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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.

The high pressure (Hyper) Compressor is one of the most critical assets within a LDPE production line. Failures starting off with simple valve leakage may lead into interstage pressure variation, load increasing and loss of load reversal and finally a main bearing failure resulting into multiple days’ downtime. This paper describes some of the challenges and a proven effectively method for monitoring Hyper compressors and its individual components. Using a series of short real-life case studies, it will be illustrated how a state-of-the-art monitoring technology helps to detect impending failures at an early stage to eliminate consequential damages and avoids to be caught off-guard. One case study describes the early indication of a developing valve failure; another provides understanding how a packing failure is detected reliably. The third case study covers aspects of a safety relevant damage resulting into an automatic compressor shutdown, which otherwise would have likely resulted into significant and costly production loss. The session will be concluded with hands-on guidance on recommended Safety Protection analysis.Copyright © 2015 by ASME

This paper predicts burst pressures of the steam generator tubes with multiple cracks using finite element (FE) damage analysis. Alloy 690(TT) tube (the outer diameter of 19.05 mm and the thickness of 1.07 mm) widely used in the nuclear power plant is considered in this study. Ductile failure at each element is predicted with the damage model known as ‘multi-axial fracture strain model’ as well as crack propagation is simulated by stress reduction technique in the FE analysis. Simplified ductile damage model for Alloy 690(TT) are determined using tube tensile test data and elastic-plastic FE analysis. FE damage analysis results are sensitive to the element size used in the crack propagation region. Using notched tube fracture test data, proper element size for Alloy 690(TT) is found. Single, collinear, parallel, non-aligned axial-cracks are considered in the simulations and the predicted burst pressures are compared with burst test data.Copyright © 2015 by ASME

In the past few decades, ultrasonic guided waves have been utilized more frequently Non-Destructive Testing (NDT); most notably, in the qualitative screening of buried piping. However, only a fraction of their potential applications in NDT have been fully realized. This is due, in part, to their complex nature, as well as the high level of expertise required to understand and utilize their propagation characteristics. The mode/frequency combinations that can be generated in a particular structure depend on geometry and material properties and are represented by the so-called dispersion curves. Although extensive research has been done in ultrasonic guided wave propagation in various geometries and materials, the treatment of ultrasonic guided wave propagation in periodic structures has received little attention. In this paper, academic aspects of ultrasonic guided wave propagation in structures with periodicity in the wave vector direction are investigated, with the practical purpose of developing an ultrasonic guided wave based inspection technique for finned tubing. Theoretical, numerical, and experimental methods are employed. The results of this investigation show excellent agreement between theory, numerical modeling, and experimentation; all of which indicate that ultrasonic guided waves will propagate coherently in finned tube only if the proper wave modes and frequencies are selected. It is shown that the frequencies at which propagating wave modes exist can be predicted theoretically and numerically, and depend strongly on the fin geometry. Furthermore, the results show that these propagating wave modes are capable of screening for and identifying the axial location of damage in the tube wall, as well as separation of the fins from the tube wall. The conclusion drawn from these results is that Guided Wave Testing (GWT) is a viable inspection method for screening finned tubing.Copyright © 2015 by ASME

The Hanford Tank Waste Treatment and Immobilization Plant (WTP), located in southeastern Washington state, will process waste slurries capable of retaining a dispersed non-condensable gas phase while in a quiescent state. Under postulated conditions, a pressure pulse generated from a deflagration or detonation within a flammable gas pocket may be transmitted into piping systems that contain the gas-liquid slurry. In general, this traveling pressure pulse will impose structural loads on the piping and its associated supports. It is necessary to understand how a pressure pulse attenuates as it propagates through the system in order to properly quantify the structural loading. Simplifications to the general equations are presented in this paper that are applicable to WTP while eliminating the numerical challenges associated with the full set of equations. This alternate set of equations is used to model the propagation and attenuation of a pressure pulse characteristic of those of interest to WTP in a slurry system that contains a small amount of dispersed non-condensable gas. The numerical results are compared to experimental data and are shown to be consistent with experimental observations.Copyright © 2015 by ASME

Nowadays, nuclear power plant (NPP) has become one of the most important energy sources to generate electricity in the world. Steam generator (SG) is a heat exchanger included in primary system of NPP. Alloy 600 MA is widely used for SG tube material and this is well-known as weakness of stress corrosion cracking. In recent year, according to increase the number of long-term operation NPP, many axial surface flaws have been found on SG tube during an in-service inspection. Therefore, many researches have been carried out to maintain structural integrity of SG tube. Commonly, flaw shape needs to be idealized to calculate a burst pressure because detected flaw shape is complicated. In this paper, validation of EPRI’s weakest sub-crack model, one of the well-known flaw idealization rule, is conducted through finite element (FE) analysis. For this, three actual flaws are assumed and these are idealized by using four flaw shape idealization methods; semi-elliptical crack model, rectangular crack model, maximum length with effective depth crack model and weakest sub-crack model. Burst pressure of each model is calculated and compared with burst pressure of actual shape crack model. As a result, if actual flaw is idealized by weakest sub-crack model, it is expected that conservative and efficient structural integrity assessment will be possible.

With strong bearing capacity, good corrosion resistance, excellent wear resistance, light weight and easy transportation and installation, Plastic pipe reinforced by cross helically wound steel wires (PSP) is widely used in oil industry, coal chemical industry, slurry transportation engineering, and sea (river) bottom water projects. Due to the PSP at middle-high pressure, an effective and reliable method of connection between pipes is particularly important. Heat-fusion weld and electro-fusion weld are usually used in middle-high PSP connections, or adding steel plate reinforcement at present. The pipe welded-joint failure is the main failure mode at service stage, causing the damage of pipelines and fluid leakage. Ultrasonic phased array inspection, which is one of the non-destructive inspection methods, is mainly used in pipe welded-joints inspection. A higher attenuation coefficient of polyolefin materials and the interference of steel mesh skeleton among PSP can cause great impact to the ultrasonic inspection; It’s worse if a steel plate is added. In order to put forward a kind of method can better detect the connection joint, this paper examines a new method of ultrasonic phased array inspection in PSP welded-joints based on customized probe, focus law and scanning mode which overcomes the difficulties found in other usual non-destructive inspection measures.Copyright © 2015 by ASME

The LDPE process involves an extremely high gas pressure in the range of 200 to 300 MPa (2000 to 3000 bar / 29 to 44 kpsi) being provided by so called Hyper compressors. Many of the old machines are still in operation and kept fit for purpose since they still render good service and maintenance costs are well acceptable versus the investment for a new unit. Legacies have been taken over by others if the original OEM does no longer exist. The Hyper compressor cylinder performance is very much associated with the special arrangement of the frame, and the operation implies a perfect movement of the plungers to reduce radial loads on the packing internals to a minimum. High accuracy alignment procedures are therefore of the essence to obtain the best life of the packings and the driving gear. Despite their substantial size and mass the manufacturing tolerances, internal gaps and clearances — particularly for the bearings and crosshead guides — are within the 1/100 mm (0.4 mil) range. As practiced for decades for old Hypers the crosshead shoes are still today scraped by hand to make them perfectly fit into their guide. On the other hand modern laser technique has proven to be the appropriate equipment to ensure the proper quality for the refurbishment of all parts and pieces. The application of such technique — both in the workshop as well as in the field — increases the accuracy of complicated assemblies and also, since laser measurement is quick, reduces down time tremendously. Last not least carefully followed check list procedures for condition verification provide the best achievable MTBM (Mean Time between Maintenance). This paper outlines particular focus points of a Hyper to keep it smoothly running for a long time.

Methods to demonstrate break preclusion for pressure retaining components in nuclear power plants are summarized in the newly developed German safety standard KTA 3206, especially the requirements for the leak-before-break assessment of crack-like leaks. In this context numerical and simplified calculation methods for both the leak opening area and fluid flow rates of crack-like leaks were examined and validated on selected experiments. Second topic of the paper is an accident analysis for a postulated leak in form of a through-wall crack in the pressurizer surge line (SL) of a German PWR Konvoi type. The initial size of the leak as well as the changing size depending on system pressure and temperature during the postulated leak accident was calculated with a FEM analysis model of a cooling loop. The reduction of the leak area amounts in the examined transient to ca. 25 % after 1 h and leads also to an approximately 23 % smaller leak rate. These results depend on the assumed position of the leak and on the initial leak size. Therefore, the results of accident analyses due to postulated leaks can be influenced by the change of the leak size during the course of the accident.

When a rigid wall is replaced by a cavity covered by a flexible plate, the plate can cause broadband sound reflection in a duct. In this paper, analytical formulations in previous studies are extended to the plate with clamped-free boundary conditions. A set of static beam functions, which are a combination of sine series and third-order polynomial, is employed as the trial functions of the plate vibration velocity. Optimization is carried out in order to obtain the widest sound reflection bandwidth. Further studies with regard to the plate under several different classical boundary conditions based on the validated model show that, a clamped-free plate in the duct has the narrowest sound reflection bandwidth. In order to understand the precise mechanism of the spectra change, the behavior of each clamped-free plate mode is also analyzed. It is found that the weak first modal response in a clamped-free plate leads to its performance degradation.Copyright © 2015 by ASME

Self-healing is the ability of a material to repair damages automatically. Approaches to self-healing are separated into two major categories, those are: 1) autonomous healing methods that depend on intrinsic mechanisms, and 2) assisted healing methods that need an external intervention. Recently, computational methods have gained a wide application to study self-healing in metals using molecular dynamics (MD) and finite element (FE) methods. These methods can be used to demonstrate and optimize different metallic alloys potential to self-heal, and to further tailor these metallic structures toward improving their mechanical and fracture properties through self-healing. Computational studies of self-healing phenomenon in metals have been small in number and scope till recently. Therefore, the current paper starts with a general introduction of different mechanisms of intrinsic self-healing in metallic structures. The paper highlights previous studies using different experimental and computational approaches to explore self-healing in metallic systems, while focusing on Iron/Steel alloys. Furthermore, the paper present authors work to study self-healing and its impact on mechanical properties of Iron. Simulations are carried on bi-crystalline iron sample to investigate the effect of alloying elements diffusion on the fracture / healing properties of iron alloys and their impact on its mechanical properties. Then the effect of the alloying elements diffusion on healing is studied upon stress application after annealing. Different samples been compared to healthy samples and cracked samples without self-healing to demonstrate the effectiveness of self-healing in Iron alloys.

Well-designed tissue engineering scaffolds are needed for effective healing by regulating cell behavior such as cell attachment, proliferation and differentiation. Scaffolds should not only exhibit biocompatibility, interconnected porosity and strength but should provide hydrophilic surface where cell adheres in-vitro and in-vivo. The aim of this study is the fabrication and analysis of porous and surface functionalized biocompatible scaffolds for bone tissue engineering. In the first part of the study, we produce porous polycaprolactone (PCL)-nano-hydroxyapatite (nHA) scaffolds using earlier proposed non-solvent induced phased separation (NIPS) and use initiated chemical vapor deposition (iCVD) for coating these scaffolds with Poly (hydroxyethylmethacrylate-co-ethyleneglycol dimethacrylate) (p(HEMA-co-EGDMA)) polymer. The goal is to increase hydrophilicity of scaffolds using iCVD coating on scaffolds fabricated using NIPS and to demonstrate its feasibility for further functionalization such as GF immobilization and release. In the second part of the paper we develop an initial analysis framework suitable for the characterization of BMP-2 growth factor (GF) release of both coated and uncoated bone scaffolds using a Finite Element Analysis taking into account diffusion and possible chemical reaction. In the experimental part, surface characterization via Fourier-transform infrared spectroscopy (FTIR) confirmed a successful conformal coating and contact angle measurements demonstrate that desired hydrophilic surface was obtained after iCVD coating. Therefore, the first part of the study demonstrated that surface modified PCL-nHA scaffolds with p(HEMA-co-EGDMA) hydrogel exhibited increased hydrophilicity that should allow for augmented compatibility with cell media by enhancing cell attachment, proliferation and differentiation in vitro. In the computational part of the paper, as a second parametric study, the effects of a possible iCVD coating were analyzed by modifying the biomaterial matrix domain and tuning its diffusion coefficient where the reaction and release is expected to occur. The diffusion coefficient of coating material was set to two different values chosen lower than the tissue domain. Simulation results for the addition of a coating layer with a larger diffusion coefficient value resulted in a decreased BMP-2 diffusion accompanied by a parallel decrease in BMP-2 concentration in the tissue with respect to time and across the domain. Overall, it is concluded that initial parametric studies showed that the release and concentration profile could be tuned based on morphological and material properties of the scaffold. Also, coating biomaterial matrix via iCVD acquired directional/anisotropic diffusion in the model domain via one-sided coating of the scaffold matrix. Formal optimization studies could be integrated to the proposed simulation model to design functional scaffolds coated with iCVD for controlled and directional growth factor release.

Milwaukee School of Engineering’s Mechanical Engineering Department, having successfully completed the accreditation of the ME program in 2018–19 under the prior a through k student outcomes, dedicated the program meetings during academic year 2019–20 to develop assessment instruments in transitioning to the new ABET Student Outcomes 1–7. By deliberately involving the entire faculty to participate in the development of instruments, a grassroots level discussion and creation ensued for each outcome. The process is showcased in this paper for Student Outcome 4 on ethics as a model to share with our engineering faculty and to highlight salient features in the developed instrument and associated rubrics. The details of performance indicators interwoven across the curriculum and the methods of data collection are provided in a tabular form for ease of expectation and implementation. How the readily available materials from the National Society of Professional Engineers could be incorporated at early years of the baccalaureate program while the outcome’s performance indicators could be assessed at a deeper level during junior and senior years are showcased in this paper. The periodic dialogue among all colleagues who were working on various outcomes ensured proper communication of what one outcome group is prescribing that we do and receive input from those who are involved with the courses in which the data needed to be collected and the performance indicators are to be assessed. The general structure of our standing committees on freshman courses, energy, mechanics, and controls also provided the cushion to review the assessment instruments and provide constructive feedback from the corresponding committee’s perspective. These details of a very interactive Student Outcomes Assessment process will be presented.

Hydrogen is well known to have a detrimental influence on the ductility of low alloy steels, reducing the fracture toughness. Standard test methods to characterize fracture toughness of steels in terms of ductile tearing resistance curves have not been developed to account for any hydrogen-driven contribution to the crack extension, Δa. Simply plotting J or CTOD against Δa is not necessarily appropriate for defining the initiation fracture toughness for tests performed in a hydrogen-charging environment. This paper explores a method to further analyse experimental data collected during fracture toughness tests, which allows the contribution of plasticity (i.e. when blunting precedes ductile tearing) to be considered separately from the initiation of crack extension (which could be by stable tearing and/or by hydrogen-driven crack extension). The principle is based on the assumption that a crack growing by a hydrogen-driven mechanism in a quasi-static fracture mechanics test performed in environment may not be associated with significant ductility in the plastic zone (which would accompany crack growth by stable tearing). The analytical method presented in this paper compares the different points of deviation from linear behavior of the components of J, to isolate the effects of ductility within the plastic zone from pure crack extension. In this way, the point of crack initiation can be defined in order to determine the relevant initiation fracture toughness; whether by blunting and stable tearing, or by hydrogen-driven crack growth. This approach offers a screening method which is illustrated using examples of fracture mechanics specimens tested in environments of varying severity (air, seawater with cathodic protection, and sour service). This method can be used to identify the relevant definition of initiation fracture toughness while allowing for a combination of ductile tearing, hydrogen-driven crack extension, or both, to be present during the test.

Construction of a cross-country pipeline involves lifting the pipeline off the skids and lowering it into the trench (lifting and lowering-in). This can introduce the highest stress magnitude that the pipe may experience over its service life. If not managed properly, overly high stresses may cause integrity issues during construction and/or service. If the girth welds are qualified and accepted using alternative flaw acceptance criteria, such as those in API 1104 Annex A and CSA Z662 Annex K, these stresses must be kept below a preset level during lifting and lowering-in to satisfy the requirements of those standards. This paper covers the development and usage of a stress analysis tool for the continuous lifting and lowering-in of pipe strings without a concrete coating or river weights. The outcome of the stress analysis can be used to develop lifting and lowering-in plans for construction crews. The core functionality of the application tool is to calculate the stresses from bending in the vertical and horizontal planes. The stresses from vertical bending are derived from an extensive analysis of continuous lifting and lowering-in processes. The stresses from horizontal bending are calculated using closed-form analytical solutions. The tool provides a graphical interface that interprets the background stress analysis results and displays information necessary for the development of lifting and lowering-in plans. The tool can be used to evaluate what-if scenarios for various tentative lifting and lowering-in scenarios. The process of using the tool to develop lifting and lowering-in plans is demonstrated in this paper through an example problem. The number of sidebooms and other lifting and lowering-in parameters such as sideboom spacing and lifting height range are changed to make the lifting and lowering-in plan easy to use for the laying contractors. Such tradeoffs can be addressed proactively with construction contractors to ensure that a mutually acceptable approach to lifting and lowering-in is taken.

At least 10 girth weld incidents in newly constructed pipelines are known to have occurred in North America. More than 30 girth weld incidents in newly constructed pipes have been identified worldwide. A review of the North American incidents identified a few main contributing factors: (1) weld strength undermatching, (2) heat-affected zone (HAZ) softening, and (3) elevated stresses/strains from normal settlement and other loads. Weld bevel geometries of manual welding processes that favor plastic straining along the softened HAZ and low strength root passes were also compounding contributing factors. Prior publications focused on the industry practices that led to the formation of those contributing factors. This paper covers the enhanced linepipe specifications and improved welding practice that aim to reduce the risk of similar girth weld incidents, thus leading to more resilient pipelines. The enhanced linepipe specifications include interim recommendations that aim to limit the upper-bound longitudinal strength for a given pipe grade and reduce the linepipe steels’ susceptibility to HAZ softening. The implementation of the interim recommendations is assisted by allowing alternative hoop tensile tests. The improved welding practice includes (1) the selection of welding procedures, including consumables, that minimizes the likelihood of weld strength undermatching and reduces the propensity for HAZ softening and (2) welding procedure qualification tests and requirements for the production of strain-resistant girth welds. The recommendations covered in this paper principally target new pipeline construction projects but are also applicable to pipe replacement projects. It is expected that pipeline operators would incorporate the recommendations in their internal procedures and work with welding contractors to execute the recommendations. The improved linepipe specifications and welding practice are expected to increase the resilience of pipelines subjected to realistic construction and in-service loads. The implementation of the recommendations requires changes to some long-standing industry practices and can only occur with collaborative efforts from all stakeholders.

Navies worldwide are increasingly considering and adopting propulsion plants with electric propulsion for cruise and ship silent operation, and gas turbines for boost propulsion for high speed. These propulsion plants, often referred to as hybrid propulsion, utilize water jets, controllable pitch propellers, or fixed pitch propellers, and have design and overall configuration to fit into naval ships with various size hulls such as would be the case with corvettes, frigates, destroyers, cruisers, etc. Therefore, size, weight, and space of the propulsion plant is important, but equally important is limiting associated machinery which must be used with a particular hybrid propulsion plant design selected. In addition, propulsion design engineers, in conjunction with naval architects, shipyards and navies, must consider fuel efficiencies, machinery efficiencies, weight of all the associated machinery, placement in the hull, first time cost, and life cycle maintenance with associated cost when selecting the configuration of the propulsion system’s associated machinery. Manning levels are dictated by these parameters and in the end, it must be realized that the purpose of the ship mission can be compromised if reliability is not high and premature failures occur. This paper is a more in depth analysis of hybrid propulsion systems for naval ships of various sizes, and analysis of the associate machinery emphasizing ship weight and space savings, fuel savings, cost savings, mean time between failures and mean time to repair which results in lower manning requirements and increased mission readiness. By the time this paper is published, more than 250 SSS Clutches will be installed in US Navy Arleigh Burke Destroyers, 32 are operating in low speed propeller shafts of British Navy Type 23 ships, 2 in the Japanese Navy’s Asuka Class and 16 in low speed propeller shafts of Royal Korean Navy FFX Batch II frigates. At the time of abstract submission, all three programs referenced above have cumulatively had zero defects attributable to SSS Clutch material, function, design, or quality. While the US Navy are given occasional reminders of why alternative clutch designs remain ineffective, unreliable and remarkedly inefficient, other nations’ vertically tiered supply chains and inexperienced engineers are shielded from similar issues.

The purpose of this paper is to introduce the basics of life cycle cost analysis for use in an undergraduate, senior-level capstone, gas turbine engine design course. This paper will support the heightened interest within the military acquisition community that now requires life cycle cost analysis to be included in the proposals submitted by defense contractors. The capstone design course includes both the gas turbine engine cycle selection and engine component design that supports a particular aircraft application. While the students have been taught how to estimate the fuel costs, engine development costs, and the time-varying production costs of engines, they have not yet been provided instruction on how to factor all three types of costs into an engineering economics, time-value-of-money, present value analysis. This paper will fill that gap and serve as a resource for the students who must now consider life cycle cost as an element in their design decision matrix along with engine performance, technical risk, and development time. The typical case compares an engine where the upfront development and production costs associated with a more advanced level of technology are high early on in the life cycle but over time has a lower fuel cost compared to an engine with a lower development and production cost but with a higher fuel cost. This paper illustrates how the aerodynamics, thermodynamics, and engineering economics can be brought together to inform and defend a decision about which of the two (or more) alternatives is best. The engineering economic analysis is spreadsheet based and uses inflation adjusted, total annual costs to calculate the present value for use in a decision matrix.

The ASME 2020 Manufacturing Science and Engineering Conference (MSEC) is the 15th annual meeting organized by the Manufacturing Engineering Division (MED) of ASME. MED and ASME MSEC focuses on manufacturing sciences, technology, and applications, including machining, materials processing, sensing, robotics, manufacturing system dynamics, and production optimization. As the conference has grown and evolved from its inception, it can be difficult to intuitively visualize and discuss the broad range of research topics covered by the MSEC community or to intuitively ascertain their evolution throughout time. This paper discusses a methodology to quantitatively model research communities within bodies of literature — specifically, the relative change of relevant topics within AMSE MSEC conference papers through time, from 2006 through 2018. The goal of this work is to not only present how research in MSEC has shifted over time, but in a broader sense to provide a discussion on how others can interpret results so that similar analysis can be produced within other research communities. This methodology can be used to identify overlap of communities, monitor growth or stagnation within the communities, to aid in developing new symposiums and communities of interest, or even to dictate future standards needs by looking at research trends and subsequent standard development.

The heavy duty diesel (HDD) engine market continues to strive for improvements in engine efficiency and durability which places ever increasing development demands on the power cylinder unit. One of the methods being developed to help meet these demands is coated cylinder bore technology. By applying a coating to the inner diameter surface of a cylinder liner the wear on the liner can be significantly reduced. The reduction in liner wear is not however the only advantage that this technology can offer. Liner coatings can also offer corrosion protection, reductions in wear on the running surface of the rings, improved scuff resistance, and enable improvements in the efficiency of the engine. New piston ring technologies will be valuable in maximizing these advantages and their contribution will be detailed. The system must be properly designed to take full advantage of all of these opportunities. In this paper both the advantages and difficulties coated liners present will be explored by evaluating the impact on the liner, rings and the fuel consumption. This paper will additionally provide details regarding the different liner coating technologies being developed today. To support these recommendations the system’s performance characteristics will be demonstrated through rig testing and engine performance measurements.Copyright © 2014 by ASME

The classic 1943 paper by F.P. Porter on IC engine torque harmonics is best known for its data tables related to the gas pressure torques. However, it also presents Porter’s work on the inclusion of inertial and gravitational torques as excitation functions for torsional vibration. This latter part is relatively obscure because (1) it is presented without any supporting analysis, (2) a number of the quantities involved are not clearly defined, and (3) Porter’s presentation is entirely tied to the US Customary Units system. The present paper explains Porter’s results, with clear definitions of all terms and an appropriate system sketch, and provides a physical motivation for each of his terms in a framework suitable for use with any consistent system of units.Copyright © 2014 by ASME

The reduction of water consumption and use is emerging as a top priority for all types of thermoelectric power plants. In the United States, thermoelectric power production accounts for approximately 41% of freshwater withdrawals [1] and 3% of overall fresh water consumption. [2] On the basis of responses to a 2011 Electric Power Research Institute (EPRI) Request for Information [3], the feasibility study [4,5,6,7] of a Thermosyphon Cooler Hybrid System (TCHS) [8], proposed by Johnson Controls, was funded under EPRI’s Technology Innovation (TI) Water-Conservation Program. The objective of this project was to further develop the TCHS design concept for larger scale power plant applications and then perform a thorough technical and economic feasibility evaluation of the TSC Hybrid System and compare it to a variety of other competitive heat rejection systems. The Thermosyphon Cooler Hybrid System reduces power plant cooling tower evaporative water loss by pre-cooling the condenser loop water through a dry cooling process employing an energy efficient, naturally recirculating refrigerant loop. This paper details the results of a detailed feasibility study that was conducted to compare the cost and performance of the TCHS to a number of other potential wet, dry, and hybrid thermoelectric power plant heat rejection systems operating under varying degrees of water constraint. Installed system cost estimates were developed for the base all wet cooling tower systems, TCHS’s of varying sizes, air-cooled condenser (ACC) hybrid systems of varying sizes, and all dry ACC systems. Optimized all wet cooling tower and all dry ACC system configurations were developed for five different climatic locations. A comprehensive power plant simulation program that evaluated the fuel and water requirements of the power plants equipped with the different heat rejection systems across the weather conditions associated with all 8,760 hours of a typical meteorological year was developed and then an extensive array of simulations were run each location. The summary data were organized in a separate interactive dynamic system comparison summary program to allow users to gain further insight into the relationships between the various heat rejection systems and the sensitivity of the results to changes in key input assumptions. This paper details the data presented in the interactive dynamic system comparison summary program. This program displays the key metrics of the Annual Net Cost of Power Production, the Annual Net Power Plant Profit, the Annual Operating Profit, and the Internal Rate of Return as a function of the Percent Annual Water Savings Required for the various heat rejection systems at each of the five studied climatic locations studied. Key results and conclusions are presented.

Wind is always blowing somewhere. From this perspective, a logical hypothesis is that a base load generator might be created by using long distance transmission to connect distant wind farms. This paper tests that hypothesis by putting numbers to it. It is generally accepted that geographic diversity has a smoothing effect on wind fluctuations for cumulative production [1]. This paper addresses the question of whether or not geographic diversity provides system capacity as well. A scenario of interest is the interconnection of wind farms on the East Coast (PJM Interconnection) with wind farms in the Midwest (MISO, the Midcontinent Independent System Operator). Wind is characterized by the Cumulative Distribution Function (DF). Effective Load Carrying Capacity (ELCC) is a metric that defines system capacity, the load that a system can deliver at an acceptable level of reliability. This paper compares standalone wind on PJM with standalone wind on MISO and with standalone wind for interconnected PJM + MISO. A fourth comparison shows the theoretical limit, what could be achieved if wind from PJM and MISO were independent of each other. This analysis quantifies the capacity benefits of long distance transmission.Copyright © 2014 by ASME

Automatic fault location on the distribution system is a necessity for a resilient grid with fast service restoration after an outage. Motivated by the development of low cost synchronized voltage phasor measurement units (PMUs) for the distribution system, this paper describes how PMU data during a fault event can be used to accurately locate faults on the primary distribution system. Rather than requiring many specialized line sensors to enable fault location, the proposed approach leverages a PMU data stream that can be used for a variety of applications, making it easier to justify the investment in fault location. The accuracy of existing automatic fault location techniques are dependent either on dense deployments of line sensors or unrealistically accurate models of system loads. This paper demonstrates how synchronized voltage measurements enable sufficiently accurate fault location with relatively few instrumentation devices and relatively low fidelity system models. The IEEE 123 bus distribution feeder is examined as a test case, and the proposed algorithm is demonstrated to be robust to variations in total load and uncertainty in the response of loads to voltage sags during a sample set of varied fault conditions.Copyright © 2014 by ASME

Photovoltaic utility-scale grid-connected power generation facilities have performance guarantee bases that often include a reference solar spectrum. EPC contractors are obligated to correct tested performance for solar spectrum, as is done for irradiance and cell temperature, to judge whether contractual performance guarantees have been satisfied. Air mass correlated with solar spectral irradiance offers a convenient way of accomplishing this. This paper offers an improvement in the versatility and accuracy of accounting for spectral effects in this manner. The effects on the spectral composition by atmospheric constituents, like aerosols and water vapor, are investigated. Spectral mismatch curves are derived that characterize the responses of the PV modules and the irradiance measurement device to both the estimated test and the reference solar spectra. Comparison of several supplier performance curves and spectral mismatch curves reveals significant discrepancies. An improvement in accuracy is proposed by the use of supplier spectral response data and estimated solar spectral profiles. Correcting for spectral effects has minimal impact at air mass values near the 1.5 reference value, but grows in significance with increasing air mass. Greater precision in accounting for solar spectral effects on PV plant performance is expected as this segment of the power generation industry matures. This paper proposes a methodology that addresses this expectation.Copyright © 2014 by ASME

This paper is related to fluid-structure interaction analysis of sodium cooled fast reactors core (Na-FBR). Sudden liquid evacuation between assemblies could lead to overall core movements (flowering and compaction) causing variations of core reactivity. The comprehension of the structure behavior during the evacuation could improve the knowledge about some SCRAMs for negative reactivity occurred in PHÉNIX reactor and could contribute on the study of the dynamic behavior of a FBR core. An experimental facility (PISE-2c) is designed composed by a Poly-methyl methacrylate hexagonal rods (2D-plan similitude with PHÉNIX assembly) with a very thin gap between assemblies. Another experimental device (PISE-1a) is designed and composed by a single hexagonal rod for testing the dynamic characteristics. Different experiments are envisaged: free vibrations and oscillations during water injection. A phenomenological analysis is reported showing the flow behavior in the gap and the structure response. Also computational simulations are presented in this paper. An efficient numerical method is used to solve Navier-Stokes equations coupled with structure dynamic equation. The numerical method is verified by the comparison of analytic models and experiments.

Current nondestructive examination (NDE) technology detection capabilities limit our ability to detect stress corrosion cracking (SCC) damage until it has progressed significantly. This work describes the continued development of an in-situ monitoring technique to detect and characterize mechanical damage caused by SCC, allowing the detection of the incipient stages of damage to components/piping. The application of this study is to prevent failures in the primary cooling loop piping in nuclear plants. The main benefit to the industry will be improved safety and component lifetime assessment with fewer inspections. The technique utilizes high resolution fiber optic strain gages mounted on the pipe outside diameter (OD). This technique has successfully detected changes in the residual stress profile caused by a crack propagating from the pipe inside diameter (ID). The gages have a resolution of less than 1 με. It has been shown experimentally for different crack geometries that the gages can readily detect the changes of approximately 10 to 60 με caused on the OD of the pipe due to crack initiation on the ID. This paper focuses on the latest in the development of the technology. Details of the previous work in this effort may be found in [1–3]. A short summary is provided in this paper. The main recent development was the full scale accelerated SCC cracking in boiling magnesium chloride (MgCl2) experiment. In conjunction with experimentation, both 2D and 3D finite element (FEA) models with thermal and mechanical analyses have been developed to simulate the changes in residual stresses in a welded pipe section as a SCC crack progresses.

This paper establishes an alternative approach for nondestructive examination (NDE) personnel qualification for the boiler and pressure vessel (B&PV) industry. This is the “white paper” developed by the Section XI, Division 2, Task Team, Performance-based NDE Personnel Qualifications. It is anticipated to be the basis for the NDE personnel qualification criteria for the revised Section XI, Division 2, REQUIREMENTS FOR RELIABILITY AND INTEGRITY MANAGEMENT (RIM) PROGRAM FOR NUCLEAR POWER PLANTS that is currently being developed. Based on review of a number of quantitative NDE reliability studies conducted to-date the current deterministic approach to NDE personnel qualification based on such schemes as ASNT SNT-TC-1A, ANSI/ASNT CP-189, EN-473, ISO-9712 and other similar approaches are not as effective as desired. The goal of this document is to present an alternative approach to the deterministic NDE personnel qualification schemes. This paper presents a systematic approach to training together with performance-based tests, psychometrically validated evaluation of knowledge and skills that will improve a NDE candidate’s performance. A majority of traditional employer-based written examinations are not developed or validated psychometrically. The use of third-party psychometrically validated examinations would replace the current practice of employer developed and administered examinations. It improves upon traditional ASNT SNT-TC-1A, ASNT/ANSI CP-189, ISO-9712, etc., requirements by including more comprehensive hands-on practical examinations on a statistically valid set of samples containing flaws representative of those expected to be encounter in shop and field conditions. The sample sets will be designed for either a “general” NDE method, or “limited” technique(s) of a method, or for industry specific sector needs, as applicable.

The design rules for clamped connections in the ASME Boiler and Pressure Vessel Code (Section VIII, Div. I, Appendix 24) were developed for two-segment clamp connectors and must be modified to accommodate alternative clamp configurations. Developing a simplified rule-based model for predicting three-segment pipe clamp connectors (3-PCC)connector pressure capacities will greatly simplify the evaluation of 3-PCC connectors. The first goal of this paper is to develop a general parametric design rule set for multiple-clamp-segment pipe by expanding upon the published requirements of the ASME Boiler and Pressure Vessel Code for two-segment pipe clamp connectors and pipe flanges using basic principles. The next goal is to apply the design rule set to a typical 3-PCC design and to summarize the rules. The results of this paper provide a parametric rule-based approach to evaluating the pressure capacity of a 3-PCC. This paper has been developed in partial fulfillment of the requirements for the Master’s Degree Program at Washington State University. This work is performed in support of the US Department of Energy, under contract to Bechtel National Inc., # DE-AC27-01RV14136.

The use of High Density Polyethylene (HDPE) is growing rapidly due to its corrosion resistance characteristics and ease of construction when compared to metal piping systems. As a result of its widespread use, a method of inspecting the piping joints is becoming essential to ensure safe, sound piping systems. This is particularly true for butt fusion joints, which can contain micro-structural defects that impact long term integrity of the piping system. These defects have proven to be difficult to detect using traditional means of inspection, such as ultrasound, because these micro-structural defects do not result in an acoustic reflector or impedance difference. This paper presents the results of a rigorous validation program for a microwave non-destructive inspection technique for HDPE butt fusions. The program includes inspection of a cross section of defect types that comprise geometric type defects, such as back and side drilled holes, and butt fusion inclusions. It also includes defects of types commonly found in field applications, such as grass, oil, fine particulate and other contaminants and procedural deviations, such as low and high pressure and longer than typical dwell times (wait time between heating the pipe ends and fusing them). The success of the microwave inspection protocol and equipment in detecting the many types of defects that comprise the set of samples has been reduced to Probabilities of Detection (POD) and Probabilities of False Alarm (POFA). These statistics have been calculated in a traditional fashion and are presented in this paper.

The Fukushima Daiichi nuclear accident shows that it is necessary to study potential severe accidents and corresponding mitigation measures for the spent fuel pool (SFP) of a nuclear power plant (NPP). This paper presents a study on the consequences of loss of heat removal accident in the spent fuel pool of a typical pressurized water reactor using the Modular Accident Analysis Program (MAAP5) code. Analysis of uncompensated loss of water due to the loss of heat removal with initial pool water level of 12.2 m (designated as a reference case) has been performed. The analyses cover a broad spectrum of severe accident in the spent fuel pool. Those consequences such as overheating of uncovered fuel assemblies, oxidation of zirconium and hydrogen generation, loss of intactness of fuel rod claddings, and release of radioactive fission product are also analyzed in this paper. Furthermore, as important mitigation measures, the effects of makeup water in SFP on the accident progressions have also been investigated based on the events of spent fuels uncovery. The results showed that spent fuels could be completely submerged and severe accident might be avoided if SFP makeup water system provided water with a mass flow rate higher than evaporation rate defined in the reference case. Although spent fuel assemblies partly exposed due to a mass flow rate of makeup water smaller than the average evaporation rate, continuous steam cooling and radiation heat transfer might maintain the spent fuels coolability as the actual evaporation was balanced by the makeup in a period of time of the order of several days. However, larger makeup rate should be guaranteed to ensure long-term safety of SFP.Copyright © 2014 by ASME

Continually increasing requirements on nowadays full scope PSA L1 and L2 as whole, which is multiplied by importance of specific data for all modes of operation of nuclear power plant, highlight role of input data used in PSA quantification process. This fact also emphasizes the role of capability to process all necessary information to analyze all nuclear plant modes by appropriate way. Even if abovementioned aspects are relevant for all parts of nowadays PSAs, their importance is critical for internal hazards including specific fire analysis. Because internal fire analysis forms one of the most challenging PSA tasks, requiring interdisciplinary work including processing and integration of extensive amount of data in such a way that fire analysis results are fully consistent with internal PSA events and can be directly incorporated into PSA project. Application of tailored information system forms one of the ways to speed up analyzing process, enhances manageability and maintainability of particular PSA projects and provides effective reporting mean to document process of work as well as traceable and human readable documentation for customers. Such information system also allows implementing rapid changes in processing input data and reduces the risk of human error. Usage of information systems for modification of input data for Living PSA is invaluable. Transparent highly automatized processing of input data allows the analyst to obtain more accurate and better insight to evaluate aspects of particular fire and its consequences. This paper provides brief overview of VUJE approach and experience in this area. The paper introduces general purpose of database developed for PSA needs containing data for relevant PSA structure system and components as well as information relevant for flood and fire analyses. Paper explains as this basic data source is enhanced by adding several relatively independent tiers to employ all common data for fire PSA purpose. Paper also briefly introduces capability of such system to generate integrated documentation covering all stages of fire analyses, covering all screening stages of fire analysis as well as future plans to enhance this part of work in such a way to be capable to build automatic interface between PSA model and fire database to enable PSA model parameters automatic updating and expansion of fires in combinations of initiating events (for example Fire and seismic event).

The objective of this paper is to modify the current existing CANFLEX® fuel-bundle design to examine its ability to withstand high-temperature conditions of a proposed generic reactor with nuclear steam reheat. One of this reactor’s characteristics is having Super-Heated Steam (SHS) channels in addition to Pressurized-Water (PW) channels in order to increase the thermal efficiency of the plant by about 7–12%. This increase may be attained by raising the outlet temperature of the SHS-channels coolant to about 550°C. Operating at the higher temperatures will definitely have an effect on the mechanical and neutronic properties of fuel-channel materials, specifically on fuel-sheath and pressure-tube materials. This paper compares Inconel-600 and SS-304 in order to determine the most suitable material for SHS-channel’s sheath and pressure tube. This is achieved by comparing strength of materials by performing stress- and displacement-analysis simulation using NX8.5 software (NX8.5, 2009). The analysis in this paper can also be applied to other Nuclear-Power Plants (NPPs) that require operating at higher temperatures such as Super-Critical Water-cooled Reactors (SCWRs).

To address the need to develop new nuclear reactors with higher thermal efficiency, a group of countries, including Canada, have initiated an international collaboration to develop the next generation of nuclear reactors called Generation IV. The Generation IV International Forum (GIF) Program has narrowed design options of the nuclear reactors to six concepts one of which is the SuperCritical Water-cooled Reactor (SCWR). Among the Generation IV nuclear-reactor concepts, only SCWRs use water as the coolant. The SCWR concept is considered to be an evolution of Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs), which comprise 81% of the current fleet of operating nuclear reactors and are categorized under Generation II nuclear reactors. The latter water-cooled reactors have thermal efficiencies in the range of 30–35% while the evolutionary SCWR will have a thermal efficiency of about 40–45%. In terms of a pressure boundary SCWRs are classified into two categories, namely, Pressure Vessel (PV) SCWRs and Pressure Channel (PCh) SCWRs. A generic pressure channel SCWR, which is the focus of this paper, operates at a pressure of 25 MPa with inlet and outlet coolant temperatures of 350 and 625°C, respectively. The high outlet temperature and pressure of the coolant make it possible to improve the thermal efficiency. On the other hand, high operating temperature and pressure of the coolant introduce a challenge for material selection and core design. In this view, there are two major issues that need to be addressed for further development of SCWR. First, the reactor core should be designed, which depends on a fuel channel design (for PCh SCWR). Second, a nuclear fuel and fuel cycle should be selected. Third, materials for core components and other key components should be selected based on material testing and experimental results. Several fuel-channel designs have been proposed for SCWRs. These fuel-channel designs can be classified into two categories: direct-flow and re-entrant channel concepts. The objective of this paper is to study thermal-hydraulic and Neutronic aspects of a re-entrant fuel channel design. With this objective, a thermal-hydraulic code has been developed in MATLAB which calculates the fuel centerline temperature, sheath temperature, coolant temperature and heat transfer coefficient profiles. A lattice code and a diffusion code were used in order to determine the power distribution inside the core. Then, the heat flux in a channel with the maximum thermal power was used as an input into the thermal-hydraulic code. This paper presents the fuel centerline temperature of a newly designed fuel bundle with UO2 as a reference fuel. The results show that the maximum fuel centerline temperature and the sheath temperature exceed the temperature limits of 1850°C and 850°C for fuel and sheath, respectively.

Accident at Fukushima Dai-Ichi nuclear power plant significantly affected the nuclear industry at time when everybody was expecting the so called nuclear renaissance. There is no question that the accident has at least slowed it down. Research into this accident is taking place all over the world. In this paper we present the findings of research on Fukushima nuclear power plant accident in relation to the Czech Republic. The paper focuses on the analysis of human performance during the accident. Lessons learned from the accident and main human errors are presented. First the brief factors affecting the human performance are discussed. They are followed by the short description of activities on units 1–3. The key human errors in the accident mitigation are then identified. On unit 1 the main error is wrong understanding and operation of isolation condenser. On unit 2 the main errors were unsuccessful depressurization with subsequent delay of coolant injection. On unit 3 the main error is the shutdown of high pressure cooling injection system without first confirming that different means of cooling are available. These errors lead to fuel damage. On unit 1 the fuel damage was probably impossible to prevent, however on unit 2 and 3 it could be probably prevented. The lessons learned for the Czech Republic were presented. They can be summarizes as follows: be sure that plant personnel can and knows how to monitor and operate the crucial plant components, be sure that the procedures on how to fulfill the critical safety functions are available in the symptomatic manner for situations when there is no power available at the plant, train personnel for these situations and have sufficient human resource available for these situations.Copyright © 2014 by ASME