Waste is an issue for all industries, including those in the energy sector. When it comes to nuclear energy the waste needs to be compared to the alternatives to ensure we evaluate it with a sense of perspective. For instance, across the technologies full life cycle, producing electricity from solar energy results in 200 to 300 times more toxic waste compared to making electricity with nuclear energy. This includes waste during mining, operation and at the end of life. The nature of the waste from using solar energy and the nature of its toxicity is somewhat different, but it makes the point that perspective matters. No sector is free of toxic waste. 

Solar Panel Waste

The burning of coal results in coal ash, also known as fly ash. Fly ash contains contains arsenic, lead and mercury which are chemically toxic substances. Fly ash is also slightly radioactive and a coal power plant will release around a hundred times more radiation into the environment than a nuclear power plant producing the same amount of energy. 

In the scheme of things however solar, coal and nuclear are all much safer than being without electricity. Poor people in various countries rely on wood for fuel to heat their homes and to cook with and the smoke from domestic fires is a much bigger risk to human health. 

Nuclear Waste

Nuclear waste is toxic for a mix of reasons. One relates to its chemical nature and the other relates to its radioactive nature. 

Radioactive toxicity is different to chemical toxicity in certain key regards. For starters it is much easier to detect and to locate radioactive material. Also, radioactive material typically becomes less toxic over time. Rapidly at first but then more gradually in the longer term. Whilst some forms of heavy metals remain chemically toxic essentially forever. In practice waste from nuclear energy is often toxic in both regards but the fact remains it does become less toxic over time and eventually the chemical toxicity will dominate. Just as chemical toxicity typically dominates from the get-go with most waste from other sectors. 

Radioactivity

Why are radioactive materials hazardous? The reason is that they emit high energy particles. The hazard relates to how much energy is in these particles and for how long the radioactive material continues to emit these particles.

These high energy particles that are emitted come in different forms such as alpha, beta and gamma particles. 

Alpha particles are just helium atoms. Like the helium we put in party balloons. Except they are extremely hot (high energy) when emitted. 

Beta particles are just electrons. Like we have in the electrical wires inside our homes. Except they are extremely hot (high energy) when emitted. 

Gamma waves are high energy photons. Similar to the photons that come out the end of a torch but at much higher energy levels. 

Ultimately these forms of radiation are hazardous because they carry a lot of energy. Not because the particles are in any way exotic. Those particles once they have rapidly dissipated their energy are no different to material that is everywhere in nature.

Like the electricity in your house wiring this hazardous energy is not a danger to human health if we are insulated (or isolated) from it. Hazardous is not the same as dangerous. 

Insulating humans from these energetic particles is well understood from an engineering perspective just as insulating electrical wires in your home is well understood. If you are not scared of electricity, you need not be scared of radiation. 

α = alpha             β = beta              γ = gamma

High-level nuclear waste

How radioactive waste is and for how long determines if we call it high-level waste or low-level waste. The primary high-level waste from nuclear energy is the solid fuel rods that are removed from the reactor. These are called spent nuclear fuel and they are metal tubes containing solid ceramic fuel pellets. Relative to the energy produced the amount of such waste is very tiny.

Spent nuclear fuel is very hot for several years and is kept in a pool of water to dissipate the heat. After a few years is stored in concrete containers to keep it isolated from humans whilst it further cools down just using the air over several decades. Later it can be disposed of in a deep tomb underground but there is no hurry because it is safe in the concrete casks.

 

High level waste cooling in concrete casks. 

Low-level nuclear waste

Low-level waste is often disposed of in a manner more consistent with waste from other industries. It includes things like gloves, overalls and hand tools that nuclear workers have used for safety.

Gloves used by nuclear worker.

This sort of solid waste is packed in barrels which are typically marked in yellow to designate their nature. This sort of waste is typically buried but it does not require deep disposal. As the barrels are essentially the same as oil barrels people often mistakenly think the content is liquid. However, gloves and overalls are obviously solid, and the drums are just a convenient way to seal them in. 

 Low level nuclear waste. Gloves etc. 

DNA Damage

Low levels of radiation, like you might get from a stroll in the sunshine, may often be beneficial because they stimulated our DNA repair mechanisms. Like all animals we have significant DNA repair mechanisms.

Under normal conditions it is estimated that each human cell is subject to approximately 70,000 lesions per day (Lindahl and Barnes, 2000). The majority of lesions (75%) are single-strand DNA (ssDNA) breaks, which can arise from oxidative damage during metabolism or base hydrolysis.

Our bodies are equipped to deal with DNA damage and to undertake repair. Even at more elevated levels of damage. However, beyond a certain threshold even our natural defence mechanisms can be overwhelmed. The dose makes the poison and something what is medicinal in low doses can become dangerous in high doses. 

Most people face far more hazard of DNA damage from chemical toxins. Which is why we should be mindful of all types of hazards but also realistic about what doses actually matter. Even those that work a lifetime in the nuclear energy sector are almost always kept safe and are generally at vastly more risk simply driving to and from work. 

Future Nuclear

Commercial nuclear energy has been around about as long as commercial solar panels. Both sectors continue to see innovation. As does the somewhat newer technology of large grid batteries. Above we have examined how things are today but the future offers many opportunities for innovation and improvement. 

Only a tiny percentage of the energy has been extracted from the fuel in a conventional reactor. There is a lot of potential for recycling spent nuclear fuel. There are also reactor types on the drawing board that convert the fuel to electricity with much better efficiency.

The future is bright for nuclear energy. Or it can be if we end prohibition.