botkin and keller environmental science 5e chapter 19 nuclear energy and the environment

Botkin and KellerEnvironmental Science 5e

Chapter 19

Nuclear Energy and the Environment


Nuclear Energy

• Nuclear Energy– The energy of the atomic nucleus

• Nuclear Fission– The splitting of the atomic nuclei

• Nuclear Fusion– The fusing of atomic nuclei

• Nuclear Reactors– Devises that produce controlled nuclear fission


Fission Reactors• As fission occurs, energy is released. • Major components of a fission reactor:

• Core, control rods, coolant, reactor vessel

• Burner Reactors: a type of nuclear reactor that consumes more fissionable material than it produces

• Meltdown: a nuclear accident in which the nuclear fuel forms a molten mass that breaches the containment of the reactor, contaminating the outside environment with radioactivity.


Sustainability and Nuclear Power

• Nuclear Radiation occurs when when a radioisotope spontaneously undergoes radioactive decay and changes into another isotope

• 3 types of nuclear radiation: Alpha, Beta, Gamma• Breeder Reactor:

– a type of nuclear reactor that utilizes between 40-70% of its nuclear fuel and converts fertile nuclei to fissile nuclei faster than the rate of fission

– Produces nuclear fuels


Nuclear Energy and the Environment

• Nuclear Fuel Cycle: – the process involved in producing nuclear

power from the mining and processing of uranium to controlled fission, the reprocessing of spent nuclear fuel, the decommissioning of power plants and the disposal of radioactive waste

– Each part of the cycle is associated with different potential environmental problems


Effects of Radioisotopes

• Radioisotope: an isotope of a chemical element that spontaneously undergoes radioactive decay

• Effect Environment in 2 Ways– Emitting radiation– Entering ecological food chains


Radiation Dose

• Curie (Ci) unit of radioactivity – (equal to 37 billion nuclear transformations per second)

• Becquerel (Bq) radioactive decay – (1 decay per second)

• rads (rd) dose of radiation delivered by radioactivity• grays (Gy) same, but in SI units

• Rems (rems) equivalent dose, normalized by radiation and tissue type

• sieverts (Sv) same, but in SI units


Radiation and Health

• LD-50 is about 5000 mSv (5 Sv)

• 1000 – 2000 mSv: vomiting, fatigue, abortion of fetuses less than 2 months, temporary sterility

• 50 mSv: maximum dose per year in industry– (30 times average natural background)

• 1-5 mSv: maximum dose per year for public


Nuclear Power Plant Accidents

• Three Mile Island (Harrisburg, PA)– Valve malfunction and human error– Partial core meltdown,

• Chernobyl– Radiation in Sweden detected in power plant 4/28/86– Cooling system failed (human error)– Top of building over reactor exploded. – 30 km zone dose received 0.43 Sv– Expected cases of leukemia, large numbers of thyroid

cancer seen


Radioactive Waste Management• Low-Level Radioactive Waste

– Waste materials that contain sufficiently low concentrations or quantities of radioactivity so as not to present a significant environment hazard if properly handled

• Transuranic Waste– Radioactive waste consisting of human-made radioactive

elements heavier than uranium– Contaminated clothing rags, tools, etc.

• High-Level Radioactive Waste– Extremely toxic nuclear waste, such as spent fuel

elements from commercial reactors. – How do we dispose of this waste material?

botkin and keller environmental science 5e chapter 19 nuclear energy and the environment

Documents

type of nuclear reactor

nuclear transformations

nuclear accident

nuclear powernuclear

gammabreeder reactor

maximum dose

radioactive elements

reactor vesselburner