Single Pressure Vessel Research Articles

Characterization of a highly integrated, natural convection-driven, condensing methanol reactor

A highly integrated, natural convection-driven, condensing methanol reactor with the catalyst bed, heat integration section and liquid product separation in a single pressure vessel without moving parts is successfully tested. Space-time yields of up to 600kgMeOHmcat.−3h−1 are demonstrated, comparable to other CO2-to-methanol processes. The internal recycle by natural convection is successfully achieved as well as significant heat integration. A further reduction of heat losses to the environment is needed for autothermal operation. The dynamic characteristics of the process, with fast start-up times, a high turn-down ratio add to the potential to deal with intermittent feed supply. Overall the LOGIC 2.0 reactor concept is a promising process configuration for green methanol production.

Mathematical modeling of reverse osmosis system design and performance

ABSTRACT Reverse osmosis (RO) is one of the most effective technologies for water desalination. However, the RO system's performance is contingent on its design parameters and operating conditions. In this study, a computational model for RO desalination performance prediction was developed. The study compares the performance parameters of the RO system utilizing various types of membranes with the established model using a single pressure vessel and seven membrane elements within the pressure vessel. This study looked at two different feed water concentrations. The first is for saltwater with a concentration of 40,000 mg/L, while the second is for seawater with a concentration of 32,000 mg/L. WAVE software assessed the findings of the generated model to the recovery ratio, feed pressure, salt rejection, and permeate concentration of each membrane element inside the pressure vessel. The results of the study show good similarity between the simulation model results and the results obtained by WAVE software as they are illustrated in Figures 4–7.

Design and analysis of single and multi-layer pressure vessel

This article presents a comprehensive investigation on the design and evaluation of monoblock pressure vessels using computer-aided design (CAD) and computer-aided engineering (CAE) software. Pressure vessels, commonly known as sealed cylindrical shells, are engineered to withstand high internal pressure and enhance structural robustness. The vessels feature a multi-layered structure that incorporates inherent safety mechanisms. They find widespread applications in diverse industrial sectors, including automotive, aeronautics, nuclear power, and biotechnology. This study utilizes established materials such as Steel-s515-gr70, Aluminium Alloy (6061-t6), and Grey Cast Iron to design a pressure vessel configuration comprising multiple layers, which aims to reduce stress and improve the security and longevity of the vessel. The CREO (8.0) software is employed for accurate modeling and optimization of the vessel's geometry, while the ANSYS (2022 R1) software enables static structural analysis to assess its performance under various loading scenarios. By utilizing CAD and CAE tools, this research aims to advance the techniques for designing and analyzing pressure vessels. The combination of pre-existing materials and a complex layered design serves to mitigate stress and enhance the safety and efficiency of the pressure vessel. The findings of this study contribute to the overall understanding of pressure vessel design and analysis, with the ultimate goal of developing pressure vessels that are safer and more efficient in diverse industries.

CINEMA-SMART development and its application to SBLOCA analysis for Korean small integral reactor

The Korean small integral reactor of SMART (System-integrated Modular Advanced ReacTor) was developed, which contained core, reactor coolant pumps, steam generators and pressurizer within a single reactor pressure vessel. In the code development of severe accident sequence analysis for the SMART, a CINEMA (Code for INtegrated severe accidEnt Management Analysis)-SMART has been developing from an initiation event to a containment failure including fission product behavior in the vessel and the containment. The CINEMA-SMART is composed of CSPACE, SACAP (Severe Accident Containment Analysis Package), and SIRIUS (SImulation of Radioactive nuclide Interaction Under Severe accident), which are capable of core melt progression with thermal hydraulic analysis of the RCS (Reactor Coolant System), severe accident analysis of the containment, and fission product analysis, respectively. The main sequence of a SBLOCA (Small Break Loss Of Coolant Accident) for the SMART has been analyzed using CINEMA-SMART computer code. This analysis is focused on an evaluation of core melt progression and containment thermal hydraulic behavior during a severe accident. The CINEMA results have shown that the integrity of the containment can be maintained during the SBLOCA accident in the SMART.

Simulation of a Station Blackout Accident for the SMART Using the CINEMA Code

SMART is a small-sized integral type PWR containing major components within a single reactor pressure vessel. Advanced design features implemented into SMART have been proven or qualified through experience, testing, or analysis according to the applicable approved standards. After Fukushima accident, a rising attention is posed on the strategy to cope with a Station Blackout (SBO) accident, which is one of the representative severe accidents related to the nuclear power plants. The SBO is initiated by a loss of all offsite power with a concurrent failure of both emergency diesel generators. With no alternate current power source, most of the active safety systems that perform safety functions are not available. The purpose of SBO analysis in this paper is to show that the integrity of the containment can be maintained during a SBO accident in the SMART (System-integrated Modular Advanced ReacTor). Therefore, the accident sequence during a SBO accident was simulated using the CINEMA-SMART (Code for INtegrated severe accidEnt Management and Analysis-SMART) code to evaluate the transient scenario inside the reactor vessel after an initiating event, core heating and melting by core uncovery, relocation of debris, reactor vessel failure, discharge of molten core, and pressurization of the containment. It is shown that the integrity of the containment can be maintained during a SBO accident in the SMART reactor. It has to be mentioned that the assumptions used in this analysis are extremely conservative that the passive safety systems of PSIS and PRHRS were not credited. In addition, as ANS73 decay heat with 1.2 multiplier was used in this analysis, actual progression of the accident would be much slow and amount of hydrogen generation will be much less.

Heat removal from RBMK reactor core using non-regular means

RBMK type reactor is a boiling light-water-reactor with a graphite moderator. Several important design features of RBMK are unique and very complex compared with: the fuel assemblies are located in individual channels rather than a single pressure vessel, these fuel channels are placed in a massive graphite moderator block; the rods of reactor control and protection system are placed in different channels, parallel to the fuel channels in graphite moderator block. Such design provides additional opportunity for heat removal from the reactor in the cases of beyond design-basis accidents. This paper discusses possibility of heat removal from the RBMK-1500 core using weak heat conduction mechanisms: heat removal from outer surface of drum separators and steam – water piping using air ventilation means; heat removal from graphite stack using direct water supply into reactor cavity; heat removal from fuel channels through the core graphite structures by control rods cooling system; heat removal in loss of long term cooling case using de-pressurisation of the reactor coolant system and water supply using complex of non-regular means. The provided analyses discuss advantages and capacities of these different means.

Improving second-pass permeate quality using thin film nanocomposite (TFN) membranes

Since the initial development of thin film nanocomposite (TFN) reverse osmosis membranes, a concerted effort has been made to optimize performance in first-pass seawater applications in order to lower energy usage. As the potential for greater energy savings can be harder to achieve in brackish water (BW) and second-pass seawater applications, increased membrane rejection is an attractive goal for many BW plants. A pilot plant was identified in Israel utilizing ground water with total dissolved solids of 2,900 ppm that suited an experiment to demonstrate the potential for TFN membranes to provide better salt rejection at the same projected feed pressures as standard Thin Film Composite (TFC) BW membranes. The pilot was undertaken using TFN membranes (400 square foot elements) in Stage 2 of the Lahat BW desalination facility. Eight (8) elements were loaded in a single pressure vessel. Feed water was taken from the concentrate of the plant’s Stage 1 train and had an average conductivity of 5,864 μS/cm. Average feed temperature was 26.8°C, feed pH was 7.6, and feed pressure was 12.2 bar. The pilot’s recovery was 63%. After collecting two months of operating data on a daily basis, the operation of the pilot and, in particular, the permeate quality proved to be stable. Daily data was normalized to element test conditions: 2,000 ppm NaCl, 225 psi, 25°C, 15% recovery, and pH 8. This normalization showed a stable element flux performance of 10,700 GPD (40.5 m3/d) and 99.75% rejection. The flux data obtained compares well with TFC membranes. However, the element rejection is up to 0.25% higher than average TFC elements, based on published specifications from membrane manufacturers. TFN technology is demonstrating the potential to enhance the performance of TFC elements which are applied to BW projects. This study found that TFN membranes deliver higher rejection than standard TFC elements in BW situations.

Autopsy of NF membranes after 5 years of operation at the Ummlujj SWRO plant

Application of nanofiltration (NF) membrane pretreatment to conventional seawater desalination processes at the Ummlujj SWRO plant generated much interest in the use of NF membranes in seawater desalination industries (thermal and SWRO). The present study was carried out to evaluate the condition of NF membrane elements after 5 years of continuous operation at the Ummlujj NF-SWRO plant. A total of 6 NF membranes removed from Ummlujj during annual replacements were subjected to performance evaluation. Out of the six elements, two NF elements from a single pressure vessel were subjected to autopsy and analyses based on their poor performance and also due to the fact both membranes (positioned 5th and 6th within the pressure vessel) were in continuous operation for 5 years. Autopsy included visual inspection, chemical and biological analyses of foulants as well as scanning electron microscopy and energy dispersive x-ray studies. The appearance and foulant contents on both membrane surfaces were the same and ...

Meeting the energy challenge through innovations in passive nuclear power technology

A large fraction of the world's nuclear power stations are currently expected to retire during the first quarter of the twenty-first century. Whilst the replacement of these older stations with new nuclear capacity is highly desirable from the standpoint of emissions abatement and resource conservation, this option has hitherto been regarded as expensive compared with fossil fuel alternatives, and it has been hindered by the difficulties of demonstrating safety in ways which can be appreciated by the general public. This paper shows how both of these key obstacles can be overcome through the application of passive safety technology to the well proven and widely deployed PWR concept. The US NRC licensed Westinghouse AP600 system is used to illustrate how unequalled levels of safety and reliability have been achieved using considerably simplified safety systems which rely on natural phenomena such as gravity, evaporation, and condensation. These simplified systems employ far fewer components (pumps, pipes, valves, and so on) than conventional plants, and hence require only around half the conventional building volume. The consequent savings in capital cost, construction time and cost, and operation and maintenance costs deliver generation economics which, for the AP600, are superior to those of currently available nuclear plant and are competitive with oil and coal. A larger unit currently under development at Westinghouse, the AP1000, promises to be directly competitive with natural gas. Finally, the international IRIS reactor project is used to illustrate how the PWR concept can be integrated within a single pressure vessel to deliver an economic, inherently safe, and proliferation resistant design of around 300 MW(e). It is concluded that passive safety system technology provides nuclear power with the potential to compete economically with all other alternative forms of generation, and delivers high levels of safety in a way which can be more readily understood and accepted by the public.

99/02073 A study on the use of phase change material to improve the heat transfer characteristics of nickel-hydrogen single pressure vessel batteries: Spencer, S. and Garner, C. Proc. Intersoc. Energy Convers. Eng. Conf. [computer optical disk], 1998, 33, IECEC329/1–IECEC329/6

99/02073 A study on the use of phase change material to improve the heat transfer characteristics of nickel-hydrogen single pressure vessel batteries: Spencer, S. and Garner, C. Proc. Intersoc. Energy Convers. Eng. Conf. [computer optical disk], 1998, 33, IECEC329/1–IECEC329/6

Fatigue design of an autofrettaged thick-walled pressure vessel using CAE techniques

In order to increase the fatigue life of an autofrettaged thick-walled pressure vessel, computer aided engineering techniques were applied. The fatigue life increase of the external grooved pressure vessel was achieved by relieving the high-stress concentration at the external groove. Shape optimization of the external groove incorporating the finite element stress analysis was performed, resulting in an optimized double grooved pressure vessel which showed a 34% decrease in maximum equivalent stress compared with the conventional single grooved pressure vessel. The fatigue life increase of the double grooved pressure vessel was verified by the simulation fatigue tests using C-shaped specimens, resulting in a 10-times-longer fatigue life. The predicted fatigue life of the pressure vessel using the local strain approach agreed with the simulation fatigue life within a factor of three.

Current status of nickel-hydrogen battery technology development

Nickel-hydrogen (NiH2) batteries are widely used in Earth-orbital satellites. Several advanced NiH2 cell and battery designs are under development, including common pressure vessel (CPV)» single pressure vessel (SPY), and dependent pressure vessel designs. Cells are being manufactured in sizes ranging from 64 to 250 mm in diameter. CPV NiH2 batteries, utilizing low-cost 64-mm cell diameter technology, have been designed and built for several small satellite programs. An advanced 90-mm-diam NiH2 cell design is being manufactured for the space station program. Production 250-mm-diam SPY batteries are currently under construction and initial testing has shown excellent results. Cell component level development is aimed at reducing battery cost while improving performance and maintaining reliability and cycle life. NiH2 cycle life testing is being continued and cells have currently completed more than 95,000 accelerated low-Earth-orbit charge/discharge cycles and 30 eclipse seasons in accelerated geosynchronous-Earth-orbit testing. Nickel-metal hydride battery development is continuing for both aerospace and electric vehicle applications.

Integral nuclear power reactor with natural coolant circulation. Investigation of passive RHR system

The development of a small power (up to 240 MWe) integral PWR for nuclear co-generation power plants has been carried out. The distinctive features of this advanced reactor are: primary circuit arrangement in a single pressure vessel; natural coolant circulation; passive safety systems with self-activated control devices; use of a second (guard) vessel housing the reactor; favourable conditions for the most severe accident management. A passive steam condensing channel has been developed which is activated by the direct action of the primary circuit pressure without an automatic controlling action or manual intervention for emergency cooling of an integral reactor with an in-built pressurizer. In an emergency situation as pressure rises in the reactor a self-activated device blows out non-condensable gases from the condenser tube bundle and returns them in the steam-condensing mode of the operation with the returing primary coolant condensate into the reactor. The thermo-physical test facility is constructed and the experimental development of the steam-condensing channels is performed aiming at the verification of mathematical models for these channels operation in integral reactors both at loss-of-heat removal and LOCA accidents.

Advanced technologies for CANDU reactors

The inherent features of a reactor based on multiple pressure tubes, rather than a single pressure vessel, provide CANDU with considerable flexibility for continuous design improvements. Of particular significance is the presence of a large volume of cool heavy-water moderator within the core. This can act as a heat sink for passive heat rejection during high-temperature accidents. We describe elements of our R&D program that are aimed to exploit this benefit. Similarly, safety, reliability and economy are the focus for our exploration of advanced technologies in the areas of advanced fuel and fuel channels, improved heavy-water production and computer-based systems that facilitate reactor design, construction and operation.

Design of the Safe Integral Reactor

The Safe Integral Reactor (SIR TM) is an innovative pressurized water reactor (PWR) design with enhanced safety which has been developed jointly by ABB Combustion Engineering, Inc., Rolls-Royce and Associates Ltd., Stone & Webster Engineering corporation and AEA Technology. The concept is a unitized primary coolant system in which the reactor core, the pressurizer, the reactor coolant pumps, and the steam generators are contained in a single reactor pressure vessel. This simplified reactor coolant system is coupled with a reliable, easily operated and maintained balance of plant utilizing a pressure suppression containment. The safety systems are primarily passive, relying on natural circulation and a large heat capacity rather than active, AC-powered equipment. The design is intended to meet the requirements for passive light water reactors being developed in the United States and jointly sponsored by the Electric Power Research Institute and U.S. Department of Energy, and requirements for small, safer light water reactors (LWRs) in the United Kingdom.