Mesh, robots and radioactivity

Above: Continuous communications to robotics while receiving real-time feedback on maintenance requirements allows operators to make swift decisions

Global energy operators face two urgent obstacles: producing more energy and lowering their impact on the environment. Hydropower and nuclear power have emerged as frontrunners in energy production due to their low greenhouse gas emissions and, in contrast to variable renewable resources like wind and solar, solid reliability. Hydropower is currently the largest source of low-carbon power, closely followed by nuclear. But nuclear power reactors operate at the highest average monthly and annual capacity compared to any other energy source, producing maximum power more than 92% of the year.

Nuclear companies have turned to advanced technologies to augment operations to become even more efficient in energy production and support even greener operations. Robust, intelligent, and automated robots that react to their surroundings have been readied to withstand radioactive environments to nullify radiological hazards for human operators. By taking over mundane tasks such as cleaning up radioactive waste or actively monitoring and maintaining the plant, the introduction of technology can clearly enhance safety and production. But as often is the case, many technologies can also significantly strain the communications network within a plant and outpace its capacity.

The operations carried out in nuclear plants are the epitome of mission-critical. From the moment of deployment in ongoing 24/7 plant operations, operators cannot afford to risk any downtime. Drop-offs in wireless signals, even for a short period, can not only mean productivity loss but also risk plant worker safety. A fully redundant, self-optimizing network infrastructure that can withstand a nuclear plant’s notoriously radioactive and hazardous environment is required to keep operations constantly moving.

Robotic robustness

Even though robots have been produced for many decades, they were previously unable to adequately complement human workers in various duties. This is no longer the case given technology developments. Robots with adequate mobility, sensors, size, and tooling have now been developed to succeed in the most hazardous and advanced industrial environments. Ongoing technical advancements, particularly in artificial intelligence and sensors, have made nuclear robotics more capable and cost-effective. This is also driving its market expansion, which is predicted by Global Market Insights to reach an annual value of USD$5bn by 2032. With an increasing emphasis on safety and efficiency, operators have begun to appreciate the benefits of automated technologies and are implementing them into their operations.

Robotics come in all shapes and sizes, such as crawling and flying across sites or sensing and grabbing onsite materials. The major advantage of robots over humans in radioactive environments is that they are made of steel and silicon rather than organic cells and their fragile DNA. Deploying robotics to monitor and inspect equipment in radioactive settings eliminates worker safety risks by completely removing them from the situation. Robots also have discrete sensing capabilities able to identify and target maintenance needs more accurately.

Although robots are increasingly autonomous, they do not operate in isolation and continuously send and receive data. The greatest challenge of supporting robotic and autonomous solutions is therefore keeping them connected to a data network. Safety and security are significant obstacles in such an environment, requiring real-time optimisation and complete visibility. Expanding interconnectivity puts pressure on the network that must ensure the security and authenticity of the communications traffic moving in, out, and across it. To achieve and maintain peak productivity and efficiency, mission-critical applications must run on a communications network that offers reliable, agile, and adaptable connectivity that can thrive in diverse, evolving, mobility-driven environments. These critical networks cannot afford downtime.

Radiating pain in the network

The many mission-critical operations within nuclear plants need help to afford to experience data loss or lag that ultimately leads to stoppages. Proactively detecting anomalies in nuclear operations before they have any inadvertent effect on plant availability and safety is also paramount. Continuous communications to robotics while receiving real-time feedback on maintenance requirements allows operators to make swift decisions.

Cable infrastructure, such as optical fibre, can be susceptible to heat produced in nuclear environments with reactors. Destruction of these cables can cause downtime and a complete shutdown of operations. Radiation can also interrupt molecular chains in materials, especially plastics, causing them to break down, causing defects and making the cable inoperable.

When deploying conventional wireless networks such as Long-Term Evolution (LTE), enterprise Wi-Fi, or 5G technology, operators can experience connectivity difficulties. For instance, some mobile devices need more infrastructure capabilities, so they can only connect to one access point at a time. This means that if an access point fails, all devices connected to that access point are disconnected from the network entirely. Under these circumstances, access points become a potential area
of single point failure. Similarly, Wi-Fi communications have always faced mobility challenges. A connection must drop before a new connection can be made, which is inconvenient for robotics constantly traversing rugged and dispersed locations. The best case is that these are 2-5 second dropouts. In the worst case, the robot stops, and operators must manually send a person to get the robot connected to the next hotspot, reintroducing the potential for workers to be exposed to radiation.

Furthermore, wireless communications use radio frequencies (RF), meaning the metal is a huge obstacle. The RF used in wireless networks cannot go through metal but has to go around it. Using 5G worsens the problem as it uses millimetre wavelengths, which cover a very short distance. Any obstruction can halt communication. This is a significant concern in an environment such as a nuclear plant with large metal structures surrounding areas where robotic operations are envisaged.

A nuclear plants’ critical network connectivity must therefore navigate both the obstacles onsite and withstand the significant challenges of radiation and contamination to enable robotics to function efficiently and provide operators with real-time data.

Ensuring on-the-go connectivity for robotics and operations

In many cases, the only way to get around physical obstructions is by using machine-to-machine (M2M) broadband wireless communications and a network with M2M connectivity is a huge boost. A mesh network using multiple communication nodes can automatically identify and transmit data between them and support M2M networking. These nodes can automatically adjust themselves to find the fastest and most stable connections. Mesh networks can easily scale up and down quickly by adding or removing nodes. Data can be seamlessly rerouted depending on the bandwidth needs, signal strength, or competing traffic. Wireless mesh technology can therefore overcome RF interference, congestion, and infrastructure outages autonomously. Where mobile assets are equipped with mesh nodes, the mobile robots remain connected to the network with no drop-outs.

It is also less expensive than wired infrastructure, such as fibre and other alternatives. The savings result both from the network’s cost and the ability to leverage robotic solutions to replace more expensive static infrastructure. Resilient coverage across a broad area through mobile robotic technology – in place of many cameras, sensors, and workers – can reduce the initial required technology investment and eliminate the recurring costs within a nuclear plant.

A drone, or swarm of drones, can facilitate omnidirectional coverage over an extended area while simultaneously providing maintenance and monitoring data. Ground vehicles can enjoy freedom of movement, expanding the network as they roam. The mesh structure has no single point of failure as data pathways form wherever connectivity is needed, empowering the around-the-clock productivity that operators desire. Support for a wide range of frequencies ensures adequate bandwidth is always available. And, because the wireless mesh is a private network, transmission is faster than over public solutions, and operators never pay for data either.

Not only does this provide robotics with the connectivity required to roam seamlessly across a nuclear plant, but operators gain a more detailed understanding of the overall state of their maintenance needs through transmitted audio and video.

An example of the use of robotics in the sector comes from nuclear management and decommissioning services company Createc Ltd, which deploys robotics with advanced sensors to solve technical and human challenges. To ensure its solutions could withstand the harsh radioactive environments of nuclear plants, Createc arranged for testing to establish whether critical electronics and networks were capable of functioning while exposed to extremely high levels of gamma radiation. At the Harwell Science and Innovation Campus, where controlled exposure to a Cobalt 60 (60Co) source is possible, Rajant’s BreadCrumb® ES1 mesh node was irradiated. It withstood a total exposure of 214 Sieverts in the testing period, 21,000 times the annual limit for nuclear workers.

New technologies play a vital role across the nuclear lifecycle, including delivering the next generation of nuclear power plants, monitoring atomic assets, and supporting waste management and decommissioning. Robotics can provide significant advantages in the form of increased reliability and efficiency combined with reduced risk. Now that they are ready to withstand the harshest conditions and undertake complex tasks with AI and automation, the network that supports them must follow suit to unlock these capabilities. Intelligent networks, such as wireless mesh, can navigate the obstacles that come into play in nuclear operations, ensuring connectivity is always available for these mobile robotic appliances.

Author: Erich Smidt, Vice President, Rajant Corporation