Modeling of thermal properties of a TeO2 target for radioiodine production
| Autor: | M Rajčević, D Košutić, J. J. Čomor, Ž Stevanović |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Nuclear and High Energy Physics
Thermodynamic equilibrium Prandtl number Thermodynamics thick target tellurium oxide helium 010403 inorganic & nuclear chemistry 7. Clean energy 01 natural sciences 030218 nuclear medicine & medical imaging 03 medical and health sciences symbols.namesake 0302 clinical medicine Thermal conductivity Thermal Fluid dynamics Instrumentation Physics iodine cooling of target Mechanics Nusselt number 0104 chemical sciences Boundary layer Heat flux symbols |
| Zdroj: | Nuclear Instruments and Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment |
| ISSN: | 0168-9002 |
| DOI: | 10.1016/j.nima.2003.11.147 |
| Popis: | Three radionuclides of iodine (I-121, I-123 and I-124) are of great interest for modern nuclear medical diagnostics. They can be all produced by the (p,n) nuclear reaction using isotopically enriched solid TeO2, targets. The produced radioiodine can be rapidly separated from the target material by dry-distillation from the melted target after the irradiation. Since TeO2 has low thermal conductivity, the most critical issue in the design of a production target is the provision of its effective cooling in order to avoid melting of the oxide layer during the irradiation. A compact solid target irradiation system (COSTIS) has been designed for the irradiation of TeO2 targets, suitable for routine production of radioiodine. The target is a circular Pt-disk that carries the TeO2 melted into a circular grove in the center of the disk. The target coin is manually inserted into COSTIS, fixed pneumatically in the irradiation position, released remotely after irradiation and falls down driven by gravity into a transport container. The engineering design of the cavity for helium cooling of the front face of TeO2 and the impinging water jet cooling the back face of the target disk was done based on a simulation of the thermal behavior of the target during the irradiation. A straightforward numerical method for the prediction of the thermal properties of the solid target has been developed. The approach is based on calculations without using the common practice of Prandtl and Nusselt empirical correlation. The fluid flow description in the boundary layer was refined in such a way, that the heat flux, exchanged between the solid and fluid, is obtained directly from Fourier law. The governing equations are based on the local thermodynamic equilibrium and conservation equation of mass, momentum and energy. In order to solve the set of governing equations, the finite-volume method is used. This procedure gives rapid answers whether the proposed geometry satisfies the design criteria. (C) 2003 Elsevier B.V. All rights reserved. 21st World Conference of the International-Nuclear-Target-Development-Society, Nov 04-08, 2002, Argonne, IL |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect