Some experiences of critical software development

Validation of a digital computer program to be used in a nuclear power plant protection system must meet quality assurance requirements. Digital systems have not traditionally been used on nuclear reactor protection systems. Licensing of digital system software requires providing assurance that the software performs its intended function. To provide added assurance, the Babcock and Wilcox Company performed software validation on the digital program intended for use on a protection system. Software validation of the Reactor Protection System-II digital program presented a multi-faceted challenge. Quality assurance requirements were imposed on the project. Certain validation ground rules were specified. No known methods existed for proving program correctness for nontrivial software. No precedence had been set to estimate the quality or quantity of testing required as a method of validation. Project schedule constraints were imposed. The need for more documentation than normally furnished was recognized, but how much and what kind was not clear. This paper relates how this challenge was met through a discussion of how the project was performed and the lessons learned through those experiences. A test method was devised within validation ground rules and project schedule constraints to validate that software performed the specified functions. Orderly methods of testing and evaluating were implemented and documented in compliance with a plan to provide auditable, traceable evidence of the validation effort and the digital component program performance.

The integrated Protection System (IPS) is intended to perform the protection functions of the Italian Nuclear Power Plants. The IPS is based on a distributed microprocessor system architecture, and is designed to be highly reliable. The reliability is assured, from others, through the use of redundancy and functional diversity. Failures that, in spite of redundancy, can impair the system are the Common Mode Failures (CMF) (1).

Over the past 20 years, the nuclear power industry in the United States (U.S.) has been slowly replacing old, obsolete, and difficult-to-maintain analog technology for its nuclear power plant protection, control, and instrumentation systems with digital systems. The advantages of digital technology, including more accurate and stable measurements and the ability to improve diagnostics capability and system reliability, have led to an ever increasing move to complete these upgrades. Because of the difficulties with establishing digital systems safety based on analysis or tests, the safety demonstration for these systems relies heavily on establishing the quality of the design and development of the hardware and software. In the United States, the U.S. Nuclear Regulatory Commission (NRC) has established detailed guidelines for establishing and documenting an appropriate safety demonstration for digital systems in NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition,” Chapter 7, “Instrumentation and Controls,” Revision 5, issued March 2007 [1], and in a number of regulatory guides and interim staff guidance documents. However, despite the fact that the United States has a well-defined review process, a number of significant challenges associated with the design, licensing, and implementation of upgrades to digital systems for U.S. plants have emerged. Among these challenges have been problems with the quality of the systems and the supporting software verification and validation (V&V) processes, challenges with determining the optimum balance between the enhanced capabilities for the new systems and the desire to maintain system simplicity, challenges with cyber security, and challenges with developing the information needed to support the review of new systems for regulatory compliance.

NASA has completed a preliminary mission and systems study of nuclear electric propulsion (NEP) systems for “split‐sprint” human exploration and related robotic cargo missions to Mars. This paper describes the study, the mission architecture selected, the NEP system and technology development needs, proposed development schedules, and estimated development costs. Since current administration policy makers have delayed funding for key technology development activities that could make Mars exploration missions a reality in the near future, NASA will have time to evaluate various alternate mission options, and it appears prudent to ensure that Mars mission plans focus on astronaut and mission safety, while reducing costs to acceptable levels. The split‐sprint nuclear electric propulsion system offers trip times comparable to nuclear thermal propulsion (NTP) systems, while providing mission abort opportunities that are not possible with “reference” mission architectures. Thus, NEP systems offer short transit times for the astronauts, reducing the exposure of the crew to intergalactic cosmic radiation. The high specific impulse of the NEP system, which leads to very low propellant requirements, results in significantly lower “initial mass in low earth orbit” (IMLEO). Launch vehicle packaging studies show that the NEP system can be launched, assembled, and deployed, with about one less 240‐metric‐ton heavy lift launch vehicle (HLLV) per mission opportunity ‐ a very large cost savings! Technology development cost of the nuclear reactor for an NEP system would be shared with the proposed nuclear surface power systems, since nuclear systems will be required to provide substantial electrical power on the surface of Mars. The NEP development project plan proposed includes evolutionary technology development for nuclear electric propulsion systems that expands upon SP‐100 (Space Power ‐ 100 kw) technology that has been developed for lunar and Mars surface nuclear power, and small NEP systems for interplanetary probes. System upgrades are expected to evolve that will result in even shorter trip times, improved payload capabilities, and enhanced safety and reliability. Non‐nuclear technology development for the NEP system is estimated to cost about $721 M (1993 $). Nuclear technology development costs are not included in the costs in this report, since these costs will be incurred in the nuclear surface power development program. NEP Phase A/B studies are estimated to cost about $154 M. Flight system hardware development (Phase C/D) is estimated to cost about $2.8 B, and fabrication of flight hardware is estimated to be about $7.8 B for four mission opportunities in 2009, 2011, 2014, and 2016.

<p indent=0mm>After the Fukushima nuclear accident in Japan, the safety requirements of nuclear energy systems are constantly increasing. A series of new nuclear energy systems are under development, such as very high-temperature gas-cooled reactor (VHTR), lead-cooled fast reactor (LFR), gas-cooled fast reactor (GFR) and so on. In order to achieve the goals of higher safety, these nuclear systems have put forward higher requirements for nuclear materials. For example, materials working in VHTR and GFR are supposed to withstand higher temperatures, and LFR requires materials to be more corrosion-resistant. Nuclear materials have to meet these requirements under normal operating conditions, as well as in incidental and accidental conditions. Therefore, it is necessary to optimize the existing material system and develop new high-performance materials to meet the future development needs of advanced nuclear power systems. Compared with traditional nuclear materials, carbide ceramics have better mechanical properties under elevated temperatures, stronger irradiation resistance and better comprehensive thermophysical properties. Up to now, great breakthroughs have been made in the research of carbide ceramic materials and some key materials are going to be used in the new-generation nuclear systems. For example, uranium carbide (UC) is gradually replacing traditional uranium dioxide (UO₂), and silicon carbide (SiC) is acting as the main fission product barrier layer of coated fuel particles in HTGR. Other new carbide materials such as zirconium carbide (ZrC) and MAX phase carbide materials are also becoming a new research hotspot in the field of nuclear materials. Compared with other ceramic materials, the fabrication especially its densification of carbide is generally more difficult. In addition, high purity and good neutron properties are also the basic requirements of carbide ceramic materials for nuclear energy. The vapor deposition process and powder metallurgy process have been used to fabricate carbide ceramics for different components in nuclear reactors. Some new preparation methods have been developed to fabricate fuels and structural materials. For example, gelation progress is applied to prepare UCO microsphere fuel, and nano infiltration and transient eutectic (NITE) process is used in the preparation of SiC_f/SiC composites, which is potential for nuclear claddings. The irradiation-induced degradation of nuclear ceramic materials in the reactor is unavoidable. In order to evaluate the performance changes of materials under irradiation conditions, different irradiation methods such as electron irradiation, ion irradiation, proton irradiation and neutron irradiation are used. Due to its unique microstructure and properties, carbide ceramics exhibit different properties from other nuclear materials under irradiation. The performance changes of main nuclear carbide materials after irradiation are summarized, including microstructure evolution, macroscopic irradiation-induced swelling, changes in mechanical and thermal properties, etc. In general, based on the current research progress, the article reviews the application of carbide ceramics in new nuclear power systems and elaborates their service scenarios. Basic properties, preparation methods and irradiation properties of carbide ceramic materials are introduced in detail. The future development directions and the processing techniques are proposed. In the future, carbide ceramic materials should be further developed, and carbide ceramic materials will find diverse applications in the new generation nuclear systems.

This paper introduces briefly the development of nuclear energy systems from the GEN I to the advanced GEN IV, the progress of manufacturing radiation resistant materials associated with the development of nuclear energy systems and the new methods of investigating radiation properties of the structural materials for the GEN IV nuclear energy systems at first. Irradiation induced deterioration of materials properties is a bottle neck problem, which must be investigated and solved for the development of the GEN IV nuclear energy systems. Unfortunately, all the currently available neutron sources cannot meet the requirements of investigating radiation properties of structural materials irradiated by high dose neutron irradiation in the GEN IV nuclear energy systems. Therefore, two new methods of the accelerator heavy ion irradiation that simulates the high-dose neutron irradiation and the triple beam irradiation that mimics the real neutron irradiation environment in the GEN IV nuclear energy systems have been developed. These two methods are introduced in this paper. The present status of the study on radiation properties of structural materials for nuclear energy systems of the new generation and the near future development plan at China Institute of Atomic Energy (CIAE) are described also. The accelerator heavy ion irradiation facilities for different applications and the simultaneous triple beam irradiation platform with three separate accelerators or implanters have been established at the HI-13 tandem accelerator of CIAE. A series of structural materials for nuclear energy systems, such as the home-made modified austenic steel, CLAM steel, 1515 steel, Tantalum, Tungsten, etc. have been tested and investigated systematically. A superconducting linear accelerator and a variable energy heavy ion cyclotron have been imported from abroad for a better performance of the study. Combined with the currently existing facilities of 2×13 MeV and 2×1.7 MV tandem accelerators, 30 and 100 MeV proton cyclotrons, China experimental fast reactor, China advance research reactor, Miniature neutron source reactor, etc. a comprehensive and advanced system of experimental irradiation platform for structural materials of nuclear energy systems will be established in the near future for both domestic and foreign users.

This appendix was prepared by the staff divisions of the ERDA Assistant Administrator for Nuclear Energy (AANE). It supplements Chapter IV with respect to the possible impact of weapon-program transfer alternatives on each of the nonweapon defense-related programs, and where appropriate, explores transfer considerations and alternatives for these nonweapon programs and activities. There are four ERDA nonweapon defense-related programs under supervision of the AANE: (1) Special Nuclear Material Production (plutonium, tritium, enriched uranium, and other special nuclear materials and isotopes); (2) Space Nuclear Systems (development, testing, and production of nuclear power systems for space applications, and the application of space and advanced energy technology to special-purpose terrestrial systems); (3) Naval Reactors (development of naval nuclear propulsion systems); and (4) Other Military Reactors (development, when required, of surface-based nuclear power plants for military use). Each of these programs differs substantially from the weapon program, and from each of the others, in mission, operation, and other significant characteristics. At the same time, each interacts with other ERDA and DoD programs in varying ways and degrees, and has a close coupling to ERDA energy programs. Because management and funding relationships differ substantially from those in the weapon program, transfer alternatives considered here vary somewhat from those discussed for the weapon facilities.

Nuclear systems and reactors stand out by their intrinsic complexity and the wide range of scientific and technical disciplines they involve. The design, modeling, and operation of a reactor rely on the close interdependence between neutronics, thermal-hydraulics, and thermomechanics, complemented by the description of the thermodynamic cycle of the secondary circuit and the plant's control and instrumentation systems. Historically, each of these fields has led to the development of specialized computational codes, recognized for their reliability and accuracy. However, integrating these tools into comprehensive simulation frameworks has quickly raised major challenges related to interoperability, data consistency, and the heterogeneity of physical and numerical models. To address these challenges, the standardization of code coupling interfaces has attracted growing interest, particularly following the release of the Functional Mock-up Interface (FMI) standard. This standard provides a unified framework for the systematic coupling of models from different domains, thereby facilitating communication between heterogeneous software tools. In this context, three coupling strategies were developed, analyzed, and applied to various nuclear systems: coupling through a heat exchanger between two thermal systems, pressure-velocity coupling between distinct thermal-hydraulic circuits, and a multiscale coupling linking the reactor core to detailed fuel pin models. These coupling strategies were illustrated through several representative case studies. The first application focused on the simulation of load-follow operation in a simplified nuclear power plant. The second addressed the modeling of a simplified nuclear propulsion system during a trans-lunar injection. Finally, the third examined the effects of beam trips on the fuel pins of an Accelerator Driven System. Overall, these studies demonstrate the feasibility and relevance of multi-code coupling based on the FMI standard for the integrated simulation of complex nuclear systems. The results confirm that this approach represents a promising pathway toward more flexible and interoperable modeling tools for reactor design and safety analysis.

The global utilization of nuclear energy has come a long way from its humble beginnings in the first sustained nuclear reaction at the University of Chicago in 1942. Today, there are over 440 nuclear reactors in 31 countries producing approximately 16% of the electrical energy used worldwide. In the United States, 104 nuclear reactors currently provide 19% of electrical energy used nationally. The International Atomic Energy Agency projects significant growth in the utilization of nuclear power over the next several decades due to increasing demand for energy and environmental concerns related to emissions from fossil plants. There are 28 new nuclear plants currently under construction including 10 in China, 8 in India, and 4 in Russia. In the United States, there have been notifications to the Nuclear Regulatory Commission of intentions to apply for combined construction and operating licenses for 27 new units over the next decade. The projected growth in nuclear power has focused increasing attention on issues related to the permanent disposal of nuclear waste, the proliferation of nuclear weapons technologies and materials, and the sustainability of a once-through nuclear fuel cycle. In addition, the effective utilization of nuclear power will require continued improvements in nuclear technology, particularly related to safety and efficiency. In all of these areas, the performance of materials and chemical processes under extreme conditions is a limiting factor. The related basic research challenges represent some of the most demanding tests of our fundamental understanding of materials science and chemistry, and they provide significant opportunities for advancing basic science with broad impacts for nuclear reactor materials, fuels, waste forms, and separations techniques. Of particular importance is the role that new nanoscale characterization and computational tools can play in addressing these challenges. These tools, which include DOE synchrotron X-ray sources, neutron sources, nanoscale science research centers, and supercomputers, offer the opportunity to transform and accelerate the fundamental materials and chemical sciences that underpin technology development for advanced nuclear energy systems. The fundamental challenge is to understand and control chemical and physical phenomena in multi-component systems from femto-seconds to millennia, at temperatures to 1000?C, and for radiation doses to hundreds of displacements per atom (dpa). This is a scientific challenge of enormous proportions, with broad implications in the materials science and chemistry of complex systems. New understanding is required for microstructural evolution and phase stability under relevant chemical and physical conditions, chemistry and structural evolution at interfaces, chemical behavior of actinide and fission-product solutions, and nuclear and thermomechanical phenomena in fuels and waste forms. First-principles approaches are needed to describe f-electron systems, design molecules for separations, and explain materials failure mechanisms. Nanoscale synthesis and characterization methods are needed to understand and design materials and interfaces with radiation, temperature, and corrosion resistance. Dynamical measurements are required to understand fundamental physical and chemical phenomena. New multiscale approaches are needed to integrate this knowledge into accurate models of relevant phenomena and complex systems across multiple length and time scales.

Hi Reddit! My name is Phil Sharpe and I am here today with a few of my colleagues from Idaho National Laboratory (INL) and the Gateway for Accelerated Innovation in Nuclear (GAIN). This is Nuclear Science Week, so we thought it would be great to start a conversation about the future of advanced nuclear energy, including reactor designs, fuel types, industry engagement, and some of the ideal uses for advanced nuclear systems. Commercial nuclear power currently provides nearly 60 percent of the U.S. emission-free power, according to the Nuclear Energy Institute. INL is the U.S. Department of Energy's lead nuclear energy laboratory. INL experts are developing, testing and demonstrating new fuels and materials, reactor systems, advanced nuclear energy system applications, plant monitoring and safety systems, and waste management options. The scientists participating in today's AMA: Phil Sharpe​​, Ph.D., director of Nuclear Systems Design &amp; Analysis Rita Baranwal, Ph.D., director of the Gateway for Accelerated Innovation in Nuclear (GAIN)​ ​Hans Gougar​, Ph.D., director of the Advanced Reactor Technology Technical Development Office at INL George Griffith​, Ph.D., INL Manager for Small Modular Reactor Deployment​ ​Brenden Heidrich, Ph.D., Chief Irradiation Scientist, the Nuclear Science User Facilities (NSUF)​ Some fodder for discussion: • The Potential for Disruptive Innovations in Nuclear Power - http://pubs.cnl.ca/doi/full/10.12943/ANR.2014.00033 • What Will Advanced Nuclear Power Plants Cost? - https://www.eenews.net/assets/2017/07/25/document_gw_07.pdf • Advanced Test Reactor Options Study - https://art.inl.gov/INL%20ART%20TDO%20Documents/Advanced%20Demonstration%20and%20Test%20%20Reactor%20Options%20Study/ADTR_Options_Study_Rev3.pdf • Global Nexus Initiative Reports on nuclear energy – http://globalnexusinitiative.org/category/results/reports/ We’ll be back at 11 a.m. EST (9 a.m. MST) to answer your questions, ask us anything!

Modeling primary and secondary coolant of a nuclear power plant system with a unique framework (MCUF)

Human-Machine Interaction in Future Nuclear Power Plant Control Rooms – A Review

A support vector machine integrated system for the classification of operation anomalies in nuclear components and systems

The access to reliable sources of energy is the key to sustainable development of mankind. The major part of the energy consumed by people is generated with a chemical reaction of fossil fuel burning. This leads to quick depletion of natural resources and progressing environmental pollution. The contribution of the renewable energy sources to the general energy production remains insignificant. A modern 1,000 MW coal-fired thermal power plant (TPP) burns 2.5 million tons of coal per year and produces significant amount of solid and gaseous waste. TPPs are the largest consumers of atmospheric oxygen and sources of carbon dioxide. A nuclear power plant (NPP) of the same power consumes less than 50 tons of fuel per year. Environmentally significant NPP’s waste (liquid, solid and gaseous) is carefully collected, reduced in volume (evaporation, filtering, compaction, incineration, etc.) and securely isolated from the environment at the plant. The annual volume of waste for storage is less than 100 m3. The waste is under the control of a special NPP’s service and regulatory authorities. The energy of fission reaction millions of times exceeding the energy of burning has an enormous potential that mankind can receive. Four hundred and thirty-three nuclear power units with a total capacity of about 400 GW exist in the world. The accident at the Fukushima Daiichi NPP in Japan in March 2011 caused anxiety about nuclear safety throughout the world and raised questions about the future of nuclear power. Now, it is clear that the use of nuclear power will continue to grow in the coming decades, although the growth will be slower than was anticipated before the accident. Many countries with existing nuclear power programmes plan to expand them. Many new countries, both developed and developing, plan to introduce nuclear power. Some countries, such as Germany, plan to abandon nuclear energy. The IAEA’s latest projections show a steady rise in the number of NPPs in the world in the next 20 years. They project a growth in nuclear power capacity by 23% by 2030 in the low projection and by 100% in the high projection [1,2]. The basis of modern nuclear power comprises water-cooled nuclear reactors which use the energy potential of natural uranium inefficiently (thermal reactors). The thermal reactors use isotope U-235 in which the content of natural uranium is &lt;1%. Breeder reactors are capable of using the significant part of energy potential, which is unavailable to thermal light water reactors. As a result, the same starting quantity of uranium can produce 50 times more energy. These reactors can transform U-238 into fissile Pu-239 in larger amounts than they consume fissile material. This feature is called ‘breeding’ [3]. The key problem of using the basic benefitsv of nuclear power is to ensure the safety of its use, as well as decommissioning and reliable isolation of process waste from the biosphere. The long-term large-scale nuclear power should possess guaranteed safety, economic stability and competitiveness, absence of the raw material base restrictions for a long period of time and environmental sustainability (low waste). The nuclear power systems with fast neutron reactors and liquid metal coolant can satisfy these conditions. More than 40 years of Russian experience in the field of construction and operation of sodium fast reactors makes it possible to summarize and analyze the ecological features of reactors of this type, the possibility of their use for sustainable energy supply of mankind and solving environmental problems.

Design management systems have been developed and researched for traditional product and service industries. For interaction design little research has been performed on design management. The objective of this paper is to describe aspects of and provisions for industrial interaction design that influence approaches to design management within system and software development. We discuss whether there are specific conditions for design management of interaction design within the software and system development industries. The research is based on three short case studies from industrial software development. We identify some of these specific conditions; the difference between a usage and a product perspective, the design tools and practices, and the modularized and distributed processes. These issues point towards challenges facing design management within the software and system development context, as well as the need for interaction design to clarify its position as a strategic resource in software companies. The conclusions point towards the need for continued research on strategic possibilities and alternatives to organize and manage design work in software and system development.