity by the laser flash method or the specific heat by drop calorimetry. First, thermal diffusivity measurements have been performed on Armco iron and POCO AXM-5Q1 graphite. The measured values are in agreement with results obtained by other laboratories with a relative deviation of less than 6%.

Simulation of the VVER-1000 pump start-up experiment of the OECD V1000CT benchmark with CATHARE and TRAC-PF1

In the framework of joint effort between the Nuclear Energy Agency (NEA) of OECD, the United States Department of Energy (US DOE), and the Commissariat a l'Energie Atomique (CEA), France a coupled three-dimensional (3D) thermal-hydraulics/neutron kinetics benchmark for VVER-1000 was defined. The benchmark consists of calculation of a pump start-up experiment labelled V1000CT-1 (Phase 1), as well as a vessel mixing experiment and main steam line break (MSLB) transient labelled V1000CT-2 (Phase 2), respectively. The reference nuclear plant is Kozloduy-6 in Bulgaria. The overall objective is to assess computer codes used in the analysis of VVER-1000 reactivity transients. A specific objective is to assess the vessel mixing models used in system codes. Plant data are available for code validation consisting of one experiment of pump start-up (V1000CT-1) and one experiment of steam generator isolation (V1000CT-2). The validated codes can be used to calculate asymmetric MSLB transients involving similar mixing patterns. This paper summarizes a comparison of CATHARE and TRAC-PF1 system code results for V1000CT-1, Exercise 1, which is a full plant point kinetics simulation of a reactor coolant system (RCS) pump start-up experiment. The reference plant data include integral and sector average parameters. The comparison is made from the point of view of vessel mixing and full system simulation. CATHARE used a six-sector multiple 1D vessel thermal-hydraulic model with cross flows and TRAC used a six-sector, 18-channel coarse-mesh 3D vessel model. Good agreement in terms of integral parameters and inter-loop mixing is observed.

The megajoule laser program — ignition at hand

The French Commissariat a l'Energie Atomique (CEA) is currently building the Laser MegaJoule (LMJ), a 240-beam laser facility, at the CEA Laboratory CESTA near Bordeaux. LMJ will be a cornerstone of CEA's “Programme Simulation”, the French Stockpile Stewardship Program. LMJ is designed to deliver about 2 MJ of 0.35 μm light to targets for high energy density physics experiments, among which fusion experiments. LMJ technological choices were validated with the Ligne d'Integration Laser (LIL), a scale 1 prototype of one LMJ bundle, built at CEA/CESTA. Plasma experiments started at the end of 2004 on LIL, which is already open to the scientific community through the Plasma and Lasers Institute. The construction of the LMJ building itself started in March of 2003. LMJ will be gradually commissioned from early 2011, and after an experimental program to progress toward fusion, the first fusion experiments will begin late 2012.

The Megajoule laser program – Ignition at hand

The French Commissariat a l'Energie Atomique (CEA) is currently building the Laser MegaJoule (LMJ), a 240-beam laser facility, at the CEA Laboratory CESTA near Bordeaux. LMJ will be a cornerstone of CEA's “Programme Simulation”, the French Stockpile Stewardship Program. LMJ is designed to deliver about 2 MJ of 0.35 μm light to targets for high energy density physics experiments, among which fusion experiments. LMJ technological choices were validated with the Ligne d'Integration Laser (LIL), a scale 1 prototype of one LMJ bundle, built at CEA/CESTA. Plasma experiments started at the end of 2004 on LIL, which is already open to the scientific community through the Plasma and Lasers Institute. The construction of the LMJ building itself started in March of 2003. LMJ will be gradually commissioned from early 2011, and after an experimental program to progress toward fusion, the first fusion experiments will begin late 2012.

Design, optimization and development of pulse compression gratings for the MPW-HE LIL

The french Commissariat a l'Energie Atomique (CEA) develops a multipetawatt laser in the Laser Integration Line (LIL), prototype of the future Megajoule Laser [1]. This Petawatt laser line will deliver impulsions of 7.2 PW, 500 fs at the wavelength of 1053 nm. The chirped pulse amplification (CPA) method is used [2]. We work on the modelization and the fabrication of gratings used in the CPA scheme. Since damage threshold of more than 3 J/cm 2 @ 500fs are needed, we retained multidielectric gratings (MLD) instead of classical gold gratings. These gratings, developed in mid 90's, consist in a multidielectric mirror stack with its top layer engraved with a grating structure. We have been working to optimize the groove geometry of the MLD grating to minimize the E field maximum in the structure. An innovative design using a mixed metal/dielectric mirror stack was also studied. The scope of this paper is to present our main numerical results in these different domains.

The Laser Mégajoule (LMJ) Project dedicated to inertial confinement fusion: Development and construction status

Abstract The French Commissariat a l’Energie Atomique (CEA) began the construction of the Laser Megajoule (LMJ), a 240 beams laser facility, at the CEA Laboratory CESTA near Bordeaux. The LMJ will be a cornerstone of the CEA “Programme Simulation”, similar to LLNL “NIF” facility. The LMJ is designed to deliver 2 MJ of 0.35 μm light to targets for high energy density physics experiments and to ultimately obtain ignition and propagating burn with DT targets in the laboratory. The scientific conception and system design was completed in 1999 and was followed by the Demonstration of an Engineering Prototype which was achieved in early 2003 with operation of one beam of the Ligne d’Integration Laser (LIL) at CESTA, with 9.5 kJ of UV light (0.35 μm) in less than 9 ns from a single laser beam. The construction phase of the LMJ facility was initiated in March 2003 with the start of work on the building and the target chamber. This paper will present a summary of 2004 LIL results and a description of LMJ, which is expected to demonstrate first light performance through 240 beams by 2009.

Large-scale seismic test program at Hualien Taiwan

The large scale seismic test (LSST) program at Hualien, Taiwan, is a follow-on to the soil-structure interaction (SSI) experiments at Lotung, Taiwan. The planned SSI studies are performed at a stiff soil site in Hualien, Taiwan, that historically has had slightly more destructive earthquakes in the past than Lotung. The objectives of the LSST program are as follows: to obtain earthquake-induced SSI data at a stiff soil site having similar prototypical nuclear power plant soil conditions; to confirm the findings and methodologies validated against the Lotung soft soil SSI data for prototypical plant condition applications; to validate further the technical basis of realistic SSI analysis approaches; to support further the resolution of USI A-40 “Seismic Design Criteria” issue. These objectives are accomplished through an integrated and carefully planned experimental program consisting of soil characterization, test model design and field construction, instrumentation layout and deployment, in situ geophysical information collection, forced vibration test, and synthesis of results and findings. The Hualien LSST is a joint effort among many interested parties. The Electric Power Research Institute (EPRI) and Taiwan Power Company (Taipower) are the organizers of the program and have the lead in planning and managing the program. Other organizations participating in the LSST program are the US Nuclear Regulatory Commission (NRC), Central Research Institute of Electric Power Industry (CRIEPI), Tokyo Electric Power Compamy (TEPCO), Commissariat A L'Energie Atomique (CEA), Electricitéde France (EdF), Framatome, Korea Electric Power Corporation (KEPCO), Korea Institute of Nuclear Safety (KINS), and Korea Power Engineering Company (KOPEC). The LSST array started operation in June 1993, and is envisioned to be of five years duration.