Nuclear PowerNuclear Power

How does it work?How does it work?

Uranium-235 is Uranium-235 is often use to fuel often use to fuel nuclear power nuclear power plants. It has an plants. It has an interesting interesting property that property that makes it useful makes it useful for this because for this because it can undergo it can undergo induced fission.induced fission.

Nuclear FissionNuclear Fission

Chain ReactionChain Reaction

When the neutrons ejected from When the neutrons ejected from each fission hit another nearby each fission hit another nearby nucleus, that one splits and nucleus, that one splits and releases more neutrons, etc. This releases more neutrons, etc. This sets up a chain reaction that sets up a chain reaction that keeps going and going keeps going and going until……………..until……………..

Control Rods are put into actionControl Rods are put into action

These are made These are made of a material that of a material that absorbs neutrons absorbs neutrons and are lowered and are lowered when the when the reaction needs to reaction needs to be slowed down be slowed down or stopped.or stopped.

How is the electricity created?How is the electricity created?

The uranium bundle generates the heat which The uranium bundle generates the heat which turns the water into steam. This drives the turns the water into steam. This drives the turbine, which spins a generator to produce turbine, which spins a generator to produce power.power.

Outside the Power PlantOutside the Power Plant

Once you get past the reactor itself, there Once you get past the reactor itself, there is little difference between a nuclear power is little difference between a nuclear power plant and a coal or oil powered one.plant and a coal or oil powered one.

The containment vesselThe containment vessel

Nuclear reactors Nuclear reactors are typically are typically housed inside a housed inside a concrete liner that concrete liner that acts as a radiation acts as a radiation shield. That liner is shield. That liner is housed inside a housed inside a much larger steel much larger steel containment containment vessel.vessel.

Advantages of Nuclear PowerAdvantages of Nuclear Power

Minimal air pollutionMinimal air pollutionWater pollution is low (some thermal Water pollution is low (some thermal

pollution exists)pollution exists)Disruption of land is low to moderateDisruption of land is low to moderate

(except the mining of uranium)(except the mining of uranium)

• One pound of U-235 can produce as much One pound of U-235 can produce as much heat energy as 1,500 tons of coal!heat energy as 1,500 tons of coal!

Disadvantages of Nuclear PowerDisadvantages of Nuclear Power

Highly toxic nuclear waste produced Highly toxic nuclear waste produced (some take thousands to millions of years (some take thousands to millions of years to decay)to decay)

Lifespan of facilities only 15-40 yearsLifespan of facilities only 15-40 yearsLow net energy yield – lots of energy Low net energy yield – lots of energy

required for mining uranium, processing required for mining uranium, processing ore or dismantling the plantore or dismantling the plant

Safety and malfunction issuesSafety and malfunction issues

So where does the plutonium So where does the plutonium come from anyway?come from anyway?

Power plants create it Power plants create it when the uranium in when the uranium in their fuel fissions. their fuel fissions. Some of it ends up in Some of it ends up in the spent fuel as the spent fuel as waste.waste.

Different isotopes of Different isotopes of plutonium have plutonium have different half-lives and different half-lives and different usesdifferent uses

What is a breeder reactor?What is a breeder reactor? The Breeder Reactor was developed to use uranium-The Breeder Reactor was developed to use uranium-

238. Here's how it works. A reactor is built with a core 238. Here's how it works. A reactor is built with a core of fissionable plutonium, Pu-239. The plutonium-239 of fissionable plutonium, Pu-239. The plutonium-239 core is surrounded by a layer of uranium-238. As the core is surrounded by a layer of uranium-238. As the plutonium-239 undergoes spontaneous fission, it plutonium-239 undergoes spontaneous fission, it releases neutrons. These neutrons convert uranium-releases neutrons. These neutrons convert uranium-238 to plutonium-239. In other words, this reactor 238 to plutonium-239. In other words, this reactor breeds fuel (Pu-239) as it operates. After all the breeds fuel (Pu-239) as it operates. After all the uranium-238 has been changed to plutonium-239, the uranium-238 has been changed to plutonium-239, the reactor is refueled.reactor is refueled.

Plutonium production reactors operated by the U.S. Plutonium production reactors operated by the U.S. government during the Cold War have all shut down.government during the Cold War have all shut down.

Nuclear Power Plants in the Nuclear Power Plants in the United StatesUnited States

Who relies most on nuclear Who relies most on nuclear energy?energy?

Nuclear CatastrophesNuclear Catastrophes

The INES scaleThe INES scale

The International and The International and Radiological Event Scale is a Radiological Event Scale is a worldwide tool for communicating worldwide tool for communicating to the public in a consistent way to the public in a consistent way the safety significance of nuclear the safety significance of nuclear and radiological events.and radiological events.

Three Mile Island Three Mile Island March 1979 March 1979 PennsylvaniaPennsylvania

INES Level 5

What happened?What happened?

A cooling malfunction caused a partial A cooling malfunction caused a partial meltdown. Some radioactive water was meltdown. Some radioactive water was released as well as radioactive gas. Many released as well as radioactive gas. Many people were evacuated. The reactor did people were evacuated. The reactor did not explode as feared. No one was killed.not explode as feared. No one was killed.

A 25 year follow-up study in 2004 of A 25 year follow-up study in 2004 of 35,000 residents within a 5 mile radius of 35,000 residents within a 5 mile radius of TMI showed no significant increase in TMI showed no significant increase in deaths from cancer.deaths from cancer.

The China SyndromeThe China Syndrome This movie, This movie,

released in March released in March of 1979 depicted a of 1979 depicted a very similar fictional very similar fictional incident to that incident to that which occurred on which occurred on Three Mile Island Three Mile Island about a week after about a week after it was released in it was released in theaters!!theaters!!

ChernobylChernobylApril 1986April 1986UkraineUkraine

INES Level 7

What happened?What happened?They were running a safety check. They were running a safety check. Regulations called for a minimum of Regulations called for a minimum of 30 control rods. Only 6-8 were used. 30 control rods. Only 6-8 were used. This led to a series of events that This led to a series of events that caused rapid overheating and caused rapid overheating and deformed the core. The extra control deformed the core. The extra control rods could not be inserted and the rods could not be inserted and the core melted, causing an explosion. core melted, causing an explosion. Fires lasted for nine days.Fires lasted for nine days.

They made some BIG mistakes:They made some BIG mistakes:The emergency cooling system was turned The emergency cooling system was turned

offoffPast-due safety check was being run by Past-due safety check was being run by

inexperienced night crewinexperienced night crewAutomatic safety devices that shut down Automatic safety devices that shut down

the reactor were shut offthe reactor were shut offPower output was lowered too muchPower output was lowered too muchThe plant had no secondary containment The plant had no secondary containment

shellshell

The effectsThe effects

o It caused 30 It caused 30 immediate fatalities to immediate fatalities to workers and exposed workers and exposed approx. 500,000 approx. 500,000 people to dangerous people to dangerous levels of radiation.levels of radiation.

o Air currents carried Air currents carried radioactive particles radioactive particles high into the high into the atmosphere and atmosphere and allowed spreading.allowed spreading.

The result?The result?

These serious accidents put a These serious accidents put a definite halt on most plans to build definite halt on most plans to build new power plants in the United new power plants in the United States and caused some that States and caused some that were already built to be shut were already built to be shut down indefinitely. One such plant down indefinitely. One such plant here on Long Island is…………..here on Long Island is…………..

Shoreham Power PlantShoreham Power Plant

Customers are still paying for the6 billion dollar debt it has left.(3% surcharge on their electric bills for 30 years)

Officially decommissioned in 1989

Fukushima Daiichi DisasterFukushima Daiichi DisasterJapan: March 11, 2011Japan: March 11, 2011

Original INES Level 5/Upgraded to Level 7 in April

A powerful tsunami generated by a A powerful tsunami generated by a magnitude 9.0 quake at sea slams magnitude 9.0 quake at sea slams

into the power plantinto the power plant Damage is done to Damage is done to

four of six reactorsfour of six reactors Cooling systems failCooling systems fail Fires are set offFires are set off Hydrogen gas causes Hydrogen gas causes

explosionsexplosions Engineers use Engineers use

seawater in effort to seawater in effort to cool down corescool down cores

The Outcome?The Outcome?

The world The world becomes becomes skeptical again skeptical again about the use of about the use of nuclear energy nuclear energy as old fears are as old fears are revived .revived .

A handful of workers at A handful of workers at the plant were the plant were accidentally killed accidentally killed while trying to control while trying to control the overheating the overheating reactors.reactors.

It is estimated that It is estimated that 1,000 people will die 1,000 people will die from cancers which from cancers which result from radiation result from radiation exposure. exposure.

Electricity ProductionElectricity Production

The WorldThe World The United StatesThe United States