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Food and Beverage Processing

Food and Beverage Processing

When wandering the grocery store aisles,...

Variable Frequency Drives in Electric Actuators

Variable Frequency Drives in Electric Actuators

Electric actuators are vital for operati...

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Industry Headlines

Food and Beverage Sales Strongest in Four Years

11 HOURS AGO  |  Chris Guy

The U.S. consumer packaged goods (CPG) industry registered its strongest growth in four years in 2015, and some of the biggest gains were achieved by ...

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Industry Headlines

A.W. Chesterton Expands Training and Services Facility

17 HOURS AGO

A.W. Chesterton Company has expanded its facilities north of Boston with a new valve emissions testing facility, an expansive industrial training center and an industrial equipment service location to support its New England‐based customers.

The New England Service Center expansion provides mechanical...

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Spirax Sarco Supporting the Enbridge Ride to Conquer Cancer

1 DAY AGO

Spirax Sarco USA is teaming up with Spirax Sarco Canada for the Enbridge Ride to Conquer Cancer. From June 11-12, 2016, participants will cycle 200 km with thousands of other men and women throughout the countryside of Ontario, Canada. All net proceeds will benefit Princess Margaret Cancer Centre.

Th...

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Food and Beverage Sales Strongest in Four Years

11 HOURS AGO

The U.S. consumer packaged goods (CPG) industry registered its strongest growth in four years in 2015, and some of the biggest gains were achieved by companies targeting the fast-growing market for protein-rich foods and healthy, “mindful” snacks. These are among the findings of new resea...

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G7 Countries Vow to Support Energy Investments

1 DAY AGO

Leaders from Canada, France, Germany, Italy, Japan the UK and the U.S. have pledged to “promote investing in energy projects through the oil price crash to ensure a steady stream of supply” and “encourage financial institutions to invest in energy projects and infrastructure,&rdquo...

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Factory Orders in the U.S. Increased in March

17 HOURS AGO

New orders for factory goods rose 1.1% in March after falling a revised 1.9% in February, thanks largely to an increase in demand for defense equipment, the Commerce Department reports. This March increase in new orders was higher than the 0.6% rise economists predicted.

Durable-goods orders rose 0.8%,...

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U.S. Economy Grew 0.5% in First Quarter

2 DAYS AGO

U.S. GDP increased at an annual rate of 0.5% in the first quarter of 2016, according to the advance estimate released by the Bureau of Economic Analysis. In the fourth quarter, real GDP increased 1.4%.

The increase in real GDP in the first quarter reflected positive contributions from personal consumpt...

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Actuation in Nuclear Power Plants

vmfall11_nuclear_h

The thousands of actuators used in a nuclear plant face some pretty tough conditions as well as rigorous testing.

Currently, 104 nuclear power-plant reactors are working in the United States, and all of them have operating environments that are extremely challenging. Of those 104 plants, 35 are classified as boiling and 69 as pressurized water reactors.

While the design details vary from plant to plant, each nuclear facility has thousands of valve actuators used in various processes and applications. The newest-generation nuclear plant has more than 13,000 valves.

It’s clear, then, that valve actuators play vital roles in maintaining process safety, efficiency and productivity in a wide range of situations.

This article contains a brief description of some of the special circumstances encountered in challenging nuclear environments and the different styles of actuators used to meet demanding operational and safety requirements.

STRICT GUIDELINES AND REQUIREMENTS

vmfall11_nuclear_electric_actuatorWith O-ring sealed covers in place on this electric actuator, the motor, limit and torque switches, as well as other electrical components, are housed within a pressure-tight enclosure. This keeps out dirt and moisture and prevents breathing from expansion and contraction of the internal air caused by temperature changes.All equipment used in nuclear plants built in the United States is certified under stringent guidelines mandated by the Nuclear Regulatory Commission (NRC). Verification of reactors or equipment to standards from other countries is not acceptable for the 104 working reactors in the U.S.

To understand basic requirements the nuclear power industry faces in this nation, a review of the similarities and differences between nuclear power and fossil power is helpful.

In a fossil power plant, coal might be crushed and mixed with air to boil water, which produces steam to drive a turbine. With nuclear reactions, the process is different, but the operational objective is essentially the same—to heat water to produce steam to drive a turbine. With a coal steam generator, the activity of burning the pulverized coal and producing steam is contained within what is termed the “boiler island.” Because of the strong similarity to what happens in the coal plant, many engineers and technicians in a nuclear plant refer to the area where steam generation occurs as the “nuclear island.”

vmfall11_nuclear_cutawayThis cutaway illustration shows the internal components of a typical electric actuator.Within the nuclear reactor, equipment must meet rigorous standards. Since radiation is very high, the standards require all equipment materials used in this phase of the process to withstand high levels of radiation for the life of the plant. Therefore, materials such as iron or steel are required rather than aluminum. Also, temperatures in this portion of the plant are elevated, which will affect seal materials. The combination of severe environmental conditions determines the various coatings and paints allowed for use in this area, which is known as “inside containment.”

To be suitable for service in a nuclear reactor, an actuator must go through specific testing by outside testing agencies. The test reports produced must then be reviewed not only by the actuator suppliers, but by consulting engineers and the utilities themselves. Many documents also are reviewed by the NRC.

The tests for actuators used “inside containment” apply to all styles. The plants use electric motor operators as well as pneumatic cylinder actuators and hydraulic cylinder actuators. All of these actuators must be tested to ensure they can withstand the environment for their expected lives. Also, in addition to environmental concerns, the actuators must be able to operate during extreme accident conditions such as an earthquake.

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