ESA Document - Emits - ESA

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Liquid Metal cooled
thermoelectric reactor
Table 6-1: Comparison of basic reactor design choices
6.4 Radiation protection and shielding issues
Gas-cooled particle bed
Brayton reactor
Electric power [kW] 50 50
Thermal power [kW]
(efficiency in %)
Core mass (fuel mass) [kg] 186 (54)
1250 (4%) 185 (26.9%)
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 406 of 422
1075 (93)
(rad refl. Be: 622 kg)
(axial refl. BeO: 218 kg)
Power conversion [kg] 371-712 340
Radiator mass [kg]
718
(steel: 618 kg)
(mercury: 100 kg)
Packaging [kg] 111-180 250
Total Mass [kg] 1386-1796 1665
Size (diam/height) [m]
Core: 0.45/0.6
Conv.Syst: 0.5/0.4
Both designs make use of Martian regolith for additional shielding purposes. For the purpose of
this preliminary assessment, an all-side shielding requirement is assumed together with an
acceptable dose limit at about 100 metres from the reactor site. According to preliminary
calculations such a shield would need about 10 tonnes of Martian regolith, distributed in an
about 5 metre radial layer and an about 3 metre axial (assuming a cylindrical reactor core) layer.
Options of using locally produced binding materials and deepening the core into an (artificial)
hole need to be further explored.
An example for a buried reactor core with a subsurface heat rejection unit is shown in Figure
6-1.
n/a
Core: 0.8(0.17)/1.5
Conv.Syst: 0.8/1.2