Nuclear Reactors

The United States was the first country to use nuclear power for electricity generation, with the first nuclear power plant going online in 1957 in Shippingport, Pennsylvania.

Similar to other thermal powerplants like coal, oil and gas, nuclear reaction creates heat which is used to turn water into steam. This turns the turbines attached to the generators which produce electricity.

I don't believe that the design is fixed at this time. General Atomics and others have been working on designs and one has been built in South Africa, but the companies are still working out the final design. A link is provided to an interesting read on the latest evelopments.

The advanced gas-cooled reactors, at least the ones I know, have been built in the UK but not elsewhere. The last ones built were at Heysham Stage 2 and Torness, in Scotland. As far as I can remember the number of channels was 332. I think the first answer may have been on the pebble bed reactor, which is gas cooled and advanced, but not the same as the AGR in UK.

If you are talking about the material inside which the nuclear fuel is sealed, zircaloy is about the most common. This alloy, which is available in several "flavors" including Zirc-1, Zirc-2 and Zirc-4 are each almost all zirconium (over 95%). Nuclear fuel in the form of pellets or plates is welded inside zircaloy cladding to contain all the fission fragments that will appear as the fuel is burned. This material doesn't absorb thermal neutrons very well, so it won't "dilute" the chain reaction by taking some of these neutrons out of circulation. As one might expect, the heat generated within the fuel elements is transferred out through the zircaloy and into the primary coolant of the reactor. Wikipedia has some more information on zircaloy, and a link is provided.

Nuclear fission is currently used to generate electrical energy in nuclear power plants. This process involves the splitting of uranium or plutonium atoms, which releases a large amount of energy that is used to heat water and produce steam to drive turbines and generate electricity.

• It was first used in Obninsk in former Soviet Union.
• The world's first nuclear power plant was commissioned on June 27, 1954 in Obninsk.
• The Obninsk nuclear power plant featured one 5 mWt AM-1 (Atom Mirny or Peaceful Atom) reactor to generate electricity and facilitate experimental nuclear research.

In a nuclear power plant, the nuclear reactors are (generally) fission reactors that split atoms (of nuclear fuel) through a continuous, controlled neutron chain reaction. The primary useful product of a nuclear reactor is heat. The heat is used to generate steam that will drive steam turbines to generate electric power. Reactors are also used to produce nuclear material that is then applied to medicine or to make sources for radiography (x-ray pictures of welds and stuff) and other applications. There are other applications, like the generation of plutonium which is used for weapons or fuel for other reactors. Most reactors are designed, constructed and used to generate electric power. These reactors are set up to deliver large quantities of heat that is used to produce steam. This steam is used to drive steam-driven turbines, which generate electricity. There is a ton of information about the types of reactors and the applications to which they are put available from our friends at Wikipedia. A link is provided.

The countries known to have nuclear weapons are:

United States

Russia

United Kingdom

France

China

India

Pakistan

North Korea

Israel

Germany, Italy, Japan and South Africa have the capability of building nuclear weapons but have not done so.

Canada once had nuclear weapons, but has dismantled its weapons and permanetly deacitvated its nuclear weapons program. So far it is the only country to do so.

Nuclear reactors can not explode like a nuclear bomb. A lot of bad things can happen, but that is not one of them.

Nonnuclear Explosion:

First, it is useful to distinguish "normal" explosion from nuclear bomb. (We'll get to the bomb part shortly.)

Explosions of many kinds can occur and they can occur at nuclear power plants and reactors just as anywhere else. It is not odd to have a steam powered explosion at a power plant whether it is nuclear or coal or gas because all of these types of power plants are converting heat into mechnical energy through a trubine or similar machine and the turbine generates electricity. The heat creates steam at high pressure and a mechanical failure can result in an explosion.

An explosion of the sort caused by excess heat or mechanical failure counts as one resulting from mismanagement.

Explosions can be caused by humans too. A human can place a regular bomb at a nuclear power plant or a human can fire a missile at a power plant and then the power plant, nuclear or not, explodes.

Nuclear Bomb Explosions:

The principle behind a nuclear bomb is the idea of the chain reaction. Nuclear fission is the process of a large nucleus, like uranium, breaking apart into smaller pieces and releasing energy in the process. When one nucleus decays, it causes other nuclei to decay and they in turn cause more. Such is a chain reaction, it feeds itself and the process grows and results in an explosion as long as there is enough fuel. That last part is the key because you can't make a nuclear bomb explode (or any bomb) if you run out of fuel.

Now, we get to the part about "weapons grade" nuclear material. A nuclear weapon requires a high concentration of fissionable material of the proper type and enough of it and a way to keep it in place long enough for the chain reaction to produce enough energy to be a bomb.

Nuclear reactors are not built with weapons grade material. That is essential. Further, the elaborate process of containment to hold the bomb material in place requires special engineering and that is not in a nuclear reactor. The quantity of material required for a bomb is very very large unless it is highly purified and it is not so purified in nuclear reactors.

No mismanaged nuclear plant, no nuclear plant accident of any kind, can cause a massive nuclear explosion like the blast of a nuclear weapon.

Nuclear Powered (non-bomb) Explosions:

Though a reactor can't explode like a nuclear bomb, the explosions that can occur are extremely dangerous and can spew radioactive materials widely, they are just not nuclear bomb explosions. Usually the explosions allow the radioactive core of reacting material to overheat and the radioactive material from several separate areas may combine and further heat, enhancing the ongoing nuclear chain reactions. It is not possible to go through explanations of the various scenarios, but under the worst conditions, the heated material explodes like a regular bomb and spreads itself over a large area destroying everything nearby. It is not nearly as large as a true nuclear bomb which can level a city. What is does do is spead a lot of radioactive material around. The process does not even have to explode to do that, it can just heat up enough to vaporize radioactive materials that are then released.

All of the examples of nuclear reactor disasters fall into the category on non-bomb disasters. All were and will be the type that creates and disperses harmful radioactive material and that is the core of the problem.

Final Note:

Though no sane design of a nuclear reactor could explode like a nuclear bomb, the process of making the materials the reactor uses is a process that could potentially make weapons grade material. Further, the used fuel can serve as a starting material for bomb making. In that case, it is not the reactor but the treatment of material before or after that can be directed towards a weapon.

The subject gets very complicated and this little description could not provide a person with enough information to say they understand it. More reading is recommended.

Uranium is a common radioactive element used in nuclear power stations to generate energy through a process known as nuclear fission. It provides a sustainable and efficient source of power by splitting atoms and releasing heat energy. Proper handling and containment measures are essential due to its radioactive properties.

Some of the consequences of nuclear leaks and meltowns include radioactive contamination in areas surrounding the leaks. Loss of life, pollution, and even long term damage to the land is also caused by nuclear leaks.

Well, scientists have been researching fusion reactors for over 50 years, but nuclear fusion is much more difficult to achieve than nuclear fission, which is what current nuclear power technology is based on. There are many reasons for this, but while there have been tests and advancements in the field, scientists have yet to a) create a sustainable and stable nuclear fusion reaction and b) create a reaction that has a greater output than input.

If we were to perfect the technology and use it commercially, it would probably give the earth unlimited technology as it would have an energy output similar to that of a star.

This condition is called a meltdown (or core meltdown or nuclear meltdown). The fuel becomes too hot (quite probably due to a loss of coolant accident - LOCA) and it melts, melting its way in turn through the cladding or "protective layer" of metal around the fuel pellets themselves. This dumps highly radioactive spent fuel (and all those nasty radioactive byproducts of fission - the fission fragments) into the primary coolant to be circulated around the plant. This is a major accident, and emergency shutdown procedures - and emergency cooling - will probably have to be initiated to cool the core enough to keep the problem from getting completely out of control and resulting in the so-called China syndrome. In this accident scenario, the superheated core melts its way through the reactor vessel and through the thick concrete floor of the reactor building and into the ground spreading the radioactive contamination outside the containment building itself. Note that the core continues to generate huge quantities of heat for hours after shutdown (even in a melted condition), so failure of the primary cooling system will result in a disaster if emergency cooling isn't effective.

The nuclear reactor of a nuclear power plant is usually considered to be the core and the pressure vessel in which it is encased. The control rods, which are in the core (and pulled some or all of the way out to run the reactor) have their associated rod drive motors on top of the pressure vessel. Instrumentation ports are up there, too. All of these things are generally considered to be the "nuclear reactor" portion of the primary system in the plant. A link is provided to a picture posted at Wikipedia. It has a portion of it colored to show the reactor core, but the pressure vessel is "cut away" to view the core. The control rods (#1 in the drawing) are shown as being on top. That's incorrect. The rod drive motors and control rod lead ("leed" and not "led") screws are up there. (The lead screws connect the control rods, which are down in among the fuel bundles, to the rod drive motors, which are up on top of the pressure vessel's cap.) The rods belong in the core, or in the area above the core when they are pulled out. The whole thing, the core, the vessel, and the rod drive motors as well as the instrumentation on top are considered to be the "nuclear reactor" in a power plant. If asked to identify the picture, the most correct response is probably, "It's a cut-away drawing of a nuclear reactor." That means everything in the picture is part of the nuclear reactor.

India primarily uses uranium and thorium as radioactive elements for its nuclear reactors. Uranium is the primary fuel for Pressurized Heavy Water Reactors (PHWRs), while thorium is used in some reactors as a fertile material for breeding fissile uranium-233.

Usually Uranium 235 but sometimes Plutonium 239

The KAMINI (Kalpakkam Mini) reactor is a Uranium-233 fueled, demineralized light water moderated and cooled, beryllium oxide reflected, low power nuclear research reactor. It is located in the post irradiation examination facility of Radio Metallurgy Laboratory, Indira Gandhi Centre for Atomic Research, Kalpakkam, India. A link is provided to the Wikipedia article.

There are no hazards from nuclear power stations. However, these stations need careful design, good quality during installation, skillful operators, good maintenance, and application of good safety rules during operation and when dealing with nuclear waste.

The Three Mile Island incident in 1979 was a partial meltdown resulting from equipment malfunctions and operator errors, with no immediate fatalities and limited off-site impact. In contrast, the Chernobyl disaster in 1986 was a full-scale meltdown caused by a flawed reactor design and operator errors, resulting in immediate deaths, widespread radioactive contamination, and long-term health and environmental consequences.

In brief, both accidents involve gross failure of a nuclear reactor. The two reactors are of different types, so there are some things that are unique to each plant. Both had the reactor cores damaged catastrophically. And in both cases, radiation was released ourside fuel element cladding and outside containment barriers. What is different is that in the Chernobyl disaster, the atomic pile caught fire. I was built using graphite blocks for moderators. At Three Mile Island (TMI), there was no fire. The radiation released at TMI was some nasty stuff including fission fragments from failed fuel element cladding, but it was released in limited quantities. TMI was an accident. In Russia, things were different. It was a disaster. At Chernobyl, as the core burned, massive clouds of highly radioactive fission byproducts (from the failed fuel elements) were caught up in the fire column and swept aloft with the smoke and heat. This caused the surrounding area to have to be evacuated and some of it was actually abandoned. The small city of Pripyat became a ghost town. This newly constructed community of about 50,000 or so was abandoned. People just walked away. They literally left everything behind and departed with just the clothes on their backs. There were a number of fatalities at Chernobyl, and none at TMI. Some reactor workers and a number of emergency personnel responding to the fire died of radiation sickness. And a number of civilians lost their lives within a few weeks of the accident. One account logged by a helicopter pilot (several choppers dumped water on the fire from aloft) said that in the night, the column of smoke and debris from the fire glowed in the darkness due to the radioactivity. Helicopter pilots were among those who died as a result of their heroic efforts to douse the flames. Links are provided to relevant Wikipedia articles.

The "nuclear reactor time bomb" theory was popularized by author and scientist Amory Lovins in the 1970s. Lovins argued that nuclear reactors posed safety risks and could lead to catastrophic accidents or intentional sabotage, likening them to a ticking time bomb.

Not from nuclear effects, though any large industrial plant built in a rural area must have some effect just due to the buildings where previously it was open country

First you have to better define working. If "working" means having nuclear material that can actually do something then you don't. If you try you'll probably at best end up in jail and at worst giving yourself radiation poisoning. However if what we define as working gets some play room then there are a few designs out there that work. Most involve some way to boil water (preferably electrical, like a cheap espresso machine as they have safeties) and then turning a turbine to make electricity. You just have the boiler hidden inside a containment structure like a real reactor and print off a picture on what a core should look like.

I'm currently looking into this for outreach programs and will post my findings.