Nuclear Physics

Isotopes are determined by the number of neutrons in an atom's nucleus. Each isotope of an element has the same number of protons in its nucleus but a different number of neutrons. Isotopes of an element have the same chemical properties but different atomic masses.

Atoms are indeed very small, but there are even smaller particles that make up atoms, such as protons, neutrons, and electrons. These subatomic particles are the building blocks of atoms and are themselves much smaller than atoms.

During beta decay, a neutron can turn into a proton, an electron (beta particle), and an antineutrino. This process occurs when a neutron in an atomic nucleus changes into a proton while emitting an electron and an antineutrino to conserve electric charge and lepton number.

In general, if we lower the control rods, the rate of nuclear reactions decreases. The control rods are neutron absorbers, and lowering them will push them into the upper area of the core where fissions are occurring. The neutrons released during these fission events may be absorbed by the control rods that have just been lowered into the vicinity. This will cause the rate of fission to go down.

Positrons don't last long because they are anti-electrons; they are antimatter. And they will combine with an electron after their appearance, and do so in a relatively short period of time. Both particles are oppositely charged and attract each other. And in an event called mutual annihilation, the total mass of both the positron and the electron are converted into energy.

The amount of energy obtained from nuclear fuel is expressed as so many megawattdays per tonne, in a liquid water reactor (LWR) it is now around 60,000 MWd/tonne. So if a reactor power output is say 3000 MW (thermal), in one day it will use up 1/20 tonne of fuel, and in a year it will use 18.25 tonne. With reactors that can be refuelled during operation, or during short shutdown periods, the individual fuel assemblies can be changed as required giving flexibility, this applies to the advanced gas-cooled reactors (AGR's) built in the UK. With LWR's where the top of the pressure vessel has to be removed for fuelling, this is only possible during long outages (though they have become much shorter with practice), and so a large proportion of the fuel is changed each time. When a reactor has settled into a routine of regular fuelling outages, this would probably be at about two yearly intervals, and about 1/3 of the fuel changed each time, so any particular assembly could stay in the reactor for about six years on average.

The sun uses nuclear fusion to create energy, and nuclear power plants use nuclear fission to create energy. Fusion and fission are different, but they are both nuclear processes. They involve the manipulation of atomic nuclei, and because relatively huge amounts of energy are associated with these structures (the nucleui of atoms), lots of energy can result from the fusion or fission of even a small amount of material.

The atoms that are radioactive are those with unstable nuclei. There is no easy way to tell which is which, so the isotope has to be looked up.

All elements have at least some radioactive isotopes. There are 36 elements for which all radioactive isotopes are synthetic or fission products, so for practical purposes, there are no radioactive isotopes of them in nature, except where introduced by human activity. They include most of the common elements we find in nature, but not all.

There are 44 elements that are found as stable isotopes, but at least traces of radioactive isotopes are found in nature. Among these are hydrogen, carbon, sodium,

silicon, chlorine, and potassium, all of which are necessary for life. Radioactive potassium, in particular, is present as 0.012% of all potassium.

For another group of elements, including technetium, promethium, and all with atomic numbers of 83 (bismuth) or more, there is no isotope that is stable.

Generally speaking, a nuclear meltdown involves the release of highly radioactive materials into the nuclear plant where the reactor is. These very nasty substances may not be held within a containment structure, and they could escape into the environment. Once loose, they pose a threat to all life within the area. Further, the radioactive materials may be carried by air into surrounding regions, or captured by ground water and spread further in that manner.

Radioactive materials can cause tissue damage, and if even small amounts are ingested or (worse) inhaled, they can irradiate a living thing from the inside. Radioactive contamination of an area may make it unsuitable for habitation by people, and we could see a whole city evacuated and left to become a ghost town. The Russian city of Pripyat (in Ukraine) is a prime example.

Levels of radioactivity may not be sufficient to be "immediately" fatal to life in the area, but cancers and other medical issues will spike for individuals exposed. More people will become ill and die than would have in there were no radiation. Birth defects will become more frequent as well among peoples living in a radioactive environment.

I think in order to answer this question, we may basically understand the very basics of Radiation:

Basically radiation consists of several types of subatomic particles, principally those called gamma rays, neutrons, electrons and alpha particles. That shoot through space at a very high speeds (something like 100,000 miles per second). They can easily penetrate deeply inside the human body damaging some of the biological cells (DNA, for example) which the body is composed.

This damaging can cause a fatal cancer to develop. In case it reaches the reproductive cells, it can cause genetic defects in later generations of offspring.

Answering to your question, this is dangerous and can cause several troubles to one's health (such as cancer and other fatal mutations).

Increases. An increase in temperature typically increases the rate of chemical reactions, including radioactive decay. This means that at higher temperatures, the rate of decay of a radioactive element will be faster, resulting in a shorter half-life.

The radioactive alpha particle has the same structure as the atomic nucleus of helium. They are usually formed and emitted during alpha decay.

No, two nuclei do not combine to form one nucleus in nuclear fission. It is the process of nuclear fusion that speaks to the combination of two nuclei to form one nucleus. The two nuclei are fused to form a new nucleus. Nuclear fission is the "breaking" or "splitting" of an atomic nucleus into two (or possibly more) smaller fragments.

The basic concept is that certain heavy nuclei, notably uranium 235 and plutonium 239, can be split or fissioned by capturing a neutron, giving rise to other lighter nuclei, further neutrons, and released energy. By careful arrangement of the nuclear fuel a chain reaction can be produced which is self-sustaining and produces a lot of thermal energy. See the link below for more reading

Beta minus radiation consists of an electron emitted from the nucleus of an atom. This occurs when a neutron changes into a proton within the nucleus, resulting in the emission of an electron and an antineutrino. Beta minus radiation is often involved in radioactive decay processes.

The nuclear binding energy per nucleon is similar to the surface tension in a liquid drop, causing nuclei to behave like stable liquid drops. Additionally, the deformation of the nucleus due to forces acting between nucleons can be described using the liquid drop model, where the nucleus has a defined surface and volume.

After 10 days, 1/2 of the original isotope will remain since its half-life is 5 days. This means 6kg of the original isotope will remain after 1 half-life, which remains the same after 10 days since another half-life has passed.

The time it takes for 50 percent of the nuclei in a radioactive sample to decay to its stable isotope is called the half-life of the radioactive element. It is a characteristic property of each radioactive isotope and can vary greatly among different elements.

If we use uranium-238 as our starter isotope, what happens is that a nuclear decay event happens (in this case an alpha decay) and the U-238 transforms into a daughter isotope thorium (Th-234). The half-life of this transition is 4.5 billion years. Thorium-234 then undergoes a decay. And the process continues until a stable isotope is created as the last daughter of a decay chain. Note that there will be different half lives for the transition events, and the modes of decay will vary depending on what daughter is now the parent in the next decay event. Use the link below to see all the steps. The chart will show the whole chain including the half-life of isotope undergoing decay, the decay mode, and the daughter. Follow along using the keys and the process will reveal itself.

Astatine has many isotopes, each with its own half life. The longest in my list is At209 at 8.1 hours, and At215 is listed at 0.1 ms. The shortest are just listed as 'short' reflecting the small quantities.

No, a delta particle is not a fast moving electron given off by a nucleus during radioactive decay. The electron described here is a beta particle, and specifically a beta minus particle. It is given off in (no surprise) beta minus decay. A link to a related question can be found below.

The half life of a radioactive element is the time it takes for half of the atoms in a sample to decay. It is a measure of the rate of radioactive decay and is a constant characteristic of each radioactive isotope.

The strong force is powerful only when neutrons and protons are very close together, within the nucleus of an atom. It acts to bind the nucleons (protons and neutrons) together due to the exchange of particles called gluons. Beyond a certain distance, the strong force becomes negligible compared to electromagnetic forces.