Confinement Fusion Facility Research Articles

Influence analysis on main part stiffness in the mirror array system about the mirror rotation angle

Abstract The mirror array system is widely used in the large-scale inertial confinement fusion (ICF) facility. The rotation responses of array mirrors have a great influence on the beam drift stability of the ICF facility, while the stiffness of each component in the mirror system has a different effect on the rotation response of the mirrors. Here, we perform the sensitivity analysis on the stiffness of the main part to investigate the rotation angle of a typical 2×2 mirror array system forced by a broadband ambient random vibration. According to the sensitivity analysis results, an improved mirror array system is obtained. Subsequently, the dynamic simulation is carried out on the new system. The simulation results show that the rotation root mean square (RMS) response of the improved mirror system is about reduced 50 %, indicating that a better stability can be achieved in the new system. This study presents a way for the stability design of the mirror array system in a large scale ICF facility.

Untrafast smoothing scheme based on dynamic interference structure between beamlets of laser quad

Aiming at the high requirements for illumination uniformity on the target in laser-driven inertial confinement fusion (ICF) facilities, an ultrafast smoothing method based on dynamic interference structure between beamlets of a laser quad is proposed. The basic principle of this scheme is to use a conjugate phase plate array to add the conjugate phase modulation to the multiple beamlets of a laser quad with a certain wavelength difference. Consequently, every two beamlets are coherently superposed in the far field to generate a dynamic interference pattern, resulting in the fast redistribution of the speckles introduced by continuous phase plate inside the focal spot and further improving the illumination uniformity on the target on a picosecond timescale. The coherent beamlets with a certain wavelength difference can be generated by using a broadband seed laser. Taking the laser quad of the typical ICF facilities for example, the physical model of the ultrafast smoothing method based on dynamic interference structure of beamlets is built up. The influences of the phase-plate type, the peak-to-valley value of the phase modulation and the wavelength difference between the beamlets are analyzed quantitatively, and the smoothing characteristics of the focal spot are discussed in detail and compared with those from the traditional temporal smoothing scheme such as smoothing by spectral dispersion. The results indicate that the directions of the moving speckles in the focal spot are determined by the phase-plate type. However, the required time to achieve stable illumination uniformity, i.e, the decay time, is determined by the wavelength difference between the beamlets. Moreover, the illumination uniformity on the target becomes better with the increase of peak-to-valley value of the phase modulation at first and then remains almost the same. Thus, the ultrafast smoothing method based on dynamic interference structures with well-designed phase arrays and wavelength combinations of the beamlets can realize the multi-directional and multi-dimensional speckle sweeping inside the focal spot, and further improving the irradiation uniformity on the target within several picoseconds or sub-picoseconds. Combining with the traditional beam smoothing scheme, better illumination uniformity can be achieved on an ultrashort timescale. This novel scheme can be used as an effective supplement to the existing temporal beam smoothing techniques.

Neutron activation analysis for cement elements using an IECF device as a high energy neutron source

In this study, Neutron Activation Analysis (NAA) for cement elements using an Inertial Electrostatic Confinement Fusion (IECF) facility as a high energy neutron source is investigated.

Design of Transport Beams Arrangement in Target Area of SG-III Facility

In target area of Inertial Confinement Fusion (ICF) facility, the rectangular beams arrangement at the main amplifier (MA) output is mapped to the spherical-geometry beams configuration near the target chamber. The beams are imported into the final optical assemblies with special angles. In this paper, the transport beams arrangement design of SG-III facility is described. Firstly, the primary requirements of the transport beams arrangement in ICF target area system are given. Then the typical transport beam pathway from the MA output to the target chamber center is analyzed. The general layout, beams path length, and the parameters of transport mirrors are discussed for the transport beam arrangement.

Cryogenic fuel targets for inertial fusion: Optimization of fabrication and delivery conditions

The paper addresses the main problems associated with the fabrication of cryogenic fuel targets and their delivery to the irradiation zone of an inertial confinement fusion (ICF) facility. Optimal solutions of these problems have been developed at the Lebedev Physical Institute for the case of free-standing direct-irradiation cryogenic targets. In contrast to the traditional technology, the approach proposed and demonstrated is shown to conform to all requirements of the current ICF program: (a) quality of fuel layering, (b) stability of layering, and (c) minimization of tritium inventory. This technology is the basis for a designed device of introducing cryogenic targets into the chamber of an ISKRA-6 high-power laser facility being developed in Russia.

Adaptation of selected diagnostic techniques to magnetic confinement fusion experiments

The paper concerns several diagnostic techniques, which have been used in pulsed-power plasma experiments, i.e. Plasma-Focus and Z-Pinch devices, and which can be adapted to studies of Magnetic Confinement Fusion (MCF) facilities, e.g. Stellarators and Tokamaks. The application of Nuclear Track Detectors (NTDs) for time-integrated ion measurements in MCF experiments is described and the use of such detectors for time-resolved ion measurements is discussed. The application of special Cerenkov-type detectors for time resolved measurements of fast runaway electrons is considered. Also discussed is the use of selected nuclear reactions for measurements of fusion products, e.g. fast neutrons.

Pulsed stress loading of bare ICF first walls

Abstract There is currently a great deal of uncertainty about the nature and magnitude of mechanical and thermal wall loading anticipated in future Inertial Confinement Fusion (ICF) Facilities. This uncertainty is aggravated by the fact that laser and heavy ion driven reactors will have a much different heat and shock loading than light ion driven systems. The purpose of this presentation was to quantitatively illustrate the differences that can occur in a laser driven facility versus one in which the targets are compressed by light ion beams. The laser driven SIRIUS-M technology test facility and the light ion driven Target Development Facility (TDF) were chosen as the base examples for this study. A few of their key parameters are listed below.

Geometrical, Spectral and Temporal Differences Between ICF and MCF Reactors and Their Impact on Blanket Nuclear Parameters

Geometrical and spectral differences between inertial confinement fusion (ICF) and magnetic confinement fusion (MCF) facilities lead to significant variation of up to ∼ 60% in peak values and profi...