Journal of Electrical & Electronic Systems

Poly(diethyl vinylphosphonate-co-2-chloroethyl methacrylate) (P(DEVP-co-CEMA)) copolymers are synthesized by free radical copolymerization initiated by benzoyl peroxide. The reactivity ratios for the free radical copolymerization of CEMA (M1) and DEVP (M2) are r1 = 19.45 and r2 = 0.11, respectively. The desired amphiphilic copolymers with relatively low polydispersity index (PDI) and different DEVP contents are isolated and purified from the reaction mixtures through precipitation fractionation. The structures and molecular characteristics of the obtained products are characterized by 1 H NMR, FTIR, and SEC analysis. All of these fractionated copolymers have a unimodal distribution and moderate PDI. The thermal properties of the P(DEVP-co-CEMA) copolymers are investigated by TGA and differential scanning calorimetry (DSC) measurements. Single glass transition temperature (Tg) appears in the DSC profiles differing from the existence of two Tgs in the blend of poly (diethyl vinylphosphonate) and poly (2-chloroethyl methacrylate), which indicates the random structure of the copolymers.

The MALDI–ToF mass analysis further reveals that DEVP and CEMA units are randomly distributed in the copolymer chains. The self-assembly behavior of the P(DEVP-co-CEMA) copolymers in aqueous solution is preliminarily investigated. Keywords: amphiphilic copolymers; 2-chloroethyl methacrylate; diethyl vinylphosphonate; phosphorus-containing polymers; radical polymerization; self-assembly Introduction Phosphorus-containing polymers are particularly attractive for their extensive application in fuel cells flame retardant and the biomedical field. Phosphorus-containing polymers include genetic materials DNA and RNA, and synthetic polymers functionalized at the main chain and those functionalized at the side chain. Vinylphosphonate is one of the simplest vinyl monomers with the phosphonate groups at the side chain. Since the late 1940s, different routes for vinylphosphonate synthesis have been reported.  

Researches on the polymerization of vinylphosphonates are following shortly after. So far, quite a number of reports have been published investigating the polymerization of vinylphosphonates with the methods of radical, anionic, coordinative-anionic and living rare earth metal-mediated group transfer polymerization. Among these techniques, coordinative-anionic polymerization and living rare earth metal-mediated group transfer polymerization are efficient to generate poly(vinylphosphonates) with higher molecular weight and higher conversions. Except for poly(vinylphosphonic acid) (which can be obtained in high yield and moderate molecular weight by free radical polymerization), relatively few investigations into the homo and copolymerization of vinylphosphonate monomers via radical polymerization have been reported. The few reports show that vinylphosphonate monomers fail to homopolymerize to high molecular weight products by the method of radical polymerization (especially for diethyl vinylphosphonate (DEVP)), which usually lead to low yields and provide polymers of low molecular weight.

In the case of radical copolymerization, the final results were either unsuccessful or afforded insufficient characterization. Arcus reported the copolymerization of DEVP with styrene initiated by tert-butyl hydroperoxide and determined the reactivity ratios of this monomer pair. For relatively low DEVP contents in the copolymers, DEVP is reluctant to enter the growing polymer chain as compared to styrene. Except for styrene, radical copolymerizations of DEVP with ethylene glycol dimethacrylate, methyl methacrylate ,acrylonitrile and trimethoxyvinylsilane are achieved, but afford inadequate characterization. Therefore, radical copolymerizations of DEVP with other monomers to get relatively high DEVP-containing copolymers with clearly characterized structure are still a significant and challenging issue.

The monomer 2-chloroethyl methacrylate (CEMA) is of special interest as halogen-functionalized comonomer for easy modification and post cross-linking. With initiating haloalkyl groups, graft copolymers can be prepared via atom transfer radical polymerization (ATRP). The chlorine atoms can be readily substituted by nucleophiles, for instance, azide groups, and then followed by click coupling of alkyne end-functionalized polymers to gain new properties. Therefore, CEMA is a potential comonomer for DEVP to broaden the applications of phosphorus-containing polymers. To date, to the best of our knowledge, there is no report on the copolymerization of DEVP with CEMA. What is more, due to the existence of both hydrophobic units (CEMA) and hydrophilic units (DEVP), the copolymers are able to self-assemble into nanoparticles in aqueous solution, which are promising in the fields such as microreactors and encapsulation of guest molecules. The modified copolymers show great potential in biomedical fields for polyphosphonates and proved to be high biocompatibility and adjustable degradability. Meanwhile, the chemical incorporation of a phosphorus-containing flame retardant into a methacrylate polymer via copolymerization may eliminate the leaching and heterogeneous problems associated with the additive approach. Herein, we synthesize a series of amphiphilic random copolymers, namely poly (diethyl vinylphosphonate-co-2- chloroethyl methacrylate) (P(DEVP-co-CEMA)), through free radical copolymerization using benzoyl peroxide (BPO) as initiator. The synthesis route of these random copolymers is presented in Scheme 1. Copolymers with relatively narrow molecular weight distribution are isolated through precipitation fractionation for the detailed investigation. The structures of the copolymers are confirmed by 1 H NMR, 31P NMR, Fourier transform infrared (FTIR), and MALDI–ToF mass analysis.

The thermal properties of P(DEVP-co-CEMA) copolymers are determined by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA) measurements. Preliminary investigations on self-assembly behaviors of the copolymers in water are also performed, and the nanoparticles formed in water are observed by TEM. Experimental Materials Triethyl phosphite (98.0%, Aladdin Reagent, China), ethylene bromide (99.0%, Aladdin Reagent, China), triethylamine (Sinopharm Chemical Reagent, China), benzene (Sinopharm Chemical Reagent, China), methacryloyl chloride (J&K Chemical Reagent, China), and 2-chloroethanol (Shanghai Nanxiang Reagent, China) were used as received. BPO (Shanghai Lingfeng Chemical Reagent, China) was recrystallized from methanol twice before use. THF was refluxed over potassium/benzophenone ketyl before use. All the other chemicals were used as received unless otherwise specified. Synthesis of CEMA 2-chloroethanol (10 mL) and triethylamine (22 mL) were dissolved in THF (50 mL), then methacryloyl chloride (15 mL) was added slowly under argon atmosphere while cooling the solution in an ice bath. The reaction mixture was stirred for 48 h at room temperature and then filtered.

The emergence of pressurized sealing technology has played a major role in eliminating the hidden dangers of running, emitting, dripping, and leaking in production equipment in the process industry, and has produced huge economic and social benefits. This article briefly introduces the definition, characteristics and relevant national standards, industry standards, laws and regulations of pressurized sealing technology. At the same time, from the technical perspectives of stress analysis, safety assessment, and safety structure, the pressure pipeline leaking and sealing process under pressure was deeply discussed, and the theoretical basis, evaluation criteria and practical methods to ensure construction safety were put forward. Pipelines are widely used for the transportation of hydrocarbon fluids over millions of miles all over the world. The structures of the pipelines are designed to withstand several environmental loading conditions to ensure safe and reliable distribution from point of production to the shore or distribution depot. However, leaks in pipeline networks are one of the major causes of innumerable losses in pipeline operators and nature. Incidents of pipeline failure can result in serious ecological disasters, human casualties and financial loss. In order to avoid such menace and maintain safe and reliable pipeline infrastructure, substantial research efforts have been devoted to implementing pipeline leak detection and localisation using different approaches.

This paper discusses pipeline leakage detection technologies and summarises the state-of-the-art achievements. Different leakage detection and localisation in pipeline systems are reviewed and their strengths and weaknesses are highlighted. Comparative performance analysis is performed to provide a guide in determining which leak detection method is appropriate for particular operating settings. In addition, research gaps and open issues for development of reliable pipeline leakage detection systems are discussed.

The use of pipeline is considered as a major means of conveying petroleum products such as fossil fuels, gases, chemicals and other essential hydrocarbon fluids that serve as assets to the economy of the nation.  It has been shown that oil and gas pipeline networks are the most economical and safest mean of transporting crude oils and they fulfill a high demand for efficiency and reliability.

For example, the estimated deaths due to accidents per ton-mile of shipped petroleum products are 87%, 4% and 2.7% higher using truck, ship and rail, respectively, compared to using pipelines. However, as transporting hazardous substances using miles-long pipelines has become popular across the globe in recent decades, the chance of the critical accidents due to pipeline failures increases. The causes of the failures are either intentional (like vandalism) or unintentional (like device/material failure and corrosion) damages, leading to pipeline failure and thus resulting in irreversible damages which include financial losses and extreme environmental pollution, particularly when the leakage is not detected in a timely way.

The average economic loss due to incidents of pipeline leakages is enormous. Over the past three decades, pipeline accidents in USA damaged property which costed nearly $7 billion, killed over 500 people and injured thousands. For example, the incident of pipeline explosion in the community of San Bruno, California, USA on September 6, 2010 killed eight people, and injured more. In a similar incident of pipeline defect that occurred in Michigan, USA on July 26, 2010, more than 840,000 gallons of crude oil spilled into Kalamazoo River with estimated cost of $800 Million. The causes of pipeline damage vary Sensors 2019, 19, x community of San Bruno, California, USA on September 6, 2010 killed eight people, and injured more than fifty. In a similar incident of pipeline defect that occurred in Michigan, USA on July 26, 2010, more than 840,000 gallons of crude oil spilled into Kalamazoo River with estimated cost of $800 million. The causes of pipeline damage vary. Shows a pie chart that illustrates statistics of the major causes of pipelines failure which include pipeline corrosion, human negligence, defects during the process of installation and erection work, and flaws occurring during the manufacturing process and external factors. Hence, it is possible to reduce the loss rate, injuries and other serious societal and environmental consequences due to the pipeline failures.

During the long-term water flooding phase, the oil recovery operation becomes more difficult due to the reservoirs' permeability, which increases considerably during the oil field development process. In general, to ameliorate the conditions for good enhanced oil recovery, it necessary to improve the displacement efficiency of displacement agents and improve sweep efficiency. Therefore, the alkali/surfactant/polymer combination flooding system techniques have been the required solution for enhanced oil recovery. However, in porous media, the reservoir temperature and salinity, the sheer deterioration, and the dilution effect affected the viscosity and viscoelasticity of the alkaline-surfactant-polymer combination's flooding systems. In addition, on the polymer molecular, the negative alkali ion neutralizes and forming a band molecule structure. The polymer's molecular structure is transformed and changed. Consequently, the polymer solution's viscosity and viscoelasticity are decreased. Our group’s previous studies reported that the dispersed particle gel prepared by shearing bulk gel has excellent characteristics, such as softness, viscoelasticity, high-temperature tolerance, thermal stability, and high expansion. The dispersed particle gel can plug the high permeability zones through aggregation in pores and throats and can also effectively improve the profile control through direct plugging or bridging across pore throats in the formation.

The addition of dispersed particle gel to strengthened the alkali/surfactant/polymer combination flooding system interleaves in the three-dimensional network structure and has a synergistic viscosity increase effect by increasing the combination flooding system's stability in the solution.

The effect of the interfacial tension and viscosity on the combination flooding system was investigated.  The results indicate that, the dispersed particle gel strengthened alkali/surfactant/polymer combination flooding system has a comfortable network structure and higher viscosity and viscoelasticity. The aging time and salinity affected the capacity of the interfacial tension reduction of the system. The increase in interface elasticity produces significantly positive effects on the combination flooding system stability. The interfacial tension decreased to an ultralow level, and the reaction of those actions in the system make the viscoelasticity and rheological property of the dispersed particle gel strengthened alkali/surfactant/polymer flooding system performant. Therefore, the dispersed particle gel strengthened alkali-surfactant-polymer ï¬?ooding technology have the ability and good reaction to be developed as a new type of the combination ï¬?ooding technology for enhanced oil recovery.

In recent years, a newly developed dispersed particle gel (DPG) has attracted significant attention because of its excellent properties and a good application prospect in an enhanced oil recovery process. The preparation method is convenient and easy to scale up for the field application. The dispersed particle gel with sizes ranging from submicron to micron can block the high permeability layers by accumulating in large pore spaces or directly plugging small pore throats. Furthermore, the dispersed particle gels can achieve in-depth profile control due to the elastic deformation and migration into the reservoir's porous media. These characteristics have demonstrated great potential for the dispersed particle gels to strengthen the alkali/surfactant/polymer combination flooding system. The polymers used are the principal sources of viscosity in the system; the surfactant and alkaline produce the synergistic effect by generating the ultralow oil-water interface tension. The added dispersed particle gel has a synergistic viscosity increase effect, temperature tolerance, and thermal stability. However, the combined flooding system suffers from the surfactant loss and chromatographic separation that affect the chemical components' synergistic effect for enhanced oil recovery. In this paper, the chromatography separation effects linked to a new method of oil displacement mechanism based on the dispersed particle gel strengthened Alkali/Surfactant/Polymer as a novel combination flooding system was investigated. The addition of dispersed particle gel in the Alkali/Surfactant/Polymer combination flooding system could interleave in the system's network structure and increase the viscosity stability by strengthening the flooding system to improve the oil recovery capacity. The novel dispersed particle gel strengthened alkali/surfactant/polymer flooding systems have a high displacement e�ciency and a better-swept volume capacity considering the oilfield requirement for the enhanced oil recovery process. The effects of polymer, surfactant, alkaline, and dispersed particle gel concentration on the combination flooding system were evaluated, furthermore the impact of external factors on the system such as salinity; aging time was described. The results showed that the effects of external factors aging time and salinity slightly affected the system's interfacial reduction capacity. The increase in interface elasticity produced significantly favorable effects on system stability. For the displacement mechanism, when the dispersed particle gel strengthened alkali/surfactant/polymer combination flooding system moved in a porous medium, the dispersed particle gel passed through the pore throat directly or by deformation depending on the system's pressure variation.

Furthermore, the phase separation was formed due to the combined component's effects, resulting in the differential migration between the systems, which led to different degrees of chromatographic separation phenomenon to affect the displacement mechanism. As we can see in the micro visualization simulation experiment, the residual oil interacted with Alkali molecules and form the in-situ surfactant, which makes the remaining oil emulsified, as well the surfactant adsorbed by DPG particles, make the crude oil emulsified and get enhanced. The chromatography and micro visualization experiments results of the dispersed particle gel strengthened alkali/surfactant/polymer combination

Collapse of casings during production has been reported on many occasions in different fields. Regardless of the root for the failure of the casings, this is due to stresses applied to the casing exceeding its ultimate strength. Failure of the casing similar to any pipe could be due to compressional, tensional, and burst or collapse forces due to various loads being applied to the casing string. Although several analytical models have been developed based on elastic or plastic approaches to estimate the ultimate strength of casing, it has been shown that these methods underestimate the casing strength. Casings’ mechanical and geometrical parameters, effective in-situ stresses, temperature, formation properties and other intervening are simultaneously required for a complete design of casing. To simulate the failure of casing in the presence of various forces, numerical modeling is a robust approach that can be employed. In this study, finite element simulation was used through the use of ABAQUS software to model the failure of casings in one of the wells located in the southern part of Iran. The results revealed that increasing the diameter to thickness (D/t) ratio decreases the ultimate strength of casing, leading to unexpected failure in the wells under consideration. It was also shown that eccentricity drastically reduces the strength of casing. Since the numerical results of current study were in an acceptable agreement with experimental studies, numerical simulation method proposed here can be used to predict the casing collapse.

Casing is a set of several steel pipes joined together and used to protect the wellbore after it is drilled. The casing is subjected to various loads in short term during drilling and long terms during production. Buckling due to axial load and burst and collapse as a result of high internal and external pressures, respectively, are examples of excessive loads and subsequent casing failure mechanisms. Casing damage is perhaps one of the most frequently reported failures in oil and gas drilled wells. This may happen during reservoir depletion due to excessive load caused by buckling or change in temperature gradient. Casing failures induced by formation compaction have also been observed in various reservoirs located at the North Sea, the US Gulf of Mexico, California, South America and Asia. These examples demonstrate that casing must be designed appropriately in order to resist excessive external forces during its intended life.  A casing with lower diameter to thickness ratio (D/t) and higher material strength will be more resistance to applied forces. However, optimum sizes should be chosen for economical purposes.  To determine the proper casing specifications the worst loading condition that the casing may experience during its life should be identified. During installation, casing experiences a combination of pressure, bending and axial loads, but when it reaches to its predetermined location it would be under external pressure only. Practically, the hydrostatic pressure applied to the outside surface of casing inside the annulus space during drilling phase before cementing is perhaps the most important load to be considered for the design of casings. Practical methods initially used for prediction of casing collapse were principally based on the empirical solutions. These equations have been developed to establish a linear or nonlinear relationship between collapse pressure and important parameters causing a casing to collapse. From the reported literature the ratio of outside diameter to wall thickness (D/t), initial ovality and eccentricity are the most important geometrical parameters of the casing to be considered for design purposes.

The important mechanical properties include the Young's modulus, Poisson's ratio and the yield strength of casing. Residual stress and applied axial stress are also needed to be considered. However, it is important to realize that casing collapse occurs under plastic regime, as a result of which yield stress based on Von-Mises failure criterion has been embedded into the empirical equations. Further investigations have suggested that considering the yield stress through the Von-Mises criterion underestimates the collapse strength. Therefore, several equations were proposed later to predict the collapse of casing including both elastic and plastic behavior of the pipe. The casing in that study was assumed to have an elastic–plastic behavior and showed to be accurate when it was used for collapse prediction of metal pipes. The analytical equations proposed for estimation of collapse strength are limited to the assumptions used in their development and are reliable for specific type of materials. Numerical simulations may be used alternatively for such analysis. In this study, an elastic-plastic FEM model was used to analysis the collapse strength of casing in one well located in South part of Iran.

In this essay, two techniques were used to treat the drill cuttings resulting from oil-based drilling fluid. Whereas amounts of drill cuttings were taken from the southern Rumaila fields, prepared for testing and fixed with 100 g per sample and contaminated with two types of crude oil, one from the southern Rumaila fields and the other from the eastern Baghdad field with concentrations of 10% and 15% w/w in mass. Samples were treated first in the microwave with a power applied of 540 & 180 watt and a time period of 50 minutes. It was found that the results reached below 1% w/w in mass, except for two samples they reached below 1.5% w/w in mass. Then, the sample with the highest treated concentration of 14100 PPM was treated on three groups of earthworms, which are 5, 10 and 15 in numbers. After the appropriate conditions were prepared for testing and for an incubation period of 21 days, the results highlighted the effectiveness of the succession process by reaching concentrations below 5000 PPM.

In this research paper, two techniques were used to treat the drill cuttings resulting from the oil-based drilling fluid. The drill cuttings were taken from the southern Rumaila fields which prepared for testing and fixed with 100 gm per sample and contaminated with two types of crude oil, one from Rumaila oilfields with Sp.gr of 0.882 and the other from the eastern Baghdad oilfield with Sp.gr of 0.924 besides contamination levels of 10% and 15% w/w in mass .Samples were treated first with microwave with a power applied of 540 & 180 watts as well as a time of 50 minutes. It was found that the results reached below 1% w/w in mass, except for two samples they reached below 1.5% w/w in mass .Then, the sample of 1.41% w/w in mass, which has the highest contamination level after microwave treatment, was treated on three groups of earthworms. After the appropriate conditions, samples were prepared for treating by earthworms and for an incubation period of 21 days, the results highlighted the effectiveness of the succession process by reaching concentrations below 0.92%, 0.65%, and 0.42% w/w in mass

Waste disposal operations from the oil and gas industry, unexpected accident leakage, or improperly disposing of drilling waste, have quite serious consequences for human health and the environment in general. When contaminated drill cuttings are removed with the remaining drilling fluids, especially with oil-based mud (OBM), the chemical fractions of liquids begin to seep into the ground, causing the elimination of existing organisms and contaminated groundwater. Normally, the remains of the drilling mud (whether it was oil-based mud or water-based mud) and the drill cuttings are associated with the presence of various hydrocarbon concentrations and heavy materials. The saturated and unsaturated hydrocarbon concentrations are greater in the oil-based mud, these concentrations can reach about 50% and this percentage is more than that in water-based mud (WBM).

Accordingly, it is more toxic than WBM. Since the disposal of drilling waste had become a global problem that causes escalating anxiety, especially for researchers and oil companies, due to the multiple negative impacts on public and environmental health, oil and gas wells drilling in Iraq cannot be an exception in this manner. Drilling waste produced by the exploration and production industry is coming in the second place of international ranking for the largest volume of waste produced. The waste disposal problem has become an important point in achieving a good environmental management system. In general, contamination of drilling fluids with drill cuttings waste is an inevitable result of successful drilling operations; therefore, drill cuttings waste accumulation ought to go through the treatment and disposal option after all. In that situation of the drill cuttings that need to be handled earlier to disposal, there are numerous feasible selections including land-farming, bioremediation, solidification, thermal desorption, stabilization, and cuttings re-injection, etc. Land reclamation is a regularly utilized bioremediation strategy in which the oil-contaminated drill cuttings are applied to the land where evaporation synchronically with the natural organisms of the soil combines to diminish the pollution of the waste. Among these ways, bioremediation can be considered as a well-proven and environmentally acceptable technology that employs microorganisms (i.e. bacteria, fungi, and or earthworms) to biologically eliminate oil contaminated waste into nontoxic remnant and reduce contaminant concentrations to acceptable levels. Vermiculture or worms farming is a well-steady technique for remediating organic wastes and decompose them into a material eligible for receiving essential nutrients to increase flora growth. Earthworms are an important indicator of soil health, as their presence means the quality of the soil and its absence means the opposite.

Earthworms are also a good predictor of toxicity measurement and have been used to assess environmental risks. However, scientific information remains limited about the sensitivity of earthworms to contaminated soil, as well as their viability and mechanism of treating the soil. Several important studies have highlighted the activity of earthworm use to promote hydrocarbon contaminant loss from soil. On the other hand, microwave drying is one of the modern technologies used industrially and at home, which showed effective results in its practical applications and brought about an ever-increasing change with drying various materials. The treatment levels accomplished by the microwave drying process were significantly greater than those used in the solid control system. The microwave technique is a treatment method for handling waste of many kinds and has multiple advantages. It is also easy to use and fast to accomplish, as well as it can be controlled remotely and with great flexibility. Furthermore, the microwave can reach the required temperature in less than 1% of the time required by traditional heating methods. Besides, the microwave technique is preferred as it considered to be a source of clean energy.

Pipeline and Oilfield equipment are expected to perform safely, continuously and reliability for the life of the assets.  The equipment is designed to be robust when used in harsh environments and have the ability to be maintained to extend the safe operation of the equipment.   Maintenance schedules, seal and gasket materials, and operational and maintenance procedures can be updated as needed to be in compliance with changing operational needs or regulatory requirements.   More difficult or not possible to change is the design and the material of the in-service equipment.    Regulations and design codes are continuously evolving, driven by the experiences of the industry.  These design code revisions represent bo th proactive measures and reactive changes to improve the experiences within the industry.  This paper brings into focus the opportunity to evaluate operational equipment, as example a pipeline closure,  that was designed in accordance with former codes and standards and may or may not be incompliance with the safe operations and designs as measured against today’s current codes and standards.   We will also evaluate the impact of using non-OEM components to maintain oilfield equipment. ASME Codes and Standards, industry regulations, and corporate management plans continue to evolve and are applied to new purchase equipment. Bringing awareness to existing, older equipment, identifying safety risks that may be present, and next steps for mitigation are within the natural life cycle of our oil and gas equipment.

 The aging: of nuclear power plants is one of the most important issues facing the nuclear industry worldwide. Aging encompasses all forms of degradation to nuclear power plant components, systems, and structures that result from exposure to environmental conditions or from operational stresses. Both the degradation from aging and actions taken to address the aging, such as increased maintenance and testing, can significantly impact human: performance in the plant. Research: into the causes and effects of aging as obtained through the assessment of operating experience and testing have raised questions regarding the adequacy of existing industry standards for addressing the concerns raised by this research. This paper discusses these issues, with particular emphasis in the area of equipment qualification and human performance.

The U.S. NRCs hardware oriented engineering research program for plant aging and degradation monitoring has evaluated the susceptibility to aging of systems^ structures, and components (SSCs) important to the safe operation of nuclear power plants (NPPs). The principal goals of the program, known as the Nuclear Plant Aging Research Program (NPAR),. are to understand the effects of age-related degradation in NPPs and to manage them effectively. Results have been achieved in the area, of electrical, control, and instrumentation (ECI) components encompassed by EEEE standards. Through the NRCs NPAR Program, degradation mechanisms and aging management techniques have been or are being evaluated for bistabies, switches, transmitters, inverters, I&C modules, cable penetrations, and isolation devices. In addition, the ECI components associated with systems such as the Emergency Diesel Generators, Control Rod Drive Systems, and Emergency Core Cooling Systems have been addressed for their aging significance. An evaluation of the operating experience of these components and systems, coupled with a determination of the materials of construction, operating and environmental stresses, and failure modes, causes, and effects have provided the NRC with the technical basis required to assure the continued safe operation of present reactors through the license renewal period. An understanding of the aging process has been achieved in the NPAR Program. Aging is the cumulative degradation to aa SSC from operational and environmental mechanisms such as cycling, transients, vibration, testing, temperature, and humidity^ These types of stresses have resulted in the degradation of certain subcomponents such as electrolytic capacitors, fuses, or power semiconductors which, can effect the operation, of various ECI equipment. Similarly, aging degradation associated with the mechanical properties of elastomers, connectors, and fuse holders have also resulted in ECI failures. To a large degree, mitigation of this degradation is accomplished through a comprehensive maintenance program which incorporates predictive and condition monitoring techniques. Some questions remain, however, particularly related ta the industry's need to factor agingrelated data into equipment qualification programs and staffing practices. The latter are associated with the additional maintenance and testing often required to manage aging.

The U.S. NRCs hardware oriented engineering research program for plant aging and degradation monitoring has evaluated the susceptibility to aging of systems^ structures, and components (SSCs) important to the safe operation of nuclear power plants (NPPs). The principal goals of the program, known as the Nuclear Plant Aging Research Program (NPAR),. are to understand the effects of age-related degradation in NPPs and to manage them effectively. Results have been achieved in the area, of electrical, control, and instrumentation (ECI) components encompassed by EEEE standards. Through the NRCs NPAR Program, degradation mechanisms and aging management techniques have been or are being evaluated for bistabies, switches, transmitters, inverters, I&C modules, cable penetrations, and isolation devices. In addition, the ECI components associated with systems such as the Emergency Diesel Generators, Control Rod Drive Systems, and Emergency Core Cooling Systems have been addressed for their aging significance. An evaluation of the operating experience of these components and systems, coupled with a determination of the materials of construction, operating and environmental stresses, and failure modes, causes, and effects have provided the NRC with the technical basis required to assure the continuedsafe operation of present reactors through the license renewal period.  the operating experience of these components and systems, coupled with a determination of the materials of construction, operating and environmental stresses, and failure modes, causes, and effects have provided the NRC with the technical basis required to assure the continued safe operation of present reactors through the license renewal period.  To a large degree, mitigation of this degradation is accomplished through a comprehensive maintenance program which incorporates predictive and condition monitoring techniques. Some questions remain, however, particularly related ta the industry's need to factor agingrelated data into equipment qualification programs and staffing practices. The latter are associated with the additional maintenance and testing often required tomanage aging.