By Ritesh Gupta

The nuclear power industry is increasingly looking at sophisticated options for monitoring and controlling plants’ processes and equipment.

Being an integral part of a plant’s operations, the instrumentation and control (I&C) system is quite significant for plant modernisation as well as new plant construction.

Ensuring the safety of the U.S. nuclear fleet remains the number one priority of the industry. In a broad sense, addressing performance-related issues is a consideration throughout all operations of the plant and safety measures are incorporated into the solution.

To ensure the long-term operational excellence of the fleet, utilities are addressing obsolescence and procurement issues in many plant systems, including improving existing I&C systems, says Carl Fisher, vice president - Global and US; I&C and Electrical Systems at Areva, a company that designs and supplies requisite systems included in the new reactors supply or to be installed in reactors during their modernisation programmes.
 

Pressure on performance

Many plants are facing increasing challenges related to aging and obsolete components. Utilities, for example, need to identify long-term partners who can be sure these challenges are being addressed in the safest, most competitive way available, meeting all regulatory requirements and making obsolescence a non-issue for their operations.

According to Fisher, obsolescence in the context of the nuclear industry refers to components that are no longer manufactured and qualified to the regulated standards, or are no longer available from their original fabricators.

“Often the aging U.S. plants have parts that need to be repaired and sometimes replaced before the end of plant life. This presents a unique challenge as many manufacturing firms who provided the original parts in the 1970s and 80s are no longer in business or no longer certified to provide nuclear-grade parts to these plants,” says Fisher.

The company works on solutions for many obsolescence challenges at the Areva Solutions Complex in Lynchburg, Virginia.

As a full-service campus of eight facilities, the complex helps U.S. electric utilities and equipment manufacturers meet ever-increasing safety requirements for nuclear electricity production, with the unique ability to package engineering and services to extend plant life and improve plant operations.

“We also approach these challenges by offering “Integrated Procurement Solutions” (IPS), which consists of four modules that can be provided separately or integrated to meet nuclear utility supply chain demands,” says Fisher.

IPS supports the aging nuclear fleet by providing the industry with safety-related equipment that is no longer available. It is one way to address obsolescence, inventory and classification processes. IPS addresses a number of issues, including:

• Commercial Grade Dedication and Component Testing and Qualification (through U.S. Technical Centre at the Areva Solutions Complex)

• Procurement Engineering

• Inventory Optimisation

• Risk-Informed Procurement

In conjunction with IPS, Areva’s Nuclear Parts Centre supports the management of obsolescence of mechanical, I&C and electrical products.
 

Better systems, better performance

The industry is relying on digital technology to combat obsolescence while also improving plant reliability. As far as improvements in the I&C systems is concerned, the industry is evolving from analog-based systems to digital systems to address obsolescence while improving operations through system self-diagnostics, automated testing, on-line maintenance, enhanced redundancy and more readily available information.

Fisher claims that Areva is the only supplier that has supported the successful licencing, engineering, procurement, installation and commissioning of a full-scope digital Instrumentation and Control (I&C) Protection System in the US market. As part of this project, two units are currently installed with a third slated for this autumn.

“We are currently in discussions with the NRC during the pre-licensing phase for all safety-related systems required for completion of a U.S. nuclear plant,” says Fisher.

The I&C system features several subsystems with their electrical and electronic equipment. According to Areva, this includes sensors which supply measured data, programmable controllers to process those signals, and drive the actuators, and monitoring and control means for use by the plant operators.
 

Optimisation

The industry has been evolving the way it approaches outage and refueling services. When it comes to refueling outage, Areva focuses on establishing a process that it applies to every refueling outage.

First, Areva observes good process rigour that stations utilise to scope their outage.

“Our team works with the plant’s engineers to recommend scope and modifications to the station to ensure reliable and safe operation of the facility,” says Fisher.

Work Control and Senior Management reviews are also conducted to ensure that other aspects of scope are considered.

“We also review all scope to ensure that the safe and reliable operation of the station is maintained “breaker-to-breaker”- from the point the plant turbines go offline, to the time when they are powered on to generate electricity for the public,” says Fisher.

As with most projects at nuclear energy plants, it is important that utilities work with a partner who is fully qualified to perform the activities related to reactor vessel maintenance.

Utilities must also utilise and adhere to formal procedures for all activities to ensure no mistakes are made.

One of the biggest mistakes, but easiest to avoid making is to use basic Human Performance tools common for all projects within the industry, such as a questioning attitude and nuclear safety principles to prevent errors in the first place, says Fisher.