A review of in-pile fuel safety tests of TRISO fuel forms and future testing opportunities in non-HTGR applications

Innovative concept for an ultra-small nuclear thermal rocket utilizing a new moderated reactor

NEMO: A mission to search for and return to Earth possible life forms on Europa

The purpose of this study is to calculate radial void fraction distributions of equal sized spheres in annular packed beds (APBs) and to obtain a radial void fraction correlation from these distributions that can be incorporated in APB transport models.

Radial void fraction correlation for annular packed beds

NASA LeRC was selected to lead nuclear propulsion technology development for NASA Also participating in the project are NASA MSFC and JPL The US Department of Energy will develop nuclear technology and will conduct nuclear component, subsystem, and system testing at appropriate DOE test facilities NASA program management is the responsibility of NASA/RP The project includes both nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) technology development This report summarizes the efforts of an interagency panel that evaluated NTP technology in 1991 Other panels were also at work in 1991 on other aspects of nuclear propulsion, and the six panels worked closely together The charters for the other panels and some of their results are also discussed Important collaborative efforts with other panels are highlighted The interagency (NASA/DOE/DOD) NTP Technology Panel worked in 1991 to evaluate nuclear thermal propulsion concepts on a consistent basis Additionally, the panel worked to continue technology development project planning for a joint project in nuclear propulsion for the Space Exploration Initiative (SEI) Five meetings of the panel were held in 1991 to continue the planning for technology development of nuclear thermal propulsion systems The state-of-the-art of the NTP technologies was reviewed in some detail The major technologies identified were as follows: fuels, coatings, and other reactor technologies; materials; instrumentation, controls, health monitoring and management, and associated technologies; nozzles; and feed system technology, including turbopump assemblies

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Nuclear thermal propulsion technology: Results of an interagency panel in FY 1991

Design of particle bed reactors for the space nuclear thermal propulsion program

Despite decades of efforts to reduce rocket launch costs, improvements are marginal. Launch cost to LEO for cargo is ∼$10,000 per kg of payload, and to higher orbit and beyond much greater. Human access to the ISS costs $20 million for a single passenger. Unless launch costs are greatly reduced, large scale commercial use and human exploration of the solar system will not occur. A new approach for ultra low cost access to space—Maglev Launch—magnetically accelerates levitated spacecraft to orbital speeds, 8 km/sec or more, in evacuated tunnels on the surface, using Maglev technology like that operating in Japan for high speed passenger transport. The cost of electric energy to reach orbital speed is less than $1 per kilogram of payload. Two Maglev launch systems are described, the Gen‐1System for unmanned cargo craft to orbit and Gen‐2, for large‐scale access of human to space. Magnetically levitated and propelled Gen‐1 cargo craft accelerate in a 100 kilometer long evacuated tunnel, entering the atmosphere at the tunnel exit, which is located in high altitude terrain (∼5000 meters) through an electrically powered “MHD Window” that prevents outside air from flowing into the tunnel. The Gen‐1 cargo craft then coasts upwards to space where a small rocket burn, ∼0.5 km/sec establishes, the final orbit. The Gen‐1 reference design launches a 40 ton, 2 meter diameter spacecraft with 35 tons of payload. At 12 launches per day, a single Gen‐1 facility could launch 150,000 tons annually. Using present costs for tunneling, superconductors, cryogenic equipment, materials, etc., the projected construction cost for the Gen‐1 facility is 20 billion dollars. Amortization cost, plus Spacecraft and O&M costs, total $43 per kg of payload. For polar orbit launches, sites exist in Alaska, Russia, and China. For equatorial orbit launches, sites exist in the Andes and Africa. With funding, the Gen‐1 system could operate by 2020 AD. The Gen‐2 system requires more advanced technology. Passenger spacecraft enter the atmosphere at 70,000 feet, where deceleration is acceptable. A levitated evacuated launch tube is used, with the levitation force generated by magnetic interaction between superconducting cables on the levitated launch tube and superconducting cables on the ground beneath. The Gen‐2 system could launch 100’s of thousands of passengers per year, and operate by 2030 AD. Maglev launch will enable large human scale exploration of space, thousands of gigawatts of space solar power satellites for beamed power to Earth, a robust defense against asteroids and comets, and many other applications not possible now.

Maglev Launch: Ultra Low Cost Ultra/High Volume Access to Space for Cargo and Humans

The Compact MITEE-B Bomodal Nuclear Engine for Unique New Planetary Science Missions

The performance capabilities and technology features of ultra compact nuclear thermal rockets based on very high power density (30 Megawatts per liter) fuel elements are described Nuclear rockets appear particularly attractive for carrying out missions to investigate or intercept near-Earth objects (NEOs) that potentially could impact on the Earth Many of these NEO threats, whether asteroids or comets, have extremely high closing velocities, ie, tens of kilometers per second relative to the Earth Nuclear rockets using hydrogen propellant enable flight velocities 2 to 3 times those achievable with chemical rockets, allowing interaction with a potential NEO threat at a much shorter time, and at much greater range Two versions of an ultra compact nuclear rocket based on very high heat transfer rates are described: the PBR (Particle Bed Reactor), which has undergone substantial hardware development effort, and MITEE (MIniature ReacTor EnginE) which is a design derivative of the PBR Nominal performance capabilities for the PBR are: thermal power ≃1000 MW thrust ≃45,000 lbsf, and weight ≃500 kg For MITEE, nominal capabilities are: thermal power 100 MW; thrust ≃4500 lbsf, and weight ≃50 kg Development of operational PBR/MITEE systems would enable spacecraft launched from LEO (low-Earth orbit) to investigate intercept NEO's at a range of ∼100 million kilometers in times of ∼30 days

High‐Performance Ultra‐light Nuclear Rockets for Near‐Earth Objects Interaction Missions

A new ultra compact nuclear engine concept, MITEE (MI¯niature R_eactor E_nginE_), is described, and its performance evaluated for various solar system exploration missions The MITEE concept is based on the Particle Bed Reactor (PBR), with modifications that enable a smaller, lighter nuclear engine A range of MITEE Engine designs is described Representative design parameters for the baseline MITEE reactor are: 75MW(th) power level, 1000 second Isp, 100 kilogram mass, 10 MW/Liter fuel element power density, 39 cm core diameter/height Total engine mass, including turbo pump assembly, nozzles, controls, and contingency, is estimated to be 200 kilograms Using the MITEE engine, ultra fast, lightweight solar system exploration missions are enabled A range of such missions has been analyzed using the MULIMP code, and are described

George Maise

Papers

Design of particle bed reactors for the space nuclear thermal propulsion program

Maglev Launch: Ultra Low Cost Ultra/High Volume Access to Space for Cargo and Humans

The Compact MITEE-B Bomodal Nuclear Engine for Unique New Planetary Science Missions

High‐Performance Ultra‐light Nuclear Rockets for Near‐Earth Objects Interaction Missions

MITEE: A new nuclear engine concept for ultra fast, lightweight solar system exploration missions