1. Nuclear Power Plant How A Nuclear Reactor Works

2. Pressurized Water Reactor - Nuclear Power Plant

3. 1. Main Parts of a Nuclear Reactor 1.Fuel Pellets stacked in long metal tubes (fuel rods). These are arranged in bundles in the reactor with space between them for control rods. 2.Moderator Slows down neutrons so they have a greater probability of colliding with another uranium atom. Usually water or graphite.

4. 1. Main Parts of a Nuclear Reactor 3.Control System Control rods are filled with substances that absorb neutrons (boron or cadmium). These help control the rate of the reaction. 4.Heat Removal System The reactor must be cooled to prevent overheating and melting of the core. Heat is carried away by water and used for steam production. 5.Radiation Shield Thermal (steel) shield protects the walls of the reactor vessel from radiation damage. A concrete shield protects the workers from radiation.

5. 2. Disposal Of Nuclear Waste When most usable uranium has fissioned, the “spent” fuel assembly is removed from the reactor. Until a long term storage facility is operational (Yucca Mountain, NV?), “spent” fuel is stored in water pools at the reactor site. Water removes leftover heat and serves as a radiation shield.

6. 3. Nuclear Meltdown Refers to melting fuel in a reactor when there is an inability to remove heat effectively. Causes include a loss of coolant in the system and/or failure of the reactor to shut down when faulty. If a meltdown does occur, a release of radiation occurs only if there is a major failure in the containment structure (pressure, fire, explosion).

7. 4. Advantages and Disadvantages of Nuclear Fuel