Nuclear Thermodynamics

Thermodynamics is a broad field of science that focuses on the generation, transfer, storage, and conversion of energy. It looks at the effects of work, energy, and heat on a system. Nuclear thermodynamics, on the other hand, is a branch that deals with these fundamental principles and definitions often applied to nuclear power plants.

The knowledge of thermodynamics is essential to nuclear engineers who work with nuclear power reactors on a day-to-day basis. A nuclear reactor is the primary heat source in nuclear power plants.  The heat they produce is used to generate steam, which then turns a turbine to generate electricity. Most nuclear power plants have a 1,000-MWe electricity-generating capacity.

Thermodynamics as a whole has its foundation on four universally-accepted laws, which define thermodynamic systems at equilibrium and describe energy, entropy, and temperature. Here’s an overview of each.

The Zeroth Law

Two systems at thermal equilibrium alongside a third are all at equilibrium with each other.

The First Law

The total increase in the internal energy of an isolated system is equivalent to the heat it supplies after subtracting the work done by it.

The Second Law

The entropy of a closed system can never decrease. The sum of the entropies of all interacting systems can only increase.

The Third Law

As the temperature of a closed system gets closer to absolute zero, the associated entropy approaches a constant value K.

The thermodynamic efficiency of the turbines in nuclear power plants is subject to the limitations imposed by the second law of thermodynamics. This puts the overall efficiency of a plant at approximately 33 percent (one-third) of the thermal power produced. Therefore, the fission reaction required to produce 1,000 MWe of electricity is 3,300 MW worth of thermal power.

The most well-known application of nuclear thermodynamics is in the production of electricity, which can be used to power homes, businesses, schools, and hospitals. It also has a wide range of applications in multiple sectors, including:

• Consumer products
• Food and agriculture
• Scientific research
• The environment
• Water resources