Nuclear reactor moderator maintains calm state - control rods versus coolant or water and water can evaporate so needs fresh supply to get rid of contaminnants - fission not the same thing as fishing bob and bait but both related to physics

The moderator and control rods together control the rate of reaction in the core of the nuclear reactor. Most nuclear reactors use water as a moderator, which can also act as a coolant, although some do use graphite rods. So perhaps controls rods or the moderator can be the coolant to maintain a cool state for the nuclear reactor - replacing used water with contaminants would likely improve safety so really a nuclear reactor or power plant being close to water such as the North Sea is really critical to safety.

Control rods in a traditional sense - A rod, plate, or tube containing a material such as hafnium, boron for example used to control the power of a nuclear reactor. By absorbing neutrons, a control rod prevents the neutrons from causing further fissions.

Neutrons have no or nowt electrical charge; it is neutral. Neutrons are extremely dense. Proton like positive have an electrical charge.

Control rods seek to control atoms really and seek to stop the neutrons the negative energy charge from becoming positive so control rods seek to stop overheating in a nuclear reactor but also a coolant which is water can do the same. Nuclear reactors can be built with control rods or without using a coolant and both control rods and a coolant is known as a moderator. Moderators seek to maintain a calm state and a vital to safety in a nuclear reactor.

So what is fission exactly? Dirty energy in a nutshell problems with nuclear waste and this view is held by John Mason MSP Scottish politician working for the Scottish National Party. Fission occurs when a neutron slams into a larger atom, forcing it to excite and split into two smaller atoms also known as fission products. Additional neutrons are also released that can initiate a chain reaction. When each atom splits, a tremendous amount of energy is released.

Fusion more modern and sustainable mirrors the moon and the stars and does not have big issues around nuclear waste and it is where two light atomic nuclei combine and release energy, while fission is the process of splitting two heavy, unstable atomic nuclei into two lighter nuclei, also releasing energy - although less than with fusion.

An atom is just a concept term defines a chemical element and goes from negative to positive so it changes its status and this is really how energy works at a fundamental level think negative lights off and then lights on, computer and laptop powered up - smartphones, laptops and tablets battery powered think Direct Current also think Lithium batteries not solar powered like some calculators in the past also the One Laptop Per Child solar powered laptop for Africa by Nicolas Negroponte.

A physics teachers might want to impress students but they may not understand how to build a nuclear reactor and a physics tutor or teacher might say an atom consists of a central nucleus that is surrounded by one or more negatively charged electrons. The nucleus is positively charged and contains one or more relatively heavy particles known as protons and neutrons.

Protons, neutrons and a nucleus might be fancy terms - but really atoms are about changes in energy status at the most fundamental level. Think in the computer world binary digits zero and one used to represent data. Zero and one also two states used in circuitboards for zero for off and one for on. Changing states, holding or storing data, erasing data, having energy or turning off the power losing everything and NAND flash memory stores data when the power is off. Mobile smartphones and tablets use NAND flash and they are definitely not built in the United Kingdom at the present time more like Asian countries perhaps South Korea, China or Japan. Distributing production of mobile and tablet devices actually minimises transportation and cuts energy requirements in the long term.

Atomic nuclei consist of electrically positive protons and electrically neutral neutrons. These are held together by the strongest known fundamental force, called the strong force.

Understanding nuclear reactors is about definition of terms like atomic, atom, fission and fusion - understanding the difference between fission and fusion can still be difficult after a definition.

What is atomic? Think the atomic bomb dropped during the second world war on Pearl Harbour in Japan by the Americans and it made real people on the ground suffer horrendous or harmful health issues and killed many within a considerable distance or radius. Atomic in conventional terms linked with warfare but atoms are part of nuclear energy also nuclear physics.

Fission and fusion is about releasing energy, charged particles into the atmosphere consider the Hadron Collider in Switzerland designed to simulate the Big Bang - this is how Earth was supposedly formed, but really no-one really knows how the shared world or planet known as Earth came into being - it has always been present during human civilisation.

Consider Physics is about the realm of what is possible in the real physical boundless world well there are limits or boundaries to an extent although the ocean can be very deep at the Mariana Trench the deepest part in the Asia Pacific region.

We are all bound by gravity this is where everything falls to Earth but objects in water can float that are made of air recall tyres, lilos and children may wear arm bands.

Dense objects without air sink - humans need air and need to stay at the surface. While humans can hold their breath underwater they cannot do it for very long and require oxygen tanks or breathing apparatus - scuba diving is where humans have a mask and breathe through a tube that comes into contact with the surface above water.

Humans tread water kick legs to float or bob on the surface think fishing bob and bait - humans learn to swim to get through the water otherwise humans will sink or drown then there are sharks, alligators and crocodiles in tropical waters which can kill humans, bite off arms and legs.

In fishing, fisherman, bob something in the water as bait for fish to catch them - fish thus go for the bait and get caught. Fisherman can catch too many fish, have to throw some back and the European Union has fish quotas to protect fish stocks but sadly fish thrown back into the water may not survive.