Nuclear and Radiation

Nuclear and Radiation

1. Describe in words what happens during nuclear fission. Use uranium-235 as an example, explaining how the reaction is started and what the products are.

Nuclear fission refers to a process whereby an atom’s nucleus gash into two or more nuclei, referred to as products of fission. When a free neutrons strike the Uranium-235 nucleus, it gash into two atoms that are smaller known as fission fragments, and other more neutrons. End products are a large amount of energy and gamma photons.

2. Lise Meitner, in about 1939, explained what happened during nuclear fission of Uranium and why a large amount of energy is released during nuclear fission. What is the explanation for this release of energy? Explain the connection of this phenomenon to Einstein’s theory of relativity, as described in the famous equation E = mc2.

Since nuclear fission is a process of splitting a nucleus into two parts, there is energy release due to a considerable mass decrease. This indicates that during this process, some of the mass of the atom is converted into energy. In nuclear fission, mass is observed which the same in Einstein’s theory of relativity, where he says that in any reaction taking place within the universe, the mass was conserved.

3. Explain what is meant by a self-sustaining nuclear chain reaction, using the fission reaction of uranium-235 as an example. Where was this first demonstrated, and when?

It is a process that takes place when a single nuclear reaction results in an average of more or one consequent nuclear reaction, therefore leading to a potential self-propagating sequence of these reactions. The process is apparent in heavy isotopes like Uranium-235; the nuclear reaction chain releases millions of times much energy in a single response as compared to other chemical reactions. This process of self-sustaining chain reaction in the nuclear was first demonstrated in Chicago Pile-1, on the year 1942, 2^nd December, during research done by Enrico Fermi.

4. Summarize the content of the famous Einstein-Szilard letter to President Roosevelt in August 1939. What action was taken as a result of this letter?

On 2^nd August, the year 1939, Einstein wrote a letter to President Franklin Roosevelt addressing a caution that the Nazis may be planning to develop nuclear weapons and that the United States should stockpile ore from Uranium and commence work on their atomic armaments. Six years afterward, in August 1945, the bombs, Fat Boy and Little Man were sent on Nagasaki and Hiroshima in Japan. This affected children, women, sailors, and soldiers all together; the detonations contributed to the end of World War II but started the Cold War that subjugated the final half of the 20^th century. This action made Einstein regret writing the letter.

5. How is the energy released by nuclear fission converted into electrical power in a nuclear reactor? Summarize the steps.

In the core of a nuclear reactor, the Uranium is arranged in bundles. These rods, together with Uranium are organized into bundles. The bundles of Uranium are placed inside a container and immersed in a coolant (in this case, water). The heat generated by the bundles of Uranium should be controlled to avoid overheating, which may result in the melting of the reactor. The Uranium bundle rods are lowered and raised to control the temperature of the core as required. These rods can as well be reduced further down to stop heat generation and shut down the core reactor to change the fuel or in case of any emergency issue. The first step in the production of electrical energy is permitting the water inside the core reactor that holds bundles of Uranium to expand by turning into steam. In the following step, the vapor leaves the container to rotate the turbine. The turbine rotates the generator, and ultimately the generator generates power.

6. Control rods are used to start up and shut down a nuclear reactor. How are the control rods used, and how do they cause the reactor to start up and shut down?

Control rods are devices utilized to suck up neutrons for the reaction of the nuclear chain occurring within the core to be stopped or slowed down by taking them out slightly. Control rods are essential in offering total control of the fission process by making sure it stays active, whereas thwarting it from reacting beyond control. The process is designed in such a manner that the control rods that are responsible for absorbing the neutrons are penetrated between fuel rods to shut down the reaction chain. If all control rods are entirely removed, the reactor starts up and begins to run hotter because the reactivity is generally above 1.

7. Where are the nuclear reactors in New Jersey located, and when did they initially start operating? How much longer are they expected to continue working?

There are three nuclear reactor stations in New Jersey; they are Oyster Creek located in Lacey Township, Hope Creek located in the Lower Alloways, and Salem situated in Lower Alloways. The Salem power plant started in the year 1977, the Oyster Creek station began in 1969, and the Hope Creek power plant opened in 1986. The Oyster Creek was expected to continue operating until 2029, but it was completely locked in September 2018. Hope Creek is expected to continue working until the year 2026.

8. Describe what is meant by alpha, beta, and gamma radiation in separate sections below. In each case, they also summarize their relative energies and abilities to penetrate the skin, and the relative threats they pose to animal life.

Alpha radiation

Alpha radiation refers to the name given to an emitted alpha particle (helium nuclei). Generally, the alpha particles have much higher energy as compared to gamma and beta because they have considerable mass, which is similar to two neutrons and two protons. They are the least harmful in terms of external contact. They do not go through the skin deeply. But when ingested or inhaled, an alpha particle can be very destructive. Conversely, they don’t result in radiation sickness but can cause cancer of the lung.

Beta radiation

Beta radiation refers to a process of emitting positrons or electrons; since they contain an electron, they are slightly heavier than gamma particles but have less energy than the alpha particles. They are approximately 8000 times smaller in size than the particles of alpha, thus making them more hare harmful. When exposed externally, it can result in burns, damage of tissues, and radiation sickness; when ingested or inhale, they cause extreme harmfulness than external exposure.

Gamma radiation

This is the name utilized for energetic photons emissions. They have no mass, therefore, no charge. They are the most harmful radiation, having no mass, they posse’s high energy photons which can penetrate numerous forms of matter. If an individual is exposed to the gamma rays, they penetrate the skin and affect all the tissues going up to the bones. They cause harmful radiation sickness and damages.

9. Define what is meant by a radioactive half-life. Then, as an example, calculate what percentage of the radioactivity being emitted from a source with a half-life of 10 years would remain after 80 years.

Radioactive half-life refers to the measure of time taken by a given substance to be reduced into half as a series of decay, thus radiation emission.

10. Where is most of the used radioactive material from nuclear reactors being stored while it decays? How long will it be before this waste is no longer dangerous?

The best storing technique is geological disposal; it is the process of burrowing the most radioactive waste deep into the ground where a human being cannot reach. Depending on the temperature, several isotopes will take minutes or hours to decay, whereas others may take more than 25 years to decompose and turn to be less harmful.

11. Summarize the three most significant nuclear accidents to date in separate sections, as listed below. In each case, explain the origins of the accident, their short-term effects on the surrounding populations, and the current status of the sites where these accidents occurred.

• 3-Mile Island, Pennsylvania, USA, 1979

An accident that took place at this power station was a result of a human and mechanical error at the utilization of the plant that later resulted in the most dangerous commercial accident related to nuclear in the history of the United States. The accident as well occurred to the incomplete meltdown that led to the discharge of harmful radioactive gasses all over the atmosphere. Approximately 2.5 million persons were exposed to little amounts of the gasses when exposed to the atmosphere. At present, the plant is permanently locked, and 99% of the fuel that was there has been removed. The coolant system present was entirely drained, and radioactive water evaporated and decontaminated.

• Chernobyl, Ukraine, USSR, 1986

The accident that took place in this power station was a result of a flawed reactor that was operated by personnel with inadequate skills. The fires and explosions released approximately 5% of the radioactive reactor into the surrounding that led to the deposition of radioactive materials in numerous portions of Europe. On the night of the accident, two plant members died, and further 28 persons died in the following week due to syndrome caused by acute radiation. Currently, the plant and the zone around are governed by the Ukraine State Agency on Exclusion Management Zone

• Fukushima, Japan, 2011

The accident that happened at this power station was triggered by an earthquake that failed the cooling of reactors and power supply. The three cores melted in the next following three days. Though there were no cases of death in the accident, more than 100,000 persons were shifted from their homes by the government. At present, Fukushima has been maintained in a steady situation. The accident resulted in water cut off to the reactors; thus, heat is being generated by a fuel, and explosions of hydrogen took place.

12. Summarize the importance of nuclear energy concerning climate change and global warming.

The nuclear power station generates no emissions of greenhouse gas when performing its operations. In the year 2018, a nuclear power plant produces roughly 10% of the total electricity consumed worldwide. As well as increasing renewable sources of energy and fuel shifting to gas from coal, higher nuclear energy generation played a role in balancing global carbon dioxide emissions. Nuclear power – as a dispatchable source of low carbon in electricity production – can contribute to the evolution to clean energy in the upcoming days.

13. Summarize the arguments in favor and against the continued use and further development of nuclear energy.

Argument against

• It is expensive and unsafe

The accidents that have occurred in different parts of the world have indicated that nuclear energy is unsafe when not in proper control. Nuclear plants are as well expensive to establish and further excess cost of storing waste from radioactive.

• Renewables

Renewable sources of energy are ready to substitute nuclear power; in fact, the world could rely on renewable sources of energy 100% by 2050. Furthermore, technology is developing every passing day.

• Nuclear-absent world

Up to date, Iran has an ongoing program for developing nuclear; the analyst continues to caution that it could be a program for developing nuclear weapons. This may trigger a war between Iran and her enemies by thinking that Iran is doing so to protect herself. So the absence of nuclear energy will result in a free and peaceful world.

Argument for

• It is safe

The technology is presently safe, and it is progressing to get more reliable and safer every day. For instance, an old plant Fukushima has the latest development of nuclear reactor designed in a manner less likely to experience a meltdown. The causes of the previous accident (tsunamis and earthquake) are currently less common.

• Climate change

It is essential to utilize all the sources of energy present because renewable energy sources are unable to overcome nuclear energy. The substitutes of nuclear power are gas and coal, which could diminish anytime.

• Potential

Nuclear power would possibly cater to the requirement of energy all over the world. So it is worth research to be conducted in that field because it is guaranteed for clean and plentiful energy.

14. Give one example of the use of radiation treatment in medicine (there are many). Include a description of the nuclear reaction involved.

Radiation therapy can be utilized to destroy cancer cells by reducing tumor size before surgery.

Radiation therapy destroys cells of cancer by damaging the molecules that are inside the body of an individual that is responsible for carrying genetic information and transfer from one generation to another. The process can smash up the DNA either by creating charged particles or directly.