Implications Fission Reactors And Nuclear Science Applications English Language Essay

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The Purpose of this paper is to inform people on the basic principles of a nuclear reactor, the problems and benefits associated with waste or by-products from a nuclear reactor. Also contains a look at thorium reactors and Fast Breeder Reactors and Explains their advantages over current reactors, explains the current planned reactors and the promises they bring.

run through of how the reaction occurs and the vital factors in a nuclear reaction. And a Quick brief on what is to come and what is to be expected of the next generation of nuclear reactors.


As the world starts technologically advancing and populations start physically expanding, people need large sources of power to fuel their daily activities. The main purpose of the Nuclear reactor is to provide the power that is demanded by the populace. They also Produce Useful radioactive isotopes in Agriculture, Engineering and Medicine.

However, in order to do all these things they have a high cost, and the drawbacks are hazardous. Despite this, recent advancements and theoretical developments have provided the blue prints for safer and less detrimental modern reactors.

This report includes a detailed breakdown of the basic principles of a nuclear reactor and how energy is produced. It will also cover several other things such as Uses for waste products, uses of by products from the reaction (neutron scattering) and newer designs for nuclear reactors that optimize energy collection and reduce waste production.


For a Nuclear reactor several things are needed in the actual reaction in order for the reactor to generate energy. The main goal of the reaction is to generate heat and to do this a reactor requires:

1. Fissile Material (fuel)

2. Coolant

3.Reactivity Control

4. Electricity Power generation

5. Drawbacks


Fuel - For the reaction to occur a thermal fuel or fissile material is necessary to start the process, this is usually an isotope of an element with a large atomic radius, such as U-235. Isotopes are different types of atoms of the same chemical element, due to there being a larger or smaller number of neutrons inside the nucleus of the atom, the amount of protons remain the same however.

Because of the large and unstable nucleus of these isotopes they are often called radioactive isotopes, due to the constant radioactive decomposition of the element due to alpha and beta decay. This unstable state makes them perfect candidates for fission reactions. When an Unstable Isotope such as U-235 is struck by neutron, it will sometimes cause the atom to 'split' into two smaller elements and release several free neutrons to be used in further fission reactions.

When the Atom splits, the two new Atoms move apart at incredible speeds which is then converted to heat as they slow down due to the use of a moderator (e.g. water). This heat is then absorbed by the coolant.


A coolant in the nuclear reaction is used to remove the heat generated in the reaction and carry it elsewhere. It can also be used to absorb heat from the moderator, and in some cases the coolant is the moderator (such as in a standard U-235 reactor) e.g. Water as it has a very high heat capacity. uesc_07_img0406.jpg

Picture retrieved from sourced from Oak Ridge National Laboratory

Reactivity Control and Power Generation

The rate of reaction in a nuclear reactor is controlled by using control rods that are made out of a nuclear poison so that they can absorb neutrons. The fewer neutrons in the reactor, the less fissile reactions taking place. This is seen when the control rods are pushed deeper into the reactor, they absorb more neutrons, lowering the amount of reactions. And when they are pulled out, there are more free moving neutrons so more fission reactions take place.

The energy released in the fission process generates heat, some of which can be converted into usable energy. A common method of gathering this thermal energy is to use it to boil water to produce steam which will then turn a steam turbine connected to a generator in order to produce electricity.

Drawbacks of nuclear reactors

Although they are capable of producing tremendous amounts of energy, Nuclear reactors are hazardous as they can melt down at any time if accidents occur causing wide spread destruction (Chernobyl).

The waste products of your average U-235 reactor are still very radioactive and dangerous to organic compounds. It has a half life of hundreds of thousands of years meaning it takes that long to decay to half the original amount. As it decays it emits alpha radiation (helium nucleus, 2+ valency), beta decay (increase of atomic number and production of one free electron 1- Valency) and Gamma radiation (high frequency electromagnetic waves).

The waste products from standard U-235 reactors can also be used to create nuclear weapons from waste products such as Pu-239

Neutron Scattering

Neutrons readily interact with atomic nuclei and magnetic fields making them useful probes of structural and magnetic measurements of compounds.

Because neutrons are so readily produced in nuclear reactors it makes nuclear reactors a vital source for structural and magnetic analysis of compounds such as in proteins and DNA.

ANSTO is an organization leading the way in neutron scattering analysis, because neutron scattering provides such accurate breakdowns of substances down to the molecular level. ANSTO offers a large variety of these analyses through the use and hire of its equipment and reactors. This has helped many scientists in a range of fields obtain extremely accurate information regarding the structure of materials under different conditions at atomic or molecular levels.

Uses of waste products

Although the waste products of nuclear reactors have negative impacts there are quite a few positive impacts and uses of nuclear waste.

Cobalt-60 can be used in industrial radiography as it emits short range gamma rays and x-rays. The gamma rays pass through the material and are then collected; this detects any faults or problems with the desired material. Cobalt-60 is primarily used as it only emits short range gamma rays for the extent of its use until it decays too much.

In medicine, Ga-67 can be used to help scans in identifying areas of infection or injury in the body. The human body tends to treat Ga-67 as iron and so it sends it to areas of infection or injury. Scanning devices such as X-rays can then detect where the Gallium-67 has gone and allows doctors to see where internal injuries or infections may be. Because Gallium-67 is slightly radioactive in that it emits low energy radiation not harmful to the human body the nuclear scanning techniques can detect it.

Modern Reactors

As Humanity continues to advance it technological capacity we are coming up with better nuclear reactors with optimum power production and very little or less hazardous nuclear waste.

These new nuclear reactors are often classified as generation IV reactors. Although many of them are still under design and construction, they hold very promising futures for nuclear reactors in all countries.

Fast Breeder Reactors

Fast Breeder Reactors make use of non-fissile material e.g. U-238 and convert it to fissile material (Pu-239) this is possible because of the use of a liquid sodium coolant that allows absorption of neutrons in the fuel.

Because the reactions are fast and the energy is absorbed by the liquid metal, a moderator is not required therefore making all nuclear reactions involving this reactor faster than a standard reactor, generating more power, and uses radioactive waste such as U-238 as its fuel source lowering the amount of radioactive waste left over from other nuclear reactors


Fast Breeder reactor

Unknown Source

found on Wikipedia

Thorium Reactors

Thorium Reactors are the most attractive modern generator at this point in time as all countries have their own personal supply within their own lands. As well as this, thorium generally only occurs in one isotope (Th-232) so it is not necessary to separate it from other thorium isotopes unlike with Uranium fuel we're there are usually several other isotopes mixed in with U-235.

Thorium reactors also don't produce any serious detrimental radioactive waste besides U-233 which is still extremely hard to chemically separate from the original compound, therefore almost no uranium can be proliferated for the construction of nuclear weapons.

Because the Thorium fuel usually requires an isotope of uranium to start the chain fission reaction it means that it cannot start rapidly releasing neutrons into the fuel source and cause a meltdown.

Thorium also uses molten lead as the coolant and the moderator which allows for easy capture of thermal energy from the reactor.

\mathrm{n}+{}_{\ 90}^{232}\mathrm{Th}\rightarrow {}_{\ 90}^{233} \mathrm{Th} \xrightarrow{\beta^-} {}_{\ 91}^{233}\mathrm{Pa} \xrightarrow{\beta^-} {}_{\ 92}^{233}\mathrm{U}+\mathrm{n}\rightarrow {}_{\ 92}^{232} \mathrm{U}+2\mathrm{n}

\mathrm{n}+{}_{\ 90}^{232}\mathrm{Th}\rightarrow {}_{\ 90}^{233} \mathrm{Th} \xrightarrow{\beta^-} {}_{\ 91}^{233}\mathrm{Pa}+\mathrm{n} \rightarrow {}_{\ 91}^{232}\mathrm{Pa}+2\mathrm{n} \xrightarrow{\beta^-} {}_{\ 92}^{232}\mathrm{U}

\mathrm{n}+{}_{\ 90}^{232}\mathrm{Th}\rightarrow {}_{\ 90}^{231} \mathrm{Th} + 2\mathrm{n} \xrightarrow{\beta^-} {}_{\ 91}^{231}\mathrm{Pa}+\mathrm{n} \rightarrow {}_{\ 91}^{232}\mathrm{Pa} \xrightarrow{\beta^-}{}_{\ 92}^{232}\mathrm{U}

{}_{\ 92}^{232}\mathrm{U} \xrightarrow{\ \alpha\ } {}_{\ 90}^{228}\mathrm{Th}\ \mathrm{(73.6\ a)}

{}_{\ 90}^{228}\mathrm{Th} \xrightarrow{\ \alpha\ } {}_{\ 88}^{224}\mathrm{Ra}\ \mathrm{(1.9\ a)}

{}_{\ 88}^{224}\mathrm{Ra} \xrightarrow{\ \alpha\ } {}_{\ 86}^{220}\mathrm{Rn}\ \mathrm{(3.6\ d,\ 0.24\ MeV)}

{}_{\ 86}^{220}\mathrm{Rn} \xrightarrow{\ \alpha\ } {}_{\ 84}^{216}\mathrm{Po}\ \mathrm{(55\ s,\ 0.54\ MeV)}

{}_{\ 84}^{216}\mathrm{Po} \xrightarrow{\ \alpha\ } {}_{\ 82}^{212}\mathrm{Pb}\ \mathrm{(0.15\ s)}

{}_{\ 82}^{212}\mathrm{Pb} \xrightarrow{\beta^-\ } {}_{\ 83}^{212}\mathrm{Bi}\ \mathrm{(10.64\ h)}

{}_{\ 83}^{212}\mathrm{Bi} \xrightarrow{\ \alpha\ } {}_{\ 81}^{208}\mathrm{Tl}\ \mathrm{(61\ s,\ 0.78\ MeV)}

{}_{\ 81}^{208}\mathrm{Tl} \xrightarrow{\beta^-\ } {}_{\ 82}^{208}\mathrm{Pb}\ \mathrm{(3\ m,\ 2.6\ MeV)}

Equations Taken directly from Wikipedia - Thorium fuel cycle


While we can expect to see these brand new, efficient, helpful and correctional (in that it uses up old radioactive waste) nuclear reactors like the thorium and fast breeder reactors springing up over the next 10 years, plans are already laid down for the construction of even more efficient and safer power plants over the next 20 years with most advanced types of generation IV reactors being planned for construction in 2032. It certainly seems like a brighter future for Nuclear reactors ahead. And as we continiue our scientific endeavours we are finding more uses for the waste products of nuclear reactions, making them more renewable and more beneficial for civilisation