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Wednesday, 10 September 2014

Fukushima No. 2 scrambled to avoid same fate as sister site Fukushima No. 1




 


This is the fifth in a series on the Fukushima nuclear catastrophe based on the accounts of people who struggled to contain the crisis in its early stages. Job titles and ages are as of March 2011.

Fukushima No. 1 wasn’t the only nuclear complex facing a critical situation after the magnitude-9.0 earthquake of March 11, 2011, unleashed a monster tsunami on the coast of Tohoku.
Tokyo Electric Power Co.’s Fukushima No. 2 plant, located about 12 km south of the No. 1 plant, also saw seawater pumps and electrical equipment flooded by the tsunami, which led three of its four reactors to lose key cooling functions.
Still, the extent of the damage was less devastating than that at its sister plant and one off-site power source that remained operable provided more leeway for workers to deal with the emergency.
For No. 2 plant chief Naohiro Masuda, 53, the worst situation imaginable was to lose control of both plants at the same time.
So when he watched on television as an explosion rocked the No. 1 reactor building at the other complex on March 12, Masuda issued an order that could be seen by some as coldhearted.
“Don’t allow anyone (from Fukushima No. 1) to enter our emergency response office building,” the plant chief said.
The building houses the emergency first-aid station.
Masuda’s decision reflected his determination to keep the developments at the other site from hampering stabilization efforts at his plant.
Workers exposed to radiation or injured by the explosion were certain to be transported to Fukushima No. 2.
Masuda believed that he had to limit the radiation contamination inside his complex so as not to affect the workers’ efforts.
He told his subordinates to prepare a place away from the office building for the No. 1 workers. His decision was later criticized by some No. 1 workers, who said they felt they were treated “like garbage.”
An area to scrub away radiation contamination and an aid center were set up inside a facility next to the main gate. The plant’s gymnasium was also readied as a shelter for workers from No. 1.
By the night of March 12, everything was ready to receive the No. 1 workers. But Masuda noticed many of his own workers appeared anxious. To reassure them, he gathered them together and told them he would “make sure that you won’t end up with any health problems. Don’t worry.
“So I don’t want you to go home. Keep hanging in there,” he added.
Through a teleconference system Tepco was using to share information in real time, staff at the No. 2 plant could see how things were going in the No. 1 facility’s emergency response office.
Masuda recalled the conversation he had with the No. 1 plant chief, Masao Yoshida, when they met for dinner two nights earlier. They chatted about the soon-to-arrive cherry blossoms.
“It’s going to be a spree at the cherry-viewing party,” Yoshida had said.
Masuda thought of what Yoshida was going through, knowing he would be making difficult decisions to send people to areas where radiation exposure was inevitable.
But Masuda had to do his own job. People were trying to bring powerful heat removal systems back into service to achieve a stable state of cold shutdown at reactors 1, 2 and 4.
Water injections into the reactors had continued thanks to the off-site power source called the Tomioka line, but steam was trapped inside the reactors and the pressure was building.
If this continued, the plant’s technical team estimated, workers might have to carry out an emergency release of radioactive steam at around 4 a.m. on March 14 to prevent a rupture of the containers, an operation called venting. This would have been the first time such an operation would be undertaken at Fukushima No. 2.
To restore the heat removal systems, the plant had to replace motors to activate seawater pumps that had been crippled by the tsunami, and install power cables to restore electricity supply to the motors.
Three motors, weighing 1 ton each, were delivered to the plant on the morning of March 13 from a Toshiba Corp. factory in Mie Prefecture, with the help of a Self-Defense Forces aircraft.
A trailer carrying a large amount of power cables had also arrived in front of the main gate. But because the driver was too scared to enter the plant, workers had to bring another truck to carry the cables the rest of the way.
As the vital supplies reached the plant, Masuda said “I want everyone available to go out (to install the cables).”
With the cables, workers had to connect the radioactive waste disposal building, which was receiving electricity, and three buildings housing the motors for seawater pumps.
About 200 workers were involved in the operation to lay a total of about 9 km of cables. Usually, such work would take four or five days, even with the same number of workers. But the mission was finished in one day.
At 1:24 a.m. on March 14, the residual heat removal system for the No. 1 reactor was activated, and cooling started. It was only two hours before the assumed deadline to start the first venting operation.
The heat removal systems for reactors 2 and 4 were also restored, leading all four reactors at the No. 2 plant to achieve a cold shutdown by March 15.
Although the No. 2 plant succeeded in avoiding a critical situation, there were times when Masuda was irritated by officials in Tepco’s head office in Tokyo because they appeared to be out of touch with the situation on the ground.
Masuda was startled when an official in the head office asked at around 6 p.m. on March 11 whether it was possible to stop using the Tomioka line. Using the electricity from the line, workers were able to continue injecting water into reactors and check the water level inside them.
“If we don’t have this line, No. 2 is finished,” Masuda said during a teleconference. “And then, it will become the same as 1F (the Fukushima No. 1 plant).”
He guessed that the head office thought that cutting off the line might be helpful in speeding up the restoration of power in a part of Tepco’s service area that had been blacked out by the March 11 earthquake.
At one point Masuda asked for the head office to send 4,000 tons of water for the reactor-cooling operation. Instead, the office arranged to send a 4,000-liter water truck, possibly thinking that the request had been for drinking water.
When that happened, Masuda told his subordinates: “Don’t rely on others. Let’s do things by ourselves.”
A single misstep could have altered the fate of Fukushima No. 2. But the plant managed to keep the severity of the incident at level 3 on the international scale of nuclear accidents.
The crisis at Fukushima No. 1 was eventually rated at the maximum, level 7.
Source: Japan Times
 http://www.japantimes.co.jp/news/2014/09/10/national/fukushima-2-scrambled-avoid-fate-sister-site-fukushima-1/
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