Bob Reid

Phase 1 Space Fission Propulsion System Testing and Development Progress

Successful development of space fission systems requires an extensive program of affordable and realistic testing. In addition to tests related to design/development of the fission system, realistic testing of the actual flight unit must also be performed. If the system is designed to operate within established radiation damage and fuel bum up limits while simultaneously being designed to allow close simulation of heat from fission using resistance heaters, high confidence in fission system performance and lifetime can be attained through a series of non-nuclear tests. The Safe Affordable Fission Engine (SAFE) test series, whose ultimate goal is the demonstration of a 300 kW flight configuration system, has demonstrated that realistic testing can be performed using non-nuclear methods. This test series, carried out in collaboration with other NASA centers, other government agencies, industry, and universities, successfully completed a testing program with a 30 kWt core, Stirling engine, and ion engine configuration. Additionally, a 100 kWt core is in fabrication and appropriate test facilities are being reconfigured. This paper describes the current SAFE non-nuclear tests, which includes test article descriptions, test results and conclusions, and future test plans. INTRODUCTION AND BACKGROUND Successful development of space fission systems will require an extensive program of affordable and realistic testing. In addition to tests related to the design/development of the fission system, realistic testing of the actual flight unit must also be completed. Because heat from fission cannot be used for full-power testing of flight units (due to radiological activation), space fission systems must be designed such that heat from fission can be very closely mimicked by some other means. While some nuclear testing will be required, the system will ideally be optimized to allow maximum benefit from non-nuclear testing during the development phase. Non-nuclear tests are affordable and timely, and the cause of component and system failures can be quickly and accurately identified. The primary concern with non-nuclear tests is that nuclear effects are obviously not taken into account. To be most relevant, the system undergoing non-nuclear tests must thus be designed to operate well within demonstrated radiation damage and fuel burn up capabilities. In addition, the system must be designed such that minimal operations are required to move from non-nuclear testing mode to a fueled system operating on heat from fission. If the system is designed to operate within established radiation damage and fuel bum up limits while simultaneously being designed to allow close simulation of heat from fission using resistance heaters, high confidence in fission system performance and lifetime can be attained through a series of non-nuclear tests. Any subsequent operation of the system using heat from fission instead of resistance heaters would then be viewed much more as a demonstration than a test i.e. the probability of system failure from nuclear effects would be very low. These types of systems, along with any other nuclear propulsion system that can be tested with existing nuclear facilities, can be characterized as Phase 1 systems. https://ntrs.nasa.gov/search.jsp?R=20020050531 2020-01-31T05:03:31+00:00Z

Results of a first generation least expensive approach to fission module tests: Non-nuclear testing of a fission system

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal-hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made.

Results of 30 kWt Safe Affordable Fission Engine (SAFE-30) primary heat transport testing

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Safe Affordable Fission Engine—30 kilowatt (SAFE30) test article are being performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made.

First Generation Least Expensive Approach to Fission (FiGLEAF) Testing Results

Successful development of space fission systems will require an extensive program of affordable and realistic testing. In addition to tests related to design/development of the fission system, realistic testing of the actual flight unit must also be performed. Testing can be divided into two categories, non-nuclear tests and nuclear tests. Full power nuclear tests of space fission systems are expensive, time consuming, and of limited use, even in the best of programmatic environments. If the system is designed to operate within established radiation damage and fuel burn up limits while simultaneously being designed to allow close simulation of heat from fission using resistance heaters, high confidence in fission system performance and lifetime can be attained through a series of non-nuclear tests. Non-nuclear tests are affordable and timely, and the cause of component and system failures can be quickly and accurately identified. MSFC is leading a Safe Affordable Fission Engine (SAFE) test series whose ultimate goal is the demonstration of a 300 kW flight configuration system using non-nuclear testing. This test series is carried out in collaboration with other NASA centers, other government agencies, industry, and universities. The paper describes the SAFE test series, which includes test article descriptions, test results and conclusions, and future test plans.