Three-Dimensional Thermal and Structural Analysis of the First Wall in the SIRIUS-P Reactor

Elsayed A. Mogahed

Fusion Science and Technology | Volume 26 | Number 3 | November 1994 | Pages 891-895

Inertial Confinement Fusion Reactor, Reactor Target, and Driver | Proceedings of the Eleventh Topical Meeting on the Technology of Fusion Energy New Orleans, Louisiana June 19-23, 1994 | doi.org/10.13182/FST94-A40267

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The thermal-structural behavior and performance of the SIRIUS-P power reactor first wall concept is analyzed. The SIRIUS-P conceptual design study is of a 1.0 GWe laser driven inertial confinement fusion power reactor utilizing near symmetric illumination of direct drive targets. Sixty laser beams providing a total of 3.4 MJ of energy are used at a repetition rate of 6.7 Hz with a nominal target gain of 118. The spherical chamber has an internal radius of 6.5 m and consists of a first wall assembly made from carbon-carbon composite material, and a blanket assembly made of SiC composite material. The chamber is cooled by a flowing granular bed of solid ceramic materials, non-breeding TiO₂ for the first wall assembly and breeding Li₂O for the blanket assembly. Helium gas (P = 0.15 MPa) is used in a fluidized bed outside the reactor to return the particles to the top of the reactor. A moving bed is chosen over a fluidized bed because of its superior heat transfer capability. The heat transfer in a moving bed depends on the level of agitation and on the effective thermal conductivity of the solid material and the interstitial gas, whereas in a fluidized bed, it is entirely dominated by the thermal conductivity of the carrier gas. This work describes the three-dimensional thermo-structural steady state analysis of the first wall coolant tubes. The performance of the first wall depends, under normal operating conditions, on the thermal loading conditions and internal coolant pressure loading conditions. The analysis utilizes a commercial finite element analysis code with complete 3-D modeling. The analysis shows that the stresses are dominated by bending due to the internal pressure of the He gas; modifying the shape of the tube from purely elliptical at the midplane, while keeping the flow area constant, reduces the stresses. A comparison between the results of this 3-D model with a previous 2-D study shows a pronounced effect on the temperature distribution. On the other hand, the 3-D model has a smaller effect on the stress distribution. In general the design examined is shown to be capable of withstanding the loading conditions imposed, although the effect of such factors as pulsed or partially loaded operation should be carefully examined.