Evaluation of the Neutron and Gamma-Ray Heating in the Radiation Shielding and Magnet Coils of the VISTA Spacecraft
Evaluation of the Neutron and Gamma-Ray Heating in the Radiation Shielding and Magnet Coils of the VISTA Spacecraft
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VISTA 航天器辐射屏蔽和磁体线圈中的中子和伽马射线加热评估
DOI：
10.13182/fst98-a41
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
A. Sözen
中科院分区：
文献类型：
--
作者：
S. Şahin;H. Şahin;A. Sözen
对用于地球轨道以外载人或重型货物深空飞行任务的惯性聚变能推进设计概念的基本核数据进行了评价。核聚变动力储存在惯性约束的燃料芯块碎片中，借助磁性喷管提供火箭推进力。磁喷嘴的超导磁体通过大规模屏蔽来保护免受中子和伽马射线辐射。在整个屏蔽过程中，由中子和伽马射线引起的核加热已经被计算出来。作为这一设计概念的一个关键问题，特别注意到在超导磁体线圈的核加热。在S16 P3近似下，利用具有高角分辨率的Sn方法，将空间角划分为160个扇区，计算了中子和γ射线在线圈中的穿透率。当聚变功率为17500 MW时，线圈中的总峰值核生热密度为64.5 μW/cm 3。峰值中子加热密度为30.8 μW/ cm 3，峰值γ射线加热密度为40.6 μW/ cm 3（在不同的点上）。然而，线圈中的体积平均热生成要低得多，即，中子、伽马射线和总核加热分别为2.17、8.49和10.66 μW/cm 3。圆锥形冷冻氢喷射剂通过中子在氢上散射并偏转到真空中，将流向航天器的中子减少了12.5倍，此外，空间中的几何中子通量衰减了1/r2，这些计算结果可以帮助提高星际空间运输应用设计概念飞行器的可信度。
Basic nuclear data for a design concept with inertial fusion energy propulsion for manned or heavy cargo deep space missions beyond earth orbit have been evaluated. Fusion power deposited in the inertial confined fuel pellet debris delivers the rocket propulsion with the help of a magnetic nozzle. The superconducting magnets of the magnetic nozzle are protected against neutron and gamma-ray radiation by a massive shielding. Throughout the shielding, the nuclear heating, caused by neutrons and gamma rays has been calculated. As a critical issue for this design concept, special attention is paid to the nuclear heating in the superconducting magnet coils. The neutron and gamma-ray penetration into the coils is calculated using the S n methods with a high angular resolution in r-z geometry in S 16 P 3 approximation by dividing the solid space angle in 160 sectors. Total peak nuclear heat generation density in the coils is calculated as 64.5 μW/cm 3 by a fusion power of 17500 MW. Peak neutron heating density is 30.8 μW/ cm 3 , and peak gamma-ray heating density is 40.6 μW/ cm 3 (on a different point). However, volume-averaged heat generation in the coils is much lower, namely, 2.17, 8.49, and 10.66 μW/cm 3 for neutron, gamma-ray, and total nuclear heating, respectively. A conically shaped frozen hydrogen expellant reduces the neutron streaming toward the spacecraft by a factor of ∼12.5 via neutron scattering on hydrogen and deflection into vacuum, in addition to the geometric neutron flux attenuation in space by 1/r 2 , The results of these calculations can help to increase the credibility of the vehicle for interplanetary space transport applications design concept.