Nuclear safety considerations for manned space flight
Nuclear safety considerations for ground checkout, launch and in-orbit operations of reactors for earth orbital manned space stations
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Nuclear safety considerations for ground checkout, launch and in-orbit operations of reactors for earth orbital manned space stations
The National Aeronautics and Space Administration (NASA) launched the Jet Propulsion Laboratory's (JPL) two Voyager spacecraft to Jupiter in 1977, each using three radioisotope thermoelectric generators (RTGs) supplied by the Department of Energy (DOE) for onboard electric power. In 1986 NASA will launch JPL's Galileo spacecraft to Jupiter equipped with two DOE supplied RTGs of an improved design. NASA and JPL are also responsible for obtaining a single RTG of this type from DOE and supplying it to the European Space Agency as part of its participation in the International Solar Polar Mission. As a result of these missions, JPL has been deeply involved in space nuclear safety as a user. This paper will give a brief review of the user contributions by JPL - and NASA in general - to the nuclear safety processes and relate them to the overall nuclear safety program necessary for the launch of an RTG. The two major safety areas requiring user support are the ground operations involving RTGs at the launch site and the failure modes and probabilities associated with launch accidents.
Nuclear explosives and weapon systems require special consideration because of their political and military importance, their destructive power, and the potential consequences of an accident. The special consideration translates into specific requirements promulgated by Department of Energy (DOE) O 452.1E “Nuclear Explosive and Weapon Surety,” and Department of Defense (DoD) Directive 3150.02 “DoD Nuclear Weapon System Safety Program.” The Los Alamos National Laboratory (LANL) W-Division Nuclear Explosive Safety Office mission is to coordinate LANL participation in Nuclear Explosive Safety Studies (NESS) and Nuclear Weapon System Safety Studies (NWSS); to provide qualified members and advisors to the studies; to liaise with the National Nuclear Security Administration (NNSA), the DoD, other national laboratories, the Nevada Test Site, and Pantex Plant with regards to nuclear explosive and weapon system safety. These orders and directives define nuclear detonation as an energy release through a nuclear process, during a period of time on the order of 1 microsecond, in an amount equivalent to the energy released by detonating 4 or more pounds of trinitrotoluene (TNT).
Nuclear security is one of the defining challenges of our time. Nuclear threats range from deliberate dispersal of radioactive material to contaminate the vital infrastructure to diversion and smuggling of special nuclear material for clandestine nuclear programs and nuclear terrorism, respectively. There is an associated need to develop and sustain the nuclear forensics capabilities, which requires the understanding of complex processes that occur in plasmas of nuclear materials. The area of nuclear safety has seen a resurgence of public interest, and there is a concomitant need to safely store used nuclear fuel and detect structural material failure in nuclear power systems, especially in innovative reactor designs envisioned for future adoption. Laser-produced plasmas are complicated extreme environments that can generate intense and rich, highly specific signatures of nuclear and radiological materials, which can then be explored in a wide range of applications. They include interdiction and rapid detection of nuclear materials, including their isotopic composition, detection over long distances, laboratory simulation of weapons effects, monitoring the condition of structural materials in dry cask storage containers, and novel instrumentation for nuclear power systems. We present a compilation of recent representative examples of the application of laser spectroscopy, and laser-induced breakdown spectroscopy in particular, to nuclear safety and security problems. A case is made that spectroscopic techniques based on laser-produced plasmas offer complementary, and sometimes unique, capabilities that motivate the continued exploration of their efficient production and understanding of the signatures they produce
Nuclear provides exciting solutions for real world challenges, and it is here today and will grow for tomorrow, even if the United States does not rise to the occasion due to societal or political whims of the current election cycle. In order to support Nuclear Technology, effective nuclear safety professionals are required.
Nuclear criticality safety standards provide guidance on the requirements and recommendations to establish confidence in computerized model results used to support operation with fissionable materials. By design, the guidance is not prescriptive, leaving the analysts free to determine how various sources of uncertainties are to be statistically aggregated. This report compares the analyses and key assumptions behind four notable methodologies documented in the nuclear criticality safety literature: the parametric, nonparametric, Whisper, and TSURFER methodologies. Because of the involved use of statistics entangled with heuristic recipes, the results of these methodologies are often difficult to interpret. Also, they are augmented by additional large administrative margins, eliminating the incentive to understand their differences. With the new resurgent wave of advanced nuclear systems focused on economizing operation—including advanced reactors, fuel cycles, and fuel concepts—there is a strong need to develop a clear understanding of uncertainties and their fusion methodologies to reduce uncertainties in a scientifically defensible manner. This report offers a deep dive into the various assumptions of the four noted methodologies, their adequacy, and their limitations, to provide guidance on developing confidence for the emergent nuclear systems. These systems are expected to be challenged by the scarcity of experimental data.
Radioisotope thermoelectric generator user nuclear safety tasks including failure mode and safety analyses reporting
Nuclear safety analysis as applied to a space base mission is presented. The nuclear safety analysis document summarizes the mission and the credible accidents/events which may lead to nuclear hazards to the general public. The radiological effects and associated consequences of the hazards are discussed in detail. The probability of occurrence is combined with the potential number of individuals exposed to or above guideline values to provide a measure of accident and total mission risk. The overall mission risk has been determined to be low with the potential exposure to or above 25 rem limited to less than 4 individuals per every 1000 missions performed. No radiological risk to the general public occurs during the prelaunch phase at KSC. The most significant risks occur from prolonged exposure to reactor debris following land impact generally associated with the disposal phase of the mission where fission product inventories can be high.
Presentation for INL's AI/ML Symposium. Topic: Evaluation of AI-generated documents for nuclear permitting/licensing.
Nuclear heat source for pulse jet thruster design, discussing aerospace nuclear safety and space mission applications
National Security Presidential Memorandum #20 (NSPM-20) directed the NASA Administrator to establish an Interagency Nuclear Safety Review Board (INSRB), replacing the ad hoc safety review panels used for space nuclear system launch reviews since the 1960s. NSPM-20 provides over-arching direction regarding the Board’s purpose and intent. Upon formation of this new entity, its members recognized that more detailed guidance was needed to ensure predictable and reliable performance of the Board’s functions. The Board drafted and later approved a guidance document referred to as “the Playbook” for this purpose. This paper will summarize the main features of this publicly-available document, along with providing context for its initial drafting and revision. The goal of this paper is to broaden the degree of awareness by the space nuclear system community of INSRB’s activities and intents.
The design and operations guidelines and requirements developed in the study of space base nuclear system safety are presented. Guidelines and requirements are presented for the space base subsystems, nuclear hardware (reactor, isotope sources, dynamic generator equipment), experiments, interfacing vehicles, ground support systems, range safety and facilities. Cross indices and references are provided which relate guidelines to each other, and to substantiating data in other volumes. The guidelines are intended for the implementation of nuclear safety related design and operational considerations in future space programs.
Some nuclear safety aspects of a 3.2 mWt heat pipe cooled fast reactor with out-of-core thermionic converters are discussed. Safety related characteristics of the design including a thin layer of B4C surrounding the core, the use of heat pipes and BeO reflector assembly, the elimination of fuel element bowing, etc., are highlighted. Potential supercriticality hazards and countermeasures are considered. Impacts of some safety guidelines of space transportation system are also briefly discussed, since the currently developing space shuttle would be used as the primary launch vehicle for the nuclear electric propulsion spacecraft.
The panel discussion titled "Innovations in Advanced Cybersecurity Technologies for Safety Systems Within Nuclear Power Plants (NPPs)" took place at the American Nuclear Society (ANS) Annual Meeting in Las Vegas on Tuesday, June 18, 2024. The session was moderated by Lee Maccarone of Sandia National Laboratories (SNL) and featured four experts: Benjamin Karch from Sandia National Laboratories, Ismael Garcia from the U.S. Nuclear Regulatory Commission (NRC), Trevor Taylor from Paragon Energy Solutions (ES), and Forrest Shriver from Sentinel Devices.
The results of a study to identify potential hazards arising from nuclear reactor power systems for use on the lunar and Martian surfaces, related safety issues, and resolutions of such issues by system design changes, operating procedures, and other means are presented. All safety aspects of nuclear reactor power systems from prelaunch ground handling to eventual disposal were examined consistent with the level of detail for SP-100 reactor design at the 1988 System Design Review and for launch vehicle and space transport vehicle designs and mission descriptions as defined in the 90-day Space Exploration Initiative (SEI) study. Information from previous aerospace nuclear safety studies was used where appropriate. Safety requirements for the SP-100 space nuclear reactor system were compiled. Mission profiles were defined with emphasis on activities after low earth orbit insertion. Accident scenarios were then qualitatively defined for each mission phase. Safety issues were identified for all mission phases with the aid of simplified event trees. Safety issue resolution approaches of the SP-100 program were compiled. Resolution approaches for those safety issues not covered by the SP-100 program were identified. Additionally, the resolution approaches of the SP-100 program were examined in light of the moon and Mars missions.
As the horizon of nuclear energy expands with the advent of small modular reactors, IV generation reactors, and fusion reactors, there is a growing perspective that the licensing process could benefit from a more comprehensive approach. Moving beyond traditional deterministic and PRA analysis might pave the way for a novel safety analysis paradigm propelled by the increasing computational power at our disposal. This paper explores different methodologies that can improve the outcomes of nuclear safety analysis. These range from uncertainty quantification techniques, aimed at enhancing the precision of safety margins, to deploying dynamic event trees by driving system code simulations, capturing the potential evolutions of severe accidents. These methodologies introduce innovative dimensions to safety analysis, considering the consequences of postulated events and the dynamics of accident sequences. However, they also bring forth challenges, especially in managing the complexity and sheer volume of potential scenarios. The paper touches upon some strategies to counter these challenges, emphasizing the importance of adaptability and continuous evolution in the face of emerging nuclear safety concerns. Additionally, the paper sheds light on the need for advanced tools to apply these methodologies. Among these tools is RAVEN, an open-source software designed for parametric and probabilistic analyses. Its core components, including distribution, sampler, and reduced order model, enable various applications, from risk assessment and mitigation to dynamic learning and plant control logic simulations.
The facilities at the Materials and Fuels Complex (MFC) contain a diverse collection of nuclear research and development capabilities which enable experiments and engineering to drive the world’s nuclear energy future. It is our responsibility to ensure safe, efficient, and reliable operation of MFC facilities to support INL’s nuclear science and technology and national security missions. The MFC management plan makes it clear that safely achieving this takes the right people using good processes.