The CPLEAR Electromagnetic Calorimeter

A large-acceptance lead/gas sampling electromagnetic calorimeter (ECAL) was constructed for the CPLEAR experiment to detect photons from decays of $\pi^0$s with momentum $p_{\pi^0} \le 800$ MeV$/c$. The main purpose of the ECAL is to determine the decay vertex of neutral-kaon decays \ko \rightarrow \pi^0\pi^0 \rightarrow 4 \gamma and \ko \rightarrow \pi^0\pi^0\pi^0 \rightarrow 6 \gamma. This requires a position-sensitive photon detector with high spatial granularity in $r$-, $\varphi$-, and $z$-coordinates. The ECAL --- a barrel without end-caps located inside a magnetic field of 0.44 T --- consists of 18 identical concentric layers. Each layer of $1/3$ radiation length (X${_0}$) contains a converter plate followed by small cross-section high-gain tubes of 2640 mm active length which are sandwiched by passive pick-up strip plates. The ECAL, with a total of $6$ X${_0}$, has an energy resolution of $\sigma (E)/E \approx 13\% / \sqrt{E(\mathrm{GeV})}$ and a position resolution of 4.5 mm for the shower foot. The shower topology allows separation of electrons from pions. The design, construction, read-out electronics, and performance of the detector are described

The CPLEAR detector at CERN

The CPLEAR collaboration has constructed a detector at CERN for an extensive programme of CP-, T- and CPT-symmetry studies using ${\rm K}^0$ and $\bar{\rm K}^0$ produced by the annihilation of $\bar{\rm p}$'s in a hydrogen gas target. The ${\rm K}^0$ and $\bar{\rm K}^0$ are identified by their companion products of the annihilation ${\rm K}^{\pm} \pi^{\mp}$ which are tracked with multiwire proportional chambers, drift chambers and streamer tubes. Particle identification is carried out with a liquid Cherenkov detector for fast separation of pions and kaons and with scintillators which allow the measurement of time of flight and energy loss. Photons are measured with a lead/gas sampling electromagnetic calorimeter. The required antiproton annihilation modes are selected by fast online processors using the tracking chamber and particle identification information. All the detectors are mounted in a 0.44 T uniform field of an axial solenoid of diameter 2 m and length 3.6 m to form a magnetic spectrometer capable of full on-line reconstruction and selection of events. The design, operating parameters and performance of the sub-detectors are described.

Development of electro-magnetic pump for the astrid sodium-cooled fast reactor

International audienceIn the framework of the SFR (Sodium Fast Reactor) prototype called ASTRID (Advance Sodium Technological Reactor for Industrial Demonstration), the large capacity Electro-Magnetic Pumps (EMP) as main circulating pumps on the intermediate sodium circuits is applied instead of mechanical pumps by CEA. The use of EMP has several decisive technological merits compared with mechanical pump in the reactor design, operation and maintenance. Nevertheless, some theoretical and technological developments have to be carried out in order to validate the design tools which take Magneto Hydro Dynamic (MHD) phenomena into account and the applicability of the EMP to the steady state and transient operating conditions of ASTRID. For their developments, a collaboration agreement between the CEA and TOSHIBA Corporation came into force to carry out a joint work program on the EMP for ASTRID design and development. CEA carried out the theoretical analysis, and the EMP experimental model is constructed by CEA to support these theoretical developments. This model consists of a middle-size annular EMP for the liquid metal sodium. The various testing program using this model has been started in 2016.And, TOSHIBA carried out the examination of design specification for ASTRID, an electromagnetic design, a structural design and various analyses. The structure design has been examined the placement of the sodium boundary and the withstand pressure, etc. And, if the thicknesses of the structure increase for withstand pressure, the pump efficiency falls because the loss of the electromagnetic force increases. Therefore the balance of withstand pressure and the efficiency has been considered by an electromagnetism design. This paper describes the design studies and experimental activities for the EMP development within the framework of the CEA-TOSHIBA collaborations

large electro-magnetic pump conceptual design for the astrid sodium-cooled fast reactor

International audienceWithin the framework of the French Sodium Fast Reactor (SFR) prototype called ASTRID (Advance Sodium Technological Reactor for Industrial Demonstration), an application of Large capacity Electro-Magnetic Pump (LEMP) is considered as a main concept of the circulating pump on intermediate sodium circuits by CEA. For the developing of the LEMP for ASTRID, CEA conclude a collaboration agreement with TOSHIBA Corporation in April 2012, and carry out a joint work program on design and development of LEMP. In this collaboration, the design study such as the electromagnet design, electromagnetic fluid analysis, and etc for LEMP have been perfomed. This paper describes the dedicated design studies for the LEMP development within the framework of the CEA-TOSHIBA collaboration

The fuel handling route of astrid at the beginning of the basic design

International audienceAt the beginning of the Basic Design phases of ASTRID starting in 2016, the entire fuel handling route has been challenged in order to improve some aspects like availability and investment cost. Especially, studies performed at the end of preliminary design (2010 – 2015) phase show that the availability target will be difficult to obtain with a significant risk of malfunction because of multiple handling operations in series. Two main changes have been then decided: the implementation of an in-sodium external buffer zone, similar with an insodium external storage but associated with an in-primary vessel storage to reduce its size and its allowable residual power, and the merging of the fresh subassembly storage with the spent fuel subassembly storage which allows both reduction of size and number of equipment. These new options have the first advantages to reduce drastically the number of operations that have to be done during scheduled outage and to minimize the overall Balance Of Plant. After description of the entire fuel handling route adopted for ASTRID, this paper aims at identifying the advantages of this new option and points the remaining issues or questions that will be studied in details during the current Basic Design phase

Experimental and numerical analyses of the magnetic field spatial measurement inside an electromagnetic pump channel duct

International audienceThis article is a summary of a full paper that will be presented at the XInternational PAMIR International Conference - Fundamental and Applied MHD, to be heldfrom 20 – 24 June, in Cagliari, Italy.In the framework of the ASTRID R&D programme, it has been proposed to use anelectromagnetic (EM) induction pump in the secondary cooling system. This paper describesthe current status of the experimental and numerical analysis in progress to investigate liquidsodium flow instabilities in the PEMDYN loop with the objective of better managing the EMpump and preventing magnetohydrodynamic (MHD) instability. This paper discusses theanalysis of 3D measurements of the magnetic fields along a path inside the annular linearinduction pump (ALIP) channel measured with a Hall sensor. It also describes the numericalfinite-element models that have been built to gain a more in-depth understanding of theinterdependent MHD phenomena specific to EM pump operation. These measurements wereobtained before the operative condition so as to retrieve as much information as possible onthe EM field inside the channel pump without the fluid dynamic

Study of isolation valve for sodium fast reactor

International audienceIn the context of the ASTRID (Advanced Sodium Technological Reactor for IndustrialDemonstration) project, the VELAN Company is involved in proposing an isolation valve concept to guarantythe confinement of the reactor block in the event of a severe accident scenario. An innovative and compactdesign for the isolation sodium valve was developed. Following the basic design phase studies on the sodiumsecondary loops, a dedicated valve concept was studied to evaluate the technical parameters. The large size ofthe valve ND 700 mm requires optimizing the mass and dimensions for cost control purposes and in response toseismic spectrum. After a description of the service conditions, the paper presents the mains outcomes of thetechnical parameters (mechanical behaviour, sealing performance, hydraulic performance) which led on severalvalve designs. Maintenance aspects are also considered and a proposal of a butterfly valve design is proposed fordetailed studies

Caractérisation des propriétés des joints en silicone : Application au réacteur ASTRID

National audienceLes réacteurs de 4ème génération à neutrons rapides et a caloporteur sodium sont une des filières d'avenir des réacteurs nucléaires étudiées en France et le réacteur ASTRID doit s'en faire le démonstrateur industriel. Dans le cadre du programme de RetD TECNA, les équipes CEA et TECHNETICS Group France (TGF) du Laboratoire d'étanchéité Maestral (LE) sont impliquées dans la conception de systèmes d’étanchéité pour différentes parties du réacteur experimental ASTRID. Un des volets d'etude concerne les systèmes d’étanchéité des Bouchons Tournants (BT) d'ASTRID.Une solution testée au LE consiste a juxtaposer un joint gonflable accompagnant les phases de levee et de descente des BT et un joint a lèvres massif servant lors des phases de rotation. Ces joints sont constitues d'un silicone C85MC6THT/60 (haute temperature, dureté 60 Sore A).Pour appréhender et caractériser les performances, tant en étanchéité qu'en durée de vie, de cette solution, une etude complete est en cours sur ce silicone et ces joints.Dans un premier temps, des calculs par elements finis ont été menés dans les conditions de service et en condition extreme. Ces simulations ont nécessité au préalable la caractérisation intrinsèque du silicone et la determination de loi de comportement hyperelastique. Ces aspects feront l'objet de la premiere partie de la présentation. Ensuite, une machine d'essai spéciale (diamètre de 2,5 m) a été conçue et mise au point au LE afin de mener la caractérisation des joints dans des configurations proches du reel. Cet équipement dédié permet de tester en étanchéité et en endurance des joints gonflables axiaux et des joints a lèvres rotatifs en statique et en dynamique. Les résultats de ces essais font l'objet de la seconde partie de la presentation

DEVELOPMENT OF SMALL HIGH-GAIN TUBES FOR THE ELECTROMAGNETIC CALORIMETER OF THE CPLEAR EXPERIMENT

We have designed small rectangular cross-section tubes, 4 x 4.5 mm2, working in a high-gain mode. Two of the four cathode walls are coated with high-resistivity graphite, allowing the detection of the induced pulses on external strip boards. At 3.2 kV, the collected charge on the wires, which is due to a minimum-ionizing particle, is 10 pC and can be read out without preamplification. The small size of the tubes makes them particularly suitable for use in gas-sampling calorimeters