JNTU B.Tech II POWER SYSTEMS I Previous Question Paper (March - 2022 - R15)

A modern Nuclear Power Station operates on the principle of controlled nuclear fission. The schematic components include the Nuclear Reactor, Heat Exchanger (Steam Generator), Steam Turbine, Condenser, and Generator.

The operation follows these steps:

1. The Nuclear Reactor contains fuel rods (typically Uranium-235) where fission occurs, releasing immense heat. Control rods are used to regulate the rate of the chain reaction.
2. A coolant (water or gas) circulates through the reactor core, absorbing the heat generated by the fission process.
3. This high-temperature coolant is passed through a Heat Exchanger, where it transfers heat to a secondary water circuit, converting the water into high-pressure steam.
4. The steam is directed to the Steam Turbine, where its thermal energy is converted into mechanical energy, causing the turbine to rotate.
5. The turbine drives an electrical Generator to produce electricity.
6. Exhaust steam from the turbine is cooled in a Condenser, turning it back into water, which is then pumped back to the heat exchanger to complete the cycle.

The advantages and disadvantages of a Nuclear Power Station are as follows:

Advantages:

• High energy density: A small amount of nuclear fuel produces a massive amount of energy compared to fossil fuels.
• Low fuel costs: Despite high initial setup costs, the cost of nuclear fuel is relatively low and stable.
• Environmentally cleaner: Nuclear power plants do not emit greenhouse gases like CO2 or SO2 during operation, contributing to reduced air pollution.
• Reliability: They provide a consistent base-load power supply, independent of weather conditions.

Disadvantages:

• Radioactive waste: The disposal and long-term storage of high-level radioactive waste pose significant environmental and safety risks.
• High capital cost: The initial investment for construction, safety systems, and containment structures is extremely high.
• Safety concerns: Potential for catastrophic accidents, though rare, can have widespread and long-lasting impacts.
• Decommissioning: The process of shutting down and cleaning up a nuclear plant at the end of its life is complex, expensive, and time-consuming.