Here we go. I can't take credit for writing the bulk of this. I took my facts from this article. Please read it if you have the time. It will explain a lot of "the basics" of how a nuclear reactor works, in more detail than I have included here.
How does a Nukular Reactor work?
Here is my "Basic" explanation of this Boiling Water Reactor (not the same as the Pressurized Water Reactors used by the Navy): Hot Rock (Uranium) + Neutron (small atomic particle) = Nukular Fission. Nukular Fission makes smaller radioactive particles and more neutrons, which make more fission. The chain reaction makes heat. Heat boils water (coolant) into steam. Steam spins a turbine blade roundy-roundy to generate electricity. The chain reaction is controlled using control "rods." Heat is carried away from the Hot Rock using the coolant, which keeps it from becoming Molten Rock. Good times.
So what actually happened?
(This is where I start plagiarizing)
The earthquake that hit Japan was 7 times more powerful than the worst earthquake the nuclear power plant was built for. When the earthquake hit with 8.9, the nuclear reactors all went into automatic shutdown. The nuclear chain reaction of the uranium stopped. Now, the cooling system has to carry away the residual heat. The earthquake destroyed the external power supply of the nuclear reactor. The power is needed to keep the coolant pumps working.
One set of multiple sets of emergency Diesel power generators kicked in and provided the electricity that was needed. Tsunami came (much bigger than expected). The tsunami took out all multiple sets of backup Diesel generators. The reactor operators switched to emergency battery power. The batteries were designed as one of the backups to the backups, to provide power for cooling the core for 8 hours. And they did.
Within the 8 hours, another power source had to be found and connected to the power plant. So mobile diesel generators were trucked in. The external power generators could not be connected to the power plant (the plugs did not fit). So after the batteries ran out, the residual heat could not be carried away any more.
At this point the plant operators begin to follow emergency procedures that are in place for a “loss of cooling event.” All of this, however shocking it seems to us, is part of the day-to-day training you go through as an operator, right through to managing a core meltdown.
It was at this stage that people started to talk about core meltdown. Because at the end of the day, if cooling cannot be restored, the core will eventually melt (after hours or days), and the last line of defense, the core catcher and third containment, would come into play. This design allows the core to meltdown completely without causing harm to the public.
Imagine a pressure cooker on the stove, heat on low, but on. The operators use whatever cooling system capacity they have to get rid of as much heat as possible, but the pressure starts building up. The pressure has to be released from time to time, to prevent exceeding the pressure rating of the system and causing it to rupture. The operators now started venting steam from time to time to control the pressure.
This is when the reports about “radiation leakage” starting coming in. This steam contains radioactive particles. Those radioactive particles have a very short half-life, that means that they decay very fast and split into non-radioactive materials. By fast I mean seconds. So if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all. Why? By the time you spelled “R-A-D-I-O-N-U-C-L-I-D-E”, they will be harmless, because they will have split up into non radioactive elements.
(Insert my ranting here)
**If you live on planet Earth, you are exposed to radiation EVERY SINGLE DAY. You get it from the sun, from bananas, from cigarettes, from all kinds of things.**
Sometime during this venting, the explosion happened. The fuel DID NOT explode. The reactor DID NOT explode. Hydrogen (which was generated from water dissociating into Oxygen and Hydrogen at a very high temperature) exploded. This explosion happened OUTSIDE the reactor. IT DID NOT AFFECT THE REACTOR IN ANY WAY!!! THE REACTOR IS NOT GOING TO EXPLODE.
(end rant)
The water in the vessel continued to boil. The operators continued to vent the vessel to prevent over-pressurization. Unfortunately, that meant that they were boiling the water out of the core and never replacing it. This began to uncover the fuel, which would eventually cause it to melt. As parts of the rod were uncovered, the material surrounding the fuel (NOT the fuel itself) began to melt. This allowed some Iodine and Cesium (which are created during Nukular Fission) to be released into the steam, and then into the environment.
At this point, they began using seawater to cool the fuel. The seawater will cool the fuel just the same as the pure water that is typically used, but the impurities in it can become activated, creating more radioactive material. Creating more radioactive material poses no threat to humanity or to the environment, it just makes more work for the techs who are responsible for decontaminating the facility. The seawater worked just splendidly to remove the residual heat.
To summarize:
- The plant is safe now and will stay safe.
- Japan is looking at an INES Level 4 Accident: Nuclear accident with local consequences. That is bad for the company that owns the plant, but not for anyone else.
- Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again.
- There was some limited damage to the first containment. That means that some amounts of radioactive Cesium and Iodine will also be released into the cooling water, but no Uranium or other nasty stuff (the Uranium oxide does not “dissolve” in the water). There are facilities for treating the cooling water inside the third containment. The radioactive Cesium and Iodine will be removed there and eventually stored as radioactive waste in terminal storage
My Thoughts:
- American news anchors are ignorant, and they are creating panic over nothing.
- "Radiation" is all around us. We will not begin growing 3rd eyes anytime soon.
- LOTS of engineers spent LOTS of time designing these plants so they could operate safely, even in the event of a natural disaster like this one.
- The reason that you find the information that has been released "confusing," is because YOU, CNN Lady, are NOT A NUKULAR PHYSICIST, or even a scientist of any type. You're a REPORTER. If NASA released information about a failure of one of the space shuttles, I'm sure I would find it confusing because I am NOT A ROCKET SCIENTIST.
- Saying that these reactors are not safe to operate because they were built in the 70s is like saying that it is not safe to drive a car built in the 70s. It is ludicrous. Whoever said that, I really hope someone punches you in the face for being so damn stupid.
- Nuclear power is not dangerous. Natural Disasters are dangerous.
