Korean nuclear power plant prepares for safer, longer future

Just like the cautionary tale provided by the 2011 Fukushima disaster in Japan, when it comes to nuclear reactors there is no such thing as too much safety.

Kori nuclear power plant in Busan [KOREA HYDRO & NUCLEAR POWER]

BUSAN — Just like the cautionary tale provided by the 2011 Fukushima disaster in Japan, when it comes to nuclear reactors there is scarcely such thing as too much safety.

Korea Hydro & Nuclear Power (KHNP), the state-run operator of nuclear power plants in Korea, certainly learned its lessons from the disaster, bracing for various worst-case scenarios with a 10-year plan and a budget of 1.1-trillion-won ($870 million) set up in 2011.

Safety measures employed since then include a 3.2-megawatt power generator truck and a steel barrier wall.

“There are 10 types of newly implemented safety measures following the Fukushima disaster,” said Go Geon-moon, head of technology communications at the KNHP's Kori nuclear power plant.

When the Korea JoongAng Daily and other journalists arrived at the Kori nuclear plant lying on the border between Busan and Ulsan on Thursday, the 81-centimeter-thick (32-inch), 4-meter-tall (13-foot) steel barrier wall was wide open to invite visitors into the now-dormant Kori nuclear plant Unit 1.

If a tsunami ever sweeps in from the coastline, the steel wall will be firmly shut to protect the Kori reactors from up to 10-meter-high waves, according to Go.

Emergency equipment storage at the Kori nuclear power plant in Busan [KOREA HYDRO & NUCLEAR POWER]

In March 2011, a massive earthquake and tsunami struck Japan, cutting off electricity supply to the Fukushima nuclear power plant. As a result, the electricity that was supposed to pump coolant to the reactors was shut down, leading to a partial meltdown at the Daiichi Fukushima plant and a hydrogen explosion.

The KHNP has significantly bolstered safety measures at Korea’s nuclear power plants since disaster struck Japan in 2011. A 3.2-megawatt mobile power generator truck is one such example.

The truck, alongside six units of 1-megawatt power trucks, will come into play when all of the emergency electricity supply facilities are completely shut down during a disaster. The backup power will cover at least 300 percent of the necessary electricity for the nuclear reactors. KHNP plans to have another 3.2-megawatt power supply truck by December.

Located about 40 meters above sea level to avoid flooding, the storage facility for power trucks and other emergency equipment can withstand a 7.4-magnitude earthquake, explained the KHNP.

Inside the reactor buildings, there is also hydrogen removal equipment, which converts excessive hydrogen in the air into water, preventing any explosive reactions.

The Kori power plant, standing near the eastern coastline, is the oldest nuclear power plant in Korea, housing six reactors in total.

However, Kori Unit 1, Korea’s first-ever nuclear reactor, is now standing still, set to be dismantled after 40 years of operation.

Its twin reactor, Kori Unit 2, is prepared for another 10 years of service, yet uncertainties lie ahead for both of the nuclear reactors due to various administrative setbacks and procedures.

A turbine building at the Kori Unit 1 nuclear power plant, which had once been filled with the deafening noise made by the massive turbine turning 1,800 times a minute, was now largely silent.

Kori Unit 1 first began commercial operations in 1978.

After supplying a combined 150 billion kilowatt-per-hours of electricity over the past 40 years, the plug was pulled from the reactor in June 2017, as it reached its initially approved lifetime.

The KHNP filed an application for the dismantling of Korea's first reactor in 2021, which is currently undergoing the review process by the Nuclear Safety and Security Commission.

The original plan, set in 2017, aimed to begin the disassembly in 2022 and secure a 10 percent share in the global nuclear reactor decommissioning market by 2035.

But it is unclear when the NSSC will grant approval for the plan at this point, said Park Woong, head of safety management at Kori Unit 1.

“We cannot say whether the process is moving slowly or not because there have been no preceding cases of nuclear reactor decommissioning in Korea for us to make a comparison,” said Park.

Inside a turbine building at the Kori unit 1 nuclear power plant in Busan [KOREA HYDRO & NUCLEAR POWER]

Park said that “we will have to dismantle the reactor at some point, but it needs to be done in cooperation with the local community,” and added that “when we set an example with Kori Unit 1, the dismantlement process will proceed more quickly next time.”

Shutting down the plant is not the only option for a nuclear reactor that reached its previously licensed lifespan — nuclear reactors overseas often receive a service extension.

As of 2022, 233 out of 439 operational reactor units worldwide were granted service extensions.

The 39-year-old Kori 2 reactor, located side-by-side with the shut-down Kori Unit 1, also filed for a 10-year service extension in March.

The Kori 2 reactor halted operations as its service license expired in April, and is currently renovating its facilities to extend its service time. The plan is to reactivate the reactor in June 2025 and have it run until 2033.

Mo Sang-yeong, head of the Kori Unit 1 plant, was confident that the Kori 2 reactor could even make it to an 80-year extension of service.

“It is unfortunate that Kori Unit 1 had to be shut down,” said Mo, who called for the government to enable the service license extension to come into effect on the day that the reactor can restart operations.

Operation licenses for nine reactors in Korea are going to expire in the next seven years. If all of the reactors, including Kori Unit 2, are approved for a 10-year extension, it will save over 107.6 trillion won of fuel expenses, according to the KHNP's estimate.

BY SHIN HA-NEE [shin.hanee@joongang.co.kr]