IN RECENT YEARS THE NUCLEAR industry, like other industries, has adapted to digitalisation. This, sometimes described as the fourth industrial revolution (Industry 4.0), is posing challenges and opportunities, and the industry has to adapt accordingly.

One of the technologies that is driving digitalisation of the industry is the use of wireless tools, such as ultra-high frequency (UHF) radio frequency identification (RFID).[1] RFID systems typically comprise:

  • a reader;
  • one or more antennas; and
  • tags that respond to requests made by the reader. The tags are completely passive and are activated by the energy received from the reader.

This technology may be used to identify and track people, materials, tools and equipment. Its features enable it to be directly applied in the foreign material exclusion area (FMEA).

In the FMEA, materials are tracked and identified manually, which is time-consuming, requires considerable manpower and has a high risk of human error.

UHF RFID technology reduces the time spent on material monitoring and tracking tasks and brings down both the number of staff assigned and the possibility of error. At the same time, it adds value, because it gives greater control over aspects such as verification that the tool is appropriate to the task in hand, its correct use, condition or calibration, and its radiological characterisation. It also makes it possible to easily locate lost tools anywhere in the FMEA.

GD Energy Services (GDES), an energy services company, has developed a system using this technology called Vigia. GDES worked alongside various departments of the Cofrentes nuclear power plant in Spain (owned by Iberdrola) that work, to a greater or lesser extent, with people, materials or equipment in the plant’s FMEAs. They defined the requirements to be met:

  • compliance with electromagnetic interference regulations;
  • tags must not interact with the use of material, tools or equipment (MTE);
  • tags must not become foreign materials in the FMEA;
  • mobile, autonomous and modular system; and
  • future-proof and user-friendly.

The Vigia system is composed of several mobile beacons for tracking, programmable tags, portable units for logging the tags and to check and monitor MTE.

Image: The Vigia system was used to control and monitor materials during a recent outage at Spain’s Cofrentes nuclear power plant

The mobile beacons have a reader that can be attached to several antennas. These antennas can cover a wide area. The range is adjustable and can be adapted to the environment in which each beacon is installed, allowing compliance with electromagnetic interference regulations.[2,3]

In turn, each beacon has presence-sensing features within the field of action of the antennas, which enable them to be shut down and automatically reset if necessary. This system of sensors boosts efficiency and reduces false positives and incidents. It is also able to determine whether the user is entering or exiting an FMEA.

The beacons have a graphical user interface (GUI) that enables the user to interact with the Vigia system. The GUI connects to a database containing information on all tagged items, which is updated in real time using the portable units. In addition, each beacon stores all the information on the sensors, reader status, operation of the antennas, and movements detected by it, both by logged items and tags that have not been logged. The beacons have an uninterruptible power system (UPS) capable of keeping them running for one hour in the absence of a power supply, which means they can be relocated within the plant without having to be switched off. Each beacon measures 30 x 30 x 130cm, weighs less than 20kg, has in-built wheels and can be moved without aids.

System overview

Together with the mobile beacons, Vigia has battery- powered portable units for logging all new material and for monitoring the real-time status of items in the FMEA. This unit is synchronised with the mobile beacons, streamlining the logging process. Another feature of Vigia’s portable units is the search for lost or misplaced materials, tools or equipment. It has several operating modes, which include indiscriminate or selective searches.

One of the most important aspects of the design and development of Vigia was the selection and installation of materials, tools and equipment tags. For this purpose, a market study was conducted into the various tags in use today.

The first step was to note the different materials on which they were to be installed, the use made of the materials, tools or equipment by operators and its size. The selection criteria were:

  • resistance to wear and tear;
  • best coverage/tag size ratio;
  • maximum available memory in the tag; and
  • reliability in repetition tests.

Based on the above, five models of tag were selected, adapted to metallic and non-metallic materials. Their size ranges from 0.5cm2 to 2cm2, with a volume less than 3cm3.

To facilitate installation of the tags and to prevent them from detaching, including in the event of improper use of the materials, tools or equipment, durability tests were carried out on products that had been tagged. The results of these tests, and recommendations by various tag manufacturers, revealed the best placement of the tags on the materials, tools or equipment for optimal performance.

Vigia was implemented at the Cofrentes nuclear power plant during the 22nd scheduled refuelling outage, from 3 November to 6 December 2019. Prior to the refuelling outage, the tools in the trolleys serving the tasks performed on site were tagged. Along with the tools, material and equipment within the FMEA or that were expected to be introduced to the zone later on were also tagged. People were also monitored with the same UHF RFID technology, in order to track people associated with materials, tools or equipment.

List of readings

Two Vigia beacons were installed at FMEA access points that acted as entrance and exit barriers.

The technology provided real-time control of people, materials, tools and equipment in the zone. Vigia boasts various functions. It can be used to produce reports, detect hardware or work-related incidents and view people, materials, tools and equipment inside the FMEA. It has a wide range of options for instantly acquiring and processing associated data, leading to greater, more flexible and higher-quality control over the FMEA supervision.

Although this was the first time that this system had been implemented at Cofrentes, so there was no prior experience to draw on, the project demonstrated that RFID technology enables supervisors of work conducted in an FMEA to respond quickly and specifically to real incidents that occur during periods of heavy work, such as refuelling outages.

The digitalised information from the tags enhances decision-making, provides automated control of on-site tools and eliminates paperwork — and the potential for error — from the monitoring and logging processes. This technology also enables complementary functionalities to be added to current materials, tools or equipment monitoring and tracking, such as time spent in specific areas, equipment calibration status, intensity of use of specific tools and equipment. In general its tailor-made software offers a wide range of use options.

References:

[1] Radio Frequency Identification (RFID) Technology Trends and Power Plant Applications EPRI, Palo Alto, CA:2004. TR- 1003733

[2] NRC, 2003, “Guidelines for Evaluating Electromagnetic and Radio-Frequency Interference in Safety Related Instrumentation and Control Systems,” 1.180, U.S. Nuclear Regulatory Commission, Rev. 1.

[3] Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment: Revision 4 to TR-102323. EPRI, Palo Alto, CA:2013. TR-102323-R4.

Author information: José Ignacio Roselló, Head of robotics and instrumentation at GDES; Alberto Mínguez Muñoz, Software Development Engineer at GDES; Jesús Lacalle Bayo, Innovation and Technology Director at GDES