Nuclear Flashcards
How many operation nuclear power plants are currently operating
419
What is nuclear energy
a form of energy released from the nucleus, the core of atom uranium 235
what are the two ways to produce nuclear energy
fission when nuclei of atoms split into several parts and fusion when nuclei fuse together
what is Einstein’s equation for energy
E = m c^2
Generations of nuclear energy: they are all water-cooled reactor designs, with each generation featured advanced _________________________ and ___________________
passive safety system and emergency cooling
what are the first 3 generations of nuclear energy
Generation 1: early prototypes
Generation2: commercial power
- PRW
- BWR
- CANDU
Generation 3: advanced LWRs
- CANDU 6
- System 80+
- AP600
Describe the process of nuclear fission
- A slow neutron hits uranium-235 atom, get absorbed
- The U-235 splits and makes krypton, barium, two neutrons, huge energy, gamma ray
- chain reaction starts, increase rate of 2^n
- Trillions of uranium atoms fission each second
in a nuclear reactor, generating large amounts
of heat inside the reactor vessel, which is used
to warm up water.
what are the three elements/isotopes used for commercial power plants
uranium-235, uranium-233, Plutonium-239
what are the two ways that uranium can split
U + n = Ba + Kr + 3n
U + n = Te + Zr + 2n
What are the protons and electrons in Uranium
235 protons, 92 electrons
what are the protons and electrons in Barium
142 protons and 56 electrons
What are the protons and electrons in Krypton
91 protons and 36 electrons
what are the protons and electrons in tellurium
137 protons and 52 electrons
what are the protons and electrons in Zirconium
97 protons and 40 electrons
only large nuclei with atomic numbers above _____ can undergo fission
90
Products of fission reaction usually include _____ or _______
individual neutrons, the total mass of the product is
somewhat ______ than the mass of Uranium-235.
two or three
less
the uranium 235 captures a _____ speed neutron and splits releasing thermal energy and ____ speed neutrons
slow
high
PWR: fuel? moderator? Coolant? steam generation?
Uranium dioxide (3.2%)
ordinary water
pressurized water (160 bars)
separate circuit
BWR: fuel? moderator? Coolant? steam generation?
Uranium dioxide (2.6-3.5%)
ordinary water
pressurized ordinary water which boils and produces steam directly
CANDU (Canada Deuterium Uranium): fuel? moderator? Coolant? steam generation?
un-enriched uranium dioxide (0.7%)
heavy water
heavy water pumped at pressure (90 bars)
separate circuit
What does the moderator do
slows neutrons to ensure they strike U-235 continuing the chain reaction
what do control rods do
keep the reaction in check, reactor operators raise or lower them depending on need
light water reactors (LWR) are power reactors that are cooled and moderated with _______ ______. this includes ____ _____
ordinary water
PWR, BWR
what is the neutron multiplication factor, K
the number of fission neutrons produced in a given time interval divided by the number produced in an equal time interval but slightly earlier time
If K > 1
the reactor power will increase. this may lead to a runaway condition. The reactor is supercritical
If k < 1
the reactor power will decrease. This may lead to a shutdown. The reactor is subcritical
If k = 1
the power will be steady. The reactor is critical
If the reactor is operating at the critical condition. how can we adjust the power output?
inserting or withdrawing neutron absorbing cadmium rods into the reactor core
If i insert cadmium rods into the core, what happens to the K value
the K value will decrease because the neutrons are being absorbed
The only useful output of a fission reactor is ______, which has to be removed by a _____ and transferred to a _______
heat
coolant
turbine
PWR: water at high pressure (keep from _______) and temperature removes ________ from the core and is transported to a steam ________
boiling
heat
generator
PWR: ________to _______ fuel rods of ______ m
diameter and approximately
4 m in length. The rods are arranged
into assemblies (bundles) to make
the core of the reactor.
40,000 to 50,000
0.01 m
are the control rods at the top or bottom of PWR and BWR
Top of PWR
Bottom of BWR
A BWR operates on the principle of a _______________. Water passing through the core is allowed to _____ at an intermediate __________ level
direct power cycle
boil
pressure
Why do we use heavy water as the coolant and moderator of the CANDU
D2O does not absorb neutrons as much as ordinary water does. This enables the use of natural/unenriched uranium
natural uranium consists of a mix of mostly uranium ____ with small amount of uranium ____ (____%)
238
235
0.7
D2O is used as a _______ and _______ for the CANDU
coolant and moderator
what are the main components of the sodium cooled liquid metal moderator
control rods (prevents critical)
fuel rods(uranium 235 and plutonium 239)
Containment shell: absorb radiation coming out
uses sodium to boil water and drive turbine
Pump: maintain constant water flow
What nuclear reactors use the single loop cycle
BWR, high temp gas cooled reactor HTGR if helium was used instead of steam
what nuclear reactors use two-loop cycle
PWR, CANDU pressurized heavy water reactor (PHWR) or helium HTGR
What types of nuclear reactors use three loop cycle
sodium cooled reactors - where an intermediate loop of
nonradioactive sodium is provided between the
radioactive primary loop and the steam generator
What is this: A class of small nuclear fission reactor, designed to be built in a factory, shipped to operational sites
for installation and then used to power buildings or other commercial operations.
SMR - small modular reactor
what is the electrical power output of SMR
5MWe to 300MWe
what type of system do SMR use
PWR - pressurized water reactor
what are the characteristics of the SMR
Small: both in power output and physical size
modular: factory constructed, portable and scalable
Wide applications: on-grid, off-grid or combination
Microreactors can produce _______ of energy, have a lifespan of
________, and could power up to______ homes in remote areas.
20 MW
8 years
5,000
Describe fusion
Two light nuclei merge to form a single heavier nucleus. The total mass of the resulting single nucleus is less than the mass of the two original nuclei. The leftover mass becomes energy, based on E = mc^2
what 2 elements do we currently use for fusion
deuterium and tritium
What does DT fusion produce
a neutron and a helium nucleus and energy
Define isotopes
Forms of the same element that differ in atomic mass. They have equal number of protons but differ in the number of neutrons in their nucleus
what is the equation for DT fusion
T + D = He + n
describe the Tokamak
it uses a magnetic cage in the shape of a torus created by magnetic coils. By ionizing the small amount of hydrogen, a plasma is formed that can reach temperatures of over 100 million degrees
Describe the nuclear waste storage process
spent fuel removed from reactor
spent fuel is placed in a spent fuel pool
spent fuel is placed in canisters
canisters put into casks for dry storage
transported off-site
stored at consolidated interim storage facility
transported to geological repository
what layer of the earth is nuclear waste deposited
limestone
advantages of nuclear energy
clean energy source
affordable and sustainable
energy security - safe and reliable
Jobs and economy
Disadvantages of nuclear energy
Expensive to build the power plant
High environmental cost
non-renewable uranium source
nuclear waste disposal/storage
intensive water consumption
catastrophe risk
nuclear has the highest energy density in terms of _________
mass
what is the operational lifetime of a nuclear plant
up to 60 years
nuclear produces more carbon-free _______ than ________ clean energy sources
electricity
all other
Nuclear has minimum CO2 emissions, _____ times less than solar energy
4
