nuclear energy

how much of total global primary energy does nuclear energy account for

4%

how much of global electricity general does nuclear energy account for

10%

France post 1973 oil crisis

France opted for nuclear power generation to ensure security of supply. >60% of French electricity is generated from its 56 nuclear reactors

the earth’s uranium

Probably developed during the explosion of a supernova before the formation of the solar system. The uranium atoms became part of the nebula from which Earth formed.

They gradually rose into the upper crust in granitic magma. Uranium is a relatively common metal, found in rocks and sea water.

when did uranium resources increase

in the 2000s by at least ¼ due to increase mineral exploration

where are the large reserves of uranium

Australia (28%), Canada (10%)

nuclear fission

a neutron strikes a radioactive atom, causing it to split. A fraction of the original atom is transformed into a lot of thermal and electromagnetic energy, the neutrons released during the fission of one atom strike other atoms thereby triggering more fission on a self-perpetuating chain reaction

how many nuclear reactors are currently in operation

437 over 30 countries

life time of today’s operating nuclear plants

30 or 40 years

which components need to be replaced

steam generators

obsolescence

older reactors have analogue instrument and control systems. Continuous investment is needed to maintain reliability and safety.

nuclear energy - advantages

• Virtually no greenhouse gas emissions

• Independent of oil/gas price fluctuations

• No significant risk to U supply or reserves

• Reliable and competitive

• Small-scale reactors now available

nuclear energy - disadvantages

• Poor public acceptance in some countries

• Waste disposal

• Accidents/terrorism threat

• Risks of proliferation

Chernobyl

• 100 times radiation released than the 2 atom bombs in Japan

• 30 direct human deaths

• Soil and water still contaminated

• Caused by a flawed reactor design that was operated with inadequately trained personnel

• Worst nuclear power plant accident in history in terms of cost and direct casualties (Level 7 (max), as the Fukushima Daiichi nuclear disaster in 2011)

Fukushima

causing a nuclear accident beginning on 11 March 2011. All three cores largely melted in the first three days. The power plant had not been designed to withstand this strength of earthquake.

nuclear waste

On average, the waste from a reactor supplying a person’s electricity needs for a year would be about the size of a brick. Only 5 grams of this is high-level waste – about the same weight as a sheet of paper.

1000-megawatt nuclear power station waste

three cubic metres of vitrified high-level waste per year

possible options for storage of nuclear waste - LLW

low level waste stored at site for c. 100 years. Most LLW has a half-life of < 30 years

ILW

intermediate level waste contains significant amounts of long-lived radionuclides. ILW requires shielding – not heat generating. ILW often incorporated into a matrix such as cement or bitumen

HLW

high level waste very contains significant amounts of long-lived radionuclides and is heat generating. HLW is usually converted to a liquid form and then vitrified (converted to a glass or ceramic material) for deep geological storage in tectonically stable areas. Stored in air cooled vaults

recycling of plutonium and uranium

this separated plutonium and uranium can subsequently be mixed with fresh uranium and made into new fuel rods

countries using plutonium recycling to generate electricity

France, Japan, Germany, Belgium and Russia

nuclear fusion

the process that heats the Sun and all other stars, where atomic nuclei collide and release energy (in the form of neutrons)

nuclear fusion process

Hydrogen gas is heated to very high temperatures (100 million °C) using ‘magnetic

confinement' – controlling the hot gas (plasma) with strong magnets (a ‘tokamak', a

Russian word for a ring-shaped magnetic chamber)

advantages of fusion power - very low carbon emissions

the only by-products of fusion reactions are small amounts of helium

advantages of fusion power - no long-lived radioactive waste

only plant components become radioactive and these will be safe to recycle or dispose of conventionally within 100 years

advantages of fusion power - abundant fuels

deuterium can be extracted from water and tritium is produced from lithium. Fuel supplies will therefore last for millions of years

advantages of fusion power - energy efficiency

one kilogram of fusion fuel can provide the same amount of energy as 10 million kilograms of fossil fuel

advantages of fusion power - safety

the small amounts of fuel used in fusion devices means that a large-scale nuclear accident is not possible

issues of public concerns

• Safe waste disposal

• Risk of severe accidents

• Health risks for those living in the vicinity of power plants

• Potential acts of terrorism

Nuclear energy may become an attractive option in Ireland due to

• The need for security of energy supply

• The requirement to meet our GHG emission targets

• The necessity to supplement/balance power generation from renewable sources