Abstract: Liquid metal breeders such as Lithium or the eutectic Lead-Lithium alloy PbLi have the potential for attractive breeding blankets, especially if the liquid metal serves as breeder and coolant. However, cooling of first wall and blanket structure is a challenging task because the magnetic field degrades the heat transfer and can cause a really high pressure drop. To overcome these problems, dual coolant blankets with helium cooled FW/blanket structure and a self-cooled breeding zone had been proposed, with electrical insulation by ceramic-coatings or sandwich flow channel inserts. Such concepts are in principle simpler than helium cooled blankets, but the thermal efficiency is limited to ˜35 % as in any helium cooled blankets with steel structure. A much higher efficiency up to about 45 % became feasible when the sandwich insulator was replaced by flow channel inserts (FCI) made of a SiC composite. This FCI serves as thermal insulator too, allowing an exit temperature of ˜700° C, suitable for a BRA...

Abstract: This paper presents our conceptual design for laser drivers used in Laser Inertial Fusion Energy (LIFE) power plants. Although we have used only modest extensions of existing laser technology to en...

Abstract: Sequential exposures of W surfaces to steady-state and pulsed (∼0.5 ms) plasmas have been performed in a linear divertor plasma simulator and a magnetized coaxial plasma gun to investigate ...

Abstract: Feasibility studies on applying high-temperature superconductors (HTS) to the heliotron-type fusion energy reactor FFHR are being carried out. Using HTS, we consider that the three-dimensional helical coils with a ~40 m diameter can be constructed without preparing a huge winding machine. A practical method for realizing this concept is proposed. The electromagnetic stress inside the helical coil packs is examined using an FEM analysis for double-pancake windings. The effect of error magnetic field generated by the shielding currents in HTS tapes is also examined.

Abstract: The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. The present work focuses on the pure fusion option. A key component of a LIFE engine is the fusion chamber subsystem. It must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated design that meets all of these requirements is described herein.

Abstract: The HELIOS zero-dimensional code (Version 10) is described in detail in the case of deuterium-tritium (D-T) plasmasThe part of the code described solves in a self-consistent way the thermal equil

Abstract: The transmission line (TL) subsystem associated with the ITER electron cyclotron heating and current drive system has reached the conceptual design maturity. At this stage the responsibility of finalizing the design has been transferred from the ITER Organization to the U.S. Domestic Agency. The purpose of the TL is to transmit the microwaves generated by the 170-GHz gyrotrons installed in the radio-frequency building to the launchers located in one equatorial and four upper tokamak ports. Each TL consists of evacuated HE11 wave guides, direct-current breaks, power monitors, mitre bends, polarizers, switches, loads, and pumping sections and will have a typical length that ranges from 100 to 160 m. Overall transmission efficiency could be as high as 92% depending on the specific path between a given gyrotron and launcher. All components are required to be 2-MW compatible, and their layout and organization have been optimized for simplifying the maintenance accessibility and monitoring the primary tritium barrier integrity. Two different TL layouts are at the moment under study, to accommodate the two alternative options for the European sources: four 2-MW units or eight 1-MW units. In this paper the actual design is presented and the technical requirements are discussed.

Abstract: The double emulsion (DE) droplets used for fabrication of cryogenic foam targets for inertial confinement fusion experiments require precisely controlled volumes. On-chip electric field actuated mi...

Abstract: Targets intended to produce ignition on the National Ignition Facility (NIF) are being simulated, and the simulations are used to set specifications for target fabrication. Recent design work has focused on incorporating the implications of NIF experiments that were done in fall 2009 and planning for the campaign in 2010. Near-term experiments will use Ge-doped CH, although Be and diamond are still under active consideration for 2011 and beyond. The emphasis in this paper will be on changes in the requirements over the last year, the characteristics of the 2010 CH-ablator design, and the designs for 2011 and beyond. Capsule defects of particular interest are surface perturbations on the CH ablator and composition variations in the Be shells. Complete tables of specifications are regularly updated for all of the targets. All the specifications are rolled together into an error budget indicating adequate margin for ignition with all of the designs.

Abstract: The compact (R0~1.2-1.3m) Fusion Nuclear Science Facility (FNSF) is aimed at providing a fully integrated, continuously driven fusion nuclear environment of copious fusion neutrons. This facility w...

Abstract: The development of radiation-resistant materials to sustain the harsh fusion environment represents a challenging task for divertor designers. In recent years, advanced physics simulations of the p...

Abstract: In the framework of the study of a European helium cooled lead lithium blanket concept for ITER, numerical tools are developed to complement experimental activities. Full capability to simulate num...

Abstract: The need to achieve increasingly better performance in present and future tokamak devices has made plasma control increasingly important in tokamak engineering. When high performance and robustness...

Abstract: The European HiPER project aims to demonstrate commercial viability of inertial fusion energy within the following two decades. This goal requires an extensive Research &Development program on materials for different applications (e.g., first wall, structural components and final optics). In this paper we will discuss our activities in the framework of HiPER to develop materials studies for the different areas of interest. The chamber first wall will have to withstand explosions of at least 100 MJ at a repetition rate of 5-10 Hz. If direct drive targets are used, a dry wall chamber operated in vacuum is preferable. In this situation the major threat for the wall stems from ions. For reasonably low chamber radius (5-10 m) new materials based on W and C are being investigated, e.g., engineered surfaces and nanostructured materials. Structural materials will be subject to high fluxes of neutrons leading to deleterious effects, such as, swelling. Low activation advanced steels as well as new nanostructured materials are being investigated. The final optics lenses will not survive the extreme ion irradiation pulses originated in the explosions. Therefore, mitigation strategies are being investigated. In addition, efforts are being carried out in understanding optimized conditions to minimize the loss of optical properties by neutron and gamma irradiation

Abstract: Tritium permeation through erbium oxide coatings has been modeled on the basis of experimental results. Permeation models were constructed step-by-step by the introduction of the following predomin...

Abstract: The Thermal Cycling Absorption Process (TCAP) was further studied with a new configuration. Previous configuration used a palladium packed column and a plug flow reverser (PFR). This new configuration uses an inverse column to replace the PFR. The goal was to further improve performance. Both configurations were experimentally tested. The results showed that the new configuration increased the throughput by a factor of more than 2.

Abstract: Most published results concerning deuterium-hydrogen fractionation in plants are in the range 08-1, indicating no bioaccumulation of the heavy isotope In spite this, an updated compilation of litterature data show that 77% of OBT/TFWT ratios measured in terrestrial plants and food items are greater than one, with a mean value of 192 On the other hand, OBT/TFWT ratios for aquatic samples do not show such a tritium anomaly, with 81% of the published ratios being less than 1 This strongly suggests that the cause for excess tritium in terrestrial organic matter has to be found in the atmosphere We have developed a simple model of tritium incorporation during plant growth, forced by the annual cycle of tritium in precipitation taken from the IAEA/ISOHIS database The simulated distribution of the OBT/TFWT ratios for terrestrial samples shows many similarities with the observed one Although other processes such as soil moisture with lower tritium content than atmospheric water vapour can be invok

Abstract: The main goal of the carried out investigations was to examine behaviour of hydrogen isotopes (and evaluation of interaction parameters such as coefficients of diffusion, permeation and solubility)...

Abstract: Several commercial computational fluid dynamics (CFD) codes now have the capability to analyze Eulerian two-phase flow using the Rohsenow nucleate boiling model. Analysis of boiling due to one-side...

Abstract: The centering of an ignition target capsule strongly depends on high-quality “tents” with closely matched mechanical properties. The relevant properties are tent stiffness and relaxation behavior. Tent stiffness is matched by choosing tents of equal thickness. Here, we describe recent advances in tent fabrication that have increased the quality and production rate of tents. The most significant improvement comes from the use of a meniscus coater to produce Formvar tents of high uniformity and with good control of tent thickness and good yield. Other improvements include a switch to silicon wafers as deposition substrate and standardized tent holders. The improvements have resulted in a sixfold increase of the production rate while increasing the yield by a factor of 2, despite tighter quality control.

Abstract: IFE target designers must consider several engineering requirements in addition to the physics requirements for successful target implosion. These considerations include low target cost, high manufacturing throughput, the ability of the target to survive the injection into the fusion chamber and arrive in a condition and physical position consistent with proper laser-target interaction and ease of post-implosion debris removal. This article briefly describes these considerations for the Laser Inertial Fusion-based Energy (LIFE) targets currently being designed.

Abstract: R&D activities on the tritium storage and delivery system include the development of getter beds to increase tritium recovery and delivery performance, the investigation of tritium reaction characteristics with ZrCo metal-hydride, in-bed calorimetry as tritium measurement techniques, and the development of process design technologies for the storage and delivery system such as pump performance test and bed simulator. The current status of the R&D activities on these subjects is addressed in this paper.

Abstract: The theory of control of nonaxisymmetric perturbations is dominated by the wide sensitivity range of a tokamak plasma to externally produced magnetic perturbations. External perturbations are characterized by their normal magnetic field on the unperturbed plasma surface. The first spatial distribution of on the unperturbed plasma surface in a sensitivity series is that distribution that at the smallest amplitude has a significant effect on plasma properties. The second distribution of in that series is the distribution to which the plasma has greatest sensitivity while being orthogonal to the first. Two distributions are orthogonal if the integral of their product over the unperturbed plasma surface is zero. Only a limited number of distributions in the sensitivity series can be driven to an unacceptable amplitude by credible construction errors in ITER. Essentially any external coil set that produces a nonaxisymmetric magnetic field of adequate strength with a controllable toroidal phase can null...

Abstract: Abstract Applying a tritium tracer technique, we have investigated hydrogen plasma driven permeation (PDP) through tungsten (W) near room temperature. The technique was confirmed to give reliable data on diffusion and permeation coefficients of pure W for gas driven permeation (GDP), and then it was applied to observe PDP in W near room temperature. It was found that PDP in earlier phase was controlled by diffusion giving reliable diffusion coefficients. Taking literature data at higher temperatures and present ones near room temperature determined from PDP into account, we have proposed new diffusion coefficients DUpper limit = (3.8±0.4)x10-7 exp ((-39.8±1.5) (kJ/mol)/RT), m2s-1. (1) The activation energy for permeation determined by PDP was similar to that by GDP. The extrapolation of the present data to higher temperature agreed well with Frauenfelder’s data, suggesting the activation energy of around 65 kJ/mol for permeation is quite reasonable. However prolonged measurements resulted in significant reduction of PDP. The cause of the reduction was attributed to the increase of reemission owing to surface cleaning and/or roughening by incidence of energetic hydrogen.

Abstract: In a Dual-Coolant Lead-Lithium (DCLL) blanket, tritium losses from the PbLi into cooling helium streams may occur when the liquid-metal breeder is moving in the poloidal ducts. Quantitative analysi...

Abstract: The experimental industrial plant for hydrogen isotope separation on the basis of the Combined Electrolysis and Catalytic Exchange (CECE) process has been operating safely and reliably for 15 years...

Abstract: As the new research plan of Plasma Research Center of the University of Tsukuba, we are planning to start a study of divertor simulation under the closely resemble to actual fusion plasmas environm...

Abstract: This lecture was given at the 4th ITER International Summer School in May 2010 to describe the broad research program on feedback control of magnetohydrodynamic (MHD) stability performed by the rev...

Abstract: Important advances have been made recently in the invention and application of experimental methods to control the sawtooth instability in tokamak plasmas. The primary means of control involves the application of either ion cyclotron resonance heating (ICRH), or electron cyclotron heating, with resonance very close to the q = 1 radius in the plasma core. Reported here are experiments that have successfully applied these methods to either shorten or lengthen the sawteeth deliberately, in a variety of plasma conditions, in three tokamaks: Joint European Torus (JET), TCV, and Tore Supra. It is shown that despite the sensitivity of the sawtooth period to the resonance position, sawteeth can be controlled using either real-time control of the electron cyclotron deposition, or in the case of ion cyclotron heating, very careful adjustment of the magnetic field strength and minority ion concentration. The latter technique has been guided by theoretical advances that have enabled the control of sawteeth in JET with ITER-relevant ICRH scenarios.