Parts of a nuclear reactor

1. PARTS OF A NUCLEAR REACTOR










1. FUEL
 needed in all energy-producing processes
 heart of the reactor
 the fuel consists of pellets of enriched uranium dioxide (mostly in US power plants)

2. FUEL RODS
 A 12-foot-long metal tubes
 Container of the fuel pellets
 Put together, or “bundled,” to form the fuel assembly

FUEL CYCLE
 The process of preparing the fuel, burning the fuel, and disposing of the fuel is called
the “fuel cycle.” A closed fuel cycle recycles the fuel from the last stage for reuse in
the reactor. An open fuel cycle does not recycle the fuel.

3. CONTROL RODS
 lowered or raised next to the fuel assembly to speed up or slow down the rate of the
chain reaction by absorbing some of the neutrons released in fission
 use the element boron to absorb neutrons

2.  To speed up the chain reaction, the rods are pulled up away from the fuel assembly.
To slow the reaction down, the rods are lowered next to the fuel assembly.


4. Cooling System
 Removes the heat from the reactor and keeps the core at a proper
temperature
 Powered by coolants like ordinary water, heavy water and molten sodium
Characteristics of Coolants
 non-absorbent for neutrons
 excellent resistance to high temperatures and high levels of radiation
 non-corrosive
 high boiling point for liquids
 low melting point for solids
 be easily circulated by a pump.
 In large reactors, as much as 330,000 gallons of water coolant flow through
the reactor core every minute. The water that leaves the reactor is sent to

3. either cooling towers or discharged into large bodies of water such as cooling
ponds, lakes, rivers, or an ocean.
5. Moderator
 Slowed down the fast neutrons which are released from a nuclear fission
 Fast moving neutrons strike the moderator material, which is not efficient at
absorbing them, and slows them down.
 Moderators are made of various materials. Water is an excellent moderator
because the water can also serve as a coolant. Normal water, known as “light
water,” is used in most reactors simply because it is cheap and abundant. The
only downside to using light water is that reactor fuel must be enriched when
water is the moderator.
 Another moderator material is deuterium, also known as “heavy water”
because it has an extra hydrogen atom. Deuterium is costly to manufacture,
but it does not require fuel to be enriched. Other moderator materials are
graphite and beryllium, which are used in different types of reactors.
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