Reduced shielding mass for the VISTA spacecraft
Küçük Resim Yok
Tarih
2002
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Springer Heidelberg
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
An innovative concept for the direct utilization of fusion energy with laser ignited (D,T) capsules for propulsion is presented with the so called VISTA (Vehicle for Interplanetary Space Transport Applications) concept. VISTA's overall geometry is that of a 50degrees-half-angle cone to avoid massive radioactive shielding. The 50degrees-half-angle maximizes the jet efficiency, and is determined by selecting the optimum pellet firing position along the axis of the cone with respect to the plane of the magnet coil. The pellet firing position is in the vacuum. Assuming a total fusion power production of 17 500 MW with a repetition rate of 5 Hz and 3500 MJ per shot, the propulsion power in form of charged particles has been calculated as similar to7000 MW, making similar to40% of the total fusion power. About 60% of the fusion energy is carried by the leaking neutrons out of the pellet. Most of them (96%) escape into vacuum without striking the space ship. Only 4% enter the frozen hydrogen expellant in the conical shape (about 50 gr.). Two design limits are discussed, 5 and 1 mW/cm(3). Total peak nuclear heat generation in the coils is calculated as 4.7 mW/cm(3). The peak neutron heating is 1.9 mW/cm(3) and the peak gamma-ray heating density is 2.8 mW/cm(3). However, volume averaged nuclear heat generation in the coils is much lower. It is calculated as 0.18, 0.48, and 0.66 mW/cm(3) for neutron, gamma-ray, and total nuclear heating, respectively. With higher design limits for nuclear heat generation in the coils and using natural lithium in the shielding, it was possible to reduce the net shielding mass from 595 tonne down to 170 tonne, making <3% of the vehicle mass, by a total vehicle mass of VISTA similar to 6 000 tonne.
Açıklama
Anahtar Kelimeler
space propulsion, fusion rocket, inertial fusion energy, (D,T) pellet, charged particles, frozen hydrogen expellant, magnetic nozzle, superconducting magnets, nuclear heating, neutron energy, gamma-ray energy, radiation shielding
Kaynak
Arabian Journal For Science and Engineering
WoS Q Değeri
Q4
Scopus Q Değeri
Cilt
27
Sayı
2A
