Franklin High School

2008 Critical Issues Forum

Nuclear renaissance: Benefits versus Risks

Participants:

Vinh Bui, Christina Modica,

Kalissa Morgan, Will Sorensen

Coordinator:

Rene Mendoza

Benchmark I

Background Knowledge

Objective 1-Energy Sources Present in the World

What is “Energy?” Wikipedia defines it as "a scalar physical quantity that is a property of objects and systems which is conserved by nature." ("Energy")But in today’s environment, energy entails a much broader definition. It is the basis of all human civilization, giving rise to our economies, infrastructure, and life as we know it. But what types of energy resources do we use? And how are they implemented in the world? These are the begging questions we will answer in this project.

The world’s various energy sources can be split into two categories – renewable and non-renewable. Renewable energy sources are those that can be naturally replenished in a relatively short time period. Examples of renewable sources are solar, wind, and geothermal energy. Non-renewable energy resources are those that will eventually run out or become too expensive and damaging to the environment, halting their use. For instance, the uranium ore used in nuclear power plants and fossil fuels are spent indefinitely when used once and take millennia to redevelop. Although renewable energy sources can be renewed quickly, they make up only 13% of the world’s primary energy, leaving the non-renewable energy level at 87%.

As non-renewables remain the world’s dominant energy resource, they will be the first we delve into. The largest source of non-renewables is from fossil fuels. Fossil fuels provide the world with coal, petroleum, and natural gas. These resources are present only in limited amounts, which have been formed over millions of years; they do not regenerate quickly enough. The basic technology that allows energy production from fossil fuels is burning the fuels (releasing many byproducts into the atmosphere) to produce steam, which drives a turbine and thus generates electricity. They are also used to power automobiles and in the manufacturing of numerous goods through the refinement of crude oil into petroleum-based products. Coal is the most prevalent fossil fuel used in the world and the table below summarizes the world’s distribution of coal.

Proved recoverable coal reserves at end-2006 (million tonnes (Teragrams))^[39]
Country	Bituminous (including anthracite)	Sub- bituminous and lignite	TOTAL	Share
United States of America	111,338	135,305	246,643	27.1
Russia	49,088	107,922	157,010	17.3
China	62,200	52,300	114,500	12.6
India	90,085	2,360	92,445	10.2
Australia	38,600	39,900	78,500	8.6
South Africa	48,750	-	48,750	5.4
Ukraine	16,274	17,879	34,153	3.8
Kazakhstan	28,151	3,128	31,279	3.4
Poland	14,000	-	14,000	1.5
Brazil	-	10,113	10,113	1.1
Germany	183	6,556	6,739	0.7
Colombia	6,230	381	6,611	0.7
Canada	3,471	3,107	6,578	0.7
Czech Republic	2,094	3,458	5,552	0.6
Indonesia	740	4,228	4,968	0.5
Turkey	278	3,908	4,186	0.5
Greece	-	3,900	3,900	0.4
Hungary	198	3,159	3,357	0.4
Pakistan	-	3,050	3,050	0.3
Bulgaria	4	2,183	2.187	0.2
Thailand	-	1,354	1,354	0.1
North Korea	300	300	600	0.1
New Zealand	33	538	571	0.1
Spain	200	330	530	0.1
Zimbabwe	502	-	502	0.1
Romania	22	472	494	0.1
Venezuela	479	-	479	0.1
TOTAL	478,771	430,293	909,064	100.0

http://en.wikipedia.org/wiki/Coal

Natural gas provides power generation for domestic electricity purposes, automobile propulsion, and much more. Before the gas – primarily methane – can be used, it must be extensively processed, producing many other gases, such as carbon dioxide, as condensate byproducts. Below is a map of the world’s distribution of natural gas production.

http://www.rrc.state.tx.us/commissioners/williams/energy/images/2919957WORLDGASRESERVES.gif

Petroleum remains another large source of fossil fuel energy. However, its supply is rapidly decreasing due to its overconsumption, especially by the US. This has led to soaring gasoline prices around the world and an extensive search for alternative fuels.

http://en.wikipedia.org/wiki/Image:Susquehanna_steam_electric_station.jpg

Non-renewables also provide nuclear energy through the use of uranium ore. Uranium must be mined from the Earth's surface, and once used, it is gone. When obtained, the uranium is enriched from U-238 to U-235 and used as fuel in a nuclear reactor. The reactor harnesses the energy produced by nuclear fission, heats up water, and creates steam to turn a turbine for electricity. Nuclear energy costs the same as coal production while producing much energy and does not contribute to the greenhouse effects of burning fossil fuels, but have the potential to be extremely dangerous. These aspects spark controversy in the use of the technology, although 11%

http://en.wikipedia.org/wiki/Image:World_renewable_energy_2005a.png

of the world's power stems from energy produced from nuclear reactors.

http://www.ni-photos.jmcwd.com/altahullion-wind-farm-turbines.jpg

http://en.wikipedia.org/wiki/Image:Orontes.jpg

Non-renewables create the most amount of energy present in the world, but renewables provide a means for obtaining energy indefinitely. Hydro power is the most dominant source of renewable energy. Used for millions of years, water has provided power mainly through the employment of waterwheels, hydroelectric technology, tidal power, and wave power. All water systems utilize the movement of water in oceans, lakes, rivers, and streams to turn turbines and generate electricity. The prevalence of water in the world makes this energy source so widely available. Wind power is the second most used method of renewable energy, which is harnessed through wind turbines. Placed on mostly flat, open areas, windmills are spun by the wind, and thus, turn a shaft connected to a generator, which creates electricity. A relatively simple idea, power produced by wind has quadrupled between 2000 and 2006 on a global scale. The use of wind farms produces no fuel emissions, but as usual, there are safety concerns and environmental hazards, such as on birds and other wildlife. Bioenergy consists of another energy source that involves burning biological material for energy. Biomass is obtained mainly through the burning of plant material or animal waste, such as "wood, crops, manure, and some garbage." ("Biomass...") "Biomass energy brings numerous environmental benefits—reducing air and water pollution,

http://en.wikipedia.org/wiki/Image:Solar_two.jpg

increasing soil quality and reducing erosion, and improving wildlife habitat." ("How Biomass...") Other types of bioenergy stem from alternative fuels to petroleum, such as biodiesel and various biofuels produced by ethanol, woodgas, etc. All of these use natural material easily renewed, but as they are burned to produce energy, bioenergy material still contributes to the greenhouse effect and global warming. The benefit is that the impact is much less than that of fossil fuel usage. Solar energy, energy obtained directly from the Sun, can be employed in multiple ways to provide power. Solar energy can generate electricity through photovoltaic solar cells, concentrated solar power, solar updraft towers, solar power satellites in space, etc. Each uses some form of a solar panel to concentrate sunlight and transfer it into a useable source. Geothermal energy is the last remaining renewable source. Energy is absorbed from heat present in the Earth's surface or collection of heat in the atmosphere and oceans. Either through dry steam, flash, or binary power plants, the heat gathered powers a turbine for electricity. As a renewable energy source, "water is replenished by rainfall and the heat is continuously produced inside the earth." ("Geothermal...") Geothermal plants can leave environmental concerns for regions surrounding one. Nevertheless, geothermal energy is relatively safe, clean and cost-competitive. And although geothermal energy constitutes approximately 3% of renewable energy sources, it makes up less than 1% of the world's energy output.

http://en.wikipedia.org/wiki/Image:US_historical_energy_consumption.PNG

As previously stated, non-renewable energy sources contribute to most of the world's energy yield. However, major countries use a combination of non-renewable and renewable energy sources to efficiently use resources and provide energy to their countries. In the United States, petroleum remains the largest source of energy consumed, despite wind power as the largest source of electricity produced.

Electrical Production in the United States for 2006
Power Source	Units in Operation	Total Nameplate Capacity (MW)	% of total Capacity	Annual Production (billion kWh)	% of annual production
Wind Power	341	11,603	1.08%	30.3	0.7%
Solar Energy	31	411	0.04%	2.1	0.1%
Petroleum Coke Fueled Boiler	31	1,754	0.16%	46.4	1.1%
Oil Fired Boiler	327	34,975	3.25%	7.8	0.2%
Nuclear Power	103	105,584	9.82%	787	19.4%
Natural Gas Fueled Boiler	776	97,632	9.08%	159	3.9%
Diesel Generators	4,514	8,563	0.8%	13.8	0.3%
Incinerators	96	2,671	0.25%	12.3	0.3%
Hydroelectric	4,138	96,988	9.02%	282	7.0%
Geothermal	215	3,170	0.29%	13.5	0.30%
Fuel Oil	13	956	0.09%	8.5	0.2%
Combustion Turbine Generators	2,882	155,227	14.4%	147	3.6
Combined Cycle Natural Gas	1,686	216,269	20.1%	505	12.4%
Coal Fired Boilers	1,460	333,115	30.9%	1,995	49.1%
Biomass	270	6,256	0.58%	53.5	1.3%

http://en.wikipedia.org/wiki/Energy_use_in_the_united_states

In the United Kingdom, fossil fuel energy consumption remains dominant, followed by primary electricity sources (mainly nuclear), and other renewables. China has risen to the top rungs of electricity generation in recent years. As of the end of 2007, China's "total installed electricity generating capacity...hit 710 GW." ("Energy Policy of China") Below is a graph of China's current production by source.

http://en.wikipedia.org/wiki/Image:Electricity_production_in_China.PNG

Russia remains a large player in the production of energy. As the world's second biggest producer of oil and first among non-OPEC countries, it shares 12% of global oil production. Russia also has a wide variety of other resources, such as a large coal industry, uranium ores, nuclear plants, solar energy, hydro energy, geothermal energy (the most developed renewable energy resource in Russia), and the like.

Energy sources present in the world provide different amounts depending on region, climate, and availability. However, non-renewable and renewable sources all contribute to one goal – the generation of energy. Non-renewables remain an essential resource for the world to continue operating under normal conditions. However, the depletion of fossil fuels and the increasing threat of global warming prompts numerous concerns to arise. Such concerns can be dealt with through a gradual change to nuclear power. As cost-effective, highly productive, and less wasteful than fossil fuel sources, nuclear power offers an alternative to the major employment of coal, oil, and natural gas. However, because the uranium used in the process is limited, should the world concentrate more heavily on renewable sources of energy, such as bioenergy, hydro power, and solar energy? That is a whole other topic to consider, but in the meantime, energy as we know it today is something that the world cannot be without, and the sources we gather it from, renewable and non-renewable, continue to be indispensable.

Objective 2-On the Nuclear Fuel Cycle and Related Topics

Nuclear Power has been cast in many contrasting lights in the few decades since its inception, but whether it truly is the key to a future of clean energy, the eventual bane of mankind, or an environmental scourge, it has both flaws and strengths that must be thoroughly examined. A good location to start such an examination would be the basics of the technology that begets nuclear energy. Therefore, an analysis of the workings and various types of civilian and military nuclear reactors is first in order.

Nuclear reactors derive their energy from a physical process called fission, which is the splitting of the nuclei of large, unstable atoms (called radioactive elements), into smaller, more stable nuclei. Normally fission, when it occurs in nature, is a slow, rare, spontaneous process, seldom more than a few atoms at a time; it creates the phenomenon known as radioactive decay. On the other extreme, mankind has harnessed fission to create atomic weapons, where the fission reaction becomes an uncontrollable chain reaction which continues with a tremendous release of energy until it exhausts all available fuel, leaving miles of scorched earth and a plume of radioactive dust in its wake. The fuel that powers these weapons is one of two chemical elements, either Plutonium (chemical symbol Pu) or Uranium (symbol U). Of the two, uranium is of greater concern to the purposes of nuclear power; it is obtained from the earth through a cycle called the nuclear fuel cycle which will be delved into later. Plutonium is much more rare, and is very difficult to obtain as it can only be produced by man inside another uranium-fueled nuclear reactor.

The key to a nuclear reactor is the control of a fission chain reaction to generate a stable, relatively constant output of power. This is accomplished by “moderating” the flow of neutrons which is emitted during the reaction so that only the correct amount of atoms in the fuel mass

undergo fission, generating just the right amount of energy. Most all conventional nuclear power reactors share a common basic process by which they capture this energy, which is released in the form of heat. The core consists of a set of fuel source rods surrounded by a neutron-absorbing set of control rods (frequently graphite or boron) in most cases. The fuel and control rods are suspended in the shielded and isolated reactor vessel, which is filled with a liquid moderator and heat transfer agent, most commonly water, although this is one place the various reactor design deviate substantially. This agent is used either directly to produce steam and turn a turbine to produce electricity, or indirectly produce steam by transferring energy to a secondary heat transfer system which then generates the steam to power a turbine and create electricity, thus isolating radioactivity in the first heat transfer system. There are many different designs for nuclear reactors; some of the key types, along with their benefits and drawbacks are summarized below.

Boiling Water Reactor

http://en.wikipedia.org/wiki/Pressurized_water_http://en.wikipedia.org/wiki/Pressurized_water_reactor

reactor

There is only one moderator/coolant system in a BWR, and it contains normal water. The system is not under enough pressure to keep the water from turning to steam.

Because it features only one coolant system, the radioactivity from the fuel rods permeates the entirety of the system, meaning a leak anywhere in that system releases that radioactivity into the environment.

Pressurized Water Reactor

Both the neutron moderator and the coolant (heat transfer agent) in the primary and secondary systems are normal water.

This system is advantageous in that the radioactivity of the fuel rods is contained in the primary system, and if the reactor is functioning properly should never mix into the secondary system, where it has a greater probability of being released into the atmosphere. The greater complexity of the system does mean there is a greater chance for a mechanical failure; the pressure under which the primary system also creates a greater risk for an explosion which releases much radioactivity as the pressurized water flashes to steam and rapidly expands.

Pressurized Heavy Water Reactor

These reactors are very similar to the pressurized light water reactors, except they use water that is entirely composed of Deuterium Oxide (D₂O). Deuterium is an isotope of hydrogen with two neutrons in its nucleus instead of one; the advantage to this is that heavy water is a much more effective moderator than normal water. The disadvantage lies in the extreme cost of heavy water in constructing the reactor, and in its slow decay back into ordinary water.

Many other reactor types also exist, such as liquid sodium moderated reactors, fast breeder reactors, a thorium powered reactors, but they provide a very small percentage of the world’s nuclear energy, and going into their technical details would move beyond the scope of this paper.

Because of the tremendous power inherent in the harnessing of the atom, Nuclear energy has developed a complex duality, made up of two very similar yet distinctly different sectors, the civilian sector and the military sector. Although nearly they apply fundamentally the same principles of physics, they have several key differences that drastically alter their ramifications for society.

Civilian use of nuclear energy is characterized by the use of fission power plants to generate electrical energy for public consumption. These power plants, though varied in design and scope (as detailed above), all function in similar regards. The grade of the Uranium fuel varies based on the exact specifications required for the reactor, but is generally around 5% enriched for civilian uses¹. The possible risks in producing the fuel for these civilian reactors have slim probabilities of occurring, but are severe should they come to pass, thus a thorough examination of them is warranted.

To obtain fuel to power a civilian nuclear reactor, a process must occur called the nuclear fuel cycle. This process is long and complex, and has many potential security vulnerabilities that must be addressed. It begins with the mining of raw Uranium ore. Depending on the depth of where the uranium ore is located, mining is accomplished by either surface mining (also known as open cut mining) or various underground techniques. Surface mining requires a vast amount of land to provide the surface area necessary to produce profitable quantities of ore; also, large amounts of land must be moved around on the surface, causing considerable environmental damage. Although underground mining involves less land and earth-moving, it too has unique

dilemmas which must be solved to be successful. The mine must be well ventilated to prevent radiation exposure to the miners, and be reinforced to prevent collapses, among many other difficulties. Another common mining technique is called “in situ leaching”, where deposits in sandstone are extracted by dissolving the uranium via a chemical solution of highly corrosive acids and recovering it in a deep well². Although “in situ leaching” can have drastic environmental effects, if done properly those effects can be minimized; it also avoids the need for the next step, milling. Mining has little security risks associated with it, as Uranium ore alone can not be used as a fuel source for a nuclear weapon, and its latent radioactivity is so low that it would be of little use in a dirty bomb.

Figure 1.1- Uranium ore

http://www.wise-uranium.org/nfcc.html

            The process continues with milling, extracting the uranium from the ore obtained in the mine. This is done by leaching, where a strong acid (ex: sulfuric acid) or alkaline is used to

dissolve the uranium which precipitates into a solution as a concentrate (“in situ leaching” is this same process, just done before removing the ore from the ground). This yields uranium oxide (U₃0₈), which is also called yellowcake for its color; the uranium oxide is then ready to undergo conversion. Milling again prevents few security vulnerabilities, as the uranium oxide can not be used as nuclear fuel before it is enriched. It does gain slightly more value for use in a dirty bomb; however, it is still not a strong candidate for theft for that purpose as many other radioactive materials exist that are both much easier to access and much more radioactive.

Figure 1.2- Yellowcake

http://www.uic.com.au/nfc.htm

             Since yellowcake is not usable as a fuel, it must be converted to another compound, uranium hexafluoride (UF₆), by chemical means in order to undergo enrichment. UF₆ is very hazardous because it is radioactive and can cause severe kidney damage. Uranium hexafluoride

is a solid at room temperature but can be changed to its gaseous form (which is used for enrichment) at about 134°F (57°C)³.

Converted Uranium Hexafluoride contains two isotopes of Uranium, Uranium 235 and 238. Since U-235 undergoes fission much more readily than U-238, a higher concentration of U-235 is desired, but unfortunately, U-238 is naturally far more abundant. To achieve this higher than natural concentration, enrichment by way of gas centrifugation or gas diffusion is used with uranium hexafluoride as a feed. During the process of gas centrifugation, UF₆ is placed in a sealed cylinder and rotated at a high speed. This creates a strong centrifugal force that pushes the heavier U-238 to the outside, and keeps the lighter U-235 to the center where it is collected. During gas diffusion, UF₆ solid is melted and the resulting gas is sent through pipelines where it is pumped through special filters called barriers or porous membranes. As U-235 diffuses at a faster rate than U-238 due to its smaller molecular size, and thus higher root-means-square speed (a measure of the average speed that particles of a gas are traveling), more of it passes through the barrier. After diffusion, the gas is cooled back to a solid. Finally, the resulting uranium is analyzed to measure the percentage of U-235 in the sample; the process is repeated until it meets the required enrichment level for its application⁴. However, the technical precision required in the process increases as the enrichment level desired does, so it proves very difficult to generate highly enriched uranium. Enrichment presents virtually all of possible security risks and chances for the diversion of materials; the immense technical knowledge and specialized equipment necessary to carry out enrichment virtually negates the possibility that nuclear terrorists might obtain uranium ore and enrich it themselves, however after the uranium has been enriched it becomes a prime target for theft. Terrorists seeking fuel for a nuclear weapon or dirty bomb might plot to obtain the uranium during transport, or from either the enrichment facility or the

plant it is destined to power. But a more worrying risk would be the diversion of the enriched uranium to a clandestine nuclear weapons program in a rogue state. Using the enriched uranium as fuel for a secret supply of nuclear weapons, the state could potentially release the horrors of the atomic scourge on the world, ending thousands, maybe even millions of lives in a single grotesque flash, and scattering radioactive fallout across the globe.

Figure 1.5- Centrifugation

http://www.nrc.gov/materials/fuel-cycle-fac/ur-enrichment.html

Figure 1.6- Diffusion

http://en.wikipedia.org/wiki/Nuclear_fuel_cycle

These security risks, coupled with lingering questions about the storage of radioactive waste and plant operating safety have created a “Not in my backyard” mentality in many countries that limits the expansion of the application of nuclear power. This is especially true in the US, which derives approximately 11% of its energy from nuclear power, and has constructed no new plants since the 1970’s ⁵. France, by contrast, leads the world in nuclear energy usage, producing 75% of its energy with nuclear plants; other countries that implement civilian nuclear programs include Lithuania, Spain, Japan, Canada, South Africa, Mexico, India, Pakistan, and many others⁶.

Military applications of nuclear energy tend to be much more intensive (not to mention dangerous) than civilian uses. First and foremost are nuclear weapons, which require highly enriched uranium or plutonium, which is only obtainable from a highly complex experimental breeder reactor. Thus, ordinary civilian nuclear fuel does not meet weapons specifications, making it difficult for terrorists to construct high powered nuclear weapons from stolen civilian fuel. Much easier would be for terrorists to steal an existing warhead, such as one from a loosely secured nuclear depot in the former eastern bloc, or other territories in what was the USSR. Militaries also use nuclear energy to power large naval vehicles, such as aircraft carriers. These ships carry several complex reactor systems, which generally use weapons grade fuel, which is approximately 90% enriched, as opposed to civilian reactors, which use 5% enriched, meaning the naval reactors need their fuel rods replaced once every 19-20 years as opposed to every 3 to 4 years⁷. The United States and Russia are the largest military users of nuclear energy, but other nations with internationally recognized atomic weapons programs are the United States, the former Soviet Union, the United Kingdom, France, the People's Republic of China, India,

Pakistan, and North Korea⁸. Israel is also suspected of military nuclear research, although they have never formally announced their capabilities⁹. Fuel or weapons tech stolen from any of these nations’ militaries would prove invaluable to terrorists seeking to deploy nuclear weapons or commit other acts of nuclear terrorism, or aid tremendously any rogue state seeking to create its own nuclear weapons program.

Though fraught with the possibility for nuclear terrorism and the diversion of sensitive radioactive materials into the hands of rogue nation-states, Nuclear Energy provides much needed power for humanity with unique benefits over traditional fuel sources. With proper oversight and security, the risks surrounding the Nuclear fuel cycle can be minimized, and the globe stands to gain much for an expansion of Nuclear energy.

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