L8 - Nuclear power 1 Flashcards
Which are the reactants and product in fission reactions?
A uranium-235 atom absorbs a neutron and fissions into two new atoms (fission fragments), releasing three new neutrons and some binding energy. 2. One of those neutrons is absorbed by an atom of uranium-238 and does not continue the reaction.
How is neutron speed affecting fission?
Fission probability decreases as neutron energy (and speed) increases.
Which moderators exist? Pros and cons?
Graphite
Heavy water
Water
Supercritical water
What is BWR?
A boiling water reactor (BWR) is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor (PWR), which is also a type of light water nuclear reactor.
How does half life affect the dangers of nuclear waste?
Half-life = time at which the amount of a radioactive species has decayed by its half
Radioactive waste is hazardous because it emits radioactive particles, which if not properly managed can be a risk to human health and the environment.
What is reprocessing of nuclear waste?
Reprocessing is a series of chemical operations that separates plutonium and uranium from other nuclear waste contained in the used (or “spent”) fuel from nuclear power reactors. The separated plutonium can be used to fuel reactors, but also to make nuclear weapons.
What is nuclear fuel?
Nuclear fuel is material used in nuclear power stations to produce heat to power turbines. Heat is created when nuclear fuel undergoes nuclear fission.
How and where is uranium mined, what are the potential reserves?
Over two-thirds of the world’s production of uranium from mines is from Kazakhstan, Canada and Australia. An increasing amount of uranium, now over 50%, is produced by in situ leaching.
How is uranium enriched?
Uranium can be enriched by separating isotopes of uranium with lasers.
Lasers can increase the energy in the electrons of a specific isotope, changing its properties and allowing it to be separated.
What is produced in a nuclear reactor?
They contain and control nuclear chain reactions that produce heat through a physical process called fission. That heat is used to make steam that spins a turbine to create electricity.
Which are the advantages of nuclear power?
The advantages of nuclear energy are that it produces low-cost energy.
It is reliable and releases zero carbon emissions.
There is a promising future for nuclear technology, and it has a high energy density.
Which are the challenges?
These challenges include: the notion nuclear is an out-dated technology; the cost of finance; market design; political changes; perceived competition with renewable energy; and the public’s misconceptions about radioactive waste
Which are the advantages and challenges with breeder reactors?
Three of the important lessons are that fast breeder reactors are costly to build and operate; they have special safety problems; and they have severe reliability problems, including persistent sodium leaks.
The fast breeder technology has the potential to make the production of energy from uranium 100 times more efficient than with the existing thermal reactor, reducing the amount and toxicity of radioactive waste, as well as the heat emanating from the waste, and also shortening the waste’s hazardous lifetime span
What is fusion? Advantages and disadvantages?
It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy.
The potential advantages of nuclear fusion energy are manifold, as it represents a long-term, sustainable, economic and safe energy source for electricity generation
But fusion reactors have other serious problems that also afflict today’s fission reactors, including neutron radiation damage and radioactive waste, potential tritium release, the burden on coolant resources, outsize operating costs, and increased risks of nuclear weapons proliferation
