Fukushima Dai-Ichi: How a nuclear power plant works
Although we’re not nuclear scientists here, we felt this thead might be of help for al those who wish to keep a clear interpretation on what your local news broadcast is announcing. A major number of high end press agencies was already touting on about Japan’s Fukushima prefecture becoming a refurbished edition of Chernobyl.
Also if there are any mistakes or technical nonsense do not hesitate to contact us that we can make this post as accurate as possible, but don’t make an ass of yourself and try to keep it polite, we will not tolerate any wrong behavior today.
Japan being a major player in the constantly improved development in health and safety for it’s millions of inhabitants, clearly has more than one trick up it’s sleeve to make sure IF disaster hits the spot, that the people are as safe as possible. Unfortunately a tsunami + an 8.9 earthquake is just a bit to huge for even the most water tight evacuation plan out there. The Fukushima Dai-Ichi nuclear reactor buildings located closely to the epicenter of the quake are under constant monitorring and everything possible is done to make sure IF radioactive substances hit the air, the contaminated zone would be less than the 20km barrier currently used as a safety buffer. This is Fukushima Dai-Ichi, a state of the art reactor plant which won’t blow up like the current media headlines are stating.
A) Due to the earthquake a wall got breached/cripped
B) The power went out due to the tsunami’s water reaching the building, rendering even the backup generators useless. Due to these events a hydrogen tank blew up.
C) 4 reactor cores are presently cooled with sea water (which is very corrosive and will most probably render the reactors useless after the emergency situation is moderate again.
Reactor cores can go up to 2200 degrees Fahrenheit for the core still to be functioning, only when it heats up to about 4000 degrees Fahrenheit one can say they pose an imminent risk to melting since this is about the maximum temperature where the Uranium pellet start to melt. Only when the 4000 degrees barrier is breached, the potential exposure the radioactive substances is possible since the melting Uranium would corrode/eat it’s way through the reactor.
So how does a nuclear power plant work (explained very roughly in a few basic steps):
The process is called “Nuclear Fission”, it is a reaction between a free neutron that hits a Uranium atom. The Uranium absorbes this neutron, goes into an unstable state and bursts open (explodes). This process repeats itself over and over since every time the Uranium splits, new free neutrons are released and react with other Uranium atoms.
This “splicing” interaction produces energy, not enough in small quantities, but a a pound of highly enriched Uranium produces enough energy to power a full blown submarine. Equivalent to about a million gallons of gasoline/fuel. Thus a very interesting and clean source of power when controlled properly. Uranium reactions also produce an incredible amount of heat and gamma radiation.
Nuclear reactors are mainly divided into 3 ways of status-operiation. Critical mass, Subcritical mass and Supercritical mass. Roughly speaking it’s a form of control scientists use to determin how stable the temperature of the core will be depending on the Uranium atom’s form inside. In general nuclear power plants require a combination of critical and few supercritical mass to be able to rise and lower the temperature depending on the electricity required.
Operation inside the plant consists of the reactor which is a collection of long rods filled with Uranium bundled together. These bundles are put into a pressure vessel and submerged into something similar to a very deep swimming pool (water acts as a coolant). Uranium on it’s own would overheat almost instantly, thus control rods made of materials that can absorb these neutrons are placed inside and can be raised/lowered depending on the present reactions inside the core. Making sure the temperature can be controlled at all time.
The heat produced by the reactor’s core produces steam, this steam is used to drive a turbine where spinning electricity generators produce the power you can use in your home. Different ways to cool down nuclear reactors, some work on water, some on liquid metals, some are cooled by gas,… all depending on how productive you want the cores to become.
The steam produced that drives the generators is of course radioactive, so a concrete liner which absorbed the radiation is placed inside a steel vessel which contains all of the radioactivity released in the production process. To protect these crucial steel vessels a super thick concrete outer building is build in order to make sure none of the radiation escapes the compound when an accident should occur to the steel vessels. The outer buildings are strong enough to endure earthquakes up to crashing airplaned. Unfortunately the massive earthquake at the Fukushima Dai-Ichi premises made the wall of 1 reactor building crack, yet as long as the steel vessel(s) inside are not said to be severely damaged this doesn’t pose a risk to large scale radioactive steam releases.
We also would like you to take time to read, this VERY long but extremely interesting article on the Situation over at Fukushima : Why I am not worried about Japan’s nuclear reactors. It is very in-lighting as well!