Final 3-D Neutronics Results
ARIES Electronic Project Meeting
December 4, 1998
Radiation Streaming Through NBI
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- 2 NBI's were included in 3-D model
- NBI sets on insulator between upper and middle TF-coil shells
- Neutrons streaming through NBI will induce swelling in insulators
- Swelling depends on insulator type and fluence level
- Spinel has high radiation resistance to swelling (compared to BeO, Al2O3, MgO)
- 1022n/cm2 fast n fluence (En> 0.1 MeV) results in 1% swelling in spinel
- 3-D calculations indicate that fast n flux (En> 0.1 MeV) at insulator is 5x1012 n/cm2s, resulting in < 1% swelling at end of plant life (40 FPY). This means spinel will exhibit no significant change in volume and will not cause any stress problem to TF-coil shell.
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50 cm thick shield should surround NBI ducts to attenuate streaming
radiation