Introduction The reference design of the residual ion dump (RID) for the ITER neutral beam injection (NBI) system is based on an electrostatic deflection of the residual negative and positive ions to in-line dump panels . According to 4-channels beam line concept, RID forms four narrow (about 100 mm in width) vertical channels with the aid of 5 panels (1.8 m long and 1.7 m in height). Two middle panels are negatively biased with about 20 kV. This concept has the advantage of compact design with quite moderate power density (PD) load onto the panels – peak PD is less 8 MW/m. However, such a concept has never been tested in any working NBI system, all of them. use magnetic deflection systems with remote ion dumps. Experimental investigation of the electrostatic RID concept is now started at the test stand IREK in the Kurchatov Institute. This experiment uses positive ion beam and two panels (one panel is under negative potential) which simulate the RID channel. In the ITER beam line the RID has to work in the presence of stray magnetic field with mainly vertical component, so the main physical question is in secondary electrons production and their behaviour in the crossed electric and magnetic fields, that can have an influence on the high voltage holding and state of operability. Hence, the experimental device panels are placed inside a special magnetic system which produces rather uniform vertical magnetic field in the RID volume. System Description Layout of the experimental injector stand IREK – T-15 injector prototype – is shown in Fig.1. The RID is mounted on a place of a previously used deflecting magnet.

Some results are presented for single-particle analysis of a plasma optical mass separator, applicable to the possible separation of a multicomponent ion beam, including chemical elements of nuclear reactor spent fuel in a wide range of mass numbers (M-components).

We present the results of experimental investigations of heat exchanging in a cylindrical tube heated on one side by beams of charged particles (electrons) with a high density of thermal energy. Heat removal is made by a water stream, twisted by a screw insert, having the mass velocities in the range ρw = 1870−8900 kg/(m2·sec). The experiments were carried out on a fragment of the tube in the receiver of the beams of deviated ions in the system of injection of a T-15 tokamak. The bank of experimental data includes 510 points. It is shown that under the conditions of heat removal by the twisted flow with the coefficient of twisting k = 0.897 and subcooling ~170°C the density of the flux removed can attain ~100 MV/m2 in the case of long-pulse heating. It is noted that with the number of cycles of about 70 the fatigue destruction of the surface occurs.

The results of experimental studies of the heat exchange crisis in a strongly subcooled water flow under single-sided heating are given. The studies were done with the fragments of beam dumps from the fusion facility injection system. Description of a technique for identifying an instant of the heat exchange crisis start-up is given. An empirical relationship for critical heat loading has been produced.

Abstract Some features of the heat exchange in the beam dumps in the injection systems of fusion facility are described. Experimental data on the heat exchange under boiling, their processing techniques and a mathematical conjugate heat conduction model are given. Empirical relationships representing the heat exchange under surface and film boiling of a subcooled water flow are produced.

For the creation of serviceable designs of technical means for removing driven by various sources high-intensive heat fluxes with arbitrary spatial-temporal distributions, the method of adiabatic cross-section is proposed for calculating sets of long thin-walled pipes with an arbitrary cross-section cooled by the forced coolant flow and supplied with the heat exchange intensifiers.The arguments in support of the technique feasibility and conditions for its applicability to solve definite engineering tasks are given. The adiabatic cross-section technique efficiency is provided by an organic insertion of experimental correlations, representing the thermophysical heat exchange process parameters with a subsequent analysis of the serviceability and service lives of the structures under design, into a corresponding numerical model composed of a reduced sequence of solutions for thermomechanical plane problems of the mathematical physics.Specific features of the technique are seen in calculations of the thermophysical and thermostrength parameters of heat-removing elements in the beam dumps within the injection plasma heating system of the experimental fusion reactor ITER.The results of calculations are illustrated with distributions of the thermophysical and thermostrength parameters at the most-heat-stressed cross-sections in heat-removing pipes of the calorimeter flaps under the stationary injection conditions.

The results of the heat exchange experimental studies in a cylindrical pipe under single-sided heating with beams of charged particles (electrons) of high density of thermal energy are presented.The heat removal realized by a straight fluid flow, as well as by a twisted with a screw conveyer insertion one, strongly subcooled below the saturation temperature is presented.The experiments were done with a pipe fragment of the beam collector of the T-15 tokamak injection system. An experimental correlation. to a curve of boiling, being a part of the adiabatic cross-section technique for calculating the heat removal parameters in multichannel of high power beams dumps (V.K. Naumov et al., Plasma Devices and Operations, 8, 1999), is presented.It is shown that the removed thermal flux density can attain similar to 100 MW/m(2) under the long-pulse heating (similar to 120 s) and under heat removal conditions with the twisted under heated flux of N 170 degrees C. It should be noted that the fatigue surface destruction takes place after 70 cycles of loading with the mentioned fluxes.

The results of calculations aimed at the choice of the design conditions of the heat removal from heat-accepting elements of the ITER neutral beam injection system's beam dumps are given. The results for the neutral deuterium beam system rated for the power of 16.7 MW are presented as distributions of thermophysical and thermal strength parameters in the most heat-stressed cross-sections of the heat-accepting tubes of the calorimeter flaps under stationary injection conditions.

The closed analytical solution to the problem of determining quasi-static thermoelastic stresses in circular cross-sections of heat-removing cooled elements of the beam dumps in T-15-tokamak injection system is given. The generalized analytical representation of a tangential component in the tensor of thermoelastic stresses at the borders of the pipe cross-section is given. It is realized by the non-stationary field temperature distribution in the structural material, produced from the corresponding boundary conditions of heating. The results of comparison between the distributions of a tangential component in the thermoelastic stress at the borders of the most heat-stressed cross-section of a heat-removing pipes of the beam dump in T-15 injector (calculated by the suggested relationships) in the process of heating tor 1.5 s. by the ion beam pulse are considered. They are accompanied by the corresponding calculations of the mentioned stresses on the basis of the generally-accepted approximation [1] produced from the solution to the stationary heat conduction problem.

Abstract An expansion of a numerical model for the method of adiabatic cross-section developed previously to study the pulsed asymmetric heating of pipes by an external heat flux’ for the conditions of stationary heating is given to calculate therraophysical parameters of cooled pipes containing twisted tapes. Introduction of the generalized parabolic temperature distribution across the wali matched with conditions of heating and cooling of the pipe cross-section allowed to retain a two-dimensional diagram. Adeauate stationary distributions of thermophysical parameters have been obtained by a time-limited transition for the processes of heating and cooling. The proposed modification for the technique of adiabatic cross-sections is illustrated by the results of calculations for the expected distributions of thermophysical and strength parameters in pipe cross-sections containing heat-exchange intensifiers twisted tapes within the collector of deviated ions in the T-15 tokamak injection system under possible stationary ion beam effect at a maximum heat power density of about 8 kW/cm2. Key Words: power densityadiabatic cross-sectionsstationary heat fluxfinite difference diagramunbended pipe.

(1995). Model heating of the injection system beam receptacle fragments in fusion facilities by the scanning electron beam in the studies of critical thermal operating conditions. Plasma Devices and Operations: Vol. 4, No. 2, pp. 91-100.

(1995). Finite-difference approximation of the adiabatic cross-section technique in a numerical analysis of the single-side heating process of a cooled pipe with the twisted tapeinside by an external heat flux pulse. Plasma Devices and Operations: Vol. 4, No. 2, pp. 141-161.

Abstract The main statements of the model are formulated from the statement of a general problem on determination of a temperature field in the material of a finite length-pipe, single-side heated by an external quasi-stationary heat flux with the high power density, qm ≈10 MW/m2, and with the heat removal by a coolant from the parts of wetted pipe cross-section perimeter in the surface boiling regime, as well as under forced turbulent heat removal without phase transitions in the coolant. The obtained relationships are illustrated with the corresponding calculation for a cooper pipe, within a collector, with inserted twisted tape-heated by a pulse of critical heat flux from the directed ion beam, characteristic for the prescribed mode of operation under plasma heating by injection in T-15 tokamak.