Last night, I read this statement on CNN’s website: “A nation on the brink, Japan is coping with three disasters at the same time: a major earthquake, a sweeping tsunami and a deepening nuclear crisis. Any one of these would bring a country to its knees.”
The human, environmental, and financial impact of these disasters (only one of which is partially man-made) are staggering and heart-wrenching. Medical teams that flew into Japan, to help with the rescue efforts from the earthquake and tsunami, are now fleeing the country because of the nuclear crisis. Survivors who desperately need assistance are being abandoned in their hour of greatest need.
While our thoughts, prayers, and financial assistance must stay focused on the victims, last night my inner science geek came to life when I started reading some interesting information on nuclear power (about which I knew virtually nothing) posted by a Facebook friend. I asked him if he would answer six questions for me to share on my blog, and he kindly agreed.
Chad Robison is the general manager of an electric company, and a science junkie. He has done extensive research on nuclear energy, and has a clear understanding of how energy production works. I am very grateful for his clear, cogent explanations of such a complex topic.
Q: For someone like me, who knows NOTHING about nuclear reactors, what is their purpose and how do they work?
A: Nuclear energy uses one of the two types of nuclear energy discovered last century: fission. Fusion is the other method and is what the sun is doing up in the sky. Basically what scientists figured out is that a tiny little atom produces a large amount of energy when it is split apart and when it is fused together. The massive gravity of the sun pulls hydrogen atoms together and fuses them into helium and in the process creates a large amount of energy.
Nuclear explosions take the other route and concentrate large amounts of very unstable (radioactive) materials which are just barely being held together – when it detonates, it gets a super charged push which starts off a chain reaction, and all of the atoms splitting apart hit nearby atoms causing them to split apart. This causes an instantaneous release of massive amounts of energy in a small space, which results in a nuclear bomb explosion.
Scientists then got the idea to use this energy to run nuclear power plants. Instead of putting massive amounts of radioactive material together, they put a lesser amount and refined them into fuel rods. These rods have less than what is needed to explode into a nuclear explosion, but enough to generate a slow, steady release of energy in the form of heat. These rods are allowed (in a controlled setting) to heat up past the boiling temperature of water, and water (or sometimes another substance) is passed near enough to the rods that it is turned to steam, but does not become radioactive. The steam is then sent to a turbine that turns a generator, creating electricity.
Once the rods have been used long enough, the radiation makes them no longer usable to the plant, and they are stored in cooling facilities. Here lies the problem with nuclear energy. The rods have enough energy being generated that they constantly need to be cooled. Without cooling, they give off more and more energy in the form of radiation and heat. If left with no coolant, they have nothing keeping them from getting hotter and hotter and releasing more and more radiation. The energy can become so great that the rods themselves melt (thus the term “meltdown”) and are no longer accessible due to the massive amounts of radiation being released. Once this state is reached the only option most people agree on is to cover the melted rods with sand and concrete, and cordon off the area near the site where radiation is still at dangerous levels.
Q: We keep hearing Chernobyl referenced…can you give us a brief synopsis of what happened there?
A: Chernobyl is the name of a nuclear power plant near the town of Pripyat in the Ukraine (at the time Soviet Union). In 1986 a sudden unexpected spike in power to the reactor controls caused reactor number four to explode. The explosion blew both means of nuclear radiation containment away from the core, causing a plume of radiation to be released. This was the only time, to date, that a core meltdown and containment breach has occurred in history.
To contain the breach, the reactor area was filled with concrete and a concrete dome was placed over it as well. The town of Pripyat was evacuated, 70 people were killed as a direct result of the disaster, and thousands of citizens contracted thyroid cancer as well as many other complications from the radiation exposure.
Q: What are the similarities or differences between Chernobyl and the situation in Japan?
A: The situation in Japan is similar to Chernobyl in the sense that if the reactor cores are not cooled, they will melt and could cause a containment breach similar to the one at Chernobyl. At Chernobyl the core meltdown was instantaneous; however, the problem in Japan is that while we are not yet at the point Chernobyl was at, it appears more and more (to the scientific community) that meltdown of all the reactors could be inevitable. If this happens the only course of action would be to cover the reactors and evacuate everyone nearby, just as at Chernobyl.
Q: Can you tell us what scientists are saying about the current situation? What are the options?
A: We are seeing things like near-suicide attempts by helicopter pilots to drop water on the buildings. What this says is that the people making decisions feel this is the best option for the situation. As you read in my explanation of how nuclear energy works, the cooling solution needs to be pumped inside the reactor containment wall and into the reactor core to be of any use. By dropping water onto the building it really makes people think that if that is the best we can do, then we have a very likely repeat of Chernobyl happening.
Q: Does the U.S. have reactors like the ones in Japan? Do many other countries?
A: We have 35 boiling water reactors in the United States, and 69 pressurized nuclear reactors. The Fukushima I Nuclear Power Plant in Japan is a low-pressure boiling water reactor. France also uses this type, as well as most other 1st world nations. The redundancy of safety measures at all of these power plants has created a relatively safe, carbon emission-free source of energy for many people. The disadvantage to their use is, of course, that no amount of redundancies can make any system 100% safe; and when major natural disasters cause major damage to key systems, it makes it that much harder to keep a nuclear disaster from happening.
Q: Will Japan eventually try to replace these reactors, or is the building of reactors a thing of the past?
A: No one knows what Japan will do with these reactors. If they can be salvaged and conditions are much better than we feared, I still don’t think they would rebuild them, just because of the danger this one in particular caused. Will Japan continue to generate power from its other nuclear plants? Will the government take over control of the existing plants? Will nuclear power plants only operate in zones free from potential disasters? These are questions we don’t know the answer to, but this event has thrust them into the discussion field like a screaming newborn baby. Proponents on both sides of the argument will have much to discuss in the coming years as a result of this.