M6.7 quake causes blackout at Hokkaido nuclear plant

Local news yesterday broadcast images and footage of the aftermath of the strong earthquake that rocked Hokkaido Thursday, but little mention was made of another deja vu drama that was unfolding on Japan’s northernmost island.

As the magnitude 6.7 quake toppled buildings, ripped up roads and triggered massive landslides, resulting in 16 confirmed deaths and 100s of injuries, more than half of the 5.3 million residents on Hokkaido were left without electricity as power plants went into blackout -- including the Tomari nuclear power plant.

Albeit for a relatively short time, the Hokkaido Electric Power Co.-operated nuclear plant was reduced to relying on backup generators, much as the Fukushima Daiichi Nuclear Power Plant had done with such devastating results more than seven years ago. 

In March 2011, a massive earthquake and tsunamis caused three of the six reactors there to go into meltdown causing the evacuation of more than 150,000 residents. On this occasion, the outage at the Tomari nuclear facility was relatively brief and unlike Fukushima, 600 km to the south, backup power remained intact, meaning cooling of the reactor cores could continue — a part of the “redundant” safety systems that are set up, at massive expense, within nuclear facilities around the globe.

Nonetheless, the temblor, which also damaged a local coal-fired power station among other facilities, knocked out the grid leaving many residents without electricity. More than a day on, that situation remains the same for many residents, who are also stuck in shelters rocked by aftershocks on a regular basis.

According to a government statement, the shutdown of all Hokkaido Electric's power facilities has affected around 2.95 million households, as well as business and oil and LPG terminals on the island.

While Hokkaido Electric has managed to restart some hydropower plants and one 125 megawatt coal-fired unit, its power supply capacity remains short of meeting the regional power demand, which was around 3.10 GW at the time of the earthquake.

According to one local news report Hokkaido has  more than a dozen coal-fired and other power plants located in coastal areas that combined can supply close to double that amount. The interconnected system, however, means that if one goes down that interconnectivity is adversely affected, the Fuji TV report said. It also meant that it would take time to reconnect, it added. As a result, a state minister has warned that reduced power likely would continue to affect Hokkaido for over a week.

Hokkaido Electric says it hopes to restore much of that demand by Friday, topping up the supply from its restarts with an undamaged 600 MW power cable that connects Hokkaido with Japan’s main Honshu island, where Tokyo, Osaka and other major connotations are located.
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The Tomari nuclear power plant, which restored power 10 hours after Thursday’s temblor, will be of little help: Like most of Japan’s nuclear reactors it has been out of service since the 2011 nuclear disaster in Fukushima as it undergoes stringent safety checks. While the blackout will undoubtedly caused more than just a little concern, an official said there had been no radiation leakage from the plant.