Target Development Facility Research Articles

Offline 2, ISOLDE’s target, laser and beams development facility

Offline 2 is an entirely new research and development mass separator laboratory for the ISOLDE facility located on the Meyrin site of CERN. It closely resembles beam production (for non-radioactive beams) of the on-line (radioactive) systems at ISOLDE with machine versatility and flexibility at the core of its design. The beam optics and down stream beam preparation can deliver bunched beams or continuous beams of negative or positive ions with kinetic energies up to 60 keV. The mass resolving power of the separator operating with a typical ISOLDE ion source is R∼500. All of this is housed within a highly accessible 125 m2 work area with multiple beam optics instruments to determine the beam quality, quantify modifications, develop new technologies and create alternate beam tunes, with the purpose of improving the beams and targets used during on-line operations.

Radiological Dose Calculations for the Diode Region of the Light Ion Fusion Target Development Facility

Biological dose rate calculations have been performed for a point external to the diode vacuum casing of the proposed Light Ion Fusion Target Development Facility for times following an operational period of 1 month. The primary diode material considered is Type 304LN stainless steel, with an alternative material of Al-6061-T6. Using a realistic pulse-sequence calculation scheme to account for the pulsed operation mode of the facility, it is shown that for both the stainless steel and aluminum diodes the dose rates external to the diode vacuum casing are >1 rem/h after a 1-day shutdown period. After a 1-week shutdown period, the dose rates have dropped to 90 and 12 mrem/h, respectively.

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.

Activation studies of the light ion beam target development facilitiy

Biological dose calculations have been performed for the target chamber of the Target Development Facility (TDF). Placement of a neutron moderator structure in the interior of the target chamber for the moderation of the high energy neutrons has been investigated as a viable option for lowering the biological dose rates of the chamber wall materials, Al 6061-T6 and 2¼Cr-lMo steel. Two moderator materials are considered, one made of H-451 graphite and the other of titanium hydride. In particular, a 40% porosity, 1 m thick graphite structure within the aluminum wall reduces the dose rate at the chamber wall outer surface to 13.1 mrem/h at 1 week after shutdown as compared to 1.29 rem/h without the moderator. A suitable maintenance schedule based on the 40% porosity graphite moderator design and on the allowable average dose of 1.25 rem per quarter is presented.

Fatigue Strength Analysis of the Sandia Target Development Facility Reaction Chamber

The Target Development Facility (TDF) reaction chamber will be subjected to a mechanical shock from the cavity gas after each target ignition. This impulsive pressure produces transient stresses in the cylindrical shell wall which are characterized by an oscillatory response with decreasing amplitude. Such fluctuating stresses may fatigue the wall material and limit the useful lifetime of the chamber. Lifetime estimates have been determined and comparisons are made for chambers with different sizes, alloys and target yield.

Radioactivity in the Light Ion Fusion Target Development Facility

Radioactivity and biological dose calculations have been performed for the target chamber of the Target Development Facility (TDF). Two conventional shield designs are considered. One has the target chamber submerged 3 m from the surface of a borated water pool, the other has the chamber surrounded by approximately 250 cm of concrete. The first wall materials, Al-6061 and 2-1/4 Cr-1 Mo steel and the ion beam targets, one made from BeO/sub 2/ and W and the other from CH/sub 2/ and Au, are investigated. Shielding designs are presented that reduce the dose from each of these choices of shield, first wall and target material to acceptable levels.

Light Ion Fusion Target Development Facility Preliminary Design

Light Ion Fusion Target Development Facility Preliminary Design

Target Explosion Generated Fireballs in the Nitrogen Filled Target Chamber of the Light lon Fusion Target Development Facility

Molecular nitrogen is a possible choice for the target chamber gas in the light ion beam driven target development facility. The response of a nitrogen target chamber gas to fusion target explosions is considered. Targets with yields of 200 MJ, 400 MJ and 800 MJ are considered for a target chamber 3 m in radius and 6 m high which is filled with nitrogen gas at a density of 7.07 X 10/sup 17/ molecules/cm/sup 3/. The soft x-rays and ions from the explosion of these targets are stopped in short distances in this gas and create a hot spherical fireball in the center of the target chamber. Heat fluxes and shock pressures on the target chamber first walls due to these fireballs are presented and nitrogen is shown to be an acceptable cavity gas from the point of view of first wall loading.

Dynamic Stress Analysis of Light Ion Fusion Target Development Facility Reaction Chambers

Preliminary structural analysis and design is presented for the reaction chamber of a preconceptual light ion beam target development facility (TDF). The chamber consists of a capped, reinforced cylindrical shell submerged in a water shield. Axisymmetric response is determined for blast waves generated by target ignition. From the analysis, design curves are developed for dynamic displacements and flexural stresses of the shell wall. It is shown that the added mass effect of the water can substantially reduce the response and that a practical design is possible for a range of geometric parameters and materials.

Neutron Activation and Shielding of the Light ion Fusion Target Development Facility

Neutron Activation and Shielding of the Light ion Fusion Target Development Facility

First Wall Materials Selection in the Light ion Beam Target Development Facility

The choice of material for the first wall of the Light Ion Beam Target Development Facility is discussed. Materials considered are Al 6061, Al 5086, 304 stainless steel, HT-9 (ferritic steel), Ti-6A1-4V, Cu-Be C17200, and Cu-Be C17600. The thermal response, mechanical response and induced radioactivity in first walls made of each of these materials are calculated. Minimum thicknesses of these walls are determined and cost estimates are made for the material requirements for each wall. Finally Al 6061 is suggested as the best choice of first wall material.

Light lon Fusion Target Development Facility Pre-Conceptual Design

The light ion fusion target development facility will be used to test high yield ICF targets (50200 MJ) at the rate of 10 shots per day. The 6 meter diameter cylindrical target chamber is designed as a first wall supported by a structural frame and is capable of withstanding 15,000 full yield shots over a 5 year lifetime. It is made from Al 6061, thus greatly reducing induced activity. The chamber is shielded by a water pool to allow easy access.