Abstract:Pressure drop in the ITER PFCI cable-in-conduit conductor (CICC) has been measured at CRPP using pressurized water at room temperature. The PFCI conductor is a dual channel CICC and the coolant flows in parallel in the central channel and in the annular bundle region. In our experiment the flow in the central channel is blocked and the longitudinal friction factor of the annular bundle region is deduced from measurements of pressure drop and mass flow rate. Two conductor samples are investigated, one with and … Show more
“…There have been several improvements in the design and construction of CICC since it was first proposed by Hoenig and Montgomery in 1970s [ 72 ]. The typical cross-sections of such Cable in Conduit Conductor (CICC) are shown in Figure 8 in which Type (a) CICC used in SST-1 [ 73 ], Type (b) CICC used for W7-X [ 74 ], Type (e) CICC used for ITER PF and CS conductor samples [ 75 , 76 ], Type (g) CICC used for TF conductor sample for the ITER project [ 77 ] and Type (h) CICC is ENEA conductor envisaged for the EU DEMO [ 44 ]. Figure 8 Various typical cross-sections of CICC [(a) square jacket without relief hole (b) internally round jacket without relief hole (c) round jacket without relief hole (d) square jacket with relief hole (e) internally round jacket with relief hole (g) round jacket with relief hole (h) rectangular jacket with two relief holes].…”
Section: Cryogenic Fluid Flow and Heat Transfer In Fusion Devicementioning
The constantly increasing energy consumption along with the depleting fossil fuel resources as well as owing to the fact that the nuclear fission not being an intrinsically safe method of energy generation, it has become necessary to look for other solutions to fulfil the future energy demands. Nuclear fusion, the source of energy for billions of stars, has attracted the attention of scientists and engineers despite a lot of technical challenges in the replication of the fusion process in laboratories. For fusion to take place in a device, one of the major challenges faced is the strong magnetic confinement of the plasma using large superconducting (SC) magnets, which need efficient cryogenic cooling techniques to maintain the required low temperatures for the superconducting state. In order to maintain the compactness, the SC magnets generally employ Cable in Conduit Conductor (CICC) windings, carrying high current densities, which are cooled by the forced flow of helium at ~4 K temperature to maintain the required superconducting temperatures. The construction of CICC aims to maintain the superconductivity state by optimization of various parameters such as thermal stability, the ratio of normal conductor to SC material, mechanical strength, low hydraulic impedance, current density, magnetic field, etc. The cryogenic thermal stability of the CICC is of prime importance for safe, stable and reliable operation of SC magnets. The prediction of thermal and hydraulic behavior of the CICC in large SC magnets is difficult due to the complex geometry involved, the variation in fluid properties, various heat in-flux incidences over the long length of CICC and a complex heat transport phenomenon. Another application which utilizes a forced flow cryogenic cooling in the fusion devices is a cryo-adsorption pump for creating clean and high vacuum with large pumping speed. This paper presents an overview of the forced flow cryogenic cooling schemes in fusion devices along with a systematic review of the thermal and hydraulic studies related to CICC and cryo-adsorption pump, thereby highlighting the challenges and opportunities for further improvement in their design and performance.
“…There have been several improvements in the design and construction of CICC since it was first proposed by Hoenig and Montgomery in 1970s [ 72 ]. The typical cross-sections of such Cable in Conduit Conductor (CICC) are shown in Figure 8 in which Type (a) CICC used in SST-1 [ 73 ], Type (b) CICC used for W7-X [ 74 ], Type (e) CICC used for ITER PF and CS conductor samples [ 75 , 76 ], Type (g) CICC used for TF conductor sample for the ITER project [ 77 ] and Type (h) CICC is ENEA conductor envisaged for the EU DEMO [ 44 ]. Figure 8 Various typical cross-sections of CICC [(a) square jacket without relief hole (b) internally round jacket without relief hole (c) round jacket without relief hole (d) square jacket with relief hole (e) internally round jacket with relief hole (g) round jacket with relief hole (h) rectangular jacket with two relief holes].…”
Section: Cryogenic Fluid Flow and Heat Transfer In Fusion Devicementioning
The constantly increasing energy consumption along with the depleting fossil fuel resources as well as owing to the fact that the nuclear fission not being an intrinsically safe method of energy generation, it has become necessary to look for other solutions to fulfil the future energy demands. Nuclear fusion, the source of energy for billions of stars, has attracted the attention of scientists and engineers despite a lot of technical challenges in the replication of the fusion process in laboratories. For fusion to take place in a device, one of the major challenges faced is the strong magnetic confinement of the plasma using large superconducting (SC) magnets, which need efficient cryogenic cooling techniques to maintain the required low temperatures for the superconducting state. In order to maintain the compactness, the SC magnets generally employ Cable in Conduit Conductor (CICC) windings, carrying high current densities, which are cooled by the forced flow of helium at ~4 K temperature to maintain the required superconducting temperatures. The construction of CICC aims to maintain the superconductivity state by optimization of various parameters such as thermal stability, the ratio of normal conductor to SC material, mechanical strength, low hydraulic impedance, current density, magnetic field, etc. The cryogenic thermal stability of the CICC is of prime importance for safe, stable and reliable operation of SC magnets. The prediction of thermal and hydraulic behavior of the CICC in large SC magnets is difficult due to the complex geometry involved, the variation in fluid properties, various heat in-flux incidences over the long length of CICC and a complex heat transport phenomenon. Another application which utilizes a forced flow cryogenic cooling in the fusion devices is a cryo-adsorption pump for creating clean and high vacuum with large pumping speed. This paper presents an overview of the forced flow cryogenic cooling schemes in fusion devices along with a systematic review of the thermal and hydraulic studies related to CICC and cryo-adsorption pump, thereby highlighting the challenges and opportunities for further improvement in their design and performance.
“…In this analysis we use a correction factor for the correlation of the bundle f B = 0.7 f Katheder , as assessed by pressure drop measurements of a similar dual channel CICC with no subcable wraps [9]. Due to the presence of heater (H7) and thermometers (T 17 , T 27 and T 37 ), the flow in the central channel is perturbed and the friction is larger than in the case without instrumentation.…”
Section: Flow Splittingmentioning
confidence: 99%
“…Due to the presence of heater (H7) and thermometers (T 17 , T 27 and T 37 ), the flow in the central channel is perturbed and the friction is larger than in the case without instrumentation. Therefore, we do not include the correction factor (= 0.5) suggested by measurements in the mentioned pressure drop experiment [10], i.e. in this analysis we use f H = f Showa .…”
This report describes a new method to determine the equivalent heat transfer coefficients in CICC's with parallel cooling channels, i.e. the radial heat transfer coefficient between helium flow in the cable bundle and in the central spiral, and the azimuthal heat transfer coefficient between subcables in the bundle. The method is based on the Fourier analysis of the steady state temperature traces during a heat step experiment after calibration of the thermometers. The equations for the average temperature distributions in the cable are solved analytically and the values of the equivalent transverse heat transfer coefficients are obtained as the best fit of the experimental temperature distributions. We show the results of the method by application to a short length sample experiment in the SULTAN test facility using an ITER-type CICC. The special instrumentation includes thermometers to measure the temperature in the center of the conductor and at 6 locations equally spaced in angle around the periphery of the conductor jacket, at 3 cross sections along the sample length. Heathers of different geometry allows generating a variety of heat slugs.
“…The available database for f B of the ITER CICC, including the above-mentioned TFMC sample, is summarized in Fig.l and compared with the DC, applying suitable multipliers. The database also includes data from a CSMC (CS1.2B) short sample [6] and from two Poloidal Field Conductor Insert (PFCI) short samples [7], one with and the other without last-but-one cabling stage wraps. While the TFMC sample test was performed with N 2 , the CSMC and PFCI samples were tested with HiO, which explains the different Re B range.…”
The available database for the friction factors to be used in the annular cable and in the central channel regions of cable-in-conduit conductors (CICC) for the superconducting magnets of the International Thermonuclear Experimental Reactor (ITER) is reviewed here for the first time. There is particular reference to its internal consistency as well as the correlations presently used in the ITER design criteria. Limitations and issues in the present status are emphasized and recommendations for improvements are given.
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