Nuclear Processing Plant Research Articles

Incorporating Environmental Protection Requirement in Industrial IoT Access Control Security Using Arduino Technology MQ2 and DHT11 Sensor Networks

This paper presents the development of environmental monitoring mechanism based on Arduino Sensor Technology for Industrial Internet of Things (Industrial IoT) Critical Infrastructure (CI) Protection in an Access Control role. Access control of hazardous substances is one of the most vulnerable aspects of Industrial IoT CI. The idea behind this study is to harden environmental security through live ecological monitoring of Temperature, Humidity and emitted hazardous substances or gases due to Industrial activities and processes in Smart CI places such as Nuclear Processing Plant, Thermal Generation Power Industries, Fossil Processing Plant, Military Chemical warfare plant, food processing factory, Agriculture Chemical Manufacturing Plant and many other CI industries. Live monitoring is one of the most important security requirements for any cyber-Access Control Mechanism. The literature revealed that similar systems were developed and implemented in different organizations and with different System Requirements and specifications. However, most CI industries have not automated environmental monitoring requirements and integrated the requirement into a broad institution security continuum. The consequence of neglecting environmental security is climate change. Furthermore, Toxic gas pollution affects millions of people around the world and contributes to about 5.4 percent of deaths worldwide. Pollution kills more people than the combination of malaria, AIDS, and tuberculosis hence the development of security mechanisms to monitor pollutants in the atmosphere. The main objective of this study was to develop a computer-based application for monitoring environmental hazardous substances such as extreme temperature, humidity, carbon dioxide (CO2), carbon monoxide (CO), and Smoke in the atmosphere surrounding Industrial IoT CI Industries. The system development approach employed was the Arduino engineering process model. To achieve this objective, cheaper ecological sensor Networks that include MQ2 and DHT11 Arduino Sensors are connected to Arduino Uno Microcontroller through a solderless breadboard Arduino component. The backend database was MySQL Relational database management system. The developed prototype application produced a number of results including live monitoring of temperature, humidity, CO2, CO, Smoke, and many others. A system evaluation process was conducted and the result indicated 99.999% accuracy levels. The results, it evidence that the developed prototype application can improve environmental security in Industrial IoT CI institutions.

Bio-Inspired Soft Robot for Locomotion and Navigation in Restricted Spaces

Soft robotics have been shown to be particularly versatile for accessing restricted and hazardous environments, such as nuclear and chemical processing plants, and pipelines. This paper presents a bio-inspired soft robot capable of propelling itself inside a cylindrical space. The continuum soft robot consists of three main sections, which, with coordinated inflation and deflation, enable a controlled locomotion of the robot.

Spread of Pollution from a Bottom Source in the Norwegian Sea

Simulations of the spread of radioactive contamination (RC) with cesium-137 (137Cs) as a passive impurity were performed using the Institute of Numerical Mathematics Ocean Model (INMOM) to assess the radiation threat from the Komsomolets nuclear submarine (NS) on the northeastern slope of the Norwegian Sea at a depth of 1680 m caused by the possible leakage of radionuclides from the reactor compartment into the surrounding sea water. These simulations have shown that RC in the bottom layer generally spreads along the depth slope to the north and south of the source. Such a variability of the direction of RC transport is caused by the variability of the bottom current velocities, which is confirmed by the data of field measurements. As the distance from the source increases, the concentration of RC significantly decreases due to dilution in the surrounding waters. In the interior of the sea, the concentration is several orders of magnitude lower than in the source. The inflow of RC into surface waters due to turbulent mixing and convective motions of waters in the complex three-dimensional structure of circulation in the Norwegian Sea is simulated. It is shown that the excess of the surface concentration of RC over the bottom one observed in the measurements cannot be associated with emissions from the Komsomolets. The near-surface concentration of RC is most likely caused by the spread of RC from nuclear processing plants in northern Europe. In general, it has been shown that the currently possible RC from the Komsomolets does not exceed the background level of radioactive contamination of the waters of the Norwegian Sea.

Uranium Contamination of Stainless Steel in Nuclear Processing Plants

Stainless steel coupons have been exposed to uranium-containing nitric acid solutions, in conditions similar to those found in various uranium handling nuclear facilities across the nuclear fuel cycle. Solid state analysis of the stainless steel samples and solution composition analysis were undertaken to gain a better understanding of the contamination process mechanisms. Stainless steel coupons were immersed in 12 M HNO3 containing uranium (1 g/L), in the form of uranyl, for periods of up to 255 days. Uranium contamination was observed across all time lengths of exposure. Solution analysis indicated that the levels of contamination reached an equilibrium state after ∼14 days. Investigations using Raman microscopy, synchrotron microfocus X-ray fluorescence and X-ray absorption spectroscopy showed inhomogeneous localization of uranyl species associated with the oxide layer of the stainless steel surface. Over longer time lengths of exposure these contaminant species were predominantly found to locate within intergranular regions of the stainless steel. This finding should be taken into consideration when developing decontamination protocols for corroded stainless steel that has been exposed to uranium, to facilitate metal reuse/recycle and minimize hazardous waste volumes.

Impact Simulation of Straight Tube Heat Exchanger Subject to Cross-Flow

Heat exchangers have been among the most troublesome components of both nuclear power and chemical process plants. Heat exchanger tubes are supported at intermediate points by support plates. Flow- induced vibration of tube can cause it to impact or rub against a support plate or against adjacent tubes and can result in tube fretting wear. Simulation of heat exchanger tube/ support dynamic interaction is presented. The tube/ support interaction parameters, ‘RMS Impact force’ and ‘Contact ratio’ are studied. These are significant inputs to predict fretting wear limited life of the heat exchanger tubes. An algorithm includes equilibrium iteration and variable time stepping based on convergence criteria is implemented in an in-house finite element program. The tool is validated solving documented premature failure case of shell and tube type heat exchanger.

High-accuracy CFD prediction methods for fluid and structure temperature fluctuations at T-junction for thermal fatigue evaluation

Temperature fluctuations generated by the mixing of hot and cold fluids at a T-junction, which is widely used in nuclear power and process plants, can cause thermal fatigue failure. The conventional methods for evaluating thermal fatigue tend to provide insufficient accuracy, because they were developed based on limited experimental data and a simplified one-dimensional finite element analysis (FEA). CFD/FEA coupling analysis is expected as a useful tool for the more accurate evaluation of thermal fatigue. The present paper aims to verify the accuracy of proposed numerical methods of simulating fluid and structure temperature fluctuations at a T-junction for thermal fatigue evaluation. The dynamic Smagorinsky model (DSM) is used for large eddy simulation (LES) sub-grid scale (SGS) turbulence model, and a hybrid scheme (HS) is adopted for the calculation of convective terms in the governing equations. Also, heat transfer between fluid and structure is calculated directly through thermal conduction by creating a mesh with near wall resolution (NWR) by allocating grid points within the thermal boundary sub-layer. The simulation results show that the distribution of fluid temperature fluctuation intensity and the range of structure temperature fluctuation are remarkably close to the experimental results. Moreover, the peak frequencies of power spectrum density (PSD) of both fluid and structure temperature fluctuations also agree well with the experimental results. Therefore, the numerical methods used in the present paper are of sufficiently high accuracy to be suitable for the CFD prediction of highly fluctuating flow and temperature fields.

William Fowler Felton

William Fowler Felton (“Bill”) was the doctor we would all like to have been. He was a rounded polymath, whose talents found him seconded to the special operations executive in...

J032021 流体温度変動による配管熱疲労に関する研究 : 熱荷重を評価するための流体と構造の温度変動の高精度なCFD解析手法([J032-02]エネルギープラント安全に向けた構造/熱流体/材料の達成問題(2))

Temperature fluctuations generated by the mixing of hot and cold fluids at T-junction, which is widely used in nuclear power and process plants, can cause thermal fatigue failure. The existent evaluation method of thermal fatigue provides insufficient accuracy for the evaluation result, because it was developed based on the limited experimental data and the simplified one-dimensional FEA. CFD/FEA coupling analysis is expected as a useful tool for the more accurate evaluation of thermal fatigue. The present paper aims to verify the accuracy of numerical methods of simulating fluid and structure temperature fluctuations at T-junction for thermal fatigue evaluation. The dynamic Smagorinsky model (DSM) is used for LES sub-grid scale (SGS) turbulence model, and a hybrid scheme (HS) is adopted for the calculation of convective terms in the governing equations. Also, heat transfer between fluid and structure is calculated directly based on thermal conduction by allocating grid points within the thermal boundary sub-layer. The simulation results show that the distribution of fluid temperature fluctuation intensity and the range of solid temperature fluctuation are close to the experimental results. Moreover, the peak frequencies of PSD of both fluid and solid temperature fluctuations also agree with the experimental results well. As a result, it has been proven that the numerical methods used in the present paper are of high accuracy.

Bayesian hierarchical modeling of latent period switching in small-area putative health hazard studies

In recent years, small area risk assessment modelling and data analysis around putative hazard sources has become a fundamental part of public health and environmental sciences. In this study, we address a fundamental problem in the analysis of such data, when intermittent operation of facilities could lead to evidence for latent periods of risk. This study examines the development of Bayesian models for the latent switching operating period of putative hazard sources such as nuclear processing plants and waste disposal incinerators. The developed methodology is applied in a simulation study as well as to a real data example.

Modeling and analysis of thermal damping in heat exchanger tube bundles

Abstract Most structures and equipment used in nuclear power plant and process plant, such as reactor internals, fuel rods, steam generator tubes bundles, and process heat exchanger tube bundles, are subjected to flow-induced vibrations (FIV). Costly plant shutdowns have been the source of motivation for continuing studies on cross-flow-induced vibration in these structures. Damping has been the target of various research attempts related to FIV in tube bundles. A recent research attempt has shown the usefulness of a phenomenon termed as ‘thermal damping’. The current paper focuses on the modeling and analysis of thermal damping in tube bundles subjected to cross-flow. It is expected that the present attempt will help in establishing improved design guidelines with respect to damping in tube bundles.

Design of Liquid Metal Phase Change Heat Exchanger for Next-Generation Nuclear Plant Process Heat Application

The Next Generation Nuclear Plant will most likely produce electricity and its reactor heat will be further utilized for the production of hydrogen, oil recovery from tar sands and oil shales, and other process heat applications, that will further the nation's pursuit of energy independence. An intermediate heat exchanger is required to transfer heat from the Next-Generation Nuclear Plant to the hydrogen plant (or other processes) in the most efficient way possible. Phase change heat exchangers are quite attractive in this regard, as they can transfer process heat more efficiently than for the single phase due to the advantage of high-enthalpy transport that includes the sensible heat of liquid, the latent heat of vaporization, and possible vapor superheat. This paper explores the overall heat transfer characteristics and pressure drop of the phase change heat exchanger with helium as the primary and sodium as the secondary heat exchanger coolant. For a two-phase boiling regime, the convective heat transfer coefficient is based on the concept of an additive, interacting mechanism of micro- and macroconvective heat transfer. In this analysis an improved design is proposed for given conditions, so as to obtain a lower overall pressure drop and a moderate/high overall heat transfer coefficient. The analysis presented in this paper will be useful as a guide for future experimental work for Next Generation Nuclear Plant process heat transfer.

Cancer Incidence in Municipalities near Two Former Nuclear Materials Processing Facilities in Pennsylvania—An Update

Previous studies of cancer incidence among persons living in municipalities within one mile of two nuclear materials processing and fabrication plants in Pennsylvania were extended for the years 1998-2004. It had been shown that mailing addresses for residents of rural areas often did not reflect the actual municipality of residence and, if not corrected, would bias study results. The previous studies had corrected for this bias. Accordingly for the extended study, we obtained mailing addresses from the Pennsylvania Department of Health (PDH) for 866 persons with cancer who presumably lived in one of eight minor civil divisions (MCDs) near or encompassing the former nuclear facilities, designated as Area 1 in previous studies conducted by the PDH. Street addresses were geocoded and local postmasters were asked to place rural delivery addresses, post office boxes and street addresses that could not be geocoded into the correct MCD of actual residence. Over 15% of the mailing addresses were found not to be within the boundaries of the Area 1 municipalities. After the mailing addresses of individuals with cancer were placed in their proper MCD of residence, the number of persons diagnosed with cancer (n = 708) and confirmed to have lived in Area 1 was as expected (728.4) based on cancer incidence rates in the general population of Pennsylvania (SIR 0.97; 95% CI 0.90-1.05). To further evaluate the patterns of cancer rates near these nuclear facilities and the influence of improved reporting and geocoding of addresses over time, analyses were conducted of publicly available cancer incidence data from 1990 through 2004. Based on mailing addresses, a steady decrease in the number of cancers reported in the Area 1 proximal MCDs was seen, in contrast to a steady rise in the number of cancers reported in seven adjacent but more distant MCDs from the nuclear facilities, designated as Area 2. These patterns were attributed to improvements over time in the geocoding of residential mailing addresses coupled with the gradual elimination and replacement of rural delivery addresses with street addresses. The incorrect placement of mailing addresses in residential Area 1 municipalities prior to about 2002 overestimated the number of cancers occurring among residents living in close proximity to the nuclear facilities and, correspondingly, underestimated the number among Area 2 residents. Summing Area 1 and Area 2 data showed that there was no change in cancer rates over time. These results are consistent with previous studies indicating that living in municipalities near the former Apollo-Parks nuclear facilities was not associated with an increase in cancer occurrence.

Flowsheet study of the thermochemical water-splitting iodine–sulfur process for effective hydrogen production

The Japan Atomic Energy Agency (JAEA) is performing research and development on the thermochemical water-splitting iodine–sulfur (IS) process for hydrogen production with the use of heat (temperatures close to 1000 °C) from a nuclear reactor process plant. Such temperatures can be supplied by a High Temperature Gas-cooled Reactor (HTGR) process. JAEA's activity covers the control of the process for continuous hydrogen production, processing procedures for hydrogen iodide (HI) decomposition, and a preliminary screening of corrosion resistant process materials. The present status of the R&D program is reported herein, with particular attention to flowsheet studies of the process using membranes for the HI processing.

Flocculation improves uptake of 90Sr and 137Cs from radioactive effluents

This paper presents the results of investigation on uptake of radioactive species 90Sr and 137Cs present in the liquid effluents from nuclear processing plants. Chemical precipitation process is adopted to remove radioactivity from the effluents with low and intermediate level of activity. In this process, radioactive 90Sr and 137Cs are co-precipitated along with copper ferrocyanide, ferric hydroxide and either calcium phosphate or barium sulphate. These precipitates being fine in size require flocculation for enhanced settling rate in clarifier/thickener. The flocculation by some selected high molecular weight polyacrylamide based polymers has improved the uptake of radioactive metal ions. The adsorption of these radioactive species has been found to increase in the presence of these flocculants thereby improving the decontamination factor (DF). While flocculating the precipitates, there may be some complex formation with Sr 2+/Cs +, flocculant and the substrate. This has enhanced the uptake of the radioactive metal ions from the liquid component. The plant trials have indicated the improvement of DF value due to flocculation by cationic flocculant.

Nickel-Based Superalloys for Advanced Turbine Engines: Chemistry, Microstructure and Properties

The chemical, physical, and mechanical characteristics of nickel-based superalloys are reviewed with emphasis on the use of this class of materials within turbine engines. The role of major and minor alloying additions in multicomponent commercial cast and wrought superalloys is discussed. Microstructural stability and phases observed during processing and in subsequent elevated-temperature service are summarized. Processing paths and recent advances in processing are addressed. Mechanical properties and deformation mechanisms are reviewed, including tensile properties, creep, fatigue, and cyclic crack growth. I. Introduction N ICKEL-BASED superalloys are an unusual class of metallic materials with an exceptional combination of hightemperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments. These materials are widely used in aircraft and power-generation turbines, rocket engines, and other challenging environments, including nuclear power and chemical processing plants. Intensive alloy and process development activities during the past few decades have resulted in alloys that can tolerate average temperatures of 1050 ◦ C with occasional excursions (or local hot spots near airfoil tips) to temperatures as high as 1200 ◦ C, 1 which is approximately 90% of the melting point of the material. The underlying aspects of microstructure and composition that result in these exceptional properties are briefly reviewed here. Major classes of superalloys that are utilized in gas-turbine engines and the corresponding processes for their production are outlined along with characteristic mechanical and physical properties.

Cause analysis of the fire and explosion of asphalt–salt mixture in a nuclear wastes processing plant

In order to explain the detailed cause of the fire and explosion of asphalt–salt mixture (ASM) that happened at a nuclear wastes processing plant in Japan on March 11, 1997, a special experiment device was designed to prepare the ASM samples under different feeding rate of the waste and in different concentration of phosphate in the waste. The structure and diameter distribution of salt particles in the ASMs were examined by using a scanning electron microscope, the specific surface area of the salt particles was measured by the BET method, and the reactivity of ASMs was measured by using a heat flux calorimeter (C80). It was found that both the concentration of phosphate in the waste and the feeding rate of the waste have great influences on the structure of salt particles and the reactivity of the ASM. Most of the salt particles in the ASM are porous and have larger specific surface area when prepared at low feeding rate of the waste containing phosphate, which causes the ASM has lower onset temperature and self-accelerating decomposition temperature (SADT).

Nondestructive monitoring of structural materials using automated ball indentation (ABI) technique

Materials used for high temperature components in nuclear power generation, aerospace, chemical and process plants undergo changes in their microstructure during operation in service leading to degradation in their mechanical properties. Monitoring the progressive changes in the mechanical properties is very important from the point of view of ensuring the structural integrity of the components and also for possible extension of their useful service life. Nondestructive methods for directly evaluating the mechanical properties are required for the success of any materials aging and life management program. In this paper, we describe an innovative automated technique based on ball indentation that can be used for laboratory and field applications in order to measure the mechanical and fracture properties of materials. Typical results from laboratory studies on engineering materials are also presented.

A SIMULATION OF THE TURBULENCE RESPONSE OF HEAT EXCHANGER TUBES IN LATTICE-BAR SUPPORTS

Tube failures due to excessive flow-induced vibrations are a major concern with regards to the operation of heat exchangers in nuclear power and chemical process plants. Among the possible excitation mechanisms, turbulence-induced forces have a persistent effect and thus are an important factor in determining the long-term reliability of heat exchangers. Impact forces which occur when tube/support collisions take place play a vital role in determining tube wear. To address this issue, a tube/support interaction model was implemented in an in-house finite element program and validated against three published examples. Pseudo-forces in conjunction with modal superposition were utilized in solving the nonlinear equations of motion of loose tubes in lattice-bar supports. Time-domain simulations of the nonlinear response of the tube are presented to determine the effect of various tube and support parameters on the vibratory characteristics of the systems. Special attention was paid to the effect of increased clearance on the response of tubes in lattice-bar supports. The tube response, impact force and contact ratio were analysed and represented in dimensionless form. The dimensionless parameters developed proved effective in collapsing the data pertaining to different flow velocities over single curves. These are useful in identifying the roles of several key variables in altering tube dynamics. Moreover, these parameters may also be used to scale the results to account for differences in geometrical and material properties.

An examination of different safety cultures in a nuclear processing plant

In a nuclear processing plant, four departments were compared using a 60-item questionnaire measuring safety attitudes and beliefs including the perception of managers' attitudes and behaviour, communication and risk-taking, and attitudes to taking personal responsibility for safety. Results suggest some differences at the conceptual level in addition to departmental differences and large grade differences. It is proposed that there are certainly two and possibly more differing safety cultures within this organization. The implications of this are discussed in terms of policy.

Design and Modelling of a Vibration-Powered Micro-Generator

Sensors are being used in increasingly diverse application areas where physical connections to the outside world are difficult. Examples include medical implants, sensors in nuclear processing plants, environmental monitoring and structural monitoring. If the sensor is embedded within a structure, routine maintenance duties such as changing batteries may cause significant problems. The need for having a power supply that will last for the lifetime of the sensor is therefore evident. A popular approach is to use the ambient energy within the environment of the sensor. Possible sources include solar energy, thermal energy from temperature gradients and kinetic energy in the form of environmental vibrations. Each of these approaches offers its own advantages and disadvantages, but of the three techniques mentioned the latter has attracted the least interest to date. The general approach gives rise to the term self-powered microsystem, and a review of such devices is covered by G1ynne-Jones and White]. One of the issues for vibration-based generators is that of energy storage, as the vibrations may not necessarily be present in a continuous and uniform manner. Potential storage media include lithium batteries and super capacitors. The remainder of this paper will be dedicated to the design and modelling of two possible techniques for producing vibration-based generators. The first device is a magnet and coil arrangement where relative movement between the coil and the poles of a permanent magnet generates electricity by electromagnetic induction. The second device is based on using a piezo-electric material to generate electrical energy from vibration-induced deformations (the direct piezo-electric effect). The device is fabricated using thick-film technology, with a piezo-electric paste based on lead zirconate titanate (PZT)2. Analytical solutions have been derived for a wide range of physical effects and, where appropriate, provide a relatively simple technique for modelling microsystem characteristics. In the case of the microgenerator they have been used to calculate resonant frequencies and electrical power output. Finite element analysis (FEA) is a very powerful and flexible technique for modelling complex geometries and is widely used in the design of microsystems. Typically, the structure is divided into a finite number of elements, each with precisely defined material and physical properties, and computers are used to solve the resulting matrix equations. Many FEA packages exist; the work presented here was performed using the ubiquitous ANSYS® software. FEA is particularly useful in microsystems designs to simulate characteristics such as stress distributions, deflections, resonant frequencies and mode shapes, viscous damping effects, piezo-electric coupling and thermal distributions.