Increasing ROI through Simulation and the “Digital Twin”

by | Nov 3, 2016 | Simulation & Training

Though the term “digital twin” is the new buzz word being bantered around in the industry the technology is not. Your plant’s digital twin is already on site and ready to be utilized beyond traditional operator training. Thinking of your power plant simulator as a digital twin brings a whole new set of possibilities for testing and training.

A digital twin is a virtualization of a physical asset. Because the simulator dynamically models in real-time your whole plant and each individual system, it can be used for engineering studies and virtual commissioning of plant changes. These studies provide continuous improvement opportunities as operators and engineers can evaluate tradeoffs and increase plant efficiency in line with Delivering the Nuclear Promise, or driving optimization in your thermal plant.

What would you do with a digital twin?

If you think about the concept of a digital twin in terms of your everyday life, what would you use it for? Chances are you would have it do the tasks that you don’t want to do (think – yard work, laundry, etc.) or tasks you don’t have the time to do because there are more important ones to get done, like paying the bills and getting groceries.

Simulators, acting as your plant’s digital twin, can help your plant’s operators and engineers immensely with repetitive tests and data collection. Tests can be set up ahead of time to run nuclear reactor trips and loss-of-coolant accidents (LOCA) over the evening hours while your workers are home doing their yard work. When your workers arrive in the morning they will have all of the data waiting for them. Having this data increases their efficiency and time available to complete other tasks.

You can run scenarios such as steam leaks, loss of coolant, and electrical issues to see how the nuclear plant would respond. Simulators model the buildings and atmospheres, so you can run tests to evaluate radiation levels and temperatures in defined spaces.

The industry is trying to push simulation into the engineering world

Nuclear plant reference simulators have been mandated by the Nuclear Regulatory Commission (NRC) since the 1980’s for plant operator training. So why is the industry now starting to seek new and innovative ways to use simulation beyond operator training? For starters, thermal power generation plants have been using their simulators for engineering studies, simulator-based design, and virtual commissioning for years. With digital control system upgrades being very common in thermal plants, many of these utilities have realized the value of using the simulator to evaluate the digital control system prior to implementation in the plant.

In the old day, computing power limited the depth of simulation. Now with faster computers and higher fidelity models you can model much more of the plant and maintain real-time, repeatable performance. While some plants have used the simulator as a digital twin for non-operator training initiatives in the past, the majority of plants are just now looking to simulation as a way to help them Deliver on the Nuclear Promise of finding innovative ways to reduce O&M costs. Plants can improve operational efficiency by using simulation to identify and resolve issues before placing upgrades in the plant, thereby reducing corrective actions. Running operator training on the simulator before putting new systems in place will also generate efficiencies in the training process.

The advent of cost-effective computing power has also been a motivating factor for plants utilizing copies of their simulator load to provide deeper insights and early validation of design for upgrades and design modification projects. This makes it possible for staff to complete a digital feedwater upgrade on one copy of the simulator while making a modification to reactor protection on another. This allows plant groups, like operations and engineering, the ability to validate their designs early in the process and determine how the change will affect the other systems of the plant, improving the up time and efficiency of the changes.

The nuclear industry has been utilizing engineering grade codes such as RELAP for high-fidelity containment analysis and EPRI’s MAAP code for modeling beyond-design-basis events in the engineering department for a long time. The difference is that now these codes are able to run in the simulator in real-time with repeatable performance versus the non-real-time, batch operations of the past. Tightly coupling these codes with the simulator executive provides enhanced analysis and a much improved user experience. The added insights of having an engineering grade code on your nuclear simulator will allow for better decision making as the simulator is called on more and more in the future, helping to lower O&M expenditures and keep with the goal of Delivering the Nuclear Promise.

How does IIoT factor into the simulator as a digital twin?

The Industrial Internet of Things (IIoT) is a hot topic right now in the energy industry as more and more smart components are being installed in the plants and are gathering massive amounts of data. Smart applications are being developed to translate the data into meaningful ways to improve the plant and understand what is going on in the plant, such as identifying a piece of equipment that is about to fail before it can cause an outage.

But what, if anything, does this mean for the simulator? Currently the simulator group is looking at the plant and plant events that have happened, doing some testing and administratively maintaining the simulator. Moving forward, simulation can play a major role in communicating with the plant and use the data to update and maintain the simulator, use data analytics information to make decisions to reduce O&M and corrective actions, and to find smarter ways of making business decisions.

Think of your simulator as a powerful data engine. By running thousands of what if scenarios, capturing projected plant performance, you can analyze a huge set of data that you could never have obtained from your operating plant. This gives you the opportunity to gain powerful insights into patterns and around plant operations and performance.

Practical examples of increasing efficiency

Virtual commissioning on the digital twin allows you to detect errors, save time, and reduce costs by shortening outage time. You could say it’s ALL about uptime! Design issues and other problems which are found in the simulator prior to plant implementation can significantly reduce outage time and in many cases can entirely pay for the simulator based on the savings from a shortened outage.

Thermal plant virtual commissioning on a simulator presents a great opportunity to evaluate new human machine interface (HMI) screens and a chance to verify a plant’s response to situations that you wouldn’t put your actual plant in, such as over pressurizing to test alarms and protective logic control schemes. We’ve seen customers, for example, discover an undersized pump during virtual commissioning because the simulator could tell that there wasn’t enough pump head to achieve the spray flow rate that was outlined in their procedures. If this discrepancy wasn’t found until startup, it would have resulted in an expensive design change which would have extended the outage costing even more money.

The digital twin is especially useful in the case of new nuclear plant designs, such as the AP1000, where the use of simulation enabled the designers to find several hundred I&C issues on non-safety and safety systems, early in the design process, allowing for a much simpler and less expensive fix. Common nuclear plant upgrades, such as digital turbine control upgrades, are especially suited to the use of the simulator for human factors engineering (HFE). Performing human factors engineering on the simulator allows for HMI verification, procedure validation, operator familiarization, control panel evaluation and evaluating the plant’s response to the new DCS.


You already have a digital twin sitting at your site right now. The question you should be asking yourself is “how I can use simulation for more than just training to increase ROI”? Finding innovative ways to utilize the power of your digital twin will make your simulator a much more powerful tool for both your training and engineering departments.

If you do a good job of identifying and realizing the benefits of a digital twin, your only problem will be how to increase simulator time with an already over-scheduled asset. Check out our blog post ‘Prevent training bottlenecks: 4.5 reasons why a second simulator makes good sense’.

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