Researchers at AIMD Center inside Korea Hydro & Nuclear Power (KHNP)'s central R&D center in Daejeon check the company's nuclear power plants operating across the country, April 1. A blurred screen, left, shows the reactor coolant pump at Hanul Nuclear Power Plant's unit 5 in Uljin, North Gyeongsang Province, working in real-time. Courtesy of KHNP

ULJIN, North Gyeongsang Province — Digital twin technology, now under development for application by Korea Hydro & Nuclear Power (KHNP), will enable the firm to monitor and control the country's 26 nuclear power generating units more effectively than ever before, according to the state-run company Friday.

KHNP said digital twin, a digital model of an actual physical system that serves as an indistinguishable digital counterpart, will allow its central R&D center in Daejeon to remotely oversee the units in five nuclear power plants nationwide — Kori, Wolsong, Hanbit, Hanul and Saeul — and apply immediate solutions at times of unexpected situations. The upcoming breakthrough is a revolutionary improvement from the industry's initial operations in which power plants were managed by each of their own operating systems instead of a singular organization, making the company's control over its plants inefficient and tricky.

KHNP's digital twin development is currently evolving concerning the detailed systematic blueprints of Saeul Nuclear Power Plant's units 1 and 2 in Ulsan. Its development is expected to be finished in 2026, the technology will be first deployed at Shin Kori Nuclear Power Plant's units 3 and 4 in Ulsan, where avatars will roam the facility and monitor specific parts just like a technician in real life would.

"The digital twin will allow us to simultaneously check reactor cores, turbines and generators in different power plants in a three-dimensional virtual world," a KHNP official said Friday. "The metaverse tool is a perfect counter-accident supporting measure. It is now in demand in the Czech Republic and Poland seeking to import our nuclear power technologies."

Two motor control centers stand on top of one of KHNP's two quake generators inside the company's quake-proof test center at its central R&D center in Daejeon, April 1. Courtesy of KHNP

In extension to its digital twin drive, the Daejeon base has begun monitoring Hanul Nuclear Power Plant's unit 5 in Uljin — some 290 kilometers away — through a giant computer screen showing the unit's digital replica in real-time. Known as HU#5 RCP1A Overall Status, the screen shows the unit's reactor coolant pump (RCP), with hundreds of colorful dots moving around, thereby showing the flow of the water inside the pump. The RCP monitoring system is now under testing.

The digital twin technology is part of ongoing development projects by KHNP's Artificial Intelligence Monitoring and Diagnosis (AIMD) Center in Daejeon. Having set up a complete remote command center over the power plants, the center oversees the facilities and checks for any malfunctions by detecting signs of vibrations emanating from a power plant in trouble. The magnitude of the vibrations the center can detect is so small that they are even undetectable to the plant experiencing the technical difficulty.

"By the time a power plant can detect a vibration, it is too late," an AIMD researcher said. He said vibration is a sign that signifies problems for not just a nuclear power plant but many things, from automobiles and other machines to even humans. "So we must detect it before them and discern what's wrong and how to prevent it from developing into a bigger trouble."

The AIMD center's AI uses cumulative big data on vibrations from KHNP's 12,387 mechanical parts — that comprise pumps, generators and turbines in the five power plants — and image registration deep learning.

A turbine at the Shin Kori plant's unit 1 has 10 sensors that share the machine's movements every second with Daejeon. Since August 2022, the AI has run diagnostic testing on over 26,900 parts, issued 285 alarms and prompted the company to take necessary actions 58 times. KHNP, in 2021, registered the monitoring system under the trademark Prometheus and acquired a patent as well.

"The biggest strength of AI which distinguishes itself from human labor is that it can monitor a large volume of facilities simultaneously," the AIMD researcher said. "It can also detect abnormal signs before any human can notice."

A site for Shin Hanul Nuclear Power Plant's units 3 and 4 in Uljin, North Gyeongsang Province, with the plant's units 1 and 2 on the left, April 9 / Courtesy of KHNP

At another site inside the Daejeon base, the company is testing how its power plants can withstand earthquakes in a dedicated lab. The facility's need to exist was prioritized after the world saw the 2011 Fukushima Daiichi nuclear power plant crisis and a 5.8 magnitude earthquake that rattled Gyeongju, North Gyeongsang Province, in 2016.

Inside the lab, two motor control center (MCC) structures stand, one bolted tightly to the ground and the other one only having its base panel screwed to the ground while the rest is connected to the base with spring-like movable parts. As the lab initiates an artificial tremor, replicating the conditions of a quake with 0.2 gravitational force (close to a 7.4 magnitude earthquake), the bolted MCC shakes left and right quite violently while the other one only trembles lightly as the impact is mostly transferred to its base panel.

"We're like KHNP's home doctor," a researcher at the lab said. "We can test for extreme cases mimicking up to 4 g in force. It'll be applied to existing power plants later."

KHNP is now building its latest power plants, Shin Hanul units 3 and 4, next to the now-operating units 1 and 2 in Uljin, with a cost of 10 trillion won ($7.2 billion). The APR1400, a model entirely designed by Korea, is expected to be completed in 2032 and 2033, respectively, and generate 1,400 megawatts of electricity from each unit.

"Shin Hanul units 3 and 4 will demonstrate a complete set of KHNP's latest nuclear power technologies," the company official said.