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This paper was erroneously published in ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, Vol. 2D and removed on October 13, 2021. Copyright © 2021 by ASME

Considering “Pipeline Industry’s Need of the Hour - Self Reliance and Emerging Technology Trends” as theme of pipeline conference, my submission of paper is on several use cases on technology and innovation for pipeline’s different life cycle phases. There are continual developments in pipeline industry and several of technologies were successfully implemented or under consideration phase for implementation for pipeline industry. In all phases of pipeline lifecycle of material management, project implementation as well in Operation & Maintenance (O&M) of pipeline. Several technological changes as well several of innovations in existing systems are of extensive use for enhancing pipeline safety, reliability, monitoring system as well ease of operations and maintenance. Many of systems been used for other purposes and are of great use for pipelines. This paper discusses on few of such technologies and their implementation for pipelines.

In the current paper the reliability of spring interconnections for the use in automotive applications was investigated. A commercially available connector was used for contacting a piezo-jet printed silver pad on polycarbonate. The structures were tested using vibration tests at three different temperatures (−25°C, 25°C and 85°C) and measured using four-point probe measurement system and white light spectrometry. The obtained results showed the reliability of the printed structure and the contact, despite of the contact resistance change. The reasons of this change and experimental results are discussed in the paper. The investigations described in the paper provide an initial approach to the development of spring interconnections for printed electronics.

In the paper, a new test bench for characterization and durability assessment of multi disc wet clutches for motorbike applications is presented. The design of the new test bench is inspired by the current SAE standards J2490 and J286 that refer to the testing of friction material for automatic transmissions wet clutches. Differently from the test bench described in the two standards, which is mainly designed to test the friction material, the test bench presented in this paper has been designed for testing the whole clutch, comprising all discs and the actuation mechanism. The lubrication system of the clutch utilized on the test bench is very similar to the one present on the actual motorbike. The design and instrumentation of the new test rig is analysed and discussed in the paper. The test bench has been used for the characterization of different motorbike clutches. The bench has proved to be able to measure the clutch characteristic for different temperatures and clutch wear levels. A very good repeatability of the tests has been achieved allowing for a comparison of different clutches design, friction material properties and operating conditions (temperature, ..). Some experimental results are presented and discussed in the paper.

Incorporating user trust in the development of intelligent systems is one of the new challenges in engineering design field. Trust in human-intelligent system interaction determines how much user relies on the system and directly influences the benefits that an intelligent system provides to human decision-making. This paper reviews the existing literature on trust in human-AI interaction to highlight key areas for engineering system design research to address the overarching issue of user trust in system development. We present how trust influences the use of an intelligent system, describe multiple contexts that users interact with intelligent systems and categorize ways in which trust is formed based on the literature. We classify the key factors that are critical in the formation of user trust in three categories of human user attributes, design of the intelligent system, and task characteristics. We also present the analytical models that exist in the literature used to evaluate and predict trust. This paper is not intended to be a thorough literature review but rather a position paper that provides a structure to the existing literature as a reference for engineering design research. We propose future directions for engineering system design community based on the gaps and open questions identified in the literature.

Simulations were used in lecture-based courses, Thermodynamics I and Thermodynamics II, for demonstration purposes and as digital assignments. Digital assignments were separate from the customary pencil & paper homework given once a week. The primary objective was to model the flow and heat transfer in a system, reinforce theoretical concepts, and allow study of more complex two- and three-dimensional problems. Students encounter fluid flow and heat transfer in the sophomore course, Thermodynamics I, for the first time. Velocity, pressure and temperature fields are quite complicated even for simple geometries, hard to visualize, and difficult to understand. Digital assignments go beyond basic theoretical concepts and relatively simple pencil & paper problems. Initially, there were 6 digital assignments in each course. After the first offerings and assessments, the number of assignments is expected to grow to 8–10. Scaffolding of digital assignments ensured that simulations gain in complexity as students become more familiar with both the theoretical underpinnings and the software interface. Our Mechanical Engineering program, has a freshmen graphic communication course incorporating AutoCAD and a junior CAD course with SolidWorks and Ansys. This provided both a challenge and an opportunity for lecture-based thermo-fluids courses positioned ‘in between.’ Modern computational skills were obtained outside the classroom, and that was accomplished with effective use of an on-line environment. Ansys Fluent was chosen to present and reinforce thermo-fluids fundamentals. Each digital assignment had a mesh, detailed grading criteria, and supplementary documentation. Students worked on the: (1) problem set up in the preprocessor-stage, (2) solver, and (3) postprocessor. This approach helped students (1) understand the flow and heat transfer inside the system as well as the application of conservation of mass and energy, (2) understand and interpret results by comparing them with theoretical and experimental data, (3) develop modern technical skills relevant to the demands of Industry 4.0, and (4) develop research capabilities. Simulations in the classroom and as digital assignments are a representation of the real world, and provide an egalitarian and unrestricted way for students to interact with it, acquiring skills and an appreciation for subject matter as well as the engineering profession. Semester long discussions on various aspects of digital assignments help develop a mentor-mentee bond. This approach to teaching, research and mentoring does not depend on access to laboratory facilities and funding that can reach only a limited number of students. It encourages students’ spirit of inquiry, and ultimately leads to a professional development opportunities beyond the classroom setting.

The accelerator-driven subcritical system (ADS) can transmute nuclear waste by using high-energy neutrons, which is the most effective nuclear waste disposal scheme at present. The zero-power lead-bismuth alloy device accurately constructed the interaction mode between nuclear fuel and lead-bismuth alloy coolant material, and more accurately simulated the core physical characteristics of lead-bismuth reactor. Moreover, the inherent safety of the reactor is enhanced by installing several passive safety shutdown systems. However, due to the particularity of the potential harm caused by radioactive material leakage, nuclear-grade equipment should maintain high safety performance under many working conditions, such as earthquake working conditions. To ensure the safe operation of the ADS zero-power device and the safe shutdown under seismic conditions, the motion of the control rod of the ADS zero-power device must be analyzed under seismic conditions. At present, most studies on the control rod drop analysis focus on water reactor, but this paper will analyze and calculate the control rod drop of the lead reactor. In this paper, the physical mechanism of rod falling of the control rod component is analyzed, and the influence of contact collision between the control rod component and the guide tube of the control rod on the whole rod falling time is considered. In this paper, the finite element method is used for transient analysis of ADS lead-bismuth alloy zero power reactor, and the time history diagram of the control bar position is obtained under the seismic conditions, thus verifying that ADS lead-bismuth alloy zero power reactor can be safely shut down under the safe shutdown earthquake (SSE).

Turbine Control System (DEH) and Turbine Protection System (ETS) are important auxiliary systems for turbines. Normally DEH and ETS are supplied by turbine manufacturers. This paper investigates the operation experience in Nuclear Power Plants (NPPs) in China, there are many problems including information security, maintenance inconvenience, long supply cycle guarantee, high cost and so on in DEH and ETS. This paper analyzes the problems and tries to get the reasons why DEH&ETS have these problems. The Distribute Control System (DCS) technology has been widely used in nuclear power plant in now days, so this paper puts forward a technical solution based on the safety DCS and non-safety DCS platform to realize the DEH and ETS, and according to the feasibility analysis of products, and the test results based on engineering prototype, the solution can solve the problems of DEH and ETS effectively, some performances of the DEH&ETS have been improved, and the solution has a good prospect in further.

Nuclear technology, as a high quality, clean and reliable energy supply, is attracting broad interest from countries across the world. F321 austenitic stainless steel (F321SS) is widely utilized in key components of nuclear power plant due to its excellent corrosion resistance and high temperature mechanical properties. Irradiation can easily lead to the degradation behaviors of materials, such as irradiation hardening, irradiation embrittlement and high-temperature He embrittlement, etc. Understanding such degradation is important for predicting the evolution of material behavior under irradiation and extending the lifespan of existing nuclear reactors. Ion irradiation is most commonly used to model neutron-induced damage since the irradiation conditions (temperature, flux, spectrum, etc.) can be regulated more accurately and flexibly. In this paper, the Fe-ion irradiation experiments of F321SS at different temperatures and doses were carried out, and the nanoindentation experiments under different conditions were further conducted. Irradiation hardening is observed in all specimens and strongly depending on irradiation temperature and damage dose. The hardness after irradiating increases with doses and saturates for at least 1dpa under low temperature regimes (< 300°C). However, at higher temperature (450°C and 560°C), nano-hardness reaches the peak at ∼0.5dpa and then declines. Moreover, the hardness of all specimens has a similar trend with temperature, that is, it first increases, reaches the peak, and then decreases.

With the increasing demands of versatile and long-lasting requirements of deep space missions, space nuclear reactor (SNR) power system is becoming the most potential energy source compared to conventional solar-battery and chemical energy in the future large-scale and long-life space missions. Since the very first successful launch of SNR system (SNAP-10A) in 1965, the United States, the Soviet Union / Russia, the European Union, Japan, Brazil and China have proposed various technical routes and schemes for SNR technologies over the past few decades. This paper presents a historical review of several key technologies (i.e., space nuclear reactor system and thermoelectric conversion system), especially focus on technical progress for recent decade and discusses on-going development activities. The paper also presents a forecast of potential future space applications of these key technologies.

The rules for the design of high temperature reactor components in Section III, Division 5, Subsection HB, Subpart B (HBB) of the ASME Boiler and Pressure Vessel Code contain two options for evaluating the deformation-controlled design limits on strain accumulation and creep-fatigue: design by elastic analysis and design by inelastic analysis. Of these options design by inelastic analysis tends to be less overconservative and produce more efficient designs. However, the HBB currently does not provide approved material models for use with the inelastic analysis rules, limiting their widespread use. A nonmandatory appendix has been developed to provide general guidance on appropriate material models and provide reference material models suitable for use with the design by inelastic analysis approach. This paper describes a viscoplastic model for Alloy 617 suitable for use with the HBB rules proposed for incorporation into the new appendix. The model represents the high temperature creep, creep-fatigue, and tensile response of Alloy 617 and accurately accounts for rate sensitivity across a wide range of temperatures. The focus in developing the model was on capturing key features of material deformation required for accurately executing the HBB rules and on developing a relatively simple model form that can be implemented in commercial finite element analysis software. The paper validates the model against an extensive experimental database collected as part of the Alloy 617 Code qualification effort as well as against specialized experimental tests examining the effect of elastic follow up on stress relaxation and creep deformation in the material.

The ASME Code, Section III, provides rules for the evaluation of cyclic loading that include evaluations of fatigue. These rules were first developed in the 1960s along with the original development of Section III. Since then, technology and analytical advancements have improved our understanding of the fatigue phenomenon. As an example, the developments in environmentally assisted fatigue (EAF) have become a major consideration in the low-cycle fatigue for light water reactors and plant life extension. Fatigue usage has an outsized impact on the overall cost and complexity of nuclear plants, which goes beyond just the qualification of ASME components. For example, pipe break locations, pipe whip restraints, and inservice inspections are, in part, based on fatigue analysis results. Therefore, it is important that fatigue analyses provide the most realistic assessment of fatigue with appropriate conservatism. The Section III Standards Committee has been working to keep the Code up to date with the latest research, analysis tools and fatigue data. In 2017, a Fatigue Steering Committee was formed to provide a venue for stakeholders to identify and coordinate development of updated fatigue design criteria, analysis methods, and their associated physical and thermo-mechanical properties for application to Section III of the ASME BPV Code. The stakeholders include many international organizations including the Japan Society of Mechanical Engineers. Many PVP papers have been used as the basis for the Fatigue Action Plan items. The Steering Committee completed its work in 2019 with the adoption of a Fatigue Action Plan, which provided a vision for advanced fatigue approaches. The Fatigue Action Plan recommended specific Code actions and activities to guide and coordinate the Code actions in the area of fatigue. This paper outlines the overall Fatigue Action Plan and provides an update on the implementation progress. Section III has already accomplished several actions on the Fatigue Action Plan by publishing numerous Code Cases and Code revisions that have improved the analysis tools available to designers to address fatigue. This paper provides an overview and introduction to these Code Cases and other tools for designers. The Fatigue Action Plan was largely based on addressing the need for the light water reactor fleet to address low cycle thermal fatigue. The Committee also recognizes that going forward the Fatigue Action Plan must address the needs of the growing advanced reactor community as well as other users of the Code. The paper discusses these needs and Section III plans to meet these future needs.

For many nuclear power plants worldwide the operation period will be extended to 60 or 80 years in the coming years. As the operation period increases, the importance of knowledge of ageing mechanisms increases. In the framework of LTO there is limited knowledge about ageing and structural integrity of concrete structures. Recent developments have shown that ageing of civil structures receive more attention internationally. In order to increase the knowledge in the field of civil structures, this paper focusses on investigation of ageing of civil structures and determining an ageing management strategy. Knowledge of the ageing mechanisms of civil structures and especially concrete, will lead to improvement of ageing management and assessment methods of concrete. As a first step international information was gathered on civil structures ageing issues and management thereof (see PVP2019-93029). In addition a highlevel assessment methodology was proposed. In the next step the initially proposed assessment methodology has been tested by application to a nuclear reactor. The resulting list of relevant AMPs has been verified with the outcome for another PWR with a steel containment. With this experience the assessment methodology is tested, compared and improved (see PVP2020-21838). The results indicated that the method can be used to obtain a list of plant specific AMPs. What was added to the assessment method is the link to the TLAAs for civil structures. In this follow up step the transition is made from a high level of IGALL AMPs to a practical AMPs that will deal with the right mechanism at the right location. The detailing to a level of practical work instructions for the maintenance of the plant has to be made in order to make real life implementation possible. In this step studying of relevant degradation mechanisms, relevant AMPs (like IAEA AMP305 and AMP306 ) and applicable literature in combination with the practical knowledge from operation of a reactor, has taken place. The international developments on ageing management of concrete will be included. The goal of the project is to obtain more knowledge on ageing management of civil structures and especially concrete. It will lead to an assessment method for civil ageing management and ageing management programs dealing with the relevant mechanisms at the various locations in a practical manner. The results of this ongoing work are presented in this report. For the research reactor all SSCs in scope of the Continued Safe Operation could be linked to the relevant AMP(s) and a resulting set of plant specific AMPs for civil ageing management was obtained. Including the international developments, literature and guidelines, a more general applicable list was created (Table 5 through Table 13). The conclusion is that Figure 2 represents a practical method for obtaining a set of plant specific civil AMPs ready for implementation. For representation in this paper the final outcome is given in as a generic list of actions for a generic reactor (Table 5 through Table 13). In these tables the relevant SSCs, ageing mechanisms and actions are listed. The tables represent an generic list of actions for civil ageing management that might others help develop their ageing management program. Future steps are shifting the focus from the general but practical assessment methodology to finite element modelling techniques for concrete. The assessment criteria for concrete (e.g. in ASME III, ASME XIII or Eurocode) will be investigated and investigation on the modelling of the concrete for ageing are planned.

Since the Fukushima accident, with the higher safety requirements of nuclear facilities in Japan, suppliers, manufacturers and academic societies have been actively considering the reconstruction of the safety of nuclear facilities from various perspectives. The Nuclear Regulation Authority has formulated new regulatory standards and is in operation. The new regulatory standards are based on defense in depth, and have significantly raised the levels of natural hazards and have requested to strengthen the countermeasures from the perspective of preventing the simultaneous loss of safety functions due to common factors. Facilities for dealing with specific serious accidents are required to have robustness to ensure functions against earthquakes that exceed the design standards to a certain extent. In addition, since the probabilistic risk assessment (PRA) and the safety margin evaluation are performed to include the range beyond the design assumption in the safety improvement evaluation, it is very important to extent the special knowledge in the strength of important equipment for seismic safety. This paper summarizes the research and examination results of specialized knowledge on the concept of maintaining the functions of important seismic facilities and the damage index to be considered by severe earthquakes. In the other paper, the study on reliability of seismic capacity analysis for important equipment in nuclear facilities will be reported.

The Additive Manufacture (AM) of nuclear plant components, such as small-bore globe valves, offers opportunities to reduce costs and improve production lead-times. Cost reductions can be achieved by reducing raw material quantities, removing machining operations, and eliminating the welding of sub-assemblies. Furthermore, there is the opportunity to reduce production lead-times by simplifying the supply chain, e.g. reducing the number of parts to be sourced and eliminating special operations. Such opportunities are important against a backdrop of industry striving to reduce the cost of nuclear power generation in order to ensure viability with other forms of power generation. However, AM is a relatively new and innovative manufacturing technology, and although now seeing greater use in industry, there are still very few examples of where the technology has been applied to components used in safety critical applications. Furthermore, it is not covered by the American Society of Mechanical Engineers (ASME), Section III, nuclear design code. For nuclear plant applications, it is imperative a robust safety justification is provided. This paper presents Rolls-Royce’s approach to provision of a high integrity safety justification to enable the implementation of AM small-bore globe valves, up to a nominal bore size of 2” to nuclear plant. The material of construction is AM Laser Powder Bed Fusion (LPBF) 316LN stainless steel, with a Hot Isostatic Press (HIP) bonded LPBF Tristelle 5183 low cobalt hard facing seat. The paper describes the structure of the safety justification, which follows a multi-legged approach. It provides an overview of the innovative manufacturing process, which is, to the best of Rolls-Royce’s knowledge, the first of a kind application on nuclear pressure boundary components. The paper provides a summary of the suite of materials testing and metallurgical examinations conducted, and majors on prototype functional and performance testing where comparisons are made with the previous forged form. Pressure testing is covered which includes ultimate pressure testing to 2,000 bar, as well as: functional cyclic testing, hard facing bond strength tests, dynamic loading (shock), and cyclic thermal tests. In all cases the additive manufactured small-bore globe valves performed as well, and in some cases better than the forged material equivalent.

The work in this paper relates to an improved tube to tubesheet joint in a shell and tube type heat exchanger that have dissimilar metallurgies of tube and tubesheet. This improved tube to tubesheet joint configuration will not only impart reliability and strength to the mechanical integrity of the joint but also reduce the costs of the manufacturing without compromising the functional performance of the exchanger. In a shell and tube heat exchanger, generally the material of tubes may be similar to the tubesheet or of a higher corrosion resistant grade in comparison to that of the tubesheet. Conventionally, shell and tube heat exchangers that involve dissimilar materials of tube and tubesheet are either: i. Tubes welded directly to the tubesheet with matching grade weld metal or ii. The tubesheets are clad / weld overlaid with the higher corrosion resistant material or material similar to the tube material For purpose of this study, we have considered the material of tube as stainless steel type 304L and that of tubesheet as carbon steel. The above case 1 wherein the SS-304L tubes are directly welded to the CS tubesheet, may have the following advantages: i. Manufacturing time is less. ii. Tubes are attached to the base metal and hence free from defects of weld overlay or cladding, if any. In case 2, wherein the SS-304L tubes are welded to the SS-304L clad / weld overlaid portion of tubesheet, the advantages are: i. Welding takes place between two austenitic stainless steel grades, hence PWHT is not required. ii. The tube to tubesheet joint and adjacent material is of austenitic stainless steel grade, hence has better corrosion resistance. The main objective of the work done and reported in this paper is to combine the advantages of the above two cases thereby: i. Reducing the cost of manufacturing ii. Increasing the mechanical reliability of the tube to tubesheet joint. Extensive trials were carried out on sample tube to tube sheet joints, the results and conclusions of which are reported in this paper.

This paper is based on the experience made during the design and installation of an offshore pipeline recently completed in Indonesia, where a 24” subsea production pipeline (16km long in 70m water depth) was found susceptible during design to lateral buckling. To limit the development of excessive deformation within the acceptance criteria, a mitigation strategy based on interacting planned buckles has been adopted installing three Buckle Initiators (BI) along the pipeline route. Buckling is a well understood phenomenon. However, this project was characterized by major uncertainties mainly driven by soil characterization, soil-pipe interaction, seabed mobility and soil liquefaction. These uncertainties have played a key role in the in-service buckling design. A lot of engineering efforts have been spent to go through the screening between alternative concepts, the validation of the chosen solution and its detailed engineering phase. This paper discusses the main contributing factors and how the uncertainties have been tackled. The Buckle Initiators are quite large and heavy structures with two main bars: the first ramp has an inclination equal to 30° and the pipeline has been laid on it; a second horizontal ramp was used as sleeper to accommodate the development of the lateral buckle during the operating life. A rotating arm was also used to restrict the pipeline lay corridor on the inclined ramp guaranteeing a combined horizontal and vertical out-of-straightness in the as-laid configuration. The rotating arm has been released as soon as the pipeline passed the BI permitting the pipeline to slide freely over the two BI ramps. The foundation of the Buckle Initiator has a footprint surface of about 60m2 guaranteeing its stability for different soil types characterizing the three installation areas. This more complex solution was preferred with respect to a typical sleeper to increase the robustness of the system in terms of buckle mobilization. The design of the Buckle Initiator was a multidisciplinary activity where many novel concepts were developed and many issues were faced (i.e. pipeline laying on an inclined sleeper, anti-scouring system, foundation design, etc.). The Buckle Initiator design was focused on structural calculations against design loads expected during temporary and operating conditions, geotechnical verifications, installation analysis, pipeline configuration and fatigue assessment. This paper presents all main engineering aspects faced during design and first feedbacks from field after the pipeline installation.

This paper presents the development and testing of Gator, a hydraulic Power Take Off (PTO) being commercialised for the Aquaculture market. Gator uses a novel polymer bellows to pump pressurised water through a power take off system, while also providing a non-linear force response that reduces mooring line loads over traditional mooring lines. The Gator system is comprised of 4 distinct subsystems: The Gator pump, hydraulics, turbine, and electrical storage & control. The Gator pump is a polymer component that compresses under load, pumping water through check valves into the hydraulic system. The connected hydraulic system takes the pressurised water, regulates the pressure and flow rates with an accumulator, and provides a steady flow of water to the turbine, generating electricity. This paper will provide an overview of the technical development of the Gator system over several phases, which has focussed its adaptation for use in the aquaculture industry as an inline pump on cage mooring lines. A description of comprehensive testing undertaken on a linear test rig to simulate the variable loading that the system would experience in operation will be provided as well as some of the early characterisation results from this testing.

A riser is a key component for transporting produced oil and gas from the subsea wells to the surface production vessel. Through nearly 30 years of design and implementation, Steel Catenary Risers (SCRs) have been found to have the advantages of relatively low cost and good adaptability to floating platform’s motion. This paper investigates deepwater SCR system design for the Lingshui 17-2 (termed LS17-2) project. This paper first introduces a SCR system for the LS17-2 project. The field for this project is located in the northern South China Sea, with water depth of 1220m to 1560m. LS17-2 consists of a subsea production system, a deep-draft semi-submersible (SEMI), and an export riser/pipeline. The platform was designed to have a large storage capacity with a variable draft during its operation. Based on deepwater SCR engineering experience, the key SCR design challenges are summarized from the engineering executive perspective. The challenges to the SCR system design for the LS17-2 project include harsh environment condition in South China Sea and the impact on fatigue design for the requirement of 30-years’ service life. They call for design optimization and innovative ideas. The engineering design and analysis are discussed together solutions. To demonstrate the deepwater SCR system design for LS17-2 project, examples are provided to illustrate the challenges and solutions. The experience learned from this paper should have significant relevance to future SCR design.

Bolted joints in gas turbines are used commonly to connect the parts of dissimilar materials to facilitate assembly, dis-assembly, and also to achieve modularity for advanced aero engines. In gas turbine engine, there are many rotating and stationary parts that are subjected to an extreme working environment. Bolted joints should have sufficient strength to support the mating parts such as safety critical fan/turbine discs, drums, and shaft assembly. Bolted joints are designed to avoid flange separation and slippage. This paper attempts to understand the challenges faced in designing a typical fan disc rotor plain flange type bolted assembly and structural integrity aspects under various thermo-mechanical operating loads. The understanding of stiffness of the bolt and joint members is necessary to evaluate the performance of the joint assembly. Based on literature, different approaches are used for estimating member stiffness to compare with finite element results. The effect of external loads such as thermo-mechanical loads on pretension behavior of bolted joint is studied with the help of standard commercial software platform ANSYS. Bolted joint preload loss has been assessed via the standard analytical method and validated with 3D finite element approach. This paper enables designer a quick understanding of rotor bolted joint behavior for finalization of gas turbine rotor layout, before going into complex and time consuming 3D finite element modelling and nonlinear stress analysis.

Emerging additive manufacturing technology offers many opportunities for improved cooling design in gas turbine components by enabling design of cooling passages and shapes that are not manufacturable with conventional methods. Many combustion components have already taken advantage of these design opportunities however adaptation of this technology in turbine hot gas path components has been slower due to challenges with demanding environment and restriction on material properties obtained from additive manufacturing. This paper represents application of additive manufacturing technology in an F class industrial gas turbine including design, development and validation steps of a 1st stage turbine vane. A systematic design approach was undertaken to examine all aspects of operation and cooling of the component to down-select the appropriate design, material and processing. Detail characterization of multiple relevant material properties such as LCF, fracture toughness and creep was conducted to obtain material data and generate elastic and viscoplastic models for component design. Subsequent microstructural analyses of creep specimen were conducted to evaluate creep mechanism. Cooling design studies and coupon specimen testing were conducted to determine heat transfer and flow characteristics of micro channels used in the airfoil design. Detailed conjugate heat transfer analyses were used to iterate and optimize the cooling design. Once final design requirements were achieved, a number of prototype engine components were manufactured and tested in continuous engine operation for a predetermined duration of more than 6 months. These prototype components were removed from the engine after successful operation for validation purposes. Uniform crystal temperature sensors (UCTS) were used to validate the new cooling design. Destructive microstructural evaluations were performed to determine the impact of in-service operation on additive manufactured material. Details of the design and development steps as well as the results of prototype tests and microstructural evaluations are presented and discussed in this paper. It is demonstrated that with proper considerations of the resulting material properties, adaptation of additive manufacturing technology in turbine components is feasible with a comprehensive development process.

To meet today’s and future market needs, large end-stage blades are obliged to fulfill high flexibility regarding the operational range and high efficiency goals while being prepared for daily start-stop cycles. The end-stage total efficiency can be maximized by enlarging the steam turbine exhaust area and thereby reducing the exhaust losses. Therefore, a new Low Pressure (LP) backend featuring an increased freestanding 41″ steel blade has been developed and is presented here, which is optimized for maximum efficiency over a wide range of operation conditions. To allow for such a large steel-blade to operate at 60Hz rotational speed and to meet the daily cycling demand, various aspects of the blade design were optimized. A new high strength blade steel was developed (Teuber [1]), which gives the designer freedom for aerodynamical optimizations, while keeping the mechanical utilization within the predefined, allowable limits. To maximize the cycling capability, a new fir tree root was developed which minimizes the static as well as the dynamic loading. To verify the success of the new fir-tree root design and to verify the natural frequencies for the relevant modes, an extensive validation measurement campaign was setup with a full-scale blade row in a spin-pit. Here, the airfoil, root and steeple of the end-stage blade were equipped with strain gauges. Additionally, the blade row was monitored using tip-timing sensors. The results of this validation measurement campaign are presented in this paper. They show a close agreement between the design calculations and the measured static strains and vibration responses in terms of natural frequencies as well as displacement and strain amplitudes. Additionally, a test turbine has been set-up featuring a direct scaling of the new LP backend with the new high strength steel and a pre-stage to simulate realistic operation conditions over the complete operation range. The blade performance was tested up to high mass-flows, condenser pressures of up to 300 mbar and at varying load points covering all potential load points from extreme part load to full load with minimal and maximal condenser pressure. Strain gauges as well as tip-timing are used to measure the vibration response of the end-stage blade during the measurement campaign. The results presented here show, that throughout the complete measurement campaign the blade experienced minimal excitation which led to vibration levels that allowed unrestricted operation in the complete, tested operation range. In summary this paper shows the main design features of a large full-speed freestanding end-stage blade and the validation measures that were performed to ensure that the design targets and the market requirements are fully met.

Organizing manufacturing in dynamic networks instead of inflexible production lines is one of the key aspects of Industry 4.0. This should serve to realize automation and effectiveness to a higher degree than previously achievable. For this modernization, Cyber-Physical Systems should be utilized, where a Digital Twin mirrors the behavior of its Physical Twin and makes the data during manufacturing externally available via communication interfaces. This Digital Twin should be an instantiation of a Digital Master, which must meet the requirements for communication in dynamically changing value-added networks. The networking capability of objects requires semantic information. This information is associated with rules for decision making within a value-added network. This paper addresses the need for research on how to add networking capabilities during the development of Digital Masters. With these added capabilities, the communication between Digital Masters and Twins in terms of a single part manufacturing simulation should be verifiable in a Digital Factory. For this purpose, the concept of this paper aims to outline guidelines on how to add networking capabilities to the single part, machines and other resources needed during manufacturing.

In this paper, we present a method for fabricating inexpensive, disposable, articulated instruments for minimally invasive surgery based on Japanese paper arts. Building on the literature covering the kinematics of origami, we introduce an articulated instrument design with antagonistic tendon actuation. A general method for achieving a fixed motion scaling ratio in these types of systems is also presented. Kinematic simulations and prototyping demonstrate feasibility of this concept.

Lab-grown diamond heat spreaders are becoming attractive solutions compared to traditional copper heat spreaders due to their high thermal conductivity, the ability to directly bond them on silicon, and allow for an ultra-thin silicon layer. Researchers have developed various thermal models and prototypes of lab-grown diamond heat spreaders to evaluate their cooling performance and heat spreading ability. The majority of existing thermal models are built using finite-element method (FEM) based simulators such as COMSOL and ANSYS. However, such commercial simulators are computationally expensive and lead to long solution times along with large memory requirements. These limitations make commercial simulators unsuitable for evaluating numerous design alternatives or runtime scenarios for real-world high-performance processors. Because of this modeling challenge, none of the existing works have evaluated the thermal behavior of lab-grown diamond heat spreaders on real-world high-performance processors running realistic application benchmarks. Recently, we have developed a parallel compact thermal simulator, PACT, that is able to carry out fast and accurate steady-state and transient thermal simulations and can be extended to support emerging integration and cooling technologies. In this paper, we use PACT to evaluate the steady-state and transient cooling performance of lab-grown diamond heat spreaders against traditional copper heat spreaders on various real-world high-performance processors (e.g., Intel i7 6950X, IBM Power9, and PicoSoC). By using PACT with architectural performance and power simulators such as Sniper and McPAT, we are able to run transient simulations with realistic benchmarks. Simulation results show that lab-grown diamond heat spreaders achieve maximum temperature and thermal gradient reductions of up to 26.73 °C and 13.75 °C when compared to traditional copper heat spreaders, respectively. The maximum steady-state and transient simulation times of PACT for the real-world high-performance chips and realistic applications used in our experiments are 259 s and 22 min, respectively.

Designing commercial aircraft to use liquid hydrogen (LH2) is one way to substantially reduce their life-cycle CO2 emissions. The merits of hydrogen as an aviation fuel have long been recognized, however, the handling of a cryogenic fuel adds complexity to aircraft and engine systems, operations, maintenance and storage. The fuel tanks could account for 8–10% of an aircraft’s operating empty weight, so designing them for the least added weight is of high significance. This paper describes the heat transfer model developed in the EU Horizon 2020 project that is used to predict heat ingress to a cylindrical tank with hemispherical end caps with external foam insulation. It accounts for heat transfer according to the state of the tank contents, the insulation material properties, the environment, and the dimensions of the tank. The model also estimates the rate of pressure change according to the state of the fuel and the rate at which fuel is withdrawn from the tank. In addition, a methodology is presented, that allows for tank sizing taking into consideration the requirements of a design flight mission, the maximum pressure developed, and the fuel evaporated. Finally, the study demonstrates how to select optimal insulation material and thickness to provide the lightest design for the cases where no gaseous hydrogen is extracted, and where some hydrogen gas is extracted during cruise, the latter giving gravimetric efficiencies as high as 74%.

Active aerodynamics is a promising technology to improve vehicle performance and efficiency, but so far in the automotive field the actuation methods suffer with several drawbacks that jeopardize its functioning and broad implementation. Morphing wings represent a technology already studied for aerospace applications that could help overcoming some of those issues. This paper proposes a piezoelectric transducer actuation for a composite material automotive wing and seeks to validate it through virtual models and physical tests. Experimental validation with a 3D-printed simplified wing profile confirms the feasibility of the technology and helps determining the best position for the piezo actuator. Furthermore, a FEM model is presented, where the piezo effect is simulated through a thermal analogy. An optimization of the composite stacking sequence is performed to maximize the trailing edge displacements, and its results are compared with the deflection caused by aerodynamic loads observed in the wing. The displacement of the trailing edge is in the order of tenths of a millimeter, even though further investigations are necessary to improve overall impact of the solution the preliminary results are promising.

In the recent years, the materials composing the traditional of aircrafts are being progressively replaced with lower density materials, as the Reinforced Plastics. The same trend has been highlighted in the Automotive field to assess the reduction of fuel consumption and CO2 emission. In order to achieve an optimization of maintenance a variety of on-board systems has been applied for on-line SHM based on piezoelectric transducers earned a particularly high interest for continuous monitoring on metallic and composite structures. The application of this system in automotive could enhance passenger safety, through the monitoring of the vehicle composite material structure health status. In this paper, six mathematical models for evaluating the electrical response of piezoelectric sensors have been implemented, with the aim of selecting the most effective model for damage identification. Experimental tests were carried out on three types of simpler specimens of different geometries made of different materials (steel, aluminum and carbon fiber). A correlation study has been carried on in order to support the positioning of sensors. The proposed numerical-experimental methodology is an essential foundation for the introduction of monitoring systems based on piezoelectric transducers in the Automotive sector.

Smart farming experiential learning and research endeavors have been ongoing at the University of Maryland Eastern Shore (UMES) for the past several years. Recent field implementation of contemporary technologies for variable rate fertilizer application based on multispectral drone imagery; deployment of wireless solar powered soil moisture sensor network on a field with subsurface drip and fertigation capability; and development of a sustainable platform integrated with a Cartesian robotic device powered by solar and wind energy that can seed, weed, irrigate, and capture time-lapse photography while servicing a small raised bed for specialty crops and vegetables will be described in this paper. Results from the initial phase of implementation efforts and future goals will also be highlighted.

The exploration of new lands has always been a source of motivation for mankind. Despite the common idea that our planet is fully known, a huge number of inaccessible places still remains unvisited today, especially below the surface. Recent advances in robotics allow some of these locations to be explored by unmanned vehicles. This paper presents the design of a 3-modules lighter-than-air vehicle specifically conceived to autonomously explore inaccessible caves and underground environments. The design is inspired from an arthropod, scutigera coleoptrata, a long-legged centipede commonly found in our houses. Instead of crawling on walls like its biological counterpart, the robotic scutigera hovers and flies in cave tunnels. The aim is to develop a flexible semi-rigid, segmented airship that can withstand long, smooth explorations of caves while transmitting in real-time the images and sounds that it captures. To develop the model of the system, the kinematics of the modules are obtained in the inertial frame, and the dynamic derivation of the vehicle is obtained using Kane’s equations, which can also be extended for an n-bodies system. Its motion is illustrated with a couple of simplified scenarios in the horizontal plane and only having actuation in the front, or first module, of the airship. A structural design of the modules is presented and supported with a proof-of-concept prototype.

Additive manufacturing (AM) processes are gaining popularity and are currently used in many research activities including the biomedical applications, the automotive industries and the aerospace. Laser powder bed fusion (LPBF) is an important AM process. Metallic LPBF process is experiencing significant growth, but one of the difficulties facing this growth is limited knowledge of its dimensional and geometrical performances, in addition to the inability to predict it. In this paper, we present the dimensional deviations of some LPBF-manufactured parts selected for this investigation. a uniform method was developed regarding relevant test specimens to examine dimensional deviations in order to derive dimensional tolerance values. The manufactured test specimens were measured to examine the process dimensional deviations behavior. These parts were manufactured from AlSi10Mg powder using an EOSINT M280 printer. The results show possible dimensional tolerance values that were classified from IT1 to IT11 according to the international standard ISO 286.

The adoption of additive manufacturing methods is becoming prevalent in industry. Socio-economic trends seek more customization and sustainability in production. An increase in unique service components will warrant the need for more flexible repair methods. This is particularly important for components that are difficult to access or disassemble — thus requiring an on-site repair. This paper introduces the use of 3D printing pens as a means to perform repair to additively manufacturing components. A study was conducted to assess the feasibility of using a 3D printing pen in maintenance, repair and overhaul (MRO) applications on polymer-based service products. A series of tensile tests were conducted on printed specimens, pre- and post-repair, to examine the tensile retention of the mended region. Results indicate significant retention in tensile strength in the mended specimens, supporting the notion of the pens relevance in repair and overhaul applications. Specimens that fractured within the repair region were seen to have retained (81 ± 10) % of their original tensile strength while specimens that fractured outside the region retained (86 ± 4) %. Considering the limited control of the study, results acquired encourage further analysis of the underlying mechanisms in the process, with the intent to more efficiently exploit this approach for practical structure-based repair applications.

A substantial part of the global energy mix depends upon fossil fuels that needed to be reduced to overcome the pollution and environment-related challenges. This has directed the world to shift the energy mix towards renewable energy technologies. Among the development in renewable energy technologies, the development of solar tower power plant is an active research topic. Over the past decade, advances in computers and simulation software systems have greatly expanded their use in design and development, which can facilitate the engineering activities of solar tower power plants. However, an important limitation is the visualization of three-dimensional geometrical design data onto two-dimensional computer screens. VR technologies are a great means in the visualization of 3D data. Therefore, this article attempts to illustrate a concept for the application of VR technologies in the development of solar tower power plant and lists down relevant support scenarios. The main focus of the paper is on analyzing the efficiency of the VR technology used in the design of solar tower power plants and learning from the experience gained in this process. A discussion about further scenarios ranging from on-site visualization of solar tower power plant infrastructure, installation and repair, cleaning and maintenance, etc. is included as well as future directions are pointed out. The demonstrator part consists of an Android Smartphone-based VR application and an HMD based VR application. Furthermore, a brief comparison of both the applications as well as of HMD and sVR is also provided.

The geometric shapes of coils influence the performance of a 3D IPT system. In this paper, we proposed a 3D coil design method based on (3D) printing electronics. Given a 3D transmitter coil, the center position of the receiver coil is estimated as a random seed position in the corresponding 3D surface first. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the coil. For each extension of the coil, i.e. a new turn, the shape of the coil is optimized by calculating the convex hull of the new turn in the 2D projection plane. Using this method, we are able to generate a receiver coil to transmit “just enough” power at a given seed position. Then, by fixing the receiver coil, the 3D shape of the transmitter coil can be optimized as well. This zig-zag optimization process iterates until there are few changes of the position and 3D shapes in the iteration. Experiment results with Ansys Maxwell verified the effectiveness of the proposed 3D coil design method, and highlighted possible future research directions as well.

System Engineering education typically includes content to help students learn to design and engineer large, complex systems in a structured way. In this paper, we describe the outcomes of introducing a human-centered design tool, the Inspiration Design Toolkit (IDT), to encourage students to think non-linearly. The IDT is an educational resource consisting of a deck of illustrated cards that contain provocative questions, reflection messages and icons, applicative examples, and key takeaways on microlearning units. The aim of the IDT is to improve the participants’ learning experience and course engagement, increase opportunities for them to interact with their peers and teaching team, enable them to practice and reinforce the concepts through the creation of their own IDT cards, and share the cards in the discussion to increase learners’ engagement with course material and peers. We designed the IDT for an MIT online course on System Thinking. We collected, analyzed, and synthesized qualitative and quantitative feedback from 171 course participants. Our findings suggest that IDT provides learners with a digital asset that allows them to reinforce and recall the course takeaways, and apply them to other contexts. For future research, we want to understand how learners like and use IDT through demographic differences and preferred self-identified learning styles. We discuss how these findings may help educators consider critical design principles and for creating a digital self-learning toolkit connected to the course content and increasing its content adaptability.

Approximately one-third of anthropogenic greenhouse gas emissions from energy and processing are from making products and chemicals. These emissions can be lowered if they are deliberately considered during the design of products. How can lean product and process development (LPPD) be used to build environmental considerations into the product development system? We explore if LPPD is an effective system in delivering sustainable manufacturing. We conducted case studies in the automotive and oil & gas industries in which LPPD was used to deliver significant physical changes to the product and product manufacturing. We completed semi-structured interviews with stakeholders and focused on the motivation for the change, how LPPD was either a help or hindrance, and the delivered cost savings and environmental benefits. Findings from the case studies were used to structure a workshop on LPPD and sustainability held at a leading manufacturing (industry focused) conference. In this workshop, we focused on first identifying the main environmental impacts in each industry, the physical opportunities to reduce those impacts, and how LPPD might help or hinder delivering that change. This article structures the findings from the case studies and workshop. We present a guide (with examples) for how various LPPD methods (e.g., concept papers, value stream mapping, and design guides) might be used to meet sustainability challenges (e.g., reducing the generation of manufacturing scrap). While LPPD is itself agnostic to sustainability, we suggest that it is an effective method of creating an organizational system for promoting sustainable manufacturing particularly in complex environments.

Social Impact has been widely discussed by the engineering community, but studies show that there is currently little systematic consideration of the social impact of products in both academia and in industry beyond social impacts on health and safety. This paper illustrates how Failure Mode and Effect Analaysis (FMEA) style analysis can be applied to evaluating the social impact of products. The authors propose a new method titled Social Impact Effects Analysis (SIEA), describe how it is performed, and explain the benefits of performing SIEA.

Mechatronics and control education is supported by laboratory intensive assignments that allow students acquire software and hardware skills to solve real world problems. However, COVID-19 force many schools to switch into remote learning complicating the instruction of practical assignments. This paper presents a novel proposal for interactive remote teaching of the laboratory component of the course ME-142: Mechatronics at the University of California, Merced using Digital Twins (DT) and the flipped classroom methodology. Each lab experience is composed by a set of on-demand supporting materials with the foundations of mechatronics simulation using MATLAB/Simulink to enhance and adapt the learning experience of the students. Once the students acquire advanced simulation skills, a set of Digital Twin models are provided to the students in order to begin their interaction with virtual representations of real systems for identification, analysis, controller design and validation, which are available online for remote access. By the end of the course, students were able not only to gain valuable experience with mechatronic systems but also interact and build advanced modelling techniques as Digital Twin, contributing to compensate the lack of remote hardware interaction.

The Theory of Inventive Problem Solving (TRIZ) method and toolkit provides a well-structured approach to support engineering design with pre-defined steps: interpret and define the problem, search for standard engineering parameters, search for inventive principles to adapt, and generate final solutions. The research presented in this paper explores the neuro-cognitive differences of each of these steps. We measured the neuro-cognitive activation in the prefrontal cortex (PFC) of 30 engineering students. Neuro-cognitive activation was recorded while students completed an engineering design task. The results show a varying activation pattern. When interpreting and defining the problem, higher activation is found in the left PFC, generally associated with goal directed planning and making analytical. Neuro-cognitive activation shifts to the right PFC during the search process, a region usually involved in exploring the problem space. During solution generation more activation occurs in the medial PFC, a region generally related to making associations. The findings offer new insights and evidence explaining the dynamic neuro-cognitive activations when using TRIZ in engineering design.

Most innovations happen at the intersections of disciplines. New products get designed through synergistic integration of multi-disciplinary concepts. For example, in today’s automobiles purely mechanical systems have been replaced by “by-wire” devices that are software controlled, lighter, more efficient, and reliable. While engineering disciplines are merging seamlessly in real world products, academic silos are mostly still intact. At University of Detroit Mercy, we have broken down some silos by launching the Robotics and Mechatronics Systems Engineering major. Mechatronic Systems Modeling is a mandatory course in this major. This course uses a technique of power flow called bond graphs to model mechatronic systems. This technique is not discipline specific and students with different disciplinary background can easily understand and master it. Recently, the use of Simscape, a MATLAB/Simulink tool for physical system modeling has also been added to this course. The use of these two tools in complex system modeling tasks helps students develop an understanding of engineering system behavior by moving beyond the narrow boundaries of individual disciplines. This paper describes the course content and structure, the modeling methods, selected student projects, some of the lessons learned, and several offshoot activities that have resulted from this course.

In order to characterize wastewater pumps regarding their clogging behaviour, a wide variety of test procedures with artificial wastewater exist. These tests provide a good insight into the clogging characteristics of a pump. However, conclusions about the clogging mechanisms and their sources cannot be drawn. This paper deals with the design and implementation of an optical access on the suction side of a wastewater pump to allow visualisation of the interaction between impeller and textile via high-speed recordings. The optical access is realized by an endoscope and a connected high-speed camera with a frame rate of 2000 fps and a resolution of 1024 × 1024 pixels. To ensure sufficient illumination of the impeller, a light ring assembled from 12 high power LEDs with a luminous flux of 5595 lumen are circumferentially arranged around the suction side of the pump. The light ring concept is scalable to fit any pump size. A clogging-affine impeller is developed, 3D printed and used for experimental investigations. For the investigated impeller, the blade’s upper area is identified to be crucial for pump clogging. Optical accessibility provides an important contribution to develop non-clogging impellers.

Decommissioning of the Fukushima Daiichi nuclear power station (NPS) is an unprecedented effort in which the entire plant was contaminated with radioactive materials from the accident and radiation dose levels were not low. The decommissioning workers in these sites are indicated to wear personal protective equipment (PPE) properly for radiation protection. In response to the difficulties of on-site PPE management in decommissioning site of Fukushima Daiichi NPS, this paper presents a graph-based scene understanding approach that automatically identifies whether workers at a decommissioning site are using PPE properly. The experimental results demonstrate that the high precision and high recall of the model can effectively detect decommissioning workers’ failure use of PPE and can facilitate improved safety inspection and supervision.

In terms of quality management of raw materials for nuclear power equipment, equipment manufacturers implement quality management for raw materials according to different standards, to ensure the quality and reliability of nuclear power equipment. However, through some typical cases, it is found that many manufacturers do not effectively operate the quality assurance system in the equipment raw material quality management, and there are not enough anti-counterfeiting measures, resulting in unqualified raw material quality affecting the quality of nuclear power equipment. For example, when a manufacturer purchased ASME code grade bars for manufacturing nuclear valves, the raw material supplier forged part of the test reports from the third-party laboratory to make the results meet the requirements of the standard. However, the manufacturer did not find the problem in the procurement process. By comparing the quality assurance requirements of nuclear power units under different standards, this paper analyzes the problems in the process of raw material purchasing and quality management, combined with some measures and requirements to prevention CFSI, puts forward some suggestions for optimizing the quality assurance of raw materials for nuclear power equipment.

As one of the key technologies of the fourth industrial revolution, Additive Manufacturing (AM, also called 3D printing), which is the basis of innovation design with its high degree of manufacturing freedom, has been widely used in the construction field, aerospace field, automobile manufacturing field, biomedical field, etc. With the increasing maturity of additive manufacturing technology, it has been gradually used in the field of nuclear energy in order to realize design reform. Public reports have shows that additive manufacturing for the pressure vessel fuel, some kinds of fuel pellets, parts of fuel assembly and related core components has been realized. In this paper, the advantages and challenges of additive manufacturing technology used in nuclear fuel assembly design and manufacturing are analyzed, the application status of additive manufacturing technology in the field of nuclear fuel assembly design and manufacturing is summarized, and the application development trend of the additive manufacturing technology for the fuel assembly is also clarified. In general, although the application of the additive manufacturing technology in the field of nuclear fuel assembly design and engineering is still at the stage of research, the application scope of this innovative technology will be greatly expanded with the continuous progress and improvement of the additive manufacturing technology in the near future.

The decommissioning technology of nuclear facilities has been one of the most important research directions of nuclear industry for several decades, and further enhancements are being carried out in the world. The global published patents about the decommissioning technology of nuclear facilities are investigated in this work. The technology forecasting and the development strategy of the decommissioning technology of nuclear facilities was provided from the view of patents, based on the nations, the technology field, the trend in the number of patents applications. This work will contribute to understanding the advanced developments of the decommissioning technology of nuclear facilities by a new perspective. Through quantitative statistics and content analysis, the understanding of relevant industries and technology development trend of personnel in the industry is promoted from the perspective of open patent data, a complex of technology, law and economy. Through the technology and economy behind the patent data to ensure its reliability and authenticity, this paper puts forward suggestions and prospects for the practitioners in the field of nuclear facilities decommissioning from the aspects of how to combine the research and analysis of patent situation with the development of the industry.

The conventional storage tanks are either fully restrained by hold-down connections or unanchored which are free for rocking motion during an earthquake. This generally creates a high level of seismic force due to lack of ductility or large displacement demand due to uplift, resulting in damage to tanks. However, a more efficient approach could be using partially restrained connections to control both the deflection and force at the desired levels. In this paper, an innovative generation of anchorage system has been introduced by employing the Resilient Slip Friction Damper (RSFD) as a ductile self-centring hold-down system. This new tension-only damage-free anchorage mechanism mitigates the transmitted earthquake force to storage tanks by dissipating the input energy through friction without experiencing any damage, contrary to other common ductile yielding hold-downs. In this study, based on the numerical modelling of the tanks and the hold-downs performance (validated experimentally), a comparison has been conducted between the RSFD anchorage system with other ductile concepts (eg., necked-rod and buckling-restrained systems), considering three case studies with different tank aspect ratios. The proposed system is capable of considerably decreasing the transmitted force which leads to less seismic demand for designing the tank barrel as well as the foundation.

The seismic probabilistic risk assessment is an important methodology to evaluate the seismic safety of nuclear power plants. In this assessment, the core damage frequency is evaluated from the seismic hazard, seismic fragilities, and accident sequence. Regarding the seismic fragility evaluation, the probabilistic fracture mechanics can be applied as a useful evaluation technique for aged piping systems with crack or wall thinning due to the age-related degradation mechanisms. In this study, to advance seismic probabilistic risk assessment methodology of nuclear power plants that have been in operation for a long time, a guideline on the seismic fragility evaluation of the typical aged piping systems of nuclear power plants has been developed considering the age-related degradation mechanisms. This paper provides an outline of the guideline and several examples of seismic fragility evaluation based on the guideline and utilizing the probabilistic fracture mechanics analysis code.