Energy 6 Flashcards
State the carbon intensity of nuclear power (i.e. GHG emission per unit of energy).
16 gC02eq/kwh(electric)
includes full life cycle (mining, fuel processing, decommissioning)
State the carbon intensity of coal fired power plant (i.e. GHG emission per unit of energy).
1001 gCO2eq/kwh(electric)
State the carbon intensity of wind power (i.e. GHG emission per unit of energy).
Can vary based on factors such as the manufacturing process, transportation, and installation.
3 - 20 g CO2eq/kWh electricity
State the carbon intensity of gas fired power plant (i.e. GHG emission per unit of energy).
469 gCO2eq/kwh(electric)
In the context of a nuclear power plant, what is the purpose of the moderator?
Moderator slows down fast neutrons, making them more likely to cause additional fission reactions and sustain the nuclear chain reaction.
Moderators are low atomic number atoms.
Water (hydrogen & oxygen) and graphite (carbon) are typically used.
In the context of a nuclear power plant, what is meant by the term “fission poison”?
“Fission poison” refers to a substance that absorbs neutrons, helping control the rate of fission reactions and regulate the reactor’s power output.
Common examples include xenon and samarium.
Why is enriched uranium used as a fuel, rather than natural uranium, in most nuclear power
plant?
Because it contains a higher concentration of uranium-235, which is more readily fissionable, allowing for sustained nuclear chain reactions.
Natural uranium has a lower percentage of uranium-235 and needs enrichment to increase its fissile content for efficient energy production.
What is Low Enriched Uranium (LEU)?
Less than 20% 235U is LEU (low enriched uranium).
It is used as a fuel, rather than natural uranium, in most nuclear power plants.
In the context of radiation exposure, what is the Sievert a unit of?
The Sievert (Sv) is a unit of radiation dose that measures the biological impact of ionizing radiation on living tissue.
What is a lethal dose of radiation in Sieverts?
Lethal dose is ~ 4Sv (Sievert).
But depends on factors such as:
Type of radiation
Duration of exposure
Sensitivity of the tissues exposed
What dose of radiation (i.e. background radiation) do we typically receive from sources other
Natural “Background” dose
is ~2.4mSv per person per
year
Other sources:
– Rainwater: 0.3-1
Bq/liter
– Mineral water: 6 Bq/liter
– Seawater: 13 Bq/liter
– Milk: 80 Bq/liter
– Granite: >1000Bq/kg
Medical irradiation (X-rays, radiotherapy) ~1mSv/year
Mining and atmospheric nuclear weapons tests: ~0.1mSv/year
In the context of a nuclear power plant, what is meant by “hot shutdown”?
“Hot shutdown” refers to a controlled shutdown of the reactor while it is still at an elevated temperature, usually for allowing for maintenance or refueling
3 Reactors of Fukushima Daiichi SCRAMed immediately after the
earthquake – “hot shutdown” achieved rapidly.
In the context of a nuclear power plant, what is meant by “walk away safe”?
Walk away safe” means the plant is designed to be inherently safe, requiring no active human intervention or external power sources for safety in the event of a complete loss of control or power.
Currently no reactors are “walk away” safe – Gen III+ and IV maybe.
as Gen 3 and 4 aim to advance inherent safety features.
What is the typical electrical generating capacity of modern pressurized water reactor power
plant (e.g. the EPR)?
Typically ranges from 1,000 to 1,700 megawatts electric (MWe).
Is designed to have a nominal electrical output in the range of approximately 1,600 to 1,700 MWe
The exact capacity can vary depending on the specific design and configuration of the reactor.
If a rooftop PV installation in Dublin is to provide 400W on average, estimate the area of
solar cells required (assuming optimal orientation).
Apv = 400W / 0.16 x 100W/M^2 = 25m^2 per person
A wind turbine is designed to operate in a wind of 12m/s. The diameter of the turbine
blades is 100m, and the turbine is rated at 4MW. What is the Power Coefficient (i.e. the efficiency)?
cp = Wshaft / 1/2 pAV^3
= 4x10^6 / (0.5)(1.22)(pi x (50)^2)(12)^3
=0.483 or 48.3%
A pumped hydro storage plant has an upper reservoir 250m above the lower reservoir. The upper reservoir has a depth of 15m and a surface area of 100,000m2. Calculate the maximum energy storage capacity of this facility?
E = mgh = (volume)pgh = 3.679TJ or 1.02GW
Calculate the theoretical maximum power that a wind turbine with 3000m2 blade disk can generate if the wind speed is 12m/s?
Pmax = 1/2 pAV^3 (Bertz limit)
=1.866MW
A wind turbine is rated as 2MW. Over a 1 year period it generates 4.6GWh of electricity.
What is the capacity factor?
CF = Actual Energy output / Rated capacity x 8750hrs
= 0.263 or 26.3%
A new power plant will provide 100MW of electrical power. How many homes would that service?
(assume the CRU estimate of household electricity consumption).
Number of Homes = Power plant capacity / Avg. Household consumption
= 208571 homes
A new wind farm has a maximum output of 100MW of electrical power. But has a
capacity factor for 22%. How many homes would that service? (assume the CRU estimate of
household electricity consumption).
Number of Homes = Wind farm capacity x 0.22 x 8760 / Avg. Household consumption
= 41714 homes
What is KE?
KE = 1/2 (mv^2)
What is PE?
PE = mgh
