AP Environmental Science

## Learning Outcomes

- Understand why **nuclear power** is classified as a nonrenewable energy source in AP Environmental Science
- Identify the main environmental advantages of nuclear power, including low air pollution during electricity generation
- Explain the major tradeoffs of nuclear power, including radioactive waste, thermal pollution, and accident risk
- Distinguish between low operational emissions and broader lifecycle environmental impacts
- Describe how cooling water use can affect aquatic aquatic lifes
- Apply named examples such as **Three Mile Island (1979)**, **Chernobyl (1986)**, and **Fukushima Daiichi (2011)** in exam answers

## AP Environmental Science Syllabus

For the AP Environmental Science, you are expected to understand nuclear power tradeoffs, with a focus on the following syllabus points:

- Know that nuclear power is generated from **fission** reactions in nuclear reactors
- Know that uranium fuel is finite, so nuclear power is a **nonrenewable energy source**
- Understand that nuclear plants do not emit **carbon dioxide**, **sulfur dioxide**, or **nitrogen oxides** during electricity generation
- Explain why nuclear power can still cause environmental problems through **radioactive waste**, **thermal pollution**, and fuel-cycle impacts
- Identify the environmental effects of **cooling water use**, including lower dissolved oxygen, organism harm at intake, and water loss by evaporation
- Understand that accident risk is low probability but potentially high consequence
- Be able to compare nuclear power with fossil fuels and renewables in terms of reliability, pollution, and risk
- Use named accident examples carefully and accurately in FRQ responses

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. Why is nuclear power considered nonrenewable even though it has low carbon emissions during operation?
2. What is the difference between operational emissions and lifecycle environmental impacts for nuclear power?
3. How does cooling water from a nuclear plant cause thermal pollution?
4. Name two major environmental disadvantages of nuclear power besides accident risk.
5. Why can nuclear power be described as both low-carbon and controversial?

## Introduction

Nuclear power is one of the most debated energy sources in AP Environmental Science because it combines a major climate advantage with serious environmental and social concerns. It produces large amounts of electricity with very low air pollution during operation, yet it also creates radioactive waste, depends on a finite fuel supply, and can damage aquatic waterwayss through cooling-water use.

This makes nuclear power a classic APES tradeoff topic. On the exam, strong answers do not call nuclear energy simply “clean” or “dirty.” They explain both sides precisely: low greenhouse gas emissions during electricity generation, but significant issues involving waste, thermal pollution, mining, cost, and safety.

> **Key Term: nuclear power**
> Electricity generated by using heat from nuclear fission, usually involving uranium fuel, to produce steam that turns a turbine.

## Introduction to the tradeoff: why nuclear power is attractive

### Low air pollution and low operational greenhouse gas emissions

The main environmental case for nuclear power is simple: reactors generate electricity without burning fossil fuels. That means they do not directly emit **carbon dioxide**, **sulfur dioxide**, or **nitrogen oxides** while operating. Compared with coal or oil plants, this can sharply reduce contributions to climate change, acid deposition, and photochemical smog.

That point matters in APES because students often confuse “nonrenewable” with “high-carbon.” Nuclear power is nonrenewable because uranium is finite, not because it releases large amounts of carbon during operation.

> **Key Term: nuclear fission**
> The splitting of a large atomic nucleus into smaller nuclei, releasing energy as heat.

A second advantage is reliability. Nuclear plants provide steady **baseload** electricity. Unlike wind and solar, they are not intermittent. A reactor can keep producing power at night, during calm weather, and during periods of high demand. This is why some energy planners argue that nuclear power can support a grid that also uses renewables.

Nuclear fuel also has very high energy density. A small amount of uranium can produce a very large amount of energy compared with fossil fuels. That means less fuel has to be transported and stored relative to the amount of electricity produced.

> **Test Tip:** If a prompt asks for one air-pollution benefit of nuclear power, be specific. Write that nuclear plants do not emit sulfur dioxide or nitrogen oxides during electricity generation, rather than saying only “less pollution.”

### Why “low-carbon” is not the same as “impact-free”

A common exam mistake is saying nuclear power has “zero emissions.” Better wording is that it has **low operational emissions**. The reactor itself does not burn fuel, but the wider nuclear fuel cycle still has environmental costs.

> **Key Term: lifecycle greenhouse gas emissions**
> Total greenhouse gas emissions associated with an energy source across extraction, processing, construction, operation, and disposal.

For nuclear power, those lifecycle stages include:

- uranium mining
- uranium enrichment
- plant construction
- maintenance
- decommissioning
- waste storage

So the accurate APES phrasing is: nuclear power has very low emissions during electricity generation, but it is not free of environmental impacts across its full lifecycle.

## The major costs: waste, water, and risk

### Radioactive waste and long-term storage

The strongest argument against nuclear power is the waste problem. The fuel and many reactor by-products remain radioactive for extremely long periods. This is not ordinary trash. It must be isolated from the environments and people for very long timescales.

> **Key Term: radioactive waste**
> Waste that emits ionizing radiation and can harm organisms if released into the environment.

A useful distinction is between high-level and low-level waste. Students often blur these together.

> **Key Term: spent fuel**
> Used reactor fuel that is no longer efficient for power generation but remains highly radioactive.

Spent fuel is high-level waste. It requires shielding, cooling, and secure long-term storage. Low-level waste includes contaminated clothing, filters, and tools; it is still hazardous, but much less radioactive than spent fuel.

Why is this such a serious tradeoff? Because electricity is needed now, but the waste remains dangerous for thousands of years or longer. That creates an intergenerational problem: present-day energy users gain the electricity, but future societies must maintain safe storage.

Storage is also politically difficult. Communities often resist becoming long-term waste sites. Even if engineers identify technically suitable geologic locations, public opposition can delay or block projects. So the problem is not only scientific. It is also social and political.

A second concern is security. Highly radioactive materials must be kept secure to reduce the risk of theft, sabotage, or misuse.

> **Test Tip:** In FRQs, do not say “all nuclear waste lasts millions of years.” A safer answer is that some nuclear waste remains hazardous for thousands of years or much longer, depending on the material.

### Thermal pollution and aquatic habitat damage

For AP Environmental Science, cooling water impacts are especially testable. Nuclear plants need large amounts of water to remove excess heat. That water may be withdrawn from rivers, lakes, or the ocean, used in cooling systems, and then discharged at a higher temperature unless cooled first.

> **Key Term: thermal pollution**
> The release of heated water that raises the temperature of a nearby water body.

This warmer water creates several linked problems. First, warm water holds less dissolved oxygen than cool water. Lower dissolved oxygen can stress fish and invertebrates, especially species already near their tolerance limits.

Second, higher temperatures can speed up metabolism in aquatic organisms. That means they need more oxygen at exactly the time less is available. This mismatch can increase stress and mortality.

Third, warmer conditions can encourage algal growth and bacterial growth. If algae later die and decompose, decomposers use more oxygen, making conditions even worse.

Fourth, sudden releases of unusually warm water can cause thermal shock. Organisms adapted to a narrower temperature range may die or be forced to move.

Cooling water systems also harm aquatic life even before the water is discharged. Intake structures may trap larger organisms against screens, a process called **impingement**, and may draw in eggs, larvae, and very small organisms, a process called **entrainment**. In drought-prone areas, evaporation from cooling systems can also reduce local water availability or stream flow.

### Accident risk: rare but high consequence

Major reactor accidents are uncommon, but they remain central to the nuclear debate because their consequences can be severe. This is why the best APES wording is “low probability, high consequence.”

> **Key Term: reactor accident risk**
> The possibility of a severe failure at a nuclear plant that releases radioactive material into the environment.

Three named examples matter most:

- **Three Mile Island (1979)** in Pennsylvania involved a partial meltdown with limited release
- **Chernobyl (1986)** in Ukraine caused a major explosion and severe radioactive contamination
- **Fukushima Daiichi (2011)** in Japan followed an earthquake and tsunami that disabled cooling systems

These cases should be used carefully. They show that failures can lead to evacuation, long-term contamination, health fears, and major economic disruption. But students should avoid implying that such accidents are routine.

In a strong answer, you can say that modern regulation and safety systems reduce the likelihood of severe accidents, yet the consequences of failure remain serious enough to shape public opinion and policy.

## Looking beyond the reactor: mining, enrichment, and decommissioning

### The nuclear fuel cycle creates extra tradeoffs

One reason nuclear power is not a simple solution is that its environmental impacts begin before the reactor operates and continue after it closes.

Uranium mining can disturb land, damage habitat, and generate mine tailings that may be radioactive. Mining can also contaminate nearby water if wastes are not managed well. In APES, this links nuclear power to land-use and pollution ideas, not just energy ideas.

Fuel processing adds more impacts. Uranium enrichment requires energy and creates additional waste. This stage may also involve carbon emissions, depending on the energy source used to run the process.

After decades of operation, plants must also be retired safely.

> **Key Term: decommissioning**
> The process of shutting down, dismantling, and cleaning up a retired nuclear power plant.

Decommissioning is expensive, time-consuming, and technically demanding. Structures may be contaminated and materials must be managed carefully. This means that the total cost of nuclear power includes not just construction and operation, but also long-term cleanup.

Another drawback is long lead time. Nuclear plants take many years to plan and build. That matters in climate policy because a low-carbon source is less useful for near-term emissions cuts if it cannot be deployed quickly enough.

### How to write a balanced APES judgement

When an FRQ asks you to evaluate nuclear power, aim for a structure like this:

- benefit: low air pollution and low operational greenhouse gas emissions
- cost: radioactive waste, thermal pollution, and accident risk
- qualification: uranium is finite and the fuel cycle has extra impacts
- judgement: useful in reducing fossil fuel dependence, but not a complete or impact-free solution

For example, if comparing nuclear with coal, the analysis is usually favorable to nuclear on climate and air pollution. If comparing nuclear with wind or solar, nuclear gains reliability but loses on waste and accident concerns.

The best judgement often depends on context:

- If a region needs steady electricity and wants to cut coal use, nuclear may be attractive.
- If a region has strong public opposition, limited water, or major waste concerns, nuclear may be less suitable.
- If rapid decarbonization is needed, long construction times may reduce its value.
  > **Test Tip:** APES evaluation questions reward precision. Avoid absolute claims like “nuclear power is the best solution” or “nuclear power is too dangerous to use.” Show what it depends on.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Nuclear power is a **nonrenewable energy source** because uranium is finite
- Nuclear power is generated by **fission** reactions that release heat to produce steam and turn turbines
- Nuclear plants have low air pollution and low greenhouse gas emissions during electricity generation
- Low operational emissions are not the same as zero lifecycle impacts
- Uranium mining, enrichment, plant construction, and decommissioning all add environmental costs
- **Spent fuel** is highly radioactive and creates long-term storage problems
- Nuclear waste is a major disadvantage because it must be isolated from the environment for very long periods
- **Thermal pollution** from cooling water can raise water temperature and lower dissolved oxygen
- Cooling water systems can also cause impingement, entrainment, and water loss through evaporation
- Reactor accidents are low probability but high consequence
- **Three Mile Island (1979)**, **Chernobyl (1986)**, and **Fukushima Daiichi (2011)** are key named examples
- Nuclear power provides reliable baseload electricity, which is one of its main advantages over intermittent renewables

## Key Terms and Concepts

- nuclear power
- nuclear fission
- lifecycle greenhouse gas emissions
- radioactive waste
- spent fuel
- thermal pollution
- reactor accident risk
- decommissioning


Nuclear Power - Nuclear power tradeoffs