Nuclear Energy

Fusion and Fission

We can use Nuclear energy commercially similarly to fossil fuels by breaking atoms apart (instead of combustion). Nuclear reactions have 2 possible processes - fusion and fission. In fission, a heavy atom splits into two atoms with smaller masses and some neutrons. Fusion is the opposite, with two smaller atoms combining to form a larger atom.

We have not mastered using fusion for an energy source so all our nuclear reactors currently use fission as their process.

Large amounts of energy can be released through fission by having the released neutrons split more atoms, leading to a chain reaction, a self-sustaining fission process.

Nuclear processes are the reason for elements forming in the first place!

Nuclear Power

Nuclear power is cheap once it gets up and running, is a reliable source of energy, creates huge amounts of energy (for example the 1 active nuclear plant we have in California makes 10% of the state's energy - that's about as much energy as all the solar panels we have in the state combined), and doesn't require much fuel or land to maintain. It's also considered the safest form of energy when looking at deaths directly caused by it (yes, even compared to solar). It does however still require mining to find uranium ore, has high startup and shutdown costs, needs its fuel to be stored while it continues to decay after it can no longer be used for energy, and if something goes wrong it can be catastrophic. To use nuclear power for energy production we (generally) use the following:

Nuclear Fuel: Uranium is the most common fuel source for nuclear energy, continuously undergoing fission to make more and more energy in the form of heat and radiation.
Control Rods: Control Rods are made to prevent the reaction from getting out of hand and can be raised or lowered to regulate how much the fission reaction is able to do at once. They're generally made from material that can block radiation very well for extended periods of time without undergoing fission themselves.
A Heat Sink: The heat from a reactor is most often used to boil water in some form, which is transformed into steam.
Steam Turbine: The steam that leaves the heat sink spins a turbine to create electricity.

Types of Radiation and Radioactive Decay

The radiation that you commonly hear about in media is actually ionizing radiation. This is the high-energy radiation that is strong enough to disrupt what atoms are made of (by removing or changing pieces of it through energy alone). Radiation happens when an atom has too much mass or energy to be stable. To become stable it releases waves and/or particles.

Radioactive things decay over time! They slowly lose more and more mass and energy, becoming new substances, until finally they become stable. Half-Life is the time it takes for half of these radioactive substances to decay. Different radioactive atoms have different half lives. Uranium for example slowly decays from element to element in the following way (follow the chart):

We can determine the half-life of something through the following formula:

A = Ao (1/2)t/h

A is the Final Amount of Mass of the radioactive isotope, Ao is the Initial Amount of Mass, t is time elapsed, and h is the isotope's half life.

This decay happens in specific ways, with the 3 most common types of radioactive decay being alpha decay (α), beta decay (β), and gamma decay (γ):

Alpha decay releases radioactive helium particles.
Beta decay releases an electron and makes a process occur that transforms a neutron into a proton or does the opposite by releasing a positron (the antimatter version of electron).
Gamma decay releases energy as high-frequency electromagnetic radiation.

This process can take a very long time, meaning our Uranium example above stays radioactive for thousands of years even after it is no longer Uranium-238.

Other Uses for Radiation

We actually interact with radiation all the time in small amounts. Small amounts are not dangerous, but large ones can cause major problems. It's all in the dose!

In addition to energy we use radiation for other processes in the modern world as well:

Medicine
- Iodine-131 for thyroid and brain imaging
- Gallium-67 for lung scans
- Radiation therapy
Isotopic dating – Check the age of things based on the amount of radioactive particles and half-life.
Thickness control in engineering - Radioactive source is placed on one side and the detector on the other, can check what type(s) of radiation will leave the container. If the detector goes off there is a leak at that spot.
Atomic bombs - Powerful nuclear explosives.

Nuclear Response (PSA)

While not common, high levels of radiation exposure is something you may encounter during your time in public service. There are old items and detectors that are radioactive that can be found nearly anywhere, potential for illegal dumping or exposure of waste if a nuclear plant, mine, or nuclear business isn't careful, the possibility of a spill in the case of an accident, all of which could lead to having to deal with radiation.

While innocent looking, this old set of kitchen cookware was made using uranium!

Alpha Decay uses relatively large particles and is blocked by the skin. The biggest issue is if it enters the body somehow, it's 20 times as dangerous to the body as the other two if it gets in! This means its equivalent dose is 20 while the other particles have an equivalent dosage of 1.
Beta Decay is mostly blocked by the skin as well and can be fully blocked by an Aluminum sheet or a similarly dense object.
Gamma Decay is energy and easily passes through the body! This is the most dangerous radiation commonly dealt with and is normally blocked by lead.

Effective dose is the effectiveness of the radiation based on the location of the radiation on the body. The higher the weighting factor, the more dangerous radiation is to that location (basically the whole body counts as 100% affected by radiation, while each part of the body makes up pieces of the 100% to determine the danger).

When exposed to radiation many things are similar to a chemical emergency. Removing clothing, cleaning the body with water, containing the radiation, and use of protective equipment apply. Radiation however is generally not immediately life-threatening to a first responder unlike many chemicals (it's often still a low dose even with exposure and it's not communicable as the radiation shouldn't be shedding from the person), so patient care takes precedence over contamination issues!

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