by Lisa Caraballo
I am a second year student at the Macaulay Honors College at Lehman College. I am currently taking a Macaulay Honors Seminar with Professor Eugene Chudnovsky. It is the Science and Technology Seminar at Lehman College, which focuses on energy: past, present, and future. This class has taught me very much on the types of energy the world uses today, and I have come to realize that I have taken our society’s access to energy for granted. We are approaching an end to fossil fuel-based energy, as our fossil fuel sources may be fully depleted in the next 40 years. At the rate we are going, there is almost no stopping this impending doom. This is because we all use energy in excess, and the world’s population is much too large to depend solely on renewable resources like solar and wind power. I have learned in this seminar, however, that there is one viable option, which many of us, because of mostly unnecessary fears and negative publicity, are rejecting in error. I believe nuclear energy is our only practical alternative to fossil fuels, and if we do not start changing the public’s views on this energy source soon, it may be too late to prevent the damage we are bringing upon ourselves by our overdependence on fossil fuels. In this essay, I will explain my class trip to the nuclear power plant Indian Point. Even though I was previously against nuclear energy, I will also explain how nuclear power plants work, the pros and cons of this energy source, and how I have been convinced that this is a great substitute for fossil fuel energy.
In November, my class went to visit the closest nuclear power plant to New York City—Indian Point Energy Center. It was only a 50-minute car ride away. We spent a couple of hours going through various levels of security, and then we sat down to watch a thorough PowerPoint about Indian Point and nuclear energy given by our guide Patrick Faliciano. We then were able to explore parts of the power plant with Patrick. It was an enjoyable experience, and Patrick was sociable and friendly. In certain parts of the facility, we had to wear hard hats, goggles, and earplugs to stay safe. I am grateful to my program and to Indian Point for giving us the opportunity to visit. It was a huge learning experience for me. We were even served a delicious lunch during Patrick’s PowerPoint. It was a vegetarian friendly menu, much to my delight. Our whole trip took about 6 hours, excluding travel time.
Indian Point Energy Center is a nuclear power plant. It is a three-unit facility located in Buchanan, New York, just south of Peekskill. Only two of the three units are currently in use. It sits on the east bank of the Hudson River, just 38 miles north of New York City. For 26 years, two separate companies owned the. This was inefficient. Today, the company Entergy is in charge of both facilities. Entergy owns 11 nuclear plants and Exelon, another energy company, owns 14 plants. Conglomerates were able to raise efficiency to 95% and above. According to Entergy, 1,050 people are employed in units 2 and 3.
Indian Point originally was an amusement park called Indian Point State Park. The power plant was built for Con Edison. Indian Point’s unit 1 was the first of the 3 units built. It was the first to be granted permission to become fully operational. It was originally a hybrid plant with 60% nuclear power and 40% oil. In 1964, unit 1 was shutdown. Units 2 and 3 were operating by 1974 and 1976, respectively. There used to be a smoke stack in Indian Point, but it is not in use anymore and was removed. The reactors in units 2 and 3 were both manufactured by Westinghouse. The turbine generator was manufactured by General Electric for unit 2 and by Westinghouse for unit 3. Unit 2’s net electricity rating is 1035 Mega Watts, and unit 3’s net electricity rating is 1047 Mega Watts. Both facilities make up 11% of New York electricity; they power 30-40 miles diameter of Indian Point.
Nuclear power plants are very complex, and it usually takes 4-6 years to build one plant. Westinghouse and General Electric are the two main companies that build power plants around the world. Nuclear power plants can work in a few ways; Indian Point works on a pressurized water reactor. Other reactors have a boiling water reactor, but the pressurized water reactor is more efficient. In this set up, the reactor is in a containment vessel incase of a steam explosion, it will be contained. The water in this system is pressurized to increase the boiling point. Usually the boiling point is 212 degrees Fahrenheit, but in a pressurized system, the water can reach temperatures up to 600 degrees without boiling, so a steam explosion would be 90,000 gallons of water being vaporized instantly if the steam generator pipes broke. There is no such thing as radioactive water, but there is such thing as contaminated water. Nuclear power plants purify water to keep the pipes from corroding and to prevent any extra chemical reactions between ions, as could be the case with unpurified water. It is purified to .4ppb (parts per billion). All sinks and floor drains lead to a tank, and low-level nuclear waste gets shipped away.
A great amount of effort is put into building a nuclear power plant like Indian Point. Extra precautions are taken to increase the safety of the plant and everything around it. It is a common myth that because nuclear power plants use radioactive material as a fuel, it can explode just like an atom bomb. This is false. A nuclear explosion cannot occur in a nuclear power plant, only a steam explosion can happen, which is why Indian Point has a containment vessel for the reactor.
The containment vessels for the reactors are made of 8 layers of rebar welded into a net, with high-density concrete evenly poured over it. So much steel is used in the building of the containment vessel and the rebar used is so thick, that the inside of the building was dark even before the concrete was poured. The walls are 4.5 feet thick on the sides, 2.5 feet thick on the top, and 10 feet thick on the bottom. Other than holding the reactor, steam generator, reactor coolant pump, and pressurizer, the inside of the containment vessel is mostly empty space so it could completely contain a steam explosion.
Nuclear Power plants must have a license to operate, and the license expires after 40 years. Contrary to popular belief, this 40 year time period was determined for tax/financial purposes, not because the power plant will be unable to operate the same after 40 years. No original equipment of the Indian Point Power Plant is left except the reactors; everything has been replaced to upkeep.
The reactor is about 44 feet tall and weighs about 500 tons. It is submerged in water, and the whole process of changing the fuel assemblies is done underwater as well. The reactor holds all the fuel. In a fuel assembly, the uranium pellets fill a rod one on top of the other. The fuel rods filled with pellets are groups into fuel assemblies. The pellets heat up, which heats up the metal, which heats up the water that the reactor is immersed in. The force of the steam created by this heat powers the turbine, making it turn. There are 240 pellets of uranium in each of the 204 rods in one assembly of fuel. About 193 assemblies are used in one reactor, and an assembly can be used for 6 years. One pellet of uranium is equal in energy output to about one ton of coal. There are almost 9.5 million pellets of uranium in one reactor, and in the United States there are about 104 reactors. That is a massive amount of energy output, and I believe that a lot of people are not aware of benefits like this when it comes to nuclear energy. The rods control the number of neutrons. It can be made out of silver, hafnium, cadmium, or boron, all of which absorb neutrons. Sometimes boric acid, another neutron absorber, is put into the fuel so the fuel can be evenly used. To balance the acidity of boric acid, bases like hydrazine are added to neutralize it.
The low-pressure turbine weighs 100 tons and has to spin at 1800 rpms (revolutions per minute). The shaft is 30 inches thick and 12 feet long. The resistance from the rotation is so strong that the shaft twists like rubber 280 degrees. I found that to be one of the most fascinating things I learned during my trip to Indian Point. What I also found to be very interesting that I learned both in my class and on the trip was the chemistry behind nuclear fission.
Uranium atoms remain dormant until activated within the reactor. Neutron energy is thrown at the uranium atoms until they split, creating energy. This is nuclear fission. The atoms split into two smaller atoms and at the same time, radiation and heat are created. The atom splits, and more neutrons split the smaller atoms further, creating a chain of reactions. The type of chain reaction depends on the size of the uranium. A minimum of about 6 kg of uranium is needed to start a chain reaction. This is called a critical mass. This is why the reactors use small pellets of uranium- it is a way to control the energy being released.
Uranium-238 is radioactive, but not highly radioactive. Its half-life is 4.5 billion years. After 4.5 billion years, half of the uranium present will go through an alpha decay, becoming another element. The preferred isotope of uranium for use in nuclear reactors is uranium-235. However, it cannot be obtained in the natural decay cycle, and it is found in only 1% of most uranium sources on earth. The half-life of this isotope is 250 million years, so it is slightly more radioactive than uranium-238. The uranium that is going to be used as fuel in the reactors is enriched with uranium-235 to at least 2-4%. What I find to be frightening about this enrichment process is that if a country enriches their uranium-238 with uranium-235 to 20% or above, it becomes very easy to enrich the uranium further to 90% uranium-235, which makes it possible to create an explosive chain reaction to use in nuclear weapons. I do not trust that every country, given this ability to enrich uranium, will only enrich to fewer than 5%, the current international regulation for uranium enrichment. While I am in support of nuclear energy as our main energy source, I do not support nuclear weapons.
Like all energy sources, there are pros and cons to nuclear energy, and to having nuclear power plants close to residential areas. What is important is the weight of the pros versus the cons, compared to other energy sources. I feel that many people are misinformed about the real benefits and the real downsides of nuclear energy. I know that this is true because I too was incredibly misinformed, and I learned the truth during my honors class and especially during the trip to Indian Point. I learned that Indian Point gives 100% of its power to New York City. It is the closest nuclear power plant to New York City, and it is so close because of the high need for energy in New York. New York City uses half of all New York power supply, and of the 6 nuclear power plants in New York, 30% of electricity of New York is provided by these nuclear facilities. Indian Point is the least expensive producer of electricity, so it always puts all of its electricity output 100% into the power grid of New York, even when the demand for electricity is lower like at night. In this way, the fossil fuel plants can cut back their emissions.
The main benefits of nuclear power plants are high efficiency and low emissions. In terms of efficiency, recall that a pellet of uranium, the main energy source of these power plants, is 2000 times more efficient than the same size piece of coal. In terms of emissions, uranium gives 0 emissions, unlike fossil fuels. Nuclear power plants have highly radioactive waste but the amount is negligible compared the other kinds of waste and it has the ability to be reprocessed. Our guide Patrick told us that all of the used fuel from all the reactors in the United States could fill one football stadium. Compare that to our enormous everyday waste like garbage that fills whole islands, and to the immense emissions from fossil fuels that is raising our carbon footprint and polluting our planet. Low-level nuclear waste is buried in the ground and high-level waste is reprocessed (in countries excluding the United States).
According to Patrick, based on how many nuclear reactors there are currently in the world, we have about 500 years supply of Uranium naturally occurring in the Earth. However, according to our Professor Chudnovsky, since many countries are planning to build many more nuclear reactors (ex. China plans on building 100 more nuclear power plants) there is really about a 200-year’s supply of uranium left. Also, many countries reprocess their used fuel. The United States does not reprocess because of our former President Carter’s concern of the transportation of the radioactive used fuel, which can contain trace amounts (<1%) of plutonium, a radioactive element used in nuclear bombs. A 200-year’s supply of uranium is still more than the less than 50 year’s supply of fossil fuels left. We need to switch to nuclear energy if we want to maintain the society we live in today.
Many people are concerned with the small amount of radioactive waste that is being produced by nuclear reactors. The used fuel is put in the spent fuel storage. It is a 40 feet deep pool where currently in Indian Point 1,380 fuel assemblies are stored until the radioactivity level of the fuel lowers. There is 36 years of high level waste stored there, in just one large pool. It takes thousands of years for the waste to ultimately stabilize, but only about 210 years for the radioactivity level to lower to the original low level of uranium. This storage was not meant to be a permanent storage facility, and it is already full. The United States does not reprocess fuel so Indian Point has no choice but to put lower level fuel assemblies into a container, give it a salt treatment, seal it in a bigger container, put it on a crane, and store it outside. Although this is still very safe, it is not the preferred method of dealing with this waste when we can continue to reuse it. Congress is currently debating reprocessing again.
Indian point takes water in from the Hudson River that flows next to it to cool the equipment and to use for the reactor, after purifying it. 1.7 million gallons of water per minute is being pumped out and back into the river. There was a recent newspaper article that turned the surrounding neighborhoods against Indian Point. It claimed that Indian Point kills 1.2 billion fish in a year. This was true, but most of the fish being killed were fish eggs, most of which die anyway, and there was no significant impact on the surrounding marine ecosystem. Indian Point now has a wide grating where the water is taken in preventing large objects from going in. Then the grates are sprayed to shake any fish loose, and they are flowed onto an underwater belt that transfers them back into the ocean away from the grating. 98% of fish are saved. There is now a wedge wire system too that increased the fish egg survival rate from 38% to 89%.
Another issue with the flow of river water into and out of the nuclear power plant was the temperature of the water. The water leaving the power plant is slightly but not significantly hotter than the water in the environment. A water quality certificate allows Indian Point to raise the water temperature a maximum of 4 degrees Fahrenheit a diameter of 128 feet around the plant. It turns out that around the plant there is only a 1.4-degree change, and by 200 feet around the plant, there is no difference in temperature. Again, this had no significant impact on the surrounding marine ecosystem.
Before taking this honors seminar with Professor Chudnovsky, I was anti-nuclear energy. I understood that it was cleaner energy than fossil fuels, but I was not aware that our fossil fuel sources are being depleted. I also thought that it was too high of a risk to have too many nuclear power plants around because I thought they would increase everyone’s risk for cancer or expose us to higher radiation levels. The truth is, the radiation levels are no higher than what you are exposed to on a daily basis. All radiation in the facility is well contained because the reactor is immersed in water. I was also scared of the idea of nuclear power plants because of past disastrous incidents the world has seen with power plants like Chernobyl, where many people died of radiation sickness because of an explosion in the reactors, and radiation was spread across countries. In reality, many people are misled about this incident. I learned on my trip that the set up of the Chernobyl nuclear power plant was much different than that of any used today, and especially different from Indian Point and the other US reactors. The Chernobyl reactor was covered in graphite instead of water. When the malfunction happened, instead of the reactor immediately shutting down like it would in today’s reactors, it continued to heat up because of the graphite. A steam explosion occurred when the pipes broke, and the radioactive material was swept up in the steam explosion. Another difference between Chernobyl and Indian Point is that Chernobyl had its reactor in a regular building instead of a containment vessel. The steam explosion caused the building to explode as well, and the radioactive material was exposed to the air and drifted throughout the region with the wind. This cannot occur in Indian Point; it is much safer and has a better design.
People hear about the Chernobyl incident and assume that it can happen in any nuclear power plant. This false belief needs to be extinguished if we want to prevent a disaster that will affect the whole world. Building more nuclear power plants now will help us be sustained for longer energy-wise once the fossil fuels are used up. I hope that you have learned a great deal from my essay, and changing even one opinion is a step closer to changing the world’s negative view of nuclear energy into a positive one.
