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UNIT I

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1 Read and translate the text:

History of Digital Instrumentation and Controls

Digital Instrumentation and Controls (I&C) systems have been in use for over three
decades in various applications. Fossil power plants and refineries have been using integrated
digital I&C systems since the 1980s. Digital I&C systems are widely used in almost all
industrial applications in one form or another.
The use of microprocessors and computers is not new in nuclear power plants. Early
applications were limited to programmable logic controllers and plant process monitoring
computers. In the 1980s, digital technologies were integrated into control systems for various
subsystems, starting with the auxiliary systems and then moving to primary systems. By the
1990s, microprocessors were being used for data logging, control, and display for many
nonsafety-related functions.

Foreign Nuclear Plants
In Japan, the first fully digitalized I&C system was integrated into the Kashiwazaki-
Kariwa Unit 6 advanced boiling-water reactor (ABWR) in 1996. This was followed by
Kashiwazaki-Kariwa Unit 7. France, the United Kingdom, Korea, Sweden, and other
countries have also implemented digital I&C systems in their nuclear power plants.

Domestic Nuclear Plants
In the United States, digital I&C systems have been used in many applications in nuclear
power plants, including feedwater control systems, recirculation control systems,
demineralizer control systems, main turbine controls, and many other nonsafety systems.
With the NRC approval of the Eagle Series, the Common Qualified Platform (Common Q),
Triconex, and the Teleperm XS system for safety-related applications, operating nuclear
power plants may consider their use in retrofitting digital I&C systems at their facilities.
All new nuclear power plants are being designed with integrated digital I&C systems as the
backbone of protection, controls, alarms, and display and monitoring.

Fuel Cycle Facilities
Several fuel cycle facilities make extensive use of distributed control systems and
programmlogic controllers (PLCs) based on digital design technology both in their normal
process control systems and safety control systems. An example of the use of digital
technology in process control in a fuel cycle facility would be controlling the moisture content
of steam used in a process vessel through control of the steam temperature. Digital technology
could also be used to perform a safety function as an interlock that prevents filling of a vessel
if it is not in the proper location.

2 Learn the meaning of the following words and word-combinations, word groups:

digital instrumentation and controls (I&C) systems, fossil power plants and refineries,
industrial applications, programmable logic controllers, process monitoring computers, data
logging, recirculation control systems, demineralizer control systems, main turbine controls,

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