Visualizing Environmental Science

Nuclear Energy 433

PROCESS DIAGRAM

Fission of uranium-235

occurs in the reactor

vessel, producing heat

used to produce steam

in the steam generator.

Steam leaving the

turbine is pumped

through a condenser

before returning to

the steam generator.

The steam drives a

turbine to generate

electricity.

After it is cooled,

the water is

pumped back to

the condenser.

Pumping hot

water from the

condenser to a

lake or cooling

tower controls

excess heat.

Steam turbine

Condenser

Steam

generator

Heat exchanger

Containment building

Control rod

Uranium fuel assembly

Reactor vessel

Reactor core

Liquid water under

high pressure

2

1

3

5

4

Cooling tower

Electric

generator

Electricity

Approximately two-thirds of all
nuclear power plants in the
United States are of this type.

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#OMPARISONOFENVIRONMENTALIMPACTSOF

MEGAWATTCOALANDCONVENTIONALNUCLEARPOWERPLANTS

 s4ABLE

Impact Coal Nuclear (conventional fission)

Land use 7000 hectares 800 hectares

Daily fuel requirement 9000 tons (of coal)/day 3 kg (of enriched uranium)/day

Availability of fuel, based on present economics Around 100 years 100 years, maybe longer

Air pollution Moderate to severe, depending Low

on pollution controls

Climate change risk (from CO 2 emissions) Severe Small**

Radioactive emissions, routine 1 curie 28,000 curies

Water pollution Often severe Potentially severe at nuclear waste disposal sites

Risk from catastrophic accidents Short-term local risk Long-term risk over large areas

Link to nuclear weapons No Yes

Annual occupational deaths 0. 5 to 5 0.1 to 1

*Impacts include extraction, processing, transportation, and conversion. Assumes that coal is strip-mined. (A 1000-MWe utility, at a 60 percent load factor,

produces enough electricity for a city of 1 million people.)

**Currently, nuclear power requires the use of fossil fuels for mining, construction, processing, transportation, and waste management, and so it cannot be

considered carbon free.