high school chemistry fall module: should the...

High School Chemistry

Fall Module: Should the United States Say Yes or No to Nuclear

Power?

Student Text Set

Denver Public Schools High School Chemistry • Fall Module

Should the United States Say Yes or No to Nuclear

Power?

Denver Public Schools High School Chemistry • Fall Module

Table of Contents

“Elements and Isotopes” Exploring Nuclear Energy

“Nuclear Power Safety Concerns” Council on Foreign Relations

“At U.S. Nuclear Sites, Preparing for the Unlikely” The New York Times

“How Nuclear Power Can Stop Global Warming” Scientific American

“Nuclear Accidents” Exploring Nuclear Energy

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©2014 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org

What exactly is the mysterious thing we call electricity? It is charged particles, called electrons, that are in motion. What are electrons? They are tiny particles found in atoms. Everything in the universe is made of atoms or particles derived from atoms—every star, every tree, and every animal. The human body is made of atoms. Air and water are, too. Atoms are the building blocks of the universe. Atoms are so small that millions of them would fit on the head of a pin.

Atomic StructureAtoms are made of smaller particles. The center of an atom is called the nucleus. It is made of particles called protons, which carry a positive (+) charge, and neutrons, which carry no charge, that are approximately the same size. Nuclear energy is contained within the nucleus and the strong nuclear force holds the protons and neutrons together.

Protons and neutrons are very small, but electrons are much smaller. Electrons carry a negative (-) charge and move around the nucleus in areas of probability, called energy levels. These areas are different distances from the nucleus. If the nucleus were the size of a tennis ball, the atom would be the size of the Empire State Building. Atoms are mostly empty space.

If you could see an atom, it might look a little like a tiny center of spheres surrounded by giant clouds (or energy levels). Electrons are found in these energy levels. Since protons have a positive charge and electrons have a negative charge, they are attracted to each other. This electrical force holds the electrons in their energy level. The energy level closest to the nucleus can hold up to two electrons. The next energy level can hold up to eight. Additional energy levels can hold more than eight electrons.

The electrons in the energy levels closest to the nucleus have a strong force of attraction to the protons. Sometimes, the electrons in the outermost energy level—the valence energy level—do not. In this case, these electrons (the valence electrons) easily leave their energy levels. Other times, there is a strong attraction between valence electrons and the protons. Often, extra electrons from outside the atom are attracted and enter a valence energy level. Sometimes when the arrangement of electrons is changed, energy is gained or transformed. This energy from electrons is called electrical energy.

When an atom is neutral, it has an equal number of protons and electrons. The neutrons carry no charge and their number can vary. Neutrons help hold the nucleus together.

ElementsA substance whose atoms all have the same number of protons is called an element. The number of protons is given by an element’s atomic number, which identifies elements. For example, all atoms of hydrogen have an atomic number of one and all atoms of carbon have an atomic number of six. This means that all hydrogen atoms contain one proton and that all carbon atoms contain six protons. An atom is measured by its atomic mass, which is based on its number of protons, neutrons, and electrons.

Radioactive IsotopesWhile many isotopes of the elements are stable, some isotopes are unstable and their nuclei emit particles and/or energy to become more stable. Isotopes of elements that are unstable and emit particles or energy are labeled radioactive because they are

HYDROPOWER, 6.70%

BIOMASS, 1.42%

GEOTHERMAL, 0.38%

SOLAR, 0.11%

WIND, 3.48%

Data: Energy Information Administration*Total does not add to 100% due to independent rounding

COAL37.40%

OTHER NONRENEWABLES

1.20%

URANIUM19.01%

NATURAL GAS30.29%

RENEWABLES12.09%

U.S. Electricity Production, 2012

e Elements and Isotopes

OUTER ENERGY LEVEL

Carbon AtomA carbon atom has six protons and six neutrons in the nucleus, two electrons in the inner energy level, and four electrons in the outer energy level.

INNER ENERGY LEVEL

PROTONS (+)

ELECTRONS (–)

NEUTRONS

NUCLEUS

Carbon Atom

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Exploring Nuclear Energy

2 -1

radiating particles or energy. When particles are given off, isotopes of new elements are usually made. The most common particles given off are alpha particles (a helium nucleus without electrons 4He) and beta particles (an energetic electron 0β). Release of high energy gamma radiation is also a common method of achieving stability, but the type of isotope remains the same. Unstable isotopes may give off an alpha or beta particle, but never both together. However, gamma radiation may be given off along with either alpha or beta emissions.

The following are two examples of unstable isotopes that change identities when they release particles:

Beta emission 14C -> 0β + 14N

Alpha emission 238U -> 4He + 234Th

In the first example, a neutron in the nucleus of carbon-14 releases a beta particle ( 0β) and changes into a proton. Since the atom now has seven protons instead of six, it has become a different element

nitrogen, but still has an atomic mass of 14. It is now the isotope nitrogen-14.

In the second example, uranium-238 releases an alpha particle (4He). The alpha particle is made of two protons and two neutrons. That means the atom now contains 90 protons and 144 neutrons (giving a total of 234 nucleons or particles in the nucleus). With 90 protons, it is now the element thorium and has an atomic mass of 234. It is the isotope thorium-234.

The process of nuclei becoming more stable is called radioactive decay. The time required for one half of the atoms of the original radioactive isotope to decay into another isotope is known as its half-life. Some substances have half-lives measured in milliseconds while others take billions of years. Uranium-238 has a half-life of 4.6 billion years. Short half-lives result in high activities since a large number of particles or amounts of energy are emitted in relatively short time periods.

What is Radiation?Energy traveling in the form of waves or high speed particles is called radiation. The sun produces radiant energy—energy that travels in electromagnetic waves. Wireless technologies, radar, microwave ovens, medical x-rays, and radiation therapy to treat cancer are all examples of how radiation can be used. Radiation can come in the form of electromagnetic waves (radio, microwave, infrared, visible light, ultraviolet light, x-rays, and gamma rays) and high speed particles (alpha and beta particles). Radiation is classified into two categories—ionizing radiation, which has enough energy to ionize atoms, and non-ionizing. When discussing nuclear science, radiation generally refers to ionizing radiation such as alpha particles, beta particles, and gamma rays.

Alpha particles, beta particles, and/or gamma rays can be emitted from different isotopes of elements. We say these isotopes are radioactive and also call them radionuclides. An isotope is stable when there is close to a 1:1 ratio of protons and neutrons. If an isotope has too few or too many neutrons, the isotope becomes unstable and radioactive. Many elements with fewer than 84 protons have stable isotopes and radioactive isotopes; however, all isotopes of elements with 84 or more protons are radionuclides.

A Radioactive WorldThere are many natural sources of radiation that have been present since the Earth was formed. In the last century, we have added to this natural background radiation with some artificial sources. It may surprise you to know that for an average person, 50 percent of all exposure to radiation comes from natural sources. Much of our exposure to artificial sources is attributable to medical procedures.

There are three major sources of naturally occurring radiation. They are cosmic radiation, terrestrial radiation, and internal radiation. Cosmic radiation is the radiation that penetrates the Earth’s atmosphere and comes from the sun and outer space. Terrestrial radiation is the radiation emitted from the earth, rocks, building materials, and water. The human body naturally contains some radiation. This is called internal radiation.

We are constantly using radioactive materials in our daily lives. These include medical radiation sources (such as CT scans and medical and dental x-rays), older TV’s, older luminous watches, some smoke detectors, left-over radiation from the testing of nuclear weapons, and a variety of industrial uses. Another major source of natural radiation is from radon gas, a gas commonly found in the Earth.

RadonRadon is a colorless and odorless radioactive gas found throughout the United States, and is one type of terrestrial radiation. It is formed during the natural radioactive decay of uranium and thorium atoms in the soil, rocks, and water. Since radon is a gas, it can get into the air of the buildings where we live, work, and play. According to the Environmental Protection Agency (EPA), radon causes thousands of deaths from lung cancer each year. Behind smoking, exposure to radon gas is the second leading cause of lung cancer in the U.S.

Most radon enters buildings from the soil. Radon enters buildings through cracks in solid floors, construction joints, cracks in walls, gaps in suspended floors, gaps around service pipes, and cavities inside walls. Some radon can also enter a home through the water supply. Both new and older homes are susceptible to radon gas build-up. Since most exposure to radon occurs at home, it is important to measure the level of radon in your home, and limit radon exposure where necessary.

The EPA recommends that all homes be tested for radon. Simple test kits are available at most home improvement stores, are inexpensive, and are easy to use. Qualified testers can also be used and are a good choice to perform tests when buying or selling a home.

ALPHA BETA GAMMA

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92 2 90

-1 7

-1

Elements and Isotopese

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-1

2

6/10/2015 Nuclear Power Safety Concerns - Council on Foreign Relations

http://www.cfr.org/world/nuclear-power-safety-concerns/p10534

Nuclear Power Safety ConcernsAuthor: Toni JohnsonUpdated: September 23, 2011 This publication is now archived.

Introduction

The Nuclear Renaissance

The Fallout from Fukushima

Nuclear Safety Concerns

Introduction

The March 2011 Japanese earthquake and tsunami that severely damaged the Fukushima Daiichi

power plant has dampened what had been a renewed interest in nuclear power twenty-five years

after the explosion at Chernobyl in northern Ukraine. That interest was sparked by rising

energy demands in emerging markets and developing nations as well as the need to reduce use of

fossil fuels in response to climate change, making nuclear more attractive though less

competitive than other types of power (PDF). But the 2011Fukushima incident has led to

new scrutiny of plant safety regulations and emergency measures, and to questions about reactor

design and how to deal with spent nuclear fuel. Still, while experts say Fukushima is likely to have

some impact on nuclear power going forward, it is unlikely to be as disruptive for the industry as

Chernobyl.

The Nuclear Renaissance

In 1986, an explosion at a reactor (Guardian) at Chernobyl in Ukraine spewed radiation

enough for four hundred Hiroshima-sized bombs. As a result, plans for new plants were shelved

across the globe and many politicians, particularly in Europe, pushed to phase out nuclear power.

That changed over the last decade, though, with a renewed interest in nuclear power. Two factors

helped create this so-called "nuclear renaissance"--emerging-market energy demand and

climate change. Many countries with growing economies and middle classes are looking at ways to

access reliable and diverse electricity production. With fossil fuel use increasingly less attractive

because of climate change, nuclear energy--which has a very small carbon footprint--has gained

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new attention.

Four hundred-forty reactors are operating worldwide, representing about 14 percent of global

electricity generation. Sixty power plants are under construction, and many older plants slated to

be decommissioned may be given new operating licenses. Overall, at least sixty countries that

currently do not have it have expressed interest in pursuing nuclear power.

While most of the world's nuclear power generation is in Europe and the United States, much

of the new nuclear power coming online in the next decade will be in Asian emerging markets,

particularly China and India. Nearly half of all reactors under construction are being built in China,

which plans to expand its output from nearly eleven gigawatts (GW) of power to eighty GW

by 2020. India hopes to expand its nuclear capacity to at least twenty GW by 2020, up from less

than four today.

Nineteen new reactors also are under construction in Europe as of January 2011. Almost all are in

Russia, with a handful in Bulgaria, Ukraine, and the Slovakian Republic. Only Finland

is constructing a new plant in Western Europe. However, prior to Fukushima, some Western

European governments were reconsidering plans to phase out nuclear-power plants. With coal

increasingly falling into disfavor because of climate change, many EU countries are worried that

reducing nuclear power use would lead to more dependence on natural gas imports--especially

from Russia.

Only one new reactor is being constructed in the United States, another two are expected to break

ground soon, and a little over two dozen more have made it to the planning stages.

A growing number of climate advocates argue that nuclear power could act as a stop-gap,

emissions-free technology to supplement growing renewable energy production. Some of these

advocates continue to defend the need for nuclear after the Fukushima accident. But other

environmental advocates, such as U.S.based Public Citizen and Greenpeace, say nuclear power

is not the answer to climate change even short term. "The nuclear industry has seized on the

problem of climate change to try to revive its dying industry," says Greenpeace International

(PDF). "[B]ut the reality is that wasting yet more time and money pursuing the nuclear nightmare

would be too late, too expensive, too risky."

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Many supporters and critics say nuclear power's biggest impediment is economic. Projects

are expensive and slow-developing, with a number of basic logistical hurdles that make them less

competitive than other types of energy, even with the inclusion of a carbon price. Nuclear expert

Charles Ferguson notes that when U.S. utilities even mention interest in nuclear power they

face having their stocks downgraded. "Wall Street doesn't want to take the risk," says anti-nuclear

advocate Michael Marriotte.

The Fallout from Fukushima

Since Chernobyl, the absence of high-profile accidents and concerns about global warming has

helped soften attitudes on nuclear power. CFR's 2009 world opinion project found significant

support for nuclear power in many countries as a means of energy diversification, though

concerns about nuclear safety remained high. U.S. polls also showed growing support for nuclear.

But polling since the Fukushima incident has shown support has diminished around the world--

though some experts say the reaction is more muted than following Chernobyl.

A number of experts, including Nathan Hultman, a climate policy expert at the Brookings

Institution, say the Fukushima incident will likely have different impacts in different parts of

the world. For example, Germany, the largest importer of Russian gas, has shut down seven

reactors since Fukushima. And the country's largely unpopular plans to extend the life of other

reactors past 2020 has been stopped all together. Italy renewed its moratorium on nuclear power,

and other EU countries are reviewing their future plans for nuclear power. Across the world,

countries including the United States and China also have begun new safety evaluations of their

plants to see how well they operate in situations involving issues such as earthquakes, terror

attacks, flooding, and loss of power.

"Regardless of individual regulatory and investment environments, events at Fukushima will

complicate planning for nuclear expansion for the coming years in all countries," writes Hultman.

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"Fukushima simply exposed what has always, and will always, persist with nuclear power--it is a

technology that is perceived as dangerous, and no amount of redundancy will ever be able to

completely scrub the specter of nuclear risk from discussions of energy policy."

In September 2011, the International Atomic Energy Agency endorsed an action plan (PDF) on

nuclear safety, which includes new voluntary measures to help avoid an accident similar to

Fukushima. The plan calls on governments to immediately begin safety assessments of existing

plants and allow IAEA inspectors access to plants. The plan also calls for countries to work toward

better international liability regimes. Some countries, such as Germany, France, and Canada, were

unhappy the plan did not contain stricter measures (Reuters) that mandated IAEA

inspections. However, other countries, such as the United States, India and China, stressed that the

power to ensure safety should remain in the hands of national authorities.

Nuclear Safety Concerns

A number of experts have said that the Fukushima accident will not be as bad as Chernobyl,

because the accidents at Chernobyl and Fukushima were very different. Chernobyl involved a huge

explosion, which spewed radioactive debris high into the air, while Fukushima, so far, has involved

multiple reactors as well as spent fuel pools, leaks of radioactive coolant and steam, and smaller

explosions that have damaged reactor containment.

The number of related deaths (Guardian) from Chernobyl remains in dispute, ranging from

as low as four thousand to as high as five hundred thousand. Other health effects may include high

instances of infant mortality and more than six thousand cases of thyroid cancer in children and

adolescents according to a 2008 UN report. Environmental damage in nearby areas and, in

some cases, as far away as Britain persists. CFR's Laurie Garrett notes that in contrast to

Chernobyl, Japanese authorities quickly distributed iodine tablets, which help protect the

thyroid against radiation. The total number of people harmed by the Fukushima accident is

unknown, but a number of workers at the plant have received high levels of radiation exposure and

radiation is already contaminating the food and water supplies in surrounding areas.

Many nuclear experts say Chernobyl served as a wakeup call within the nuclear industry. The

World Association of Nuclear Operators was established shortly after to serve as the

industry's self-policing watchdog and write confidential safety reviews on nuclear plants. Richard

Meserve, head of the International Working Group on Nuclear Safety, noted in a 2010 letter

(PDF) to the International Atomic Energy Agency: "Every user of nuclear power is hostage to the

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safety performance of other users because of the adverse consequences that would arise if there

were a nuclear accident anywhere."

According the World Nuclear Association, there have been eleven "serious nuclear reactor

accidents" since the inception of nuclear power, with six occurring at commercial reactors

between 1975 and 2011. These accidents happened with few or no immediate deaths--

comparatively coal, gas, hydroelectric, and oil accidents can result in hundreds of deaths per year,

the association notes. Other analysis, such as a 2010 Swedish study (PDF) and one from

ProPublica, points out that nuclear power generation per watt is responsible for fewer deaths

than other types of power--and those health effects do not include potential impacts from

climate change, which are significant for fossil fuels.

Still, nuclear power must address a significant safety issues, such as:

Meltdowns and Accidents. Human error is considered largely responsible for the 1979 Three

Mile Island accident in Pennsylvania, and design flaws triggered the Chernobyl explosion. Since

these accidents, the World Nuclear Association says the Western industry has employed "a

defenseindepth approach," with multiple safety systems, including: "high-quality" design and

construction; comprehensive monitoring and regular testing; and redundant systems to prevent

significant radioactive releases. Overall, the industry argues it has worked hard to make nuclear

power safe, and newer reactors have safety features that overcome some of the problems that led to

radiation releases at Fukushima and Chernobyl, including better shielding and passive cooling

systems.

But new reactor types still face questions--such as how well they withstand earthquakes--and

industry assurances about new reactors don't address concerns about older reactors. In the United

States, many of these have been relicensed or are in the process of being relicensed after forty years

of operation (NYT). Some environmental advocates want all twenty-three Mark I (first

generation) boiling water reactors--the same type as those that failed in the Fukushima accident--

permanently decommissioned because of inherent design flaws--including placement of the

spent fuel rods and strength of the reactor containment.

Other advocates argue that human error makes a future meltdown possible no matter how well a

plant is designed. A 2011 report from the Union of Concerned Scientists, a U.S.-based

environmental group, found that some of the fourteen "nearmisses" occurred at U.S. nuclear

plants in 2010 in part because of inadequate training, faulty maintenance, and failure to investigate

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problems thoroughly. And some nuclear experts question the degree of safety measures employed

at plants.

Nuclear Waste. Short- and long-term storage of spent nuclear fuel has been a challenge for

the industry and policymakers. Spent fuel, if not disposed of properly, could contaminate water

supplies or be used by terrorists to create a dirty bomb. In the short-term, spent fuel is stored in

pools on-site--but they only need to stay there a few months until they are cool enough to move to

dry storage (either on site or in a long-term storage facility). Still, at some plants, fuel rods are

packed in pools in numbers well above design specifications and stay in the pools long after they

are ready to be moved (R&D). Fukushima revived U.S. discussion (Beacon) about plans

for a long-term storage facility at Yucca Mountain in Nevada that had been scrapped. Meanwhile,

advocates say utilities should be required to move spent fuel to hardened, dry-cask storage as soon

as possible.

Efforts to reprocess nuclear waste are expensive and come with associated environmental and

security risks. Yet a growing number of countries--including Japan and Russia--have begun fuel

recycling projects.

Natural Disasters. The earthquake and tsunami that damaged the Fukushima plant has some

questioning the sensibility of locating plants in seismically active regions, with some

environmental advocates calling for new seismic studies before any older plants are relicensed. In

addition, there are concerns about other types of disasters such as tornados and hurricanes.

One climate advocate warns that sea level rise resulting from climate change also needs to taken

into consideration.

Security Issues. Most countries either pursuing nuclear power or currently using it have signed

on to the Nuclear Nonproliferation Treaty and have agreed to comply with rules that

ensure that they will not use nuclear technologies toward making weapons. However, any country

with nuclear technology is considered a proliferation risk. Also after 9/11, concerns arose over

the security of 104 U.S. nuclear plants, particularly Indian Point, located thirty miles north of

New York City. However, experts maintain the facilities are relatively safe.

Editor's Note: This Backgrounder was formerly entitled "Chernobyl, Nuclear Power, and Foreign

Policy."

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6/10/2015 At U.S. Nuclear Sites, Preparing for the Unlikely - NYTimes.com

http://www.nytimes.com/2011/03/29/science/29threat.html?_r=0

SCIENCE

At U.S. Nuclear Sites, Preparing for the

Unlikely

By JOHN M. BRODER, MATTHEW L. WALD and TOM ZELLER Jr. MARCH 28, 2011

WASHINGTON — American nuclear safety regulators, using a complex

mathematical technique, determined that the simultaneous failure of both

emergency shutdown systems that are designed to prevent a core meltdown

was so unlikely that it would happen once every 17,000 years.

But 20 years ago, it happened twice in four days at a pair of nuclear

reactors in southern New Jersey.

The American people, and the regulators whose job it is to protect

them from a catastrophic nuclear accident, are watching the unfolding

events at a complex of crippled reactors in Japan with foreboding and an

overriding question: Can it happen here?

The answer — probably not — from the Nuclear Regulatory

Commission is meant to reassure. But as the New Jersey accidents in 1983,

which did not result in any core damage or release of radiation, show, no

one can predict what might upend all the computer models, emergency

planning and backup systems designed to eliminate those narrow

theoretical probabilities or mitigate their effects.

“We can never say that that could never happen here,” said Anthony R.

Pietrangelo, senior vice president and chief nuclear officer at the Nuclear

Energy Institute, the industry’s main trade association. “It doesn’t matter

how you get there, whether it’s a hurricane, whether it’s a tsunami, whether

it’s a seismic event, whether it’s a terrorist attack, whether it’s a

cyberattack, whether it’s operator error, or some other failure in the plant

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— it doesn’t matter. We have to be prepared to deal with those events.”

The threats considered most serious by nuclear engineers are problems

that lead to a loss of power. Lack of power to run cooling systems for the

reactor core and for spent-fuel ponds led to the explosions and release of

radiation at the Fukushima Daiichi nuclear complex in Japan.

American nuclear facilities have backup power systems, and backups to

those. All plants are required to have batteries to provide power in the

event of a loss of power and failure of backup generators. In the United

States, 93 of the 104 operating reactors have batteries capable of providing

power for four hours; the other 11 have eight-hour batteries. Fukushima

had eight-hour batteries. It wasn’t enough.

No single analysis can discern which nuclear power plants in the

United States are most at risk for a disaster, But the probabilities of an

accident leading to damage to a reactor core have been roughly penciled

out.

A 2003 Nuclear Regulatory Commission report, based on data

submitted by plant owners, looked at the risk of equipment breakdowns,

power failures and other factors that could lead to core damage.

It found that reactor No. 1 at Three Mile Island, near Harrisburg, Pa.,

would appear to be at greatest risk. (Three Mile Island is, of course, the

plant that suffered a partial core meltdown in reactor No. 2 in 1979, the

worst accident so far in the commercial nuclear power industry in the

United States) By the commission’s calculations, such an episode would

occur there roughly once every 2,227 years. By contrast, the expected

frequency of a core damage accident at the Quad Cities facility in Illinois is

once every 833,000 years.

“These sorts of big numbers can tell you which plants need to take

steps first to fix general problems, or which plants might have wider

margins if a problem were to occur,” said David Lochbaum, a nuclear

engineer and the director of the Nuclear Safety Project of the Union of

Concerned Scientists, an environmental and nuclear watchdog group.

“They’re not going to tell you when that bad day is going to arrive.”

Regulators and federal courts have discounted the likelihood of

multiple crises hitting a nuclear facility at the same time. One federal judge,

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ruling against opponents of the Diablo Canyon nuclear plant near San Luis

Obispo, Calif., said that the odds of an earthquake setting off a nuclear

accident at the plant were negligible.

“The commission has determined that the chance of such a bizarre

concatenation of events occurring is extremely small,” the court said.

But the crisis at Fukushima shows that such natural catastrophes can

occur. The fact that the odds of a nuclear accident are unknowable and the

risks hard to measure make it in some ways more frightening than the

known — and greater — risks of driving without a seat belt or breathing the

fumes from a coal-burning power plant.

“People are scared of certain things. It’s part of our makeup,” said

Robert H. Socolow, a physicist at Princeton University. “The public is more

afraid of radiation than the experts who work with it every day. But this is

about irreducible irrationality, if you like. We are irrational, every last one

of us.”

Fresh Eye on American PlantsIn the wake of the disaster in Japan, concerns were quickly raised at

the Turkey Point nuclear power plant in Florida, on Biscayne Bay 24 miles

south of Miami. Critics pointed to the potential for a hurricane to create a

storm surge that could simultaneously sever grid power and inundate

backup generators — precisely the recipe that crippled Fukushima.

In 1992, Turkey Point took a direct hit from Hurricane Andrew,

causing a loss of off-site power for more than five days. Backup systems,

however, allowed operators to keep the reactors cool until power could be

restored. Paul Gunter, the director of the Reactor Oversight Project for the

group Beyond Nuclear, which opposes nuclear energy, joined other critics

in pointing to the Dresden nuclear facility in Morris, Ill., and the nearby

Quad Cities plant in Cordova, both of which are north of the New Madrid

seismic zone. The area registered quakes estimated to have exceeded 7.0 in

magnitude in 1811 and 1812, and is known for somewhat more regular

temblors of lesser intensity.

Exelon, the operator of both facilities, said that all of its plants are

designed to withstand substantial earthquakes, but argued that none —

including Dresden and Quad Cities, which are hundreds of miles from the

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New Madrid fault line — are actually considered to be in significant

earthquake zones.

Still, the Nuclear Regulatory Commission announced last week that it

would be conducting new seismic risk assessments next year at 17 plants —

including Dresden.

The Diablo Canyon nuclear power plant is not on the commission’s list.

The plant, on an 85-foot bluff above the Pacific Ocean, is owned by Pacific

Gas & Electric, about halfway between San Francisco and Los Angeles.

Opponents of that plant redoubled their efforts when PG&E began

seeking early renewal on its two 40-year licenses — chiefly on the ground

that the seismic studies that underwrote the original licensing in the 1970s

were inadequate, and are now sorely out of date.

A fault line discovered in 2008, called the Shoreline Fault, runs about

half a mile from the front door of Diablo Canyon. Opponents want new

seismic studies before the plant’s license is renewed, but PG&E, the Nuclear

Regulatory Commission and other experts argue that the fault poses no

threat that the nuclear facility couldn’t handle.

As at Diablo Canyon, fears of an earthquake near the Indian Point

nuclear power facility, about 30 miles north of New York City, were stoked

in 2008 when researchers at the Lamont-Doherty Earth Observatory at

Columbia University discovered a pattern of small but active faults in the

area, suggesting that earthquakes near the plant were more common than

once thought.

Gov. Andrew M. Cuomo of New York has called a special meeting with

federal regulators to discuss earthquake risks and preparedness at the

facility. Among the concerns: how to execute an orderly evacuation of one

of the most densely populated regions of the country — particularly given

that the government mandates that officials plan only for a 10-mile escape

radius.

How Risk Is CalculatedAs part of its mission to ensure the safety of nuclear power, the Nuclear

Regulatory Commission sets two goals: that the public’s risk of death from

acute radiation sickness from nuclear reactors should not exceed one-

thousandth of the risk of accidental death from all sources, and that the risk

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of fatal cancer likewise should not exceed that amount.

The commission, looking at how much radiation it would take to kill

people in accidents, and how much it would take to raise cancer rates,

decided that reactors would meet that standard if there were meltdowns

with off-site consequences only once per 100,000 years of operation.

With 104 American reactors now running, that would mean such an

event once every 1,000 years or so. The commission asserts that all plants

currently meet that safety standard, according to an analysis that looks at

the chance that any piece of equipment will fail, and what other failures

that might lead to, under a mathematical method called probabilistic risk

assessment, Martin A. Stutzke, the commission’s senior technical adviser

for probabilistic risk assessment technologies, said in an interview.

To meet the government’s goal, about 80 percent of the plants have

made changes since the early 1990s, industry experts say. Many of the

changes were to cope with new calculations of earthquake frequency and

intensity. But while the safety goal of once in 100,000 years expresses a real

number, the component failure numbers are yardsticks that may be wrong.

“The numbers have tremendous uncertainty with them,” he said. They

could be off by a factor of 10, he said.

Earthquakes are a challenge, Mr. Stutzke said, because the historical

record is so short. The Richter scale is 75 years old. For earlier records, he

said, experts study old newspaper accounts — “church bells ringing,

chimneys knocked over, this sort of thing,” he said. Geologists also use

carbon dating and other techniques to estimate the time and scale of older

earthquakes.

The inherent problem, risk experts say, is that it is hard to determine

the size of the worst natural hazard, said Douglas E. True, of ERIN

Engineering and Research in Walnut Creek, Calif.

American reactors may be better protected than those at the Japanese

plant were, because of precautions taken after Sept. 11 for a terrorist or

military attack, according to industry and government officials and

academic experts. American nuclear plant operators are required to have

diesel fuel and pumps on site or readily available nearby to provide backup

power and cooling capacity. Right after the Fukushima crisis they were

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ordered to check that they had the required equipment on hand and in

working order.

The details are classified, but the industry has emergency supplies of

pumps, hoses and generators, and the plan assumes Air Force help in

moving equipment when needed.

“We have military capability that’s pretty impressive, a transport

system that can move big pieces of equipment very quickly,” said Dale

Klein, a commission chairman in the second Bush administration. If the

diesel generators fail, he said, it makes no difference whether the cause was

attack, tsunami or earthquake; the remedy is the same.

Another former chairman, Richard Meserve, who was in that position

at the time of the 2001 attacks, said, “The challenge that we confront is that

external events obviously can occur that may be larger than you expected.”

The commission will not discuss the precautions it has in place to

contend with such events, citing security considerations.

Alternatives Carry Risks TooThere is no simple or single way to properly weigh the risks of nuclear

power against other energy sources, or other risks of modern life, said

David Ropeik, an instructor at Harvard University, consultant to industry

and author of “How Risky Is It, Really? Why Our Fears Don’t Always Match

the Facts.”

“What we’re afraid of determines how we behave, and sometimes those

behaviors become risks in themselves,” he said. He cited a study by two

researchers at the University of Michigan who found that fear of flying after

the Sept. 11 hijackings had caused an additional 1,018 highway deaths in

just the first three months after the attacks.

Radiation is a real threat, nuclear physicists say, but not as great as

many people believe it is, and not as great as other threats. Indeed, every

energy source comes with dangers, from the mine or wellhead to the

smokestack or tailpipe.

“One million people a year die prematurely in China from air pollution

from energy and industrial sectors,” said Stefan Hirschberg, head of safety

analysis at the Paul Scherrer Institute, an engineering research center in

Switzerland. More than 10,000 Americans a year die prematurely from the

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health effects of breathing emissions from coal-burning power plants,

according to the Environmental Protection Agency.

Coal mining accidents in China kill an estimated 6,000 people a year,

according to China’s Mining Ministry. In just the past year in the United

States, the Deepwater Horizon blowout killed 11 people, the Upper Big

Branch coal mine blast killed 29 and a natural gas pipeline explosion in

California killed 8.

But such statistics don’t alter the public’s view of nuclear accidents.

Michael A. Levi, senior fellow for energy and the environment at the

Council on Foreign Relations, said there is no right way to gauge risk. It is

an intensely personal matter affected by a lot of factors.

“When you hear these arguments that pollution from coal plants costs

so many thousands of lives compared to minimal or no deaths from nuclear

accidents, that may be technically true, but it leaves a lot of people cold. It’s

like saying, ‘Don’t pay attention to the twin towers falling; more people die

crossing the street,’ ” he said. “Experts should not say, ‘Here’s how you

should feel about risk.’ They should be saying, ‘Here are the facts. You

decide what matters to you.’ ”

A 2006 study of survivors of the 1986 Chernobyl accident, compiled by

the International Atomic Energy Agency, the World Bank and a number of

United Nations bodies, found that the biggest health impact was

psychological.

“The mental health impact of Chernobyl is the largest public health

problem unleashed by the accident to date,” according to the report,

“Chernobyl’s Legacy: Health, Environmental and Socio-Economic

Impacts.” “Psychological distress arising from the accident and its

aftermath has had a profound impact on individual and community

behavior,” including a sense of fatalism and dependency that has been

transferred to the next generation in the affected zone.

“There is no question we should be appropriately concerned about

nuclear power,” Mr. Ropeik said. “But ‘appropriately’ is the important

distinction. On a continuum, there is no question in my mind that the

dangers from fossil fuel burning should worry us more.”

A version of this article appears in print on March 29, 2011, on page D1 of the New Yorkedition with the headline: When All Isn’t Enough to Stop a Catastrophe.

15

4/21/2015 How Nuclear Power Can Stop Global Warming - Scientific American

http://www.scientificamerican.com/article/how-nuclear-power-can-stop-global-warming/?print=true

Energy & Sustainability » News

Permanent Address: http://www.scientificamerican.com/article/how-nuclear-power-can-stop-global-warming/

This article is from the In-Depth Report The Clean Energy Wars

How Nuclear Power Can Stop Global WarmingNuclear power is one of the few technologies that can quickly combat climate change, experts argue

December 12, 2013 | By David Biello |

When the Atlantic Navigator docked in Baltimore harbor earlier this month, the

freighter carried the last remnants of some of the nuclear weapons that the Soviet

Union had brandished in the cold war. During the past 20 years more than 19,000

Russian warheads have been dismantled and processed to make fuel for U.S. nuclear

reactors. In fact, during that period more than half the uranium fuel that powered

the more than 100 reactors in the U.S. came from such reprocessed nuclear weapons.

In addition to reducing the risk of nuclear war, U.S. reactors have also been staving

off another global challenge: climate change. The low-carbon electricity produced by

such reactors provides 20 percent of the nation's power and, by the estimates of

climate scientist James Hansen of Columbia University, avoided 64 billion metric

tons of greenhouse gas pollution. They also avoided spewing soot and other air

pollution like coal-fired power plants do and thus have saved some 1.8 million lives.

And that's why Hansen, among others, such as former Secretary of Energy Steven

Chu, thinks that nuclear power is a key energy technology to fend off catastrophic

climate change. "We can't burn all these fossil fuels," Hansen told a group of

reporters on December 3, noting that as long as fossil fuels are the cheapest energy

source they will continue to be burned. "Coal is almost half the [global] emissions. If

you replace these power plants with modern, safe nuclear reactors you could do a lot of [pollution reduction] quickly."

Indeed, he has evidence: the speediest drop in greenhouse gas pollution on record occurred in France in the 1970s and ‘80s, when that country transitioned from burning fossil fuels to nuclear fission for electricity, lowering its greenhouse emissions by roughly 2 percent per year. The world needs to drop its global warming pollution by 6 percent annually to avoid "dangerous" climate change in the estimation of Hansen and his co-authors in a recent paper in PLoS One. "On a global scale, it's hard to see how we could conceivably accomplish this without nuclear," added economist and co-author Jeffrey Sachs, director of the Earth Institute at Columbia University, where Hansen works.

The only problem: the world is not building so many nuclear reactors.

Nuclear futureChina leads the world in new nuclear reactors, with 29 currently under construction and another 59 proposed, according to the World Nuclear Association. And China has not confined itself solely to the typical reactors that employ water and uranium fuel rods; it has built everything from heavy-water reactors originally designed in Canada to a small test fast-reactor.

Yet, even if every planned reactor in China was to be built, the country would still rely on burning coal for more than 50 percent of its electric power—and the Chinese nuclear reactors would provide at best roughly the same amount of energy to the developing nation as does the existing U.S. fleet. Plus, nuclear requires emissions of greenhouse gases for construction, including steel and cement as well as the enrichment of uranium ore required to make nuclear fuel (or the downblending of uranium from nuclear weapons as in the case of the "Megatons to Megawatts" program). Over the full lifetime of a nuclear power plant, that means greenhouse gas emissions of roughly 12 grams of CO2-equivalent per kilowatt-hour of electricity produced, the same as wind turbines (which also require steel, plastics, rare earths and the like in their construction) and less than photovoltaic panels, according to the U.S. Department of Energy’s National

16



Renewable Energy Laboratory.

In other parts of the world nuclear has begun to dwindle. Japan may never restart its nuclear plants in the wake of the multiple

meltdowns at Fukushima Daiichi following the earthquake and tsunami in 2011, which also soured public opinion in many parts of the

world. Germany still plans to eliminate nuclear power and even France has announced plans to reduce its reliance on reactors. In the

U.S. the five new nuclear reactors under construction will replace the four aging reactors that closed in 2013, but as older reactors like

Oyster Creek in New Jersey and Vermont Yankee continue to shut down, the number of reactors in the U.S. may be doomed to dwindle

as well.

A big problem is cost. The construction of large nuclear power plants requires a lot of money to ensure safety and reliability. For

example, for the U.S. to derive one quarter of its total energy supply from nuclear would require building roughly 1,000 new reactors

(both to replace old ones and expand the fleet). At today's prices for the two AP-1000 reactors being built in Georgia, such an

investment would cost $7 trillion, although that total bill might shrink with an order of that magnitude.

One other idea to cut cost is to begin building smaller reactors of so-called modular design. The Tennessee Valley Authority hopes to

catalyze development of such reactors by installing one at its Clinch River site in Tennessee, former home of the U.S.’s failed attempt to

build its own commercial fast reactor.

That never-completed breeder reactor is part of a legacy of failed U.S. research and development of new types of reactors, such as the

Experimental Breeder Reactor that ran successfully in Idaho for nearly 30 years. "It's a shame that the U.S. essentially stopped R&D on

advanced nuclear power a few decades ago," Hansen noted. "By now we should be in a position where a country like China would have

some options other than coal."

New dawn?That said, nuclear reactors are beginning to get the kind of scientific attention not seen since at least the end of the cold war. Novel

designs with alternative cooling fluids other than water, such as Transatomic Power's molten salt–cooled reactor or the liquid lead–

bismuth design from Hyperion Power, are in development. Alternative concepts have attracted funding from billionaires like Bill Gates.

Transatomic Power even won the top prize from energy investors at the 2013 summit of the Advanced Research Projects Agency–

Energy, or ARPA–E, in 2013. "The intellectual power of what's been done in the nuclear space should allow for radical designs that meet

tough requirements," Gates told ARPA–E's 2012 summit, noting that the modeling power of today's supercomputers should allow even

more innovation. "When you have fission, you have a million times more energy than when you burn hydrocarbons. That's a nice

advantage to have."

ARPA–E itself, however, has no program to develop alternative reactors because of the expense of proving out novel designs and the

long timescales required to develop any of them. "We searched a lot in nuclear," ARPA–E's former director Arun Majumdar, now at

Google, said in a interview with Scientific American earlier this year. "We realized that in the nuclear business, investing $30 [million]

to $40 million, I'm not sure it would have moved the needle. … That is something that I wish I had had the budget to try."

With more money for development of novel designs and public financial support for construction—perhaps as part of a clean energy

portfolio standard that lumps in all low-carbon energy sources, not just renewables or a carbon tax—nuclear could be one of the pillars

of a three-pronged approach to cutting greenhouse gas emissions: using less energy to do more (or energy efficiency), low-carbon

power, and electric cars (as long as they are charged with electricity from clean sources, not coal burning). "The options for large-scale

clean electricity are few in number," Sachs noted, including geothermal, hydropower, nuclear, solar and wind. "Each part of the world

will have different choices about how to get on a trajectory with most of the energy coming from that list rather than coal."

As long as countries like China or the U.S. employ big grids to deliver electricity, there will be a need for generation from nuclear, coal or

gas, the kinds of electricity generation that can be available at all times. A rush to phase out nuclear power privileges natural gas—as is

planned under Germany's innovative effort, dubbed the Energiewende (energy transition), to increase solar, wind and other renewable

power while also eliminating the country's 17 reactors. In fact, Germany hopes to develop technology to store excess electricity from

renewable resources as gas to be burned later, a scheme known as “power to gas,” according to economist and former German politician

Rainer Baake, now director of an energy transition think tank Agora Energiewende. Even worse, a nuclear stall can lead to the

construction of more coal-fired power plants, as happened in the U.S. after the end of the nuclear power plant construction era in the

1980s.

Hansen, for one, argues that abundant, clean energy is necessary to lift people out of poverty and begin to reduce greenhouse gas

emissions from a swelling human population. Nuclear is one of the technologies available today—and with room for significant

improvement and innovation. In that sense, natural gas is a bridge fuel to disaster, even with some form of CO2 capture and storage,

and the world must immediately transition to renewables and nuclear.17



But significant hurdles remain, not least the decades required for design, licensing and construction of even existing nuclear technologies, let alone novel ideas. That may mean advanced nuclear power cannot contribute much to efforts to combat climate change in the near term, which leaves current reactor technology as the only short-term nuclear option—and one that is infrequently employed at the global scale at present.

In the same way, U.S. nuclear power plants have not eliminated the threat of nuclear weapons despite 20 years of megatons to megawatts. Russia retains an estimated 8,500 nuclear warheads—and the U.S. some 7,700—despite the best efforts to fission the problem away. The problem of fission and climate change is equally stuck at present. But, as Hansen wrote in an additional assessment of his new analysis, "Environmentalists need to recognize that attempts to force all-renewable policies on all of the world will only assure that fossil fuels continue to reign for base-load electric power, making it unlikely that abundant affordable power will exist and implausible that fossil fuels will be phased out."

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Exploring Nuclear Energy

Three events that have influenced people’s perception of nuclear energy are the accidents at Three Mile Island in Pennsylvania, Chernobyl in the Ukraine (former Soviet Union), and Fukushima in Japan.

Three Mile IslandIn 1979 there was an accident at the Three Mile Island (TMI) reactor. In the morning, feed-water pumps that moved coolant into one of the reactors stopped running. As designed, the turbine and reactor automatically shut down, but an automatic valve that should have closed after relieving pressure inside of the reactor stayed open. This caused coolant to flow out of the reactor and the reactor overheated, and the nuclear fuel started to melt. By evening, the reactor core was stabilized. Over the next few days there were additional dilemmas, including the release of some radioactive gas into the atmosphere, which led to a voluntary evacuation of pregnant women and pre-school aged children who lived within a five mile radius of the plant.

The accident at TMI has been the most serious in U.S. commercial nuclear power plant history, however there were no serious injuries and only small amounts of radiation were measured off-site.

ChernobylIn the Ukraine, they rely heavily on nuclear power to generate electricity. In 1986, there were four reactors operating at the Chernobyl Power Complex with two more reactors under construction. OnApril 26, 1986, while conducting tests of Unit 4’s reactor behavior at low power settings, plant operators turned off all of the automatic plant safety features. During the test the reactor became very unstable and there was a massive heat surge. Operators were unable to stop the surge and two steam explosions occurred. When air entered the reactor the graphite moderator burst into flames and the entire unit became engulfed in fire.

The steam explosions, along with burning graphite used to moderate the reactor, released considerable amounts of radioactive material into the environment. Two workers died in the initial explosion and by July, 28 additional plant personnel and firefighters had also died. Between May 2-4, about 160,000 persons living close by the reactor were evacuated. During the next several years an additional 210,000 people were resettled from areas within an approximate 20 mile radius of the plant. Soon after the accident Unit 4 was encased in a cement structure allowing the other reactors nearby to continue operating.

Today about 1,000 people have unofficially returned to live within the contaminated zone. A “New Safe Confinement” structure is being built to more securely contain the radioactive materials that remain in Unit 4. The new structure will encompass Unit 4 and the existing concrete shelter. Scheduled to be completed in 2014, the structure will be 344’ high, 492’ long, and 843’ wide. This is larger than six football fields.

Nuclear Accidentser

Baltimore

Pittsburgh

Philadelphia

Harrisburg

Washington D.C.DE

MD

NJPA

VA

Three Mile Island Nuclear Plant

RUSSIA

BELARUS

U K R A I N EChernobyl

The damaged reactor number four of Chernobyl Nuclear Power Plant

CHERNOBYL POWER PLANT

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©2014 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org

FukushimaOn March 11, 2011, one of the largest earthquakes in recorded history occurred off the coast of Japan. This earthquake created a tsunami that killed nearly 20,000 people as it destroyed buildings, roads, bridges, and railways. When the earthquake occurred, the seismic instrumentation systems worked as designed and automatically shut down the reactors at the Fukushima Daiichi Nuclear Power Station. Fukushima lost off-site power due to the earthquake damaging transmission towers. This resulted in the emergency diesel generators automatically starting to maintain the cooling of the reactors and the spent fuel pools on site. When the tsunami arrived about 45 minutes later, it was estimated to be nearly 50 feet high—much taller than the 16’ seawall constructed to protect the site. When the tsunami hit, all but one of the emergency diesel generators stopped working and DC power from batteries was lost due to the flooding that ensued. Both the emergency diesel generators and the batteries were located in the basement of the turbine building. Beyond that, four of the six reactor units were significantly damaged by the tsunami.

The loss of both AC power from the emergency diesel generators and DC power from the batteries disabled instrumentation needed to monitor and control the situation and disabled key systems needed to cool the reactor units and spent fuel pools. This resulted in damage, which is suspected to include the breech of reactor pressure vessels, leaks in primary containment vessels, and significant damage of nuclear fuel that was partially uncovered. Continued investigation will confirm exact damage as the reactor units and local areas are analyzed. Hydrogen is produced when uncovered zirconium fuel cladding reacts with water, which also resulted in two hydrogen explosions occurring in the upper part of certain reactor buildings.

Lessons LearnedMuch was learned by nuclear engineers and operators from these accidents. Although the reactor of Unit 2 at TMI was destroyed, most radioactivity was contained as designed. No deaths or injuries occurred. Lessons from TMI have been incorporated into both evolutionary and passive nuclear plant designs.

While some Chernobyl-style reactors are still operating in Eastern Europe, they have been drastically improved. Training for nuclear plant operators in Eastern Europe has also been significantly improved with an emphasis on safety.

Nearly 20,000 people lost their lives due to the tsunami in Japan, while no deaths have been attributed to radiological causes from the Fukushima accident. Radioactive material was, however, released into the air and water as a result of the accident. The effects of this contamination on the flora and fauna will continue to be monitored and studied. The Fukushima accident will improve nuclear safety as power plant operators and regulators take a closer look at the potential of natural disasters, protecting backup emergency diesel generators and batteries from being disabled, ensuring back-up systems to cool reactors and spent fuel pools are redundant and robust, and modifying hardware to improve function during emergencies.

Nuclear energy remains a major source of electricity in the United States and around the globe. The safe operation of nuclear power plants is important to quality of life and to the health and safety of individuals worldwide.

Nuclear Accidents

NORTHKOREA

CHINA

RUSSIA

SOUTHKOREA

East China Sea

North Paci�c Ocean

Sea of Japan

Nagasaki

FukushimaDaiichi

Tokyo223 kilometers (138 miles) from the plant

EARTHQUAKE9.0 Magnitude

Hiroshima

Fukushima

Minamisoma

Soma

Tamura

Iwaki

Koriyama FukushimaDaiichi

Fukushima

EVACUATION ZONE0-20 km

STAY INDOORS ZONE20-30 km

Evacuation Zones Following Earthquake

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