Nuclear reactors- What is the first thing that comes to our minds on hearing that? Most probably some scene from a sci-fi movie.
Well, this scene might soon come out of the theater screens into our daily lives. We might soon be making energy out of this commonly feared technology. Without further wait; let’s dive into the topic and get the discussion going.
What are Fusion Reactors?
For most of us who are not chemistry geeks, let’s start by understanding what ‘fusion’ is. Fusion, in layman’s terms, is the scientific term given to a process of two or more objects or substances combining to form one single unit along with the release of a large amount of energy.
This object may be two nuclei combining to form heavier nuclei(nuclear fusion), two or more chemicals forming a new compound(chemical fusion), or simply the joining of different materials to form a single unified material (material fusion).
For our further discussion, we are primarily interested in nuclear fusion which has proved to be of great interest to the science community.
Coming to the core of our article, What are fusion reactors? As mentioned earlier, nuclear fusion reactions release energy of huge magnitude. If we were able to perform such reactions in a controlled manner in a laboratory setting; we could build a device that will have the capacity to cater to all of man’s power requirements. This is exactly what we are trying to achieve.
So, a nuclear fusion reactor is a huge power plant designed to carry out sophisticated fusion reactions to generate energy. Since these reactors usually use a mixture of hydrogen isotopes as their fuel; it is an extremely eco-friendly alternative to the current energy sources. Moreover, this technology is far more efficient than our present in-use power solutions.
How Do They Work?
Coming to the most interesting part of the topic- How do you transform something as small as a nucleus into a clean energy dispenser? The answer is not quite simple, yet we have tried to break it down for you. So, the complete process of harnessing energy in such reactors occurs in 5 steps:
Hydrogen – Our Hero
There are three isotopes of hydrogen known; namely – protium, deuterium, and tritium. The fuel used in the reactors is a carefully configured mixture of the three. Protium is the most easily available form. Deuterium is generally extracted from seawater while tritium, being highly unstable in nature, needs to be bred from the lithium fed in the reactors itself.
Undressing the Atom
To carry out such a reaction, we need to provide it with a very specific environment. The fuel needs to be heated to an extremely high temperature which is generally in the range of tens of millions of degrees Celsius.
When heated to such an extent the atoms lose their electrons (thermionic emission) leaving behind naked nuclei. Our sole aim is to remove the electron cloud surrounding the nucleus; thus it can also be achieved through strong magnetic fields, lasers of high intensity, or even bombardment of particles.
The third step involves collecting the plasma (highly excited ionized atoms ) in a confined space. This serves two main functions. It prevents the plasma from touching the reactor walls as it would result in the plasma losing its energy and cooling down. Also, it helps increase the efficiency of the fourth step.
Fusion of the Plasma
The plasma consisting of positively charged ions at such high temperature and pressure are excited to the extent that they can overcome their mutual repulsion. Once the plasma attains this state, it starts to fuse together.
As a basic law of chemistry, Whenever a bond is made or an addition is done, energy is released. Abiding by the same; the fusion releases enormous energy. The most common type of fusion reaction is conducted using the deuterium-tritium pair.
Extracting the Energy
The energy released from the reactors is usually in the form of fast-moving neutrons and high-speed photons(ϒ rays). Many complex reactions take place resulting in the formation of steam as the major end product. This steam is used to drive turbines to generate electricity.
How is Fusion Reactor a Source of “Unlimited Clean Energy?”
There are many notions to support the statement. Listed below are a few of them:
1. Never-ending Fuel
The prime fuels used in the process of electricity generation through reactors are- deuterium and tritium. These hydrogen isotopes are obtained from virtually inexhaustible sources. Seawater (the main source of deuterium) is present in bountiful amounts for us to produce power for the next 900 years.
Keeping in mind that tritium can be harvested with the use of abundantly present lithium; it won’t be inaccurate if we regard hydrogen as a “never-ending fuel”. With much more technological advancements underway; we are sure to see nuclear fusions as an energy generator.
2. Astounding Efficiency
The efficiency of any technology is measured by the amount of evolvement it can provide to the human race. On the same note, using fusion reactors for producing clean energy satisfies all benchmarks.
In terms of reactors, we need to consider the energy released per unit of fuel consumption. To our surprise, fusion reactors have an energy output millions of times greater than conventional energy sources.
These reactors not only produce more energy than the present sources; they are also better suited for our mother Earth.
3. No Greenhouse Gas Emissions
We cannot emphasize enough on the damage done by greenhouse gas emissions. The greenhouse gases (CO2, CFCs, etc.) are a threat to the human population in more than one way.
Since nuclear fusions involve only an atom nucleus, there is little emission of long-lived radioactive compounds which release harmful radiations all through their life. Nor do we face the production of hazardous atmospheric pollutants associated with the fossil fuels commonly used.
4. Radio-waste Minimization
As mentioned earlier, nuclear reactions produce radioactive waste of much less magnitude when compared to fission power plants or fossil fuel power plants.
Future research will not only reduce the production of these harmful compounds but also, ensure better management of the waste produced.
5. Advanced Safety Features
The foremost prerequisite for conducting a fusion reaction was to maintain the optimum temperature; thus any process which can alter the temperature inside the reactor can be used in controlling the reaction occurring.
Also, if there is any disruption in the plasma or other fed constituents, the reaction will autonomously stop. This increases the chances of preventing catastrophic calamities.
Limits to the Soar
Every luxury has a price tag attached to it. The production of energy from fusion reactions has its cons.
1. Technical Challenges:
As already discussed, fusion reactions require very high temperatures to start; this poses a great challenge for scientists. It becomes very difficult to initiate and sustain the process.
2. Instabilities in Plasma:
If forming plasma was climbing a hill; maintaining it would be like climbing Everest. Plasma is a highly excited state of matter which can be achieved only at extremely high temperatures. Thus any alteration in the temperature can disrupt the fusion process.
3. Energy Balance:
One of the main goals of the whole process is to devise a source of unlimited clean energy, But that does not seem to happen any soon.
The reactions we can conduct are poorly efficient as the energy input far exceeds the energy released. We still need to work on building better-suited fusion reactors which can carry out self-sustained reactions.
4. Reactor Lifetime:
Being exposed to highly energized and heated particles for a continuous period of time decreases the life of the machinery. The vessel walls need frequent servicing and the fuel containers need to be built with advanced materials which are highly priced.
5. Capital Challenge
Setting up a fusion power plant is a big deal. One needs substantial investment and also adheres to the ongoing operational costs.
Currently, the main block of the path is the funding. Such plants require technology and machines which are expensive and need a precise operation. Thus making the process economically inviable and commercially unavailable.
What’s in the Future?
There is a lot of research and development needed in this niche. More and more students are intrigued by the subject and are taking up nuclear physics as their core major. With active research being conducted, the possibility of seeing nuclear fusion as the answer to the world’s energy problems may be a sure guess.
A note-worthy project going on is the ITER(International Thermonuclear Experimental Reactor). This mega project located in France is one of a kind and is on the quest of solving the chemical puzzle. Its success could pave the way for many more future demonstration reactors.
The most emphasized topic of the century is – sustainability. Future reactors will be designed to cater as an environment-friendly and virtually-limitless energy source that is also sustainable. Lowering the carbon footprint would be one of the major development motives.
Do check out this YouTube video for more information on the topic.
In a nutshell…
Nuclear fusion reactors are a big step towards advanced sustainable living. In the ever-going quest of building the unthinkable, these reactors will be a door to the future. Energy will be the next big thing for the science community to work on and being able to produce it without staking their home planet is definitely a must.