One of the most promising technologies to enable and enhance large survey capabilities for radio astronomy is the use of focal plane phased array antenna feeds, or more simply, phased array feeds (PAFs). PAFs allow for full and continuous coverage of the telescope’s field of view (FoV), and combined with cryogenic amplifiers, can result in survey speed improvements several orders of magnitude better than current multiple-feed-horn cameras. In order to locate cryogenic PAF elements and amplifiers at the telescope focal plane, a radio-frequency transparent vacuum vessel is required. Unlike typical radomes, the transmission properties must be exceptionally good when dealing with weak astronomical signals. The dome must also be sufficiently strong to carry the mechanical load on the vacuum vessel due to atmospheric pressure. Furthermore, the thermal loading on the internal cryogenic stages from the dome must be manageable for the cooling system. We have solved these problems by using a combination of welded polyethylene sheet to maintain the vacuum integrity and a closed-cell rigid foam to transfer the mechanical load to the opposite side of the vessel (a welded aluminum structure). The PAF elements and amplifiers operate at 20 K, while the foam transfers the mechanical load through an 80 K temperature stage, which also serves as a low-temperature radiation shield for the 20 K sections. The poor thermal conductivity of the foam, combined with G10-CR thermal standoffs on the opposite side, ensures the 80 K stage is sufficiently thermally isolated from room temperature conduction. The radiative loading is reduced via the usual employment of multi-layer insulation. In order to facilitate instrument maintenance and future upgrades, a modular PAF element mechanical strategy is employed. The design is such that a PAF-element-amplifier unit can be replaced without accessing the 20 K stage owing to the use of a “cryo-clamp” that uses materials with different coefficients of thermal expansion to tightly hold the units when cold. Cooling is supplied by three two-stage Gifford-McMahon cryo-coolers. This paper presents these design details for the cryostat of the ALPACA (Advanced L-Band Phased Array Camera for Arecibo), an instrument currently being designed and built for the 305 m radio telescope of the Arecibo Observatory in Puerto Rico.

A suite of High Rate Heavy Vacuum Gas Oil (HVGO) pumps in an operating Upgrader Plant experienced repeated failures; typically, less than 7 weeks. The need for online measuring tools arose that could measure pump and piping system strain changes with dynamic thermal gradients. The challenge was to record the effect on the entirety of pump component alignment and vibration. In current industrial practices no such tools and techniques are directly and comprehensively available for rotary equipment. Strain gauges are not accurate, and cannot provide broader real time strain mapping. Optical metrology can analyze the mechanical properties and behavior of all kinds of materials in various test scenarios. To date such methods are experimental and principally found in advanced application environments. At the time the method was unknown and especially in such a difficult industrial plant. In such a complex and extreme hot and cold operating service warm-up, cooling, with variations in flow and temperature, can directly and dynamically affect strain measurements. It was not certain whether optical meorology measurement techniques would be able to identify and correlate dynamic operating scenarios with the source of the pump and pipe hardware issues experienced in these Heavy Vacuum Gas Oil (HVGO) pump systems. The influence of the casing thickness and stiffness on the resulting vibration characteristics was investigated by using FEA and operational testing and dynamic analysis. Increasing the interface web thickness results in notable reduction in deformation. Comparison of the results of the live testing against the initial design was performed and studied for remedial action. Materials and heat treatment options were also evaluated and reported. The three-dimensional turbulent flow was modelled and analyzed. The application of those tools for this type of problem are described along with the other rigorous techniques employed. The range of tools included modal and vibration analysis, thermography, rotor and shaft dynamics, baseplate, frame, metallurgical analysis and ultimately compared with FEA, pipe stress modelling and strain analysis. This paper should be read in conjunction with PVP 2020-21204; Piping & Equipment Dynamics of High Rate HVGO Pumps.

A set of Heavy Vacuum Gas Oil (HVGO) pumps in a 300 kbbl/day operating Upgrader Plant experienced repeated failures; typically less than 7 weeks. The pumps run continuously in a high-pressure, high temperature and corrosive environment and their functional status directly affects the reliability of the plant. Upon research, an experimental strain measurement technique using very high resolution laser digital imagery and optical metrology was found from military and advanced aerospace applications to verify high level dimensional accuracy of critical components [1]. Application to a complex and operating bitumen upgrader was unknown. The objective of this project was to use advanced optical metrology with digital image processing techniques employing multiple laser and high-speed cameras capable of generating pump and pipe component’s real time strain images, displacement and rate of change. Optical metrology can analyze the mechanical properties and behavior of many materials and in various test scenarios [2]. Hot and cold operating service, with variations in flow and temperature all dynamically affect the strain measurements. Three significant advantages of the optical method are: i. Avoids a host of problems of strain gauge application, wiring and setup. ii. The problems of temperature sensitivity and correction are overcome. [3] iii. Gathers much more extensive data than possible with traditional methods. The vibration characteristics of the pumps and related hardware were analyzed using high resolution laser and photogrammetric digital imagery and digital strain mapping analysis to determine the characteristics that would ensure the long-term reliable and safe operation of the HVGO pumps. The stress and deformation analysis were performed on the operating pumps in a variety of normal (1280 m3/hr.) and upset operating conditions including under partial and full load conditions. Dynamic and modal analysis of the pumps was developed and analyzed. The displacement and tensor fields of the hardware including the pumps, bases and piping were measured using high resolution laser cameras and analyzed. From the high-speed data gathering and loading analysis showed the deformation and stress affecting the pump and related hardware. The key variables undermining reliable performance were revealed and from the data the necessary remedial action was determined. The pumps have operated for over 30months to the time of writing without repeat failure. This paper should be read in conjunction with PVP 2020-21203; Investigation and Resolution of the Fluid Structure Interaction of High Rate HVGO Pumps.

In this work, a two-dimensional (2D) geometrically-accurate model of the TN-32 cask is generated in ANSYS/Fluent to investigate the effect of backfill gases and their pressures on the peak cladding temperature (PCT). This model is similar to the cask being used in high-burnup (HBU) spent fuel data project lead by the Electric Power Research Institute (EPRI). Helium, nitrogen, argon, and water vapor fill gases are investigated at pressures ranging from atmospheric (∼10 5 Pa) to 100 Pa. Steady-state computational fluid dynamics (CFD) simulations that include the effect of gas rarefaction (temperature-jump) at the gas-solid interfaces are conducted. The PCT as a function of heat generation rate and pressure is reported as well as the heat generation rate that brings the cladding temperature to the radial hydride formation limit. The results show that there are competing effects between the temperature-jump and the thermal conductivity of the gas to increase the fuel rods’ temperature. The low pressures increased the PCT, with the increase being most significant for the helium backfill.

A nested confinement (inner) and containment (outer) vessel system is under development to conduct small shock-physics experiments in a high-speed proton imaging facility at Los Alamos National Laboratory. The dual vessel system is necessary to serve as a qualified confinement system and containment buffer boundary between a high explosives experiment and the environment. The paper describes the preliminary engineering design and analyses that have been performed on the outer containment pressure vessel, following ASME BPVC Sect. VIII Div. 1, for both pressure and vacuum conditions. Other engineering attributes which will be presented include an internal support structure for a nested inner vessel, an external integrated support and alignment structure for the complete vessel system, and the vacuum and gas handling equipment.

Most vacuum vessels are bodies of revolution that are cylindrical or spherical. A square vacuum vessel was developed for a specialized application that needed to be suitable for repeated, rapid sealing and unsealing, and operation at mild vacuum (∼0.5 bara). This paper discusses the challenges that we faced in fabrication and testing of the vacuum vessel. The vacuum vessel was initially tested in a test rig. A second set of challenges was encountered when the vessel was tested mounted in the system. It captures the lessons learned from fabrication, rework, and modifications that were necessary to get the vessel to pass leakage testing.

For high pressure polyethylene applications, reliable temperature and pressure measurement with extremely fast response time, is crucial in order to avoid decomposition. Furthermore instrumentation must withstand not only the high pressures and temperatures, but also the vibration present in such a challenging environment. The requirements of temperature and pressure instrumentation include high quality mineral insulated cable, production techniques such as vacuum brazing and thin film sputtering as well as testing facilities. With this information, operators will be able to select high pressure thermocouples and pressure transmitters which are specifically designed for their application.

The purpose of this paper is to describe the changes of the structure and the creep performance for Cr35Ni45Nb alloy after varying carburization. Carburizing layers with different thickness were produced in Cr35Ni45Nb alloy directly by vacuum carburizing experiment. The surface microstructure of Cr35Ni45Nb alloy was essentially changed after varying carburization. Creep performance of carburized only and carburization-creep treatment alloys were compared to study the effect of the carburization on creep for Cr35Ni45Nb heat resistant alloy. Mechanical properties of carburizing layer, carburizing transition layer and base alloy were characterized by micro-hardness, respectively. Results of creep rupture testing for the carburized and non-carburized specimens showed that carburization can influence the rupture time, failure strain and creep rate. Carburization also been proved to affect the constant of C MG and C MMG for different stress or carburizing level.

Thin wall test articles were made using Fusion Powder Bed processing of Type 316L stainless steel. This hollow structure was fabricated using a Renishaw AM250. The material was characterized in the as fabricated condition using optical, scanning electron microscopy, and tensile testing. The tensile behavior indicates high initial residual stress due to the higher than annealed material yield strength. A series of thermal treatments were investigated to determine the effect on mechanical properties and microstructural evolution. In order to determine these effects, miniature flat tensile test samples and metallographic samples were wire electrical discharge machined from the structure. These samples were vacuum heat treated at 870, 1040 and 1080°C for 30 to 120 minutes and metallographically examined to determine the microstructural evolution. The samples were tensile tested and the data are evaluated based on the power-law type relationships. AM Type 316L SS exhibits less strain hardening than wrought stainless steel. In addition, the ductility is somewhat lower in the as-fabricated condition compared to the heat-treated condition. The results of the testing and the rationale for these different behaviors will be discussed.

The objective of this work is an experimental and numerical investigation for a bol Richard Cullen ted composite flange connection for composite pipes, which are used in the oil and gas applications, and obtain a joint with high strength and high corrosion resistance. For the experimental part, we have designed and manufactured the required mould, which ensures the quality of the composite materials and controls its surface grade. Based on the ASME Boiler and Pressure Vessel Code, Section X, this GFRP flange has been fabricated using biaxial glass fibre braid and polyester resin in a vacuum infusion process. Numerically, an investigation is carried out using 3D finite element analysis (FEA) of a bolted GFRP flange joint including flange, pipe, gasket and bolts. This model has taken into account the orthotropy of the GFRP material and the non-linear behaviour of the rubber gasket material for both the loading and non-loading conditions. Furthermore, the leakage propagation between the flange and the gasket has also been simulated in this investigation by using the pressure-penetration criteria PPNC in ANSYS. Finally, the flange has been tested under the internal pressure and the agreement between the experimental and numerical results is excellent.

The main failure mode of a large vacuum spherical tank, subjected to uniformly external pressure, is buckling of thin shell. Taking a large vacuum spherical tank with volume of 18000m 3 for research objects, the different calculation methods of buckling pressure between the ASME standard, analytic method and finite element method, were compared and analyzed. Using ANSYS software, the buckling pressure of stiffened spherical tanks were analyzed, and the optimum design of the thickness, height and quantity of stiffeners are studied. The results of analysis showed that the anti-instability ability of the large vacuum spherical tank can be improved significantly by a reasonable arrangement of stiffeners.

A failure mode and effect analysis is performed on 58 centrifugal pumps of Atmospheric and Vacuum Distillation Unit in one of the plants of SINOPEC. Firstly, the failure modes of the pumps are classified. Then, the failure causes of the pumps are analyzed. After that, the influence of the failure and the risk level are determined. Finally, the maintenance strategies to reduce risk are put forward according to the equipment failure mode and risk level, which is the basis for the maintenance of pumps. The results show that the main failure modes of the centrifugal pumps are process medium leakage, unexpected stop, vibration, damage, noise, low output and of useful medium leakage. The mean time to failures of centrifugal pumps is 14533 hours, about 20 months. Nine centrifugal pumps are in the risk of high or medium-high, which accounts for 15.52% of the total number of pumps.

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.

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.

This paper presents the design and analysis of the Hydrogen Transfer Lines (HTL) in the Spallation Neutron Source Facility (SNS), Oak Ridge National Laboratory in Oak Ridge, Tennessee. SNS is a Neutron Accelerator providing intense pulsed neutron beams for scientific research into the behavior of materials. The use of supercritical Hydrogen provides moderation of these neutron beam lines. This is facilitated by the HTL, which consists of six coaxial tubes transporting supercritical hydrogen to and from the Moderators surrounding the Mercury Target inside the Core Vessel (CV). Each Hydrogen line is surrounded by a vacuum tube in order to preserve the supercritical Hydrogen temperature of −425°F (−254° C/19 K). An inert Helium tube and a Water Jacket surround the Outer Vacuum Jacket. The Hydrogen boundary is considered the primary containment boundary, with the vacuum tubing being the secondary containment boundary both considered to be safety significant. The HTL assembly tubing must be qualified as Performance Category 3 to the requirements of Department of Energy Standard 1020-1994 for Natural Phenomena Hazards. This requires a detailed dynamic analysis. The HTL must also be qualified to ASCE 43-05 for Limit State consideration for abnormal events and ASME B31.3 for sustained and occasional (upset) loadings. The design basis includes consideration of normal sustained loadings such as deadweight and pressure, as well as thermal expansion/contraction, a Design Basis Earthquake (DBE) with associated Anchor Movements (SAM) and the potential physical interaction between coaxial tubes. Intermittent spacers are provided between some of the tubes, providing a functional interspace between the Hydrogen tubing and the Vacuum Jackets. The analytical methodology involves supplementing unaddressed criteria per ASME B31.3 thus requiring the application of more detailed rules found in ASME Section III, NC-3600, ASCE/SEI 43 – 05 as well as Regulatory Requirements such as USNRC Regulatory Guide 1.61 and 1.92. To assess the potential of a postulated failure of the primary Hydrogen boundary inside the Core Vessel, NUREG 0800, Section 3.6.3, Leak-Before-Break Evaluation Procedures are employed.

One of the vacuum column made of Carbon steel (SA 285 Gr. C) was found with severe corrosion under insulation during turnaround inspection. The equipment was in service for the past 46 years. The corrosion was around the full circumference of the column at a location immediately above the stiffener ring. The wall loss was extensive, which mandated a welded full circumferential patch to encapsulate the corroded region. A full circumferential lap patch with reinforcement plug welds was designed as per ASME PCC-2 [2], fabricated and installed at site. During the dye penetrant examination of the patch plate welds, fine cracks were noted at the toe of the fillet welds. A subsequent PAUT (Phased Array Ultrasonic Testing) of patch plate welds, showed that the cracks were in column shell (base material) surface initiating from toe of the fillet weld of the patch and beneath the fillet weld. The cracks found in first few sections of welds were ground and re-welded with appropriate pre-heating and post-heating. However, some cracks were still observed in base material, although with reduced magnitude compared to previous welding. Despite proper controls in place during the welding, the challenge was, some minor cracks were re-occurring at the base material surface below fillet welds. A multi discipline review was carried out to understand the potential root cause for the cracks, detailed assessment of risks and impact due to the cracks. A risk based approach was followed, in evaluating cracks for acceptance based on API 579-1/ASME FFS-1 [1], for continued service of the column and to minimise the extension of turn around duration. Later, a long-term plan was made to replace the equipment.

During vacuum drying of used nuclear fuel (UNF) canisters, helium pressure is reduced to as low as 67 Pa to promote evaporation and removal of remaining water after draining process. At such low pressure, and considering the dimensions of the system, helium is mildly rarefied, which induces a thermal-resistance temperature-jump at gas–solid interfaces that contributes to the increase of cladding temperature. It is important to maintain the temperature of the cladding below roughly 400 °C to avoid radial hydride formation, which may cause cladding embrittlement during transportation and long-term storage. Direct Simulation Monte Carlo (DSMC) method is an accurate method to predict heat transfer and temperature under rarefied condition. However, it is not convenient for complex geometry like a UNF canister. Computational Fluid Dynamics (CFD) simulations are more convenient to apply but their accuracy for rarefied condition are not well established. This work seeks to validate the use of CFD simulations to model heat transfer through rarefied gas in simple two-dimensional geometry by comparing the results to the more accurate DSMC method. The geometry consists of a circular fuel rod centered inside a square cross-section enclosure filled with rarefied helium. The validated CFD model will be used later to accurately estimate the temperature of an UNF canister subjected to vacuum drying condition.

In this work, a geometrically-accurate two-dimensional (2D) computational fluid dynamic (CFD) model of a used nuclear fuel cask, that can contain up to 32 pressurized water reactor (PWR) used nuclear fuel (UNF) assemblies, is constructed. This model is similar to the TN-32 cask employed in the ongoing high-burnup (HBU) Spent Fuel Data Project lead by the Electric Power Research Institute (EPRI). This model is used to predict the peak cladding temperature under vacuum drying conditions. Due to the symmetry of the cask, only one-eighth of the cross-section is modeled. Steady-state simulations that include the temperature-jump boundary conditions at the gas-solid interfaces are performed for different heat generation rates in the fuel regions and a range of dry helium pressures, from ∼10 5 to 100 Pa. These simulations include conduction within solid-gas regions and surface-to-surface radiation across all gas regions. The peak cladding temperatures are reported for various heat generation rates and rarefaction conditions, along with the maximum allowable heat generation that brings the cladding temperatures to the radial hydride formation limit. The results showed that the decrease of helium pressure significantly increased the temperature of the cladding material compared to the atmospheric pressure condition.

Vacuum drying of nuclear fuel canisters may cause the temperature of fuel assemblies to considerably increase due to the effect of gas rarefaction at low pressures. This effect may induce a temperature-jump at the gas-solid interfaces. It is important to predict the temperature-jump at these interfaces to accurately estimate the maximum temperature of the fuel assemblies during vacuum drying. The objective of this work is to setup a concentric cylinders experimental apparatus that can acquire data to benchmark rarefied gas heat transfer simulations, and determine the temperature-jump coefficient at the interface between stainless steel surface and helium gas. The temperature-jump is determined by measuring the temperature difference and heat flux across a 2-mm gap between the concentric cylinders that contains rarefied helium and compare the results to analytical calculations in the slip rarefaction regime.

Nowadays, fiber reinforced composites are widely used in variety of industrial applications such as aircraft structures, automotive, pressure vessels and piping, etc. Aircraft standard fabrication process requires certain level of vacuum compaction (debulking) during the lay-up process, and a standard bagging method for curing in an autoclave. Every compacted component cured in an autoclave needs to be vacuum bagged employing edge breathers or bleeders and surface breathers. This process is repetitive and time consuming, and therefore needs further investigation. In this research, the combined effect of the removal of compaction and edge breathing on the thermomechanical behavior of plain weave woven laminated composites is studied. Tests have been conducted on 12 lamina plain weave composite specimens. Results indicated an insignificant difference on the thermomechanical properties between compacted and non-compacted specimens. Tensile, ILSS, flexural and DSC tests confirm that for the 12 lamina specimens compaction and edge breathing are not needed.