Search Results for water-recirculating systems

The corrosion process that occurs in industrial systems is often difficult to discern until extensive deterioration has occurred. For boilers to function properly, the incoming water must be processed to meet the water quality required for the boiler. This article discusses pretreatment methods of the incoming water and preboiler corrosion protection methods. It analyzes internal treatment and condensate treatment of boilers. The article discusses three types of cooling systems: once-through systems, open recirculating systems, and closed recirculating systems. The corrosion processes which occur in water-recirculating systems and the effect of dissolved gases, temperature, pH, suspended solids, dissolved salts, and scale deposition on corrosivity of water, are also reviewed. The article also considers anodic and cathodic inhibitors and the control of corrosion in municipal water systems.

Cooling towers are designed to remove heat from water in an induction system and dissipate it into the atmosphere. This article provides information on closed-loop recirculating water systems of an induction system to cool the power supply. It focuses on various types of cooling towers, namely, air-cooled heat exchangers, air-cooled heat exchangers with trim cooler, closed-circuit evaporative cooling towers, and open evaporative cooling towers. The article discusses the importance of their placement or positioning to reduce the chances of air recirculation, and concludes with a discussion on refrigerant chillers.

This article describes the corrosion mechanisms, challenges, and control methods in service water distribution systems. It provides a discussion on typical designs and water qualities for distribution systems used in fossil-fueled and nuclear power plants. The article also explains the techniques for controlling corrosion in service water systems.

Induction heating has many different applications, such as melting, heating stock for forging, and heat treating. This article begins with a discussion on the types of power supplies, namely, solid-state power supplies and oscillator tubes. It provides information on system elements, including cooling systems, power supplies, heat stations, work handling fixtures, induction or work coils, and quench systems. The article discusses the influence of system elements on induction heat treating system design. It also deals with the general theory, types, and applications of induction coils.

Hardness testing equipment is important as all results from the induction equipment are graded by the hardness testing equipment. This article includes maintenance tips and points to consider regarding hardness test equipment, power supplies, controls, programmable logic controllers, computer systems, water cooling systems, fixtures and machines, air-operated or pneumatic devices, coils, and quench systems. It also presents simple rules that need to be applied while moving the equipment from one location to another.

This article focuses on the environmentally assisted cracking (EAC) of structural materials in boiling water reactors (BWRs), reactor pressure vessels, core internals, and ancillary piping. It discusses the effects of water chemistry on materials degradation, mitigation approaches, and their impact on aging management programs. The article reviews the effects of materials, environment, and stress factors on the cracking susceptibility of ferritic and austenitic structural alloys in BWRs. It describes the methods, such as data-based life-prediction approaches and mechanisms-informed life-prediction approaches, for predicting cracking kinetics in BWRs. The article provides information on several EAC mitigation techniques for BWR components, namely material solutions, stress solutions, and environmental solutions.

This article discusses the main materials and water chemistry characteristics of the primary and secondary water circuits of a pressurized water reactor (PWR). It reviews the corrosion issues of PWR materials and the influence of corrosion and fouling on primary and secondary circuit radiation fields. The article explains the primary side intergranular stress corrosion cracking (IGSCC) in different materials, namely, nickel-base alloys, high-strength nickel-base alloys, low-strength austenitic stainless steels, and high-strength stainless steels. The secondary side corrosion in steam generator including denting, pitting, intergranular attack and IGSCC is also discussed. The article examines laboratory studies that have resulted in models and computer codes for evaluating and predicting intergranular corrosion, and considers the remedial actions for preventing or arresting intergranular corrosion. It concludes with information on the external bolting corrosion in nuclear power reactors.

The chemicals that have been used in traditional vapor degreasing have serious health and environmental hazards that have prompted the search for modified and alternative techniques. This article provides a detailed discussion on the regulatory mandates that affect the use of industrial degreasing methods. It describes the aqueous degreasing technique, which forms an attractive alternative to the traditional vapor degreasing process. The article includes information on the materials and equipment used in the process, and discusses the advantages and disadvantages of hot and dip tank systems of aqueous degreasing. It explains how to convert an existing vapor degreaser to an aqueous cleaning system.

Surface coatings are essential in all facilities that process nuclear materials or use nuclear fission for power generation. This article describes the coatings used in two basic types of Generation 3 nuclear reactor designs in the United States and their containment size. These reactors are the boiling water reactor (BWR) and pressurized water reactor (PWR). The article provides information on the loss-of-coolant accident (LOCA) identified as the design basis accident (DBA), which can rapidly de-water the core of an operating nuclear reactor. To avoid LOCA, both the BWR and the PWR include emergency core cooling systems. The article describes a DBA test and other coating performance parameters necessary for safety-related coating systems. It provides a detailed account of the selection criteria of coating types in a nuclear plant. The article concludes by highlighting protective coating strategies in Generation 3 Plants.

This article examines the understanding of persistent material changes produced in stainless alloys during light water reactor (LWR) irradiation based on the fundamentals of radiation damage and existing experimental measurements. It summarizes the overall trends and correlations for irradiation-assisted stress-corrosion cracking. The article addresses the effects of various radiation factors on corrosion. These include radiation-induced segregation at grain boundaries, radiation hardening, mode of deformation, radiation creep relaxation, and radiolysis. The article discusses a variety of approaches for mitigating stress-corrosion cracking in LWRs, in categories of water chemistry, operating guidelines, new alloys, design issues, and stress mitigation. It concludes with a discussion on the irradiation effects of irradiation on corrosion of zirconium alloys in LWR environments.

The ultrasonic machining (USM) process consists of two methods, namely, ultrasonic impact grinding and rotary USM. This article lists the major ultrasonic components that are similar to both rotary USM and ultrasonic impact grinding. It also provides schematic representations of the components used in rotary USM and ultrasonic impact grinding. The article describes the operations of the components of the rotary ultrasonic machine and ultrasonic impact grinding machine. It discusses the applications of the rotary ultrasonic machine: drilling, milling, and surface grinding. The article concludes with information on machining characteristics of ultrasonic impact grinding.

Emulsion cleaning is an industrial cleaning process that uses an organic solvent as the main active agent. This article provides information on the applications, concerns and limitations, and process parameters of emulsion cleaning. It describes the processing variables and equipment for three main stages of emulsion cleaning: immersion cleaning, secondary cleaning, and spray cleaning. In addition, the classifications, composition, and selection criteria are also discussed.

This article presents a simple cost/pricing system that is reasonably accurate and could easily be recalculated if the yearly cost of any of the basic cost components change. Using the example of a commercial heat treating facility, the operational details are categorized as atmosphere processes, induction processes, aluminum processes, high-heat processes, and secondary processes. For the purpose of calculating the heat treatment processing cost per hour and the selling price for a piece of equipment, the costs are separated into direct costs, allocated costs, capitalized cost, and general and administrative costs. The article discusses the techniques involved in allocating costs to the group of equipment, and presents a description on the cost analysis of endothermic gas.

Corrosion problems and materials selection for emissions control equipment can be difficult because of varied corrosive compounds present and the severe environments encountered. This article discusses the selection of materials for construction of flue gas desulfurization systems. It addresses the problems associated with materials for incinerator off-gas treatment equipment. The off-gases can be classified according to their corrosiveness as: industrial chemical, hospital, municipal solid, and sewage sludge. The article provides information on the selection of materials for the three most common types of dust collection equipment used in bulk solids processing, namely, fabric filters, electrostatic precipitators, and wet scrubbers. It also discusses a wide variety of corrosion problems encountered in chemical and pharmaceutical industries.

Painting is a generic term for the application of a thin organic coating to the surface of a material for decorative, protective, or functional purposes. This article provides a detailed account of the types and selection factors of paints and the various application methods, including conventional air atomized, airless, and electrostatic spray; roller coating; dip coating; flow coating; curtain coating; tumble coating; electrocoating; and powder coating. Surface preparation methods and prepaint treatments for coating systems are also discussed. The article includes information on quality control procedures, causes of paint film defects, cost calculation, and safety and environmental precautions. The composition and characteristics of organic coatings, coating system selection factors, the types of paints for structural steel, and the applications of paint on structural steel are also reviewed.

Induction heating for hardening of steels has advantages from the standpoint of quenching because parts are individually processed in a controlled manner. This article provides information on the effect of agitation, temperature, hardening, residual stresses, and quenching media, on quenching. It also describes various quenching methods for steel induction heat treating, namely, spray quenching, immersion quenching, self or mass quenching, and forced air quenching. The article also reviews quench system design and quenchants and their maintenance.