Delayed coker drums are unique in hydrocarbon processing facilities in that estimating their true design and service life has been problematic. Generally, pressure containing equipment in these facilities is designed using the notion of design life based on required pressure thickness and corrosion allowance considerations. Hence, pressure containing equipment is routinely monitored by facility inspectors for wall thickness. Although many analysts have ascribed coke drum failure to “thermal stress cycling”, the difficulty posed by the operation of coke drums results in an inability to measure or calculate the magnitude of the thermo-mechanical “stresses” and the actual number of significant exposures, that is, cycles causing fatigue damage. As well, the use of Code construction practices has been generally misapplied, for this specific equipment, as the practices are intended to define a safe design life rather than a service life. Indirect measures of service life based on shell bulge severity have fallen from favor by being ineffective. A trend to use a strain index method is somewhat more appealing but is based on static load and monotonic material property considerations rather than those properties indicative of thermal cyclic operation. Recent work has shown that thermo-mechanical strain cycling can be characterized quantitatively and used to determine a cyclic service life for both undamaged and damaged coke drums. This paper discusses some of the engineering specifics to generate a high probability estimate of coke drum fatigue service life for a new drum, a damaged-stable drum, drums with weld overlay and for drums exhibiting incremental damage.

High temperature water environments typical of LWR operation are known to significantly reduce the fatigue life of reactor plant materials relative to air environments in laboratory studies. This environmental impact on fatigue life has led to the issue of US-NRC Regulatory Guide 1.207 [1] and supporting document NUREG/CR-6909 [2] which predicts significant environmental reduction in fatigue life (characterised by an environmental correction factor, F en ) for a range of actual and design basis transients. In the same report, a revision of the fatigue design curve for austenitic stainless steels and Ni-Cr-Fe alloys was proposed [2]. This was based on a revised mean curve fit to laboratory air data and revised design factors to account for effects not present in the test database, including the effect of rough surface finish. This revised fatigue design curve was endorsed by the NRC for new plant through Regulatory Guide 1.207 [1] and subsequently adopted by the ASME Boiler and Pressure Vessel (BPV) Code [3]. Additional rules for accounting for the effect of environment, such as the F en approach, have been included in the ASME BPV Code as code cases such as Code Case N-792-1 [4]. However, there is a growing body of evidence [5] [6] [7] and [8] that a rough surface condition does not have the same impact in a high temperature water environment as in air. Therefore, application of F en factors with this design curve may be unduly conservative as it implies a simple combination of the effects of rough surface and environment rather than an interaction. Explicit quantification of the interaction between surface finish and environment is the aim of a number of recent proposals for improvement to fatigue assessment methods, including a Rule in Probationary Phase in the RCC-M Code and a draft Code Case submitted to the ASME BPV Code as described in References [9] and [10]. These approaches aim to quantify the excessive conservatism in current methods due to this unrecognised interaction, describing this as an allowance for F en effectively built into the design curve. A number of approaches in various stages of development and application are discussed further in a separate paper at this conference [11]. This paper reports the results of an extensive programme of strain-controlled fatigue testing, conducted on two heats of well-characterised 304-type material in a high-temperature simulated PWR environment by Wood plc. The baseline behaviour in environment of standard polished specimens is compared to that of specimens with a rough surface finish bounding normal plant component applications. The results reported here substantially add to the pool of data supporting the conclusion that surface finish effects in a high-temperature water environment are significantly lower than the factor of 2.0 to 3.5 assumed in construction of the current ASME III fatigue design curve. This supports the claim made in the methods discussed in [9] [10] and [11] that the fatigue design curve already incorporates additional conservatism for a high-temperature water environment that can be used to offset the F en derived by the NUREG/CR-6909 methodology. At present, this observation is limited to austenitic stainless steels.

RCC-MRx Code is the result of the merger of the RCC-MX 2008, developed in the context of the research reactor Jules Horowitz Reactor project, and the RCC-MR 2007, which established rules applicable to the design of components operating at high temperature and to the Vacuum Vessel of ITER. This code has been issued in French and English versions by AFCEN (Association Française pour les règles de Conception et de Construction des Matériels des Chaudières Electro-nucléaires) in 2012, 2015, and a new edition will be published by the end of 2018. This new edition integrates a significant evolution for the rules dedicated to the ratchetting evaluation through the so-called “efficiency diagram rule”. This rule was initially developed to present a less penalizing rule than the classical “3 Sm” rule and to analyze the interaction between creep and ratchetting in the high temperature domain. Since the first edition of RCC-MR code, several modifications have been made to this rule to improve its representativeness for this kind of damage. These modifications were motivated and justified by numerous experimental tests. The last significant evolution is thus the occasion to present through this article, the background of this rule, the major evolutions already incorporated in the code and also the on-going developments.

One of the goals of ASME Section XI is to ensure that systems and components remain in safe operation throughout the service life, which can include plant license extensions and renewals. This goal is maintained through requirements on periodic inspections and operating plant criteria as contained in Section XI IWB-2500 and IWB-3700, respectively. Operating plant fatigue concerns can be caused from operating conditions or specific transients not considered in the original design transients. ASME Section XI IWB-3740, Operating Plant Fatigue Assessments, provides guidance on analytical evaluation procedures that can be used when the calculated fatigue usage exceeds the fatigue usage limit defined in the original Construction Code. One of the options provided in Section XI Appendix L is through the use of a flaw tolerance analysis. The flaw tolerance evaluation involves postulation of a flaw and predicting its future growth, and thereby establishing the period of service for which it would remain acceptable to the structural integrity requirements of Section XI. The flaw tolerance approach has the advantage of not requiring knowledge of the cyclic service history, tracking future cycles, or installing systems to monitor transients and cycles. Furthermore, the flaw tolerance can also justify an inservice inspection period of 10 years, which would match a plant’s typical Section XI in-service inspection interval. The goal of this paper is to demonstrate a flaw tolerance evaluation based on ASME Section XI Appendix L for several auxiliary piping systems for a typical PWR (Pressurized Water Reactor) nuclear power plant. The flaw tolerance evaluation considers the applicable piping geometry, materials, loadings, crack growth mechanism, such as fatigue crack growth, and the inspection detection capabilities. The purpose of the Section XI Appendix L evaluation is to demonstrate that a reactor coolant piping system continues to maintain its structural integrity and ensures safe operation of the plant.

The 2018 edition of the RCC-MRx Code (1) will be issued, by the end of the 2018, in French and English versions by AFCEN (Association Française pour les règles de Conception et de Construction des Matériels des Chaudières Electro-nucléaires). This Code set up rules applicable to research reactor components (coming from the RCC-MX 2008 developed in the context of the Jules Horowitz Reactor project), to reactor components operating at high temperature (coming from the RCC-MR 2007) and to the Vacuum Vessel of ITER (also coming from the RCC-MR 2007). This edition takes the benefits of an important feedback of the users, such as Jules Horowitz Reactor or ASTRID project, but also from ITER and MYRRHA projects. In parallel, in compliance with the EC’s objectives and its own policy of openness, AFCEN proposes to make its codes evolve, taking into account the needs and expectations of European stakeholders (operators, designers, constructors, suppliers ...) through a workshop called CEN Workshop 64 phase 2. The end of the workshop, planned for 2018, will allow to integrate recommendations issued from this work in the code. This paper gives an overview of the performed work and also identifies the work to be done for a development of a standard such as RCC-MRx code.

A purpose of this study is an improvement of seismic proof construction for power plants to supply power stably at an emergency. At present, the most common type of power generation in Japan is thermal. In particular, coal-fire becomes base load power. A proposal of this study is that boiler structure is applied vibration control. The way is that a damper used viscous fluid is set instead of stopper between the boiler and the support structure. However, inside temperature of the boiler structure is higher than the environment of the general because it uses burning of coal and steam. Therefore, this paper shows that the damper has applicability for the environment of the boiler structure. Then it is necessary for structures to endure earthquake with long duration and long period component in Japan. The 2011 off the Pacific coast of Tohoku Earthquake had the largest energy in history of Japan with them. The damage occurred not only in Tohoku but also in far Tokyo and Osaka. Moreover, it is predicted that large earthquakes with them at the south Pacific coast of Japan occur. This paper shows that the developed damper is effective in earthquake with these characteristics by analyses and component tests.

In 2011, Great East Japan Earthquake that is the largest earthquake ever observed in Japan occurred. The earthquake had large energy, long duration and many aftershocks, and coal-fired thermal power plants were damaged by the earthquake [1]. Boiler structures in coal-fired thermal power plants are generally high-rise structures, and boilers are simply suspended from the top of the support structures in order to allow thermal expansion, so boilers easily vibrate [2]. In order to suppress vibration of boilers during earthquakes, stoppers are generally set between boilers and support structures. The stoppers are made of steel, and dissipate vibration energy by plastic deformation. However aseismic requirements for thermal power plants have been increased as a result of the Great East Japan Earthquake. Thus authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP 2017, the basic performance of the proposed damper was presented [3–5]. In this paper, influence of damper properties on lifetime of the damper was investigated by seismic response analyses. In addition, lifetime of dampers for long period and long duration earthquake waves were investigated by seismic response analyses.

Coal-fired thermal power generation became a very important power source in Japan after Great East Japan Earthquake [1]. Therefore improvement of seismic reliability of the coal-fired thermal power plants is required, because occurrence of very large earthquakes is expected in Japan. Boilers of coal-fired power plants are usually suspended from the upper end of support structures in order to allow thermal expansion of the boilers [2], so boilers easily sway during earthquakes. In order to suppress the vibration, stoppers made of steel are generally installed between boilers and their support structures. Although stoppers made of steel are effective for vibration suppression, further countermeasure for earthquakes having long duration and many aftershocks is required. Authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP2017, the basic performance of the proposed damper was presented [3–5]. In this paper, damper properties were adjusted in order to improve vibration control performance of the damper. Influence of damper properties on the performance was investigated by sensitivity analyses. In addition, influence of dispersion of damper properties was also investigated. Long period and long duration earthquake waves were considered in the analyses.

Evaluation of mechanical properties from a small amount of test material is essential in a process of development of new alloys and monitoring of degradation and damage of in-service components. Miniaturization of test specimen together with a specimen reconstitution technique enable direct method of evaluation of mechanical properties if only a limited amount of material is available. Modern types of construction steels and alloys possess improved metallurgical and mechanical properties and also demonstrate a high level of fracture toughness. In these cases, correlation and correction of size effect on fracture toughness between different specimen sizes are needed. Within this contribution the size effect of J-R curve for two sizes of three-point-bend specimens is solved. The J-R curves of three-point-bend specimens with cross-section 10 × 10 mm and 3 × 4 mm of P91 and Eurofer97 steel were determined at room temperature. The existence of size effect is proven as larger specimens demonstrate higher J-R curves than smaller specimens for both steels. Simplified mechanical model based on fracture energies initially proposed by Schindler et al. is applied to describe experimentally determined J-R curves and to predict the observed size effect between used specimen sizes.

Post weld heat treatment (PWHT) is often applied to welded pressure vessels and piping to increase the mechanical and metallurgical properties. During the PWHT, a pressure component made of a carbon steel to which PWHT is applied, is heated up to the temperature around 620 deg.C with +/− 25 deg.C tolerances and that elevated temperature is kept for 1 to 2 hours. The local PWHT of the vertical pressure vessel is sometimes planned at a construction site with vertical position, because of some restrictions relating to construction, such as limited access route to the vessel location, and limited space large capacity cranes. In the situation, it is important to assure the structural stability during PWHT. Except wind loads, it is considered that the stress applied in the shell during PWHT is usually not significant, however there have been no published strength criteria corresponds to the PWHT conditions. In this paper, the new elevated temperature tensile tests and constant stress creep strain tests of A516-Gr.70, a typical carbon steel material for pressure vessels, are conducted. Several examples of the numerical analysis using isochronous stress strain curve considering creep effect are presented. From the test result, the importance of the consideration of the creep deformation on the structural integrity assessment of PWHT operation is clarified.

The operating environment of polyethylene (PE) gas pipeline is complex and changeable. In the process of pipeline design, construction and operation, there are many fuzzy factors inducing pipeline accidents. In the paper, the fuzzy factors causing pipeline accidents were studied and analyzed, and the risk evaluation factors of PE gas pipeline were determined. According to the theory of fuzzy comprehensive evaluation, the mathematical model of fuzzy comprehensive evaluation for PE pipeline was established. In order to pursue as much accurate results of assessment as possible, the fuzzy analytic hierarchy process was used to determine the weight of each index. The safety evaluation grade of the pipeline was given by using the risk matrix method. And then the evaluation system software of PE gas pipeline risk assessment was developed. The software has been used in the risk inspection of PE gas pipeline, which provides the basis for the risk management of the pipeline.

The Standard Technical Documentation of the Association of Mechanical Engineers is elaborated by a team of experts on the base of an actual knowledge and practice as a part of a row of recommendations for an assessment of strength and reliability, choice of materials and solution of service problems of the Czech nuclear power plants. It was elaborated by the Association of Mechanical Engineers as an important help for a practice. This issue is published from the following main reasons: 1. The criteria for an assessment of reliability and safety of technical tasks have changed in a last decades by influence of development of fracture mechanics and a diagnostics of an actual components of the nuclear power plants, exposed to a static and dynamic strength in a service and to effects of an aggressive environment, leading to an origin of integrity failure. The access is changed now from an assessment of an original strength to a long-term operation and service reliability. A conception of a choice of suitable materials has changed, especially about an influence of production technology on barriers against a degradation of material mechanical characteristics. Imaginations also changed about increasing of a resistance against a damage of material components in complex service conditions. New scientific knowledge it is necessary to apply responsibly just in a construction of as important equipment as nuclear power plants are. 2. A social responsibility is increasing for economic and ecological behavior and hence manners of service control are always innovated. A problematic of a residual lifetime of those tasks is connected with. A prolongation of a lifetime without a risk of equipment failure hereto is a principal demand of capital-intensive units. 3. In a last decades a possibility of efficient use either an automatic service diagnostics or an inspection of component state in service brakes has deepened. It is necessary to enable a right engagement of this instrumentation and to interpret in a right way obtained information. 4. An international cooperation in this important region is developed, an elaboration of information and their common deepening has a substantial importance for a future of a nuclear energetic. A dissembling of service obstacles, an objective analysis of failure situations and a method of their control is today’s obvious duty of an international cooperation. Programs of all variants of a possible damage and its control must be prepared. It is impossible at once to apply all those aspects in provisions and recommendations. Issued provisions however must be constantly improved and complemented.

In recent years, with the gradual expansion of units scale for energy industries such as oil refining, chemical and natural gas, etc. in China, pressure vessels are developing toward the large and heavy direction with the maximum wall thickness reaching hundreds of millimeters and weight exceeding one thousand tons. It not only causes huge material consumption, difficulty in manufacture and processing (even beyond current capability), but probably also lead to new failure modes and mechanisms, and significant safety risks thereby. Therefore, the lightweight design and manufacture under the premise of inherent safety has become an urgent need to break through the bottleneck of manufacturing capability and realize the material and energy conservation. In this paper, the progress of lightweight design and manufacturing technology of heavy-duty pressure vessels in recent years in China is introduced from the aspects of adjustment of material allowable strength, application of high strength steel and matching of strength and toughness, cold stretch of austenitic stainless steel, structure optimization design with multi-parameter coupling, and application of composite materials. Application cases in the construction of pressure equipments such as large hydrogenating reactors, low-temperature ethylene spherical tanks, austenitic stainless steel cryogenic vessels, butyl octanol heat exchangers, etc. are also included. Finally, some suggestions on the future research are proposed including composite pressure vessels in cryogenic environment, materials genome and additive manufacturing technologies for pressure vessels.

Gathering network, which is usually characterized by various and complex structure, takes a large proportion of the overall construction cost of gas field. Optimization of pipeline routes is an effective way to reduce the investment. In this paper, a novel model for optimal route of pipeline considering complex terrains and obstacles is proposed and solved by Genetic Algorithm. Minimizing the total investment is the object of this model. Since the construction costs under different terrains are different, the distance factor L i , slope factor D i and elastic factor S i are introduced into the objective function to represent the length of the pipeline, the gradient of the pipeline, and the fluctuation of terrain. In addition, the performance of the model is verified by taking three typical situations of different terrains and obstacles as examples. The results illustrate that the proposed model can address the optimal design of pipeline routes in complex terrains. Moreover, the effects of different genetic operators on solutions are investigated, including three selection operators and two crossover operators. The study provides a guideline for designing pipeline routes in complex terrains and is also applicable to the analogous problem.

In its 2016 Edition, ASME B31.3 [1] removed its long held provision for thread engagement that deemed the lack of complete engagement acceptable if the lack of engagement is not more than one thread. This change can have implications on existing piping assemblies which prompted some clarifications in ASME PCC-1 [2]. This paper reviews some of the reasons for the change, the issues around determining a specific measurable criterion of an acceptable amount of thread engagement, and proposes alternate criteria for the new construction codes to consider that are easily measurable and enforceable.

Pneumatic pressure testing is used extensively during construction of LNG plants to avoid the problems that can be caused by water that may be left in a piping system (particularly in valves) if hydrotesting was performed. Due to the much greater compressibility of gas, there is significantly more energy (and thus risk) associated with a pneumatic test than with a hydrostatic test. A major gas project safely conducted numerous pneumatic tests with stored energies of up to 6,675 MJ. Observing a commonly used limit of 270 MJ would have resulted in hundreds of additional closure welds. This paper discusses practical aspects of performing pneumatic testing, the risk mitigations put in place and present two calculation methods that can be used to check whether exclusion zones for blast wave pressure are adequate for fragment throw.

The use of segmented joint technology allows gasket manufacturers to fabricate and supply gaskets in discrete segments, rather than the conventional one-piece construction. Segmented gaskets are required when using sheet type gaskets for flange diameters larger than the available sheet size. Typical gasket sheets are 60” × 60” or 70” × 70” square, for instance. Flanges designed for these lower stress sheet gaskets that are larger than the available sheet size to fabricate the gaskets are typically fabricated as segmented gaskets. Segmented gaskets are also utilized in smaller flange applications to facilitate maintenance activities. When replacing the tube sheet gasket in a shell and tube exchanger the entire tube sheet must be removed in order to utilize a solid, one-piece ring gasket. In some cases this is not practical or desired, so a segmented gasket is utilized which only requires the tube sheet to be removed a short distance to allow access to the sealing surface. This same scenario exists with other common process piping and vessel flanges including thermowells, lance tubes, agitator or mixer shafts, etc. Valid concerns exist when using segmented gaskets as potential leak paths are created at every joint. If the gasket material and joint design are not correctly specified and fabricated the segmented gasket may not provide the same sealing performance and reliability as the solid, un-segmented gasket. This paper will discuss the research and data found that identifies the stress multiplier for segmented/jointed gaskets to achieve the same (similar) leak rate as their solid, unsegmented gasket counterpart. This assembly or design stress multiplier will be a dynamic number that will vary based upon the gasket material and the joining technology used. Two jointing methods are evaluated in this research; the industry standard “dovetail” and the Engineered Interference Tortuous Path (EITP) joint. In practice there is currently no guidance available to guide the design or assembly of these segmented gasket applications. The purpose of this paper is to provide guidance for both design and assembly purposes.

The primary structure method is one of the effective methods to distinguish the primary stress and secondary stress. The knotty problem of stress classification can be solved by using the primary structure method and the equivalent linearization of stresses. The primary structure method has been successfully used to the finite element analyses with 2D axisymmetric elements and shell elements. A method to construct the primary structures with 3D solid elements is given in this paper, and the stress classification of cylindrical shell with nozzle is discussed in a new point view.

Jacketed gaskets have widespread use in the industry. The current revision of ASME B16.20-2017 provides several details of jacketed gasket construction and dimensions for use on ASME B16.5 or ASME B16.47 flanges. However, it does not currently provide a testing protocol to evaluate the sealing performance of this gasket style. This paper reports sealability and compression results with distinct sizes of jacketed gaskets tested based on the protocol proposed in ASME B16.20 - Spiral Wound Gaskets Performance Testing.

Design requirements for nonmetallic piping systems are significantly different from those applicable to piping made of steel and other metals, and the development of rules for nonmetallic materials requires a unique set of expertise. While other piping standards have tried to address the use of nonmetallic materials in industrial piping, they do not provide adequate requirements to cover the service limitations, design, materials, fabrication, installation, fusing or joining, and quality control which are unique to nonmetallic piping systems. To address this gap, ASME assembled the Committee on Nonmetallic Pressure Piping Systems (NPPS) in 2011 to develop standard rules for the construction of nonmetallic pressure piping systems. Over the last 7 years, the NPPS Committee has developed three new standards which are scheduled to be published in 2018: ASME NM.1 Standard on Thermoplastic Piping, ASME NM.2 Standard on Glass Fiber Reinforced Thermosetting Resin Piping, and ASME NM.3 Standard on Nonmetallic Materials. These standards cover the design, manufacture, fabrication, installation, examination, testing, and inspection of thermoplastic and glass fiber reinforced thermosetting resin piping systems suitable for pressure applications. They will also cover specifications for nonmetallic materials for piping components including material design values and limits on the use of nonmetallic materials.