Optimal control of reliability failure risk contagion dynamics in nuclear power systems

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<div class="section abstract"><div class="htmlview paragraph">THE GENERAL problem of non-air-breathing auxiliary power systems suitable for missiles and space vehicles is considered. On the basis of minimum weight it is shown that for powers less than a few kilowatts, systems such as batteries, fuel-cells, solar cells, and radioisotopes are preferred. The particular choice depends mainly upon the required duration.</div><div class="htmlview paragraph">For powers larger than a few kilowatts, either chemical propellant-mechanical conversion systems or nuclear power systems must be used. Due to shielding considerations the nuclear auxiliary power systems are primarily restricted to satellites and space vehicles. The chemical propellant systems are required for durations of a few hours and less; the nuclear systems must be used for times greater than a few hours. Various types of chemical propellant-mechanical conversion systems are described.</div><div class="htmlview paragraph">The problems involved in a nuclear power system are considered in detail and the characteristics of a typical advanced state-of-the-art system are described. This system operates on the Rankine-liquid-vapor condensing cycle. Thermodynamic properties are given for several fluids that might be considered for such a system.<span class="xref">*</span></div></div>

<div class="htmlview paragraph">Future space exploration missions will require new and innovative approaches to supplying electric power. Due to the very high transportation cost associated with the lunar and Mars missions, the mass of these power systems will be a critical factor. Power systems currently being considered for these applications include both nonnuclear and nuclear systems.</div> <div class="htmlview paragraph">For lunar applications, the 354-hour-long nighttime presents a formidable challenge to energy storage technology for nonnuclear power systems. Because of their low energy densities, energy storage systems can be prohibitively massive at higher power levels. Consequently, the nonnuclear power systems may be limited to low-power mission applications on the surface of the Moon. Eliminating or greatly reducing the need for energy storage makes these systems competitive with nuclear power systems.</div> <div class="htmlview paragraph">A Free Electron Laser (FEL) power system based in lunar orbit was examined for providing power by beaming energy to the lunar surface. The FEL power system was compared with surface-based nuclear and nonnuclear power systems over a range of user power requirements. Preliminary results show the laser power beaming system to be increasingly competitive on a mass basis with the nonnuclear power at power levels above 50 kWe. However, compared with a surface-based nuclear power plant, the laser beaming power system is an unattractive option unless, for some reason, a nuclear plant cannot be situated on the lunar surface.</div>

Heat rejection with mechanical pumped cooling loop for lunar surface nuclear reactor power system

Analysis of power load tracking and regulation performance in a distributed multi-energy coupled system with nuclear and solar sources

This report describes the conceptual design and performance of a subsea nuclear power system for application in offshore oil and gas production. The system can be designed and built with minimum additional development, based on space nuclear power technology, components, and systems completed during the past 20 years. The concept is particularly well suited to meet the requirements of the offshore oil application for adequate safety, high reliability, and acceptable costs. The system is designed to provide 3000 kWe power to oil pumps, at 4160 V, and 60 Hz, for a period of 4 years, in an automatic, unattended mode. At the end of this period, the system is returned to a refurbishment center, where the reactor core is replaced and other parts of the systems are inspected, refurbished, or replaced, as required. With this periodic refueling and maintenance, the total system design life is 20 years. The nuclear power system is largely contained within two separate pressure vessels, connected by an enclosed pipe chase. One vessel contains the reactor and liquid metal primary coolant system, while the other contains the organic Rankine power conversion systems. These modules are mounted on a barge which provides both a means to transport the system and a mounting structure for the sea floor installation. A waste heat exchanger is mounted on the deck of the barge. The nuclear power system is designed for unattended operations. It can be operated automatically in a load-following mode, or controlled remotely with the use of supervisory and instrumentation circuits.

Environmentalists and environmental scientists have criticized wind energy in various forums for its negative impacts on wildlife, especially birds. This article highlights that nuclear power and fossil-fuelled power systems have a host of environmental and wildlife costs as well, particularly for birds. Therefore, as a low-emission, low-pollution energy source, the wider use of wind energy can save wildlife and birds as it displaces these more harmful sources of electricity. The paper provides two examples: one relates to a calculation of avian fatalities across wind electricity, fossil-fueled, and nuclear power systems in the entire United States. It estimates that wind farms are responsible for roughly 0.27 avian fatalities per gigawatt-hour (GWh) of electricity while nuclear power plants involve 0.6 fatalities per GWh and fossil-fueled power stations are responsible for about 9.4 fatalities per GWh. Within the uncertainties of the data used, the estimate means that wind farm-related avian fatalities equated to approximately 46,000 birds in the United States in 2009, but nuclear power plants killed about 460,000 and fossil-fueled power plants 24 million. A second example summarizes the wildlife benefits from a 580-MW wind farm at Altamont Pass in California, a facility that some have criticized for its impact on wildlife. The paper lastly highlights other social and environmental benefits to wind farms compared to other sources of electricity and energy.

The heat transport subsystem for a liquid metal cooled thermionic space nuclear power system was modelled using algorithms developed in support of previous nuclear power system study programs, which date back to the SNAP‐10A flight system. The model was used to define the optimum dimensions of the various components in the heat transport subsystem subjected to the constraints of minimizing mass and achieving a launchable package that did not require radiator deployment. The resulting design provides for the safe and reliable cooling of the nuclear reactor in a proven lightweight design.

Space power systems upon entering the 21 century are primarily based upon photovoltaic solar arraybattery power for most earth and planetary orbiting satellites and smaller scale systems for planetary landers. Nuclear powered systems using radioisotopes have been reserved for outer planetary science and exploration with space nuclear reactors not being launched since the early 1980s. The recent interest in nuclear space power systems for very high power missions have relegated the development of advanced solar power systems to the study mode. However, these concepts are now emerging for more detailed examination. We review the current concepts for advanced high power solar systems and compare to proposed space nuclear power systems that have been under consideration. We identify the technical and feasibility issues for future development and project other relevant emerging technologies which may be developed in the latter part of the 21 century.

A review and comparison of the weights, sizes, and costs of nuclear and non-nuclear spacecraft power systems is presented and discussed. Nuclear power systems include the range below 10 kW, with an electrical output to weight ratio of 0.5 to 1.0 pounds per watt. Comparisons show that primary batteries are lighter for short-duration missions of a few hours; fuel cells are lighter for durations of one to two months; and solar-cell/secondary battery combinations are to be preferred when sunlight is adequate.

The results of a comparative analysis of the effectiveness of transport-power modules of different types (with solar and nuclear power systems, with electric and thermal rocket motors) for placing spacecraft from domestic cosmodromes into geostationary orbit using medium and heavy carrier rockets are presented. The main purpose of this analysis was to substantiate the regions of no-alternative application of nuclear power and power-propulsion systems for solving conventional and qualitatively new space problems in the interests of defense, science, and socioeconomic development of the country. It is concluded that at the present stage it is best not to use them together with medium-class carrier rockets. The results of a comparative analysis of the use of solar and nuclear transport modules together with heavy carrier rockets are presented for the assessment of solving the prospective problem of all-weather round-the-clock operational, highly detailed observation using an orbital system of spacecraft in a geosynchronous orbit, 3 figures.

The deep security of DCS(Distributed Control System) is more serious than conventional hardware problems for ship's nuclear power system. It is great significance to study the DCS deep security for operation security of ship's nuclear power system. The main characteristics of DCS deep security are obtained by comparing and analyzing the ship's nuclear power with the conventional control and information system. The DCS deep security protection system is constructed, and an improved DEMIAL method is used to analyze center degree and cause degree of the system elements. The improved scale model is proposed to construct direct relationship matrix based on Weber-Fechner law. Weights are used to synthesize multiple decision-making opinions. The main concerns of deep security protection and the system elements with large influence are analyzed. The results of the DCS deep security factors model, the protection system and the protection system elements of ship's nuclear power system, can provide valuable support for the follow-up research on the deep security technology and system of ship's nuclear power system.

Conceptual design for a 5 kWe space nuclear reactor power system

Proceeding from a modern state of technology development, one can make a conclusion that electric thrusters (ET) will be used in a near term manned Martian spacecraft. The closed Brayton energy conversion system (CBECS), having very high efficiency in MWe level of electrical power, is the most preferable for the electric thrusters power supply, as it can be used both in nuclear power systems (PS), and in ecologically pure, solar PS. Accumulated technical work already done in a space, transport and stationary closed Brayton PS, and also wide experience of the open gas turbine exploitation available in Russia, has been used in the Mars exploration program. For a one year manned Martian mission, a comparison between a nuclear and solar three-modular PS with CBECS with a total electrical power of 15 MWe is carried out. The each 5 MWe CBECS of these PS is designed on high-recuperative scheme with intermediate cooling between compressors.

In 1987, in response to a request from U.S. Air Force Space Division (AF/SD), the Department of Energy (DOE) convened a team of experts to assess the technology readiness of various nuclear power source (NPS) options being considered for the proposed Boost Surveillance and Tracking System (BSTS). NPS option s included the Dynamic Isotope Power System (DIPS), the Space Thermionic Advanced Reactor -Compact (STAR -C) and a low -power derivative of the SP -100 space nuclear reactor power system. Given the mission requirements and constraints along with performance, schedule and cost considerations, the assessment team unanimously concluded that DIPS was the only nuclear system that could deliver the required power within mission mass and schedule targets with the lowest development risk. This paper summarizes that 1 987 report within the context of the overall DIPS program.