Video Transcript
Which of the following statements correctly describe the disadvantages of nuclear fission reactors? a) Nuclear fission reactors are expensive to build. b) The planning, construction, and testing process for nuclear fission reactors takes a long time. c) Nuclear reactors are slow to start up if they are switched off and slow to switch off once running. This means that they cannot respond to changes in electricity demand. d) Nuclear fission reactors are expensive to maintain. e) Nuclear fission reactors release large quantities of carbon dioxide and methane into the atmosphere once built. f) Nuclear fission reactors produce very little electricity. g) Nuclear fission reactors produce highly radioactive waste that has to be stored securely for hundreds of years. h) The process of refining uranium to be used in fission reactors creates a lot of pollution.
Okay, so in this question, we’re trying to find the disadvantages of nuclear fission reactors. So let’s go through each option one by one. Let’s start with option a), nuclear fission reactors are expensive to build. Now, that most certainly is true. In fact, in the US, many nuclear power stations were abandoned halfway through building them. And this is because the costs got way too high. So option a) is actually true. And it is a disadvantage of nuclear fission reactors.
Moving on to option b) then, the planning, construction, and testing process for nuclear fission reactors takes a long time. This is also true. Some vision reactors could take as long as four to five years just to build. Add on top of that about a year of getting the area ready before the building process even starts and then six months of testing once everything has been built. And we can see that the planning, construction, and testing process does indeed take a long time. Therefore, option b) is a disadvantage of nuclear fission reactors.
Option c) then, nuclear reactors are slow to start up if they are switched off and slow to switch off once running. This means that they cannot respond to changes in electricity demand. Now, this option is also true. When nuclear fission reactors are used, they are used as the base load for generating power. In other words, they’re kept switched on constantly. And they produce the amount of power that is required when the demand for electricity is lowest. Then, when the demand for electricity increases, other power stations that are much faster to start up are switched on. For example, gas fired power stations are very quick to start up. And so those are used mainly when the electricity demand increases. However, nuclear power stations do take a long time to start up and switch off. And hence option c) is indeed also a disadvantage of nuclear fission reactors.
Option d) then, nuclear fission reactors are expensive to maintain. Now, this is true. There are a lot of complicated parts to a nuclear power station. And this needs to be coupled with the safety of the people working on the plant. Because remember, exposure to radioactive materials is not a good idea. So because of all of this, nuclear fission reactors are actually expensive to maintain. However, interestingly, the fuel that is used in nuclear fission reactors, that’s uranium, is actually overall slightly cheaper than the fuel used in other kinds of reactors. Taking everything into account, such as uranium mining and refining and so on and so forth, it surprisingly ends up being slightly cheaper than using something like coal, for example. So the operation and fuel costs for a nuclear power station are slightly lower. But the maintenance costs are definitely higher. And so this is a disadvantage of nuclear fission reactors.
Okay, moving on to option e) then, nuclear fusion reactors release large quantities of carbon dioxide and methane into the atmosphere once built. Well actually, this is definitely not true. Nuclear fission reactors use uranium as their fuel. And the energy in nuclear fission reactors is gained from the nuclear fission process. In other words, uranium splits into slightly smaller nuclei and releases some energy. But these slightly smaller nuclei are not carbon dioxide or methane. Of course, they can’t be because carbon dioxide is made up of multiple elements, carbon and oxygen, and methane is made up of carbon and hydrogen. So nuclear fission reactors do not release greenhouse gases into the atmosphere. And this is one of the big advantages of nuclear reactors.
Okay, moving out to option f) then, nuclear fission reactors produce very little electricity. Now, this is also not true. Nuclear fission reactors can produce as much as, if not more, energy compared to coal fired power plants or gas fired power plants. And this is because the fission process actually releases large amounts of energy. In fact, nuclear reactions are more efficient at releasing energy than chemical reactions, where chemical reactions include burning coal or burning gas. So option f) is not true; it’s not a disadvantage of nuclear fission reactors. They can produce lots of electricity. And so that’s actually an advantage of nuclear fission reactors.
Looking at option g) then, nuclear fission reactors produce highly radioactive waste that has to be stored securely for hundreds of years. Now, as we’ve said earlier, nuclear fission reactors use uranium commonly as their fuel source. And this uranium splits up into smaller nuclei. However, these nuclear are actually also unstable. And they are indeed highly radioactive.
Now, these smaller nuclei are the waste products of nuclear fission reactors. And one option is to try and recycle this waste and use it again because these nuclear are radioactive as well. However, this is are much more difficult process. And so the other option is to just store this nuclear waste. But then that means having to store radioactive waste that has extremely large half-lives, sometimes on the order of hundreds of years. And doing this safely and securely is definitely a big challenge. Therefore, option g) is a disadvantage of nuclear fission reactors.
So let’s look at option h), finally. The process of refining uranium to be used in fission reactors creates a lot of pollution. Now, when uranium is mined from the Earth, it’s not actually very pure. Only very small chunks of the rocks that we mine out of the ground end up actually being uranium. And in order to produce any decent amount of power in a nuclear fission reactor, the fuel cannot be this uranium. Or it needs to be purified. And it’s done so with the refining process that does indeed create a lot of pollution. So option h) is also a disadvantage of nuclear fission reactors. Hence, we can say that, out of the options given to us, options a), b), c), d), g), and h) are disadvantages of nuclear fission reactors.
