Progress Report 2 Decisions and Models Lunar Surface Reactor Group October 25 2004 Massachusetts Institute of Nuclear Engineering Technology Department Lunar Surface Reactor Group Overview Schedule Original schedule November 3rd completion date for all models and decisions November 15th finished Except report Revised Schedule November 3rd completion date for all models and decisions Finish November 22nd Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 2 CORE Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 3 Core Current Status Decisions made Zr3Si2 reflector material Pin fuel elements Decisions to be made this week Heat pipe coolant Bounds of operating temperature Bounds of geometry Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 4 Core Schedule Memo Method of Reflection 27 Oct Memo Structural Materials 28 Oct Deliver Bounds for Geometry Shielding 1 Nov Memo Bounds for Geometry mass 1 Nov Deliver Core Thermo hydraulics PCU 1 Nov Memo Control Mechanisms 3 Nov Memo Core Thermo hydraulics 3 Nov Memo Preliminary Model 3 Nov Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 5 Core Schedule Post Nov 3rd Accident analysis Launch accidents Feedback coefficients Power transients Spatial Model Report Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 6 PCU Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 7 PCU Current Status Decision Thermionics Inlet temperature 1800K Outlet Temperature 950K Progress Thermionic model inlet outlet temperature vs efficiency Balance between decent radiator size and generated power Heat Pipe model Heat pipe configuration to ensure 100kWe at appropriate temperature Issues to be resolved Power Transmission DC to AC conversion Heat Exchanger ISRU Needs 1800K Core Temperature verification Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 8 PCU Decision Methodology Brayton Sterling Thermionics Actual PCU 2 1 3 Outlet Temperature 3 3 3 Peripheral Systems i e Heat Exchangers A to D converter 1 1 1 Robust to forces of launch 1 2 3 Fits in rocket 3 3 3 Controllable 1 14 2 2 2 Moving Parts 1 2 3 Radiation Resistant 2 3 1 Single Point Failure 1 2 3 Proven System 2 2 2 Inlet Temperature 3 3 1 23 77 26 55 28 51 Small Mass and Size Cost 1 35 Launchable Accident Safe 1 13 High Reliability and Limited Maintenance 1 00 Total Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 9 PCU Schedule Deliverables Memo PCU Options Memo PCU Type Deliver Output Temperatures Approximation Radiator Deliver Preliminary Lunar Analysis of PCU Radiator Core Memo Scaling Options Memo Scalability Analysis for Mars Radiator Core Memo Detailed Design Piping Vessel Materials Lunar Mars Finished 1st Draft Will meet Nov 3 Post Nov 3 Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 10 Radiator Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 11 Radiator Current Status Research of thermal properties of lunar and Martian environments Programming of model for thermal calculations Tabulation of the thermal and mechanical properties of structural and functional materials Compilation of all potential radiator concepts Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 12 Radiator Schedule Application of mission specific design restrictions to list of radiator concepts Oct 27th Choice of materials and general structural design Oct 29th Modeling of radiator concepts Nov 3rd Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 13 Shielding Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 14 Shielding Current Status Gamma and neutron spectrum still unknown so have the following contingencies UPDATE 10 24 first spectrum estimate available Neutron flux 7 105 neutrons cm2 sec and thermal Neglect neutron shielding because reactor dose is less than GCR dose Neutron flux 7 105 neutrons cm2 sec but thermal Use boron 10 Neutron flux 7 105 neutrons cm2 sec but fast Use neutron absorbing metal hydride e g LiH BH 3 Gamma shielding Use lead unless neutron shield is too heavy If neutron shield is too heavy use cadmium for neutron and gamma attenuation If neutron gamma shield too heavy use surface Moon silicon oxides Mars iron oxides both have similar macroscopic gamma interaction cross sections Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 15 Shielding Schedule Choose geometry Ideally use hemispheric shell If too heavy use cylindrical shell and leave axial side unshielded If both too heavy bury core If burying core is unfeasible for other engineering conditions use cylindrical shell with exclusion zone Choose material based on above considerations in light of newly available spectrum After above decisions perform analysis with core group for shield s impact on reflection and leakage characteristics may occur after 11 3 Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 16 LSR Group Expanding Frontiers with Nuclear Technology The End Massachusetts Institute of Nuclear Engineering Technology Department LSR Group 10 25 2004 Slide 17