Environmental Engineering Reference
In-Depth Information
cool the reactor. A separate secondary circuit transports steam to turn the turbine generator. The core
holds 12 fuel assemblies, each containing 37 (2-foot) fuel rods for a total of 444 fuel rods.
Generation III reactors incorporate the most current technologies but very few have gone online. These
reactors are similar to generation II reactor designs but incorporate improved fuel technology, thermal
efficiency, passive supply systems, and a standardized design. The standard design is meant to reduce
construction and maintenance costs. The designers expect an operational life of 60 years.
Generation IV reactors are mostly theoretical in nature at this time and are not expected to be feasible
before the year 2030. Among the many types of experimental nuclear reactors are fast-breeder reactors.
Fast-breeder reactors allow fission to propagate, meaning that as one radioactive atom decays, it is al-
lowed to create other radioactive atoms. Left unchecked, these newly created atoms would themselves
decay, creating heat and more radioactive atoms (and eventually a large explosion). The trick of fast-
breeder reactors is to allow the production of additional radioactive atoms, but to disallow their decay.
Thus, fast-breeder reactors create more fissionable material than they consume. Again, this is but one of
many types of experimental nuclear reactors.
Advantages and Disadvantages of Nuclear Power
Advantages
Disadvantages
The waste from nuclear energy is radioactive and decomposes very slowly (over
thousands and millions of years).
Low emissions.
Usable technology is
readily available.
Potential catastrophic consequences could befall nature and humans if a failure or
serious accident should occur, including death.
It is possible to generate
large amounts of energy
from one plant.
There is an increased target risk for terrorism.
Plants are licensed for 40 years and then can renew their licenses or shut down
(decommission). It takes 20 years to build a nuclear power plant. Decommission-
ing of older plants is very expensive.
Uranium is a scare resource and its supply is projected to last between 100 to 200
years.
Special facilities are required for radioactive waste disposal.
Safety Issues
Safety is a major issue with nuclear power. Safety is evaluated in terms of both equipment and operator. For
equipment there are three major areas of concern:
• Control of the radioactivity using control rods
• Maintenance of the core cooling system
• Maintenance of the barriers that prevent the release of radiation
The control rods can be adjusted to control the availability of released neutrons that drive the energy reaction
used to create heat and, thus, electricity. The cooling system removes heat from the power plant, ensuring that
it does not build to the point at which it can cause an explosion. Radiation barriers are constructed to hold ra-
dioactive material if it is released in an accident.
There are several precautions taken to prevent exposure to radioactive materials at a nuclear power plant:
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