Radiation shielding mass saving for the magnet coils of the VISTA spacecraft

• Published in: Annals of nuclear energy Vol. 26; no. 6; pp. 509 - 521
• Main Authors: Sahin, S, Sahin, H M
• Format: Journal Article
• Language: English
• Published: 01.04.1998
• ISSN: 0306-4549

Radiation shielding structure of a design concept with inertial fusion energy propulsion for manned or heavy cargo deep space missions beyond earth orbit has been investigated. Fusion power deposited in the inertial confined fuel pellet debris delivers the rocket propulsion with the help of a magnetic nozzle. The nuclear heating in the superconducting magnet coils determines the radiation shielding mass of the spacecraft. It was possible to achieve considerable mass saving with respect to a recent design work, coupled with higher design limits for coil heating (up to 5 mW/cm super(3)). The neutron and gamma -ray penetration into the coils is calculated using the S sub(N) methods with a high angular resolution in (r-z) geometry in S sub(16)P sub(3) approximation by dividing the solid space angle in 160 sectors. Total peak nuclear heat generation density in the coils is calculated as 3.143 mW/cm super(3) by a fusion power of 17 500 MW. Peak neutron heating density is 1.469 mW/cm super(3) and peak gamma -ray heating density is 1.674 mW/cm super(3). However, volume averaged heat generation in the coils is much lower, namely 74, 163 and 337 mu W/cm super(3) for neutron, gamma -ray and total nuclear heating, respectively. The net mass of the radiation shielding for the magnet coils is 200 tonne by a total mass of 6000 tonne of the spacecraft.