Nuclear Energy — Benefits, Risks and Environmental Impacts
Nuclear power produces almost no greenhouse gases — yet it also creates waste that stays dangerous for thousands of years. Few science questions ask you to weigh up so much at once.
Q1 · Burning coal releases carbon dioxide. Nuclear fission does not. List one environmental advantage of nuclear power over coal, and one environmental problem nuclear power has that coal does not.
Q2 · Nuclear waste can stay dangerous for thousands of years. What challenges does that create for storing it safely?
● Know
- The environmental impacts of nuclear reactions: raw materials, stages of production, and waste
- The main benefits of nuclear energy (low greenhouse gases, reliable, high energy density)
- The main risks (waste, accidents, mining impacts, cost)
● Understand
- Why nuclear waste must be isolated for very long times (linked to half-life)
- How impacts arise at every stage from mining to decommissioning
- That energy choices involve weighing climate, safety, cost and sustainability
● Can do
- Outline the environmental impacts across the nuclear life cycle
- Evaluate the benefits and risks of nuclear energy with evidence
- Form and justify a balanced, evidence-based view on a real energy question
To understand the environmental impacts of nuclear energy, follow the fuel through its whole life cycle.
- Raw materials (mining). Uranium is mined from the ground. Mining disturbs land, uses water and energy, and can produce radioactive dust and tailings (waste rock) that must be managed so they do not contaminate soil and water.
- Production (processing and fuel-making). The ore is processed and enriched to increase the proportion of uranium-235. This uses energy and produces some radioactive and chemical waste.
- Operation (the reactor). During operation, fission releases almost no greenhouse gases — a major environmental advantage over coal and gas. However, reactors need large amounts of cooling water and there is a small but serious risk of accidents.
- Nuclear waste. The used fuel is highly radioactive and, because of the long half-lives of some products, stays dangerous for thousands of years. It must be safely contained and isolated from people and the environment for a very long time.
- Decommissioning. At the end of its life the reactor must be dismantled safely, producing more radioactive material to manage.
So nuclear energy is low-carbon in operation but carries environmental impacts at the start (mining) and the end (waste and decommissioning) of the life cycle.
A coal power station and a nuclear power station of the same output differ sharply across their life cycles. The coal station emits huge amounts of carbon dioxide every day it operates. The nuclear station emits almost no greenhouse gas while running, but creates long-lived radioactive waste and requires careful mining and decommissioning. A fair comparison must look at the whole life cycle, not just the moment of generating power.
Australia's uranium and Country: Mines such as Olympic Dam and Ranger (now closed and being rehabilitated) sit on or near Aboriginal land, and decisions about uranium mining have major significance for Traditional Owners. Managing tailings and rehabilitating mined land to protect Country is a central environmental responsibility — one where scientific knowledge and Aboriginal and Torres Strait Islander Peoples' deep connection to land must work together.
"Nuclear power has zero environmental impact because it makes no CO₂." Not quite. It is low-carbon in operation, but mining, processing, waste storage and decommissioning all have real environmental impacts. A complete answer covers the whole life cycle.
Nuclear energy is one of the most debated topics in science and society. A good evaluation lays out both sides clearly.
Benefits:
- Very low greenhouse gases during operation — a major advantage as the world tries to limit climate change.
- Extremely high energy density — a tiny mass of uranium yields enormous energy, so very little fuel is needed.
- Reliable, continuous power — unlike solar or wind, a reactor runs day and night regardless of weather.
Risks and drawbacks:
- Long-lived radioactive waste that must be safely stored for thousands of years.
- Accident risk — rare but potentially serious, as seen at Chernobyl (1986) and Fukushima (2011).
- Mining and decommissioning impacts, and high cost and long build times for power plants.
- Concerns about uranium supply and security (the same material can be misused for weapons).
Many countries also compare nuclear with renewables such as solar and wind, which Australia has in abundance. A balanced view recognises that there is no perfect energy source — every option involves trade-offs between climate, cost, safety and sustainability.
France generates about 70% of its electricity from nuclear fission, giving it some of the lowest-carbon electricity in Europe — a clear climate benefit. But France must also manage decades of accumulated radioactive waste and the cost of ageing reactors. The same technology delivers both the benefit (low emissions) and the long-term challenge (waste), which is why an evaluation must weigh them together.
Australia's energy choice: Australia has world-class solar and wind resources and abundant uranium, so its energy debate genuinely weighs nuclear against renewables. Arguments for nuclear stress reliable low-carbon power; arguments against stress cost, waste and the speed and falling price of solar, wind and batteries. As future voters, students will help decide — which is exactly why this evaluation skill is in the syllabus.
Avoid one-sided answers like "nuclear is clean so it must be good" or "nuclear is dangerous so it must be banned." A strong response weighs genuine benefits against genuine risks and reaches a justified, balanced conclusion.
Quick-fire true or false on nuclear energy and the environment.
Nuclear fission releases almost no greenhouse gases while operating.
Some nuclear waste stays dangerous for thousands of years.
Uranium mining can disturb land and produce radioactive tailings.
Nuclear power has no environmental impact at all.
Nuclear fuel has a very high energy density.
Chernobyl and Fukushima are examples of nuclear accidents.
Australia has large uranium reserves but no power reactors.
A good evaluation weighs benefits against risks.
The syllabus also asks you to investigate a chemical or nuclear reaction used in industry to produce an important product. Generating electricity by nuclear fission is one such process; producing medical isotopes is another.
Electricity from fission (recall Lesson 26): uranium-235 fuel undergoes a controlled chain reaction; the heat boils water to steam; the steam drives a turbine connected to a generator. The "important product" is reliable, low-carbon electricity. Its environmental impacts are exactly the life-cycle ones above.
Medical isotopes (recall Lesson 25): a reactor or accelerator bombards stable atoms with neutrons to make radioisotopes such as molybdenum-99 (the source of technetium-99m). The "important product" saves lives through diagnosis and treatment. Australia, through ANSTO, is a world leader in this.
For any such process, a complete investigation describes the reaction, the product and its value to society, and the environmental considerations — bringing together everything in this nuclear strand and echoing the industrial-chemistry work you did earlier in the unit (such as the Haber process in Lesson 15).
A depth-study investigation might compare two nuclear products: electricity from a fission power plant and medical isotopes from a research reactor. Both rely on nuclear reactions, both bring large benefits (clean power; life-saving medicine), and both create radioactive waste that must be managed. Setting them side by side shows how the same underlying science serves society in very different ways, with different risk-benefit balances.
An Australian industrial nuclear reaction: ANSTO's OPAL reactor is an Australian industrial process whose "product" is medical isotopes exported worldwide. It shows that a nation can run an important, beneficial nuclear industry — with strict environmental and safety management of its small waste streams — without generating nuclear electricity at all.
Investigating an industrial nuclear process means more than describing the reaction. A full answer also states the useful product, its benefit to society, and the environmental impacts — the same balanced, life-cycle thinking used throughout this lesson.
Connect the key ideas about nuclear energy and the environment. Click two connected ideas to explain the link.
Wrong: "Because nuclear power makes no CO₂, it has no environmental impact." No — it is low-carbon in operation, but mining, processing, long-lived waste and decommissioning all create real impacts across the life cycle.
Right: Nuclear power emits few greenhouse gases while running, but has environmental impacts at other life-cycle stages, especially mining and long-lived radioactive waste.
Wrong: "Nuclear waste becomes harmless after a few years." No — some waste contains long-half-life isotopes and stays dangerous for thousands of years, which is why long-term storage is such a challenge.
Right: Because some radioisotopes in the waste have very long half-lives, the waste must be isolated safely for thousands of years.
Wrong: "Either nuclear is the answer, or it should be banned outright." No — energy decisions are not all-or-nothing. A good evaluation weighs benefits and risks and recognises trade-offs against other options like renewables.
Right: Energy choices involve trade-offs. A balanced, evidence-based evaluation weighs nuclear's benefits and risks against alternatives before reaching a justified conclusion.
Australia's Nuclear Decision and Caring for Country
Australia is uniquely placed in the nuclear debate: vast uranium reserves, world-leading solar and wind, and a long-standing decision not to generate nuclear electricity. As the country works to cut emissions, the question of whether to add nuclear power keeps returning — and answering it well requires exactly the life-cycle, risk-benefit thinking developed in this lesson.
These decisions also affect Aboriginal and Torres Strait Islander Peoples directly, since much uranium lies on or near their Country, and waste-storage proposals must respect their deep connection to land and their role as custodians. Bringing together scientific evidence, environmental responsibility and First Nations knowledge is the kind of informed, balanced reasoning this whole unit has been building toward.
✍ Copy Into Your Books
▾Life-cycle impacts
- Mining: land disturbance, radioactive tailings
- Processing: energy use, waste
- Reactor: low CO₂ but needs cooling water, accident risk
- Waste: long-lived, store safely for thousands of years
- Decommissioning: dismantle reactor safely
Benefits vs risks
- Benefits: low greenhouse gas, high energy density, reliable
- Risks: long-lived waste, accidents, mining impact, cost
- Compare with renewables (solar, wind)
Industrial nuclear products
- Fission → low-carbon electricity
- Reactor → medical isotopes (e.g. Mo-99 → Tc-99m)
- Evaluate = weigh benefit, product value and impacts
Trace the Life Cycle
Take a Position
At the start, the hook asked how you would advise the government, weighing nuclear energy's benefits against its environmental impacts and risks.
Now that you have completed the whole nuclear strand — stability, decay, half-life, radioisotopes and fission/fusion — write your most balanced answer yet. State one benefit, one environmental impact, and your justified overall position. How has your view changed since Q1?
Q1. Outline three environmental impacts of nuclear energy, choosing impacts from different stages of its life cycle (raw materials, production, operation or waste). (3 marks)
Q2. Explain why nuclear waste must be stored for such a long time, linking your answer to the idea of half-life from earlier in this unit. (4 marks)
Q3. Evaluate whether nuclear energy is a good choice for reducing greenhouse-gas emissions. Weigh at least one benefit against at least one risk and give a justified conclusion. (3 marks)
Revisit Your Thinking
Go back to your Think First answers. Has your understanding changed?
- Can you now give an environmental advantage and an environmental problem of nuclear power?
- Can you explain why nuclear waste is so hard to store, using the idea of half-life?
Model answers (click to reveal)
Answers
▾MCQ 1
C — Unlike burning coal, nuclear fission releases almost no greenhouse gases while operating, which is its main climate advantage.
MCQ 2
B — Uranium mining disturbs land and produces radioactive tailings; this impact occurs at the raw-materials stage of the life cycle.
MCQ 3
D — Some of the radioisotopes in nuclear waste have very long half-lives, so the waste remains radioactive and hazardous for thousands of years and must be isolated for that long.
MCQ 4
A — A balanced evaluation recognises both the benefits (low-carbon, reliable power) and the risks (long-lived waste, accidents, cost) and weighs them for the specific situation. The other options are one-sided.
MCQ 5
B — Medical isotopes such as molybdenum-99 are produced by nuclear reactions in a reactor and are an important industrial nuclear product. Ammonia and oxygen come from chemical and biological processes, not nuclear reactions.
Short Answer 1
Model answer: Raw materials: uranium mining disturbs the land and creates radioactive tailings that must be managed to avoid contaminating soil and water. Operation: although the reactor emits almost no greenhouse gas, it requires large amounts of cooling water and carries a small risk of an accident releasing radiation. Waste: the used fuel is highly radioactive and must be stored safely for thousands of years. These impacts span the start, middle and end of the life cycle.
Short Answer 2
Model answer: Nuclear waste contains radioisotopes, some of which have very long half-lives — the time for half their atoms to decay. Because each half-life only halves the radioactivity, an isotope with a half-life of thousands of years takes tens of thousands of years to decay to safe levels. The waste therefore stays radioactive and dangerous for a very long time, which is why it must be sealed and isolated from people and the environment for thousands of years until enough half-lives have passed for its activity to fall to a safe level.
Short Answer 3
Model answer: A clear benefit of nuclear energy is that it generates large amounts of reliable electricity while releasing almost no greenhouse gases, which helps fight climate change. A clear risk is that it produces long-lived radioactive waste that must be safely stored for thousands of years, along with a small chance of serious accidents. Whether nuclear is a good choice depends on weighing the urgent need to cut emissions against these long-term risks and the availability of alternatives such as solar and wind. On balance, nuclear can be a justified part of reducing emissions where waste and safety are well managed and renewables alone cannot meet demand, but the decision must be made carefully for each country's situation.