James E. Werner

Origin of how steam rockets can reduce space transport cost by orders of magnitude

A brief sketch shows the origin of why and how thermal rocket propulsion has the unique potential to dramatically reduce the cost of space transportation for most inner solar system missions of interest. Orders of magnitude reduction in cost are apparently possible when compared to all processes requiring electrolysis for the production of rocket fuels or propellants and to all electric propulsion systems. An order of magnitude advantage can be attributed to rocket propellant tank factors associated with storing water propellant, compared to cryogenic liquids. An order of magnitude can also be attributed to the simplicity of the extraction and processing of ice on the lunar surface, into an easily stored, non-cryogenic rocket propellant (water). A nuclear heated thermal rocket can deliver thousands of times its mass to Low Earth Orbit from the Lunar surface, providing the equivalent to orders of magnitude drop in launch cost for mass in Earth orbit. Mass includes water ice. These cost reductions depend (e...

An Affordable Test Approach for Lunar Fission Surface Power Systems

The objective of the Fission Surface Power System (FSPS) development and qualification program is to assure that the components, subsystems and complete power system satisfy all of their mission requirements with a sufficiently high level of confidence. To accomplish this objective, the FSPS program will conduct nuclear and non‐nuclear development and testing in compliance with standard NASA practice for all of the reactor, power conversion, and system integration hardware and software items. The anticipated program includes extensive performance and environmental testing of components throughout their predicted operational conditions and possible fault conditions.

Hot Hydrogen Test Facility

The core in a nuclear thermal rocket will operate at high temperatures and in hydrogen. One of the important parameters in evaluating the performance of a nuclear thermal rocket is specific impulse, ISp. This quantity is proportional to the square root of the propellant’s absolute temperature and inversely proportional to square root of its molecular weight. Therefore, high temperature hydrogen is a favored propellant of nuclear thermal rocket designers. Previous work has shown that one of the life-limiting phenomena for thermal rocket nuclear cores is mass loss of fuel to flowing hydrogen at high temperatures. The hot hydrogen test facility located at the Idaho National Lab (INL) is designed to test suitability of different core materials in 2500°C hydrogen flowing at 1500 liters per minute. The facility is intended to test non-uranium containing materials and therefore is particularly suited for testing potential cladding and coating materials. In this first installment the facility is described. Automated Data acquisition, flow and temperature control, vessel compatibility with various core geometries and overall capabilities are discussed.

Ground Testing NTP Systems: A Review of Potential Test Options and Recommendation on Preferred Approach

The development of a nuclear thermal propulsion (NTP) system rests heavily upon being able to demonstrate performance of the system prior to launch. Since testing of nuclear thermal rocket (NTR) engines was suspended in 1972, a number of studies have been performed on ground test facility (GTF) needs and requirements. This paper provides a survey of the studies performed in recent years on concepts for ground testing and their current status. This paper identifies the most promising concepts and the advantages and disadvantages associated with each concept based on anticipated performance requirements for a nuclear thermal propulsion system. Detailed trade studies will need to be performed to support the decision making process. I. Introduction The U.S. Government, i.e., National Aeronautics and Space Administration (NASA), the Department of Energy (DOE), and the U.S. Air Force, initially sponsored the development of space NTP systems in the 1950s. These programs were initiated by Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL), with the LANL program being selected to proceed with development of the NTP system. The research effort was called Rover and the development of the concept was called Nuclear Engine for Rocket Vehicle Application (NERVA). Testing of the concepts was performed at the Nuclear Rocket Development Station (NRDS) at the NTS. Under the Rover Program, four reactor test series (KIWI, Phoebus, Pewee-1 and Nuclear Furnace-1) were performed to demonstrate the basic nuclear technology. KIWI, Phoebus, and Pewee-1 were open cycle systems and exhausted their effluent into the atmosphere, whereas the Nuclear Furnace-1 used an effluent treatment system to treat the hydrogen effluent before discharge to the atmosphere. In all, 13 tests were conducted in the Rover Program. The NERVA Program focused on development of a flight-rated NTR using the technologies being demonstrated in the Rover Program. The NERVA Program was performed in parallel with the Rover Program, and several of the tests overlapped the research effort. The NERVA Program consisted of two projects, the Nuclear Reactor Experiment (NRX) and the Experimental Flight Engine Prototype (XEPrime). Both of these concepts used the open cycle with effluent being discharged to the atmosphere. Eight rocket reactor tests were performed in the NERVA Program. As environmental concerns were being raised in the U.S., continued open cycle testing of NTP systems was also being questioned. At the time of termination of the Rover and NERVA Programs in January 1973, effluent treatment systems were being developed for application to future NERVA test articles based on a smaller effluent treatment system (ETS) demonstrated on the Nuclear Furnace-1 reactor. The Nuclear Furnace-1 was a 44 MWt reactor used for testing fuel integrity and performance. The hydrogen effluent, after passing through the core, was sprayed with steam to cool the gas and remove any particles from the gas flow stream. A heat exchanger was then used to reduce the temperature further before the effluent was passed through a silica gel bed to remove the water and dissolved fission products. The noble gases were removed as the effluent passed through cryogenic, activated charcoal filter beds. The exiting hydrogen stream contained no detectable fission products. For the NERVA Program, seven effluent treatment system options were studied based on the type of fuel to be tested 1 . Beaded fuel was felt to have the highest integrity, and thus trapping of noble gases would not be required. All three concepts proposed for beaded fuel were based on passing the effluent gas through water, either through lutes, water spray, or an irrigated filter and HEPA filter systems. For

A multi-mission radioisotope thermoelectric generator (MMRTG) for Mars 2020

The production of radioisotope power systems (RPS) has been an ongoing endeavor for the U.S. Department of Energy and its predecessor agencies for the past five decades. The overall mission of the RPS Program is to develop, demonstrate, and deliver compact, safe nuclear power systems and related technologies for use in remote, harsh environments (e.g., space) where more conventional electrical power sources do not work.

Affordable Development and Demonstration of a Small NTR Engine and Stage: How Small is Big Enough?

In FY11, NASA formulated a plan for Nuclear Thermal Propulsion (NTP) development that included Foundational Technology Development followed by system-level Technology Demonstrations The ongoing NTP project, funded by NASAs Advanced Exploration Systems (AES) program, is focused on Foundational Technology Development and includes 5 key task activities:(1) Fuel element fabrication and non-nuclear validation testing of heritage fuel options;(2) Engine conceptual design;(3) Mission analysis and engine requirements definition;(4) Identification of affordable options for ground testing; and(5) Formulation of an affordable and sustainable NTP development program Performance parameters for Point of Departure designs for a small criticality-limited and full size 25 klbf-class engine were developed during FYs 13-14 using heritage fuel element designs for both RoverNERVA Graphite Composite (GC) and Ceramic Metal (Cermet) fuel forms To focus the fuel development effort and maximize use of its resources, the AES program decided, in FY14, that a leader-follower down selection between GC and cermet fuel was required An Independent Review Panel (IRP) was convened by NASA and tasked with reviewing the available fuel data and making a recommendation to NASA. In February 2015, the IRP recommended and the AES program endorsed GC as the leader fuel In FY14, a preliminary development schedule DDTE plan was produced by GRC, DOE industry for the AES program. Assumptions, considerations and key task activities are presented here Two small (7.5 and 16.5 klbf) engine sizes were considered for ground and flight technology demonstration within a 10-year timeframe; their ability to support future human exploration missions was also examined and a recommendation on a preferred size is provided.

Assessing NTP Ground Test Requirements Based on Affordability Considerations

In the 1960’s and early 1970’s, development and testing of nuclear thermal propulsion systems in the United States was performed a the Nevada Test Site, near Las Vegas, Nevada. These systems were tested without containment or effluent treatment systems. The hydrogen gas would pass through the reactor core and be exhausted to the environment. Fuel element failure s resulted in fuel element particulate, fission products , and noble gases being released directly to the atmosphere. Controlled access to the test area, atmospheric dispersion and distance were the key parameters for safety of the public during these tests. Due to poor fuel element integrity, this approach was deemed no longer acceptable in the early 1970’s and an effluent treatment system was needed . This added cost to the test program, though not a factor in decision to terminate the NTP program, would have significantly increased the cost of whole NTP engine testing. At the end of the NTP program, an approach to test the NTP fuel elements in a nuclear furnace with an effluent treatment system was developed and it provided a basis for future development of the NTP system in the 1990’s. No large effluent trea tment systems were built in the 1970’s, but the approach and designs were saved for future use. The effluent treatment systems were identified as a significant cost driver in the development of the nuclear systems. As a result, the cost to develop and qu alify NTP systems in the 1990’s was significant and estimated around

Feasibility of Ground Testing a Moon and Mars Surface Power Reactor in EBR-II

1,000,000,000.00 with the ground test facilities being half to three -fourths of that amount.

A Small Fission Power System for NASA Planetary Science Missions

Ground testing of a surface fission power system would be necessary to verify the design and validate reactor performance to support safe and sustained human exploration of the Moon and Mars. The Idaho National Laboratory (INL) has several facilities that could be adapted to support a ground test. This paper focuses on the feasibility of ground testing at the Experimental Breeder Reactor II (EBR‐II) facility and using other INL existing infrastructure to support such a test. This brief study concludes that the INL EBR‐II facility and supporting infrastructure are a viable option for ground testing the surface power system. It provides features and attributes that offer advantages to locating and performing ground testing at this site, and it could support the National Aeronautics and Space Administration schedules for human exploration of the Moon. This study used the initial concept examined by the U.S. Department of Energy Inter‐laboratory Design and Analysis Support Team for surface power, a low‐temper...