Dispelling nuclear myths: what's the worst possible accident?

As you may have heard, the most recent nuclear accident occurred in Fukushima, Japan in March of 2011. During the days that followed, I happened to be in Vancouver, where radiation kits were selling like hotcakes. That was understandable, considering CNN news showed an ominous cloud of radiation rapidly encompassing the planet while toxic particles coursed across the Pacific Ocean.

 

As it turned out, however, the radiation threat to Vancouverites was all a ridiculous myth.

 

Even more ridiculous, a year or so after the event, the Senior Vice President of Development at Nextera Energy came to speak in one of my college courses about wind energy. In his push for wind, he referred to the Fukushima accident, saying “It was basically like a nuclear bomb went off.” Everyone in class believed him, and we moved on without batting an eye.

 

Seriously?!

 

What do you picture when you hear the words “nuclear accident”? Because mushroom clouds and three-headed frogs are a far cry from the real picture, even in the worst case scenario. If we want to prevent nuclear accidents in the future, we need to take the time to understand what actually happened, rather than writing off the nuclear industry as hopelessly dangerous. Because that’s a myth, too. In fact, apart from the psychological damage we inflict upon ourselves, one could argue that nuclear is pretty much the safest we’ve got.

 

Furthermore, in the case of the Fukushima accident, we faced a technical challenge that may have already been solved. Let me explain.

 

This is what took place at Fukushima, in a nutshell: beginning at 2:46 PM on March 11, 2011, the 9.0 magnitude Tōhoku earthquake raged for six minutes 130 kilometers off the coast of Japan. The quake was so large it caused Earth’s axis to shift by several centimeters. It also caused an area of the sea floor 650 kilometers wide to shift ten to twenty meters horizontally. In case you didn’t realize, that is a LOT of water.

 

When you suddenly move that much water, you create a wave – in this case, a huge one. It started off as 18 meters tall and was still 15 meters high by the time it reached the shoreline of three Japanese prefectures. The wave bulldozed 560 square km worth of coastal towns and killed 19,000 people.

 

Also along the affected coastline were eleven operating nuclear reactors at four different power plants. When the earthquake hit, all eleven reactors shut down automatically, which is exactly what they were designed to do.

 

The fuel inside of any nuclear reactor must be cooled constantly, even long after it has stopped operating. This is done by pumping water through the reactor’s core. These pumps require electricity to operate. The Fukushima earthquake caused a power outage at all eleven affected reactors, but they continued to pump water and cool down using backup power from diesel generators. In fact, within four days after the quake, eight out of eleven reactors were able to achieve a stable state of “cold shutdown” without any further incident.

 

For the remaining three, however, known as Fukushima Daiichi 1, 2, and 3 -- the giant wave, NOT the giant earthquake -- changed everything.

 

The wave hit the Fukushima Daiichi nuclear power plant about forty-five minutes after the earthquake ended. The plant’s design was based on the most recent major tsunami to strike the area following the Great Chilean Earthquake in 1960, which was only 3.1 meters tall. Even worse, the plant’s backup diesel generators were located in the basement.

 

Needless to say, the Fukushima plant was no match for the tsunami this time around. Within minutes, the wave flooded the entire site, submerging the diesel generators. It caused Fukushima Daiichi reactors 1, 2, and 3 to lose emergency power required for cooling the fuel. That caused the fuel to heat up, melt into a liquid, and leak radiation into the environment.

 

No one died or became ill as a result of the radiation, but 160,000 people were evacuated. Japan, which previously had about fifty operating reactors generating 30% of its power, immediately shut them all down – and started importing vast quantities of fossil fuels to compensate.

 

Now, the Japanese government is in the painstaking process of trying to restart its reactors under new earthquake safety laws and finds itself fighting public opposition every inch of the way. The Fukushima Daiichi reactors will take decades and billions of dollars to clean up. The entire plant must be written off.

 

The nuclear community learned a lot from what happened at Fukushima. Now, governments around the world will think twice before allowing a nuclear power plant to be built on a fault line. But would greater seismic robustness have prevented the problem?

 

Not really, because the heart of the problem was that the reactors could not cool down without electricity. What WOULD have virtually prevented the Fukushima accident, and would prevent any other power loss accident in the future, is a concept that has been around since the mid-80s. It’s called “passive safety”.

 

Simply put, passive safety means the plants are constructed in such a way that when they lose electricity, they naturally COOL DOWN, rather than heat up. Thus, they are “passively” safe, rather than requiring operator action in the event of an emergency. This is a crucial difference.

 

If the Fukushima plant had been built with passive safety features, the fuel would not have melted. No radiation would have leaked. Prior to Fukushima, the industry had never experienced this scale of a power loss-related accident. What happened at Fukushima taught the world exactly how important passive safety features can be.

 

So, are all plants being constructed today built with passive safety features? Well, not exactly.

 

The problem is the nuclear industry is a slow-moving one...and that’s an understatement. Nuclear power plants take years, if not decades, to plan and construct. They cost billions of dollars, which means it is best to run them for their full forty-year lifetime, and to extend that lifetime if possible. It is difficult for plants to keep up with technology, even if that technology is already a couple of decades old. Case in point: the Fukushima reactors were built in the 60s.

 

So, if not passive safety, what has been done to address the power loss problem? A lot, actually. For example, in the U.S., the industry implemented a program called FLEX. FLEX consists of a three pronged approach: (1) develop a site-specific strategy to maintain backup power in the event of a grid power loss; (2) have portable diesel backup generators on site; and (3) have portable diesel generators at off-site regional centres that can be deployed within 24 hours. Unlike passive safety, these measures mitigate, rather than prevent the problem -- but they’re still a pretty good start.

 

Meanwhile, experts all over the world are focused on applying passive safety technologies to the next generation of reactors. These so-called “advanced reactors” will replace older plants as they retire over the next couple of decades.

 

So, stop worrying about mutant frogs and nuclear bombs. I don’t mean to disregard what happened at Chernobyl, Fukushima, or elsewhere. But compared to many other industries, the threat to human life posed by a nuclear power plant – even, as we saw at Fukushima, in the face of one of the worst natural disasters in recent history -- is extremely small.

 

The issue at hand here is not that the nuclear industry can’t be safe. It’s that it can’t take another blow to its reputation. We already have the technology well within our grasp -- there simply shouldn’t be a ‘next accident’. Fukushima was already one too many.