Frequently Asked Questions - NUCLEAR POWER
Power plants, whether they are coal, gas, oil or nuclear, use steam to make electricity. They operate like a giant tea kettle, turning water into steam which spins giant turbines that power generators to make electricity. The primary difference between fossil and nuclear power plants is that nuclear plants use uranium as the fuel to produce steam instead of burning fossil fuels. In a nuclear power plant reactor, water is heated by a process called nuclear fission.
- Uranium atoms are split when they are struck by neutrons.
- When the atoms split, they release heat, along with two or three more neutrons.
- These neutrons then strike other uranium atoms, again causing the atoms to split, release heat and again, two or three more neutrons. This is called a chain reaction.
The steam then spins turbines that are connected to generators to produce electricity.
Nuclear power plant reactors use uranium which is referred to as nuclear fuel to generate electricity. A uranium pellet is a solid material like coal or wood and not in liquid form or a gas.
Nuclear technology application has been used by many countries around the world to produce safe, clean, reliable and affordable electricity. Further, it is known to provide base load (constant supply) of electricity.
A reactor is the core in a nuclear power plant that uses fission process (splitting of atoms) to produce electricity in a controlled chain reaction. The energy from the fission reaction is removed from the reactor by a coolant to produce steam to drive the turbines of electric generators. Thus, in a nuclear power plant, fission of nuclear fuel plays the same role as burning of coal, natural gas, or oil plays in fossil fuel power plants.
In a typical reactor, nuclear fuel stays for 12-24 months. After this period, one third of the fuel is usually waste and has to be replaced with new fuel.
Nuclear power plants emit virtually no greenhouse gases and produce no harmful emissions that deplete the ozone layer and contribute to greenhouse gases and acid rain. For this reason, countries are using or considering this source of power to cut on their carbon emissions.
Nuclear power plants emit extremely small amounts of radiation. These emissions are controlled so that it does not pose any threat to the public or the environment. Additionally, strict rules are put in place to ensure that radiation is carefully controlled at the storage site, so people, animals and the environment are not harmed.
Research has shown that it is safe to carry out agricultural activities near a nuclear power plant site without contamination to plant, animal and human life since the power plants do not emit liquid or air-borne waste. In addition, there is no negative impact from onsite spent fuel storage on the surrounding.
Nuclear plants have high security, extensive perimeters and are built to withstand the impact of a plane crash or large explosion. This means that it is difficult for terrorists to access a nuclear plant and escape undetected with fuel or radioactive material. They would need costly, difficult to obtain equipment and highly sophisticated technical knowledge to turn the stolen material into a weapon. Since the terrorist attacks of 11 September 2001, security at nuclear plants has become a major focus for governments and concerned international organizations such as the IAEA. Nuclear installations around the world have strengthened security forces, added protective barriers, limited
access to sensitive information and taken other measures commensurate with the current security risks.
It has taken decades and billions of dollars for nations like India, Pakistan, North Korea, and Iran to build a single bomb. Again, the possibility of a non-weapon state marshaling the technical and financial resources to do the same is highly unlikely.
Also referred to as spent fuel, nuclear waste is the material gotten after nuclear fuel has been used in a reactor. It looks exactly like the fuel that was initially loaded into the reactor (assemblies of metal rods enclosing ceramic uranium pellets). After chemical reactions have occurred in the reactor during electricity generation for about three fuel cycles, or three years, the contents become waste which is dangerously radioactive, and remains so for thousands of years.
When it is first removed from the reactor, it is usually so toxic that if you stood within a few meters while it was not shielded, you would receive a lethal radioactive dose within a few seconds and die of radiation toxicity within few days. In practice, spent fuel is never unshielded. It is kept under water which is an excellent shield for a few years until the radiation reduces to levels that can be shielded by concrete in large storage casks. The final disposal of this spent fuel is highly debated and argued against the use of nuclear reactors. Options include deep geologic storage and recycling. The sun would consume it well if we could get into space, but since rockets are so unreliable, we can’t afford to risk atmospheric dispersal on lift-off.