Nuclear Energy

Yes, a star glows due to the intense heat and pressure at its core, which causes atoms to undergo nuclear fusion. During this process, hydrogen atoms fuse together to form helium, releasing a tremendous amount of energy in the form of light and heat.

The disaster occurred on On 26 April 1986 at 01:23:40 a.m, in the then USSR, It is now located in Ukraine, a former soviet state.

Tritium.

What did you think it was?

The chernobyl reactor had only been finished and placed in operation a few years earlier and had been rushed in construction, skipping several important safety tests to meet the construction schedule. The primary cause of the accident that night was trying to perform one of these tests with the reactor in a very unstable range of operation that the procedures required immediate shutdown of the reactor for safety. The test supervisor ordered the operators to keep the reactor running and disable automatic shutdown and safety systems so he could proceed with the test without interruption. If they would not follow his orders he would replace them with operators that would. They did. The result was the reactor was destroyed, many people died, and vast areas around it were contaminated. RBMK reactors are inherently unsafe.

The chernobyl reactor site will remain radioactive for hundreds of thousands of years. Unfortunately the sarcophagus is already wearing out and will have to be replaced at least every 50 years.

Applications of uranium:

- nuclear fuel for nuclear power reactors

- explosive for nuclear weapons

- material for armors and projectiles

- catalyst

- additive for glass and ceramics (to obtain beautiful green colors)

- toner in photography

- mordant for textiles

- shielding material (depleted uranium)

- ballast

- and other minor applications

Disadvantages of uranium: is radioactive and toxic.

Heavy nuclides, greater than iron or nickel, have a negative mass-energy deficit, meaning that it takes more energy to fuse them than would be released by such fusion. That is why only light nuclides, such as hydrogen are realistic candidates for fusion.

The useful life of a nuclear fission reactor is typically around 40-60 years. However, this can vary depending on factors such as maintenance, upgrades, and regulatory approvals.

Radiation dosage is measured in sieverts and millisieverts, replacing the old unit called the rem. Dosage is assessed in terms of relative damage to different parts of the human body, some being more sensitive to damage than others. Acceptable dose limits are recommended by the International Commission on Radiological Protection (ICRP) and should be observed by all countries involved, though there is no guarantee of that. The following is taken from the World Nuclear Association website (www.world-nuclear.org), which is believed to be compatible with ICRP advice.

100 millisievert/year...lowest level at which any increase in cancer is evident. Above this exposure probability of cancer increases with dose.

1000 millisievert cumulative...would probably cause a fatal cancer many years later in 5 percent of persons exposed.

1000 millisievert single dose...would cause temporary sickness such as nausea and decreased white cell count, but not death (but see above for long term effect)

5000 millisievert single dose... would cause death within one month of half those receiving it

10,000 millisievert single dose... fatal in a few weeks.

Against the above which are all large doses, the average dose to US nuclear industry employees is quoted as 2.4 millisievert/year. so for a 40 year working life this amounts to 96 millisieverts cumulative.

The current limit for nuclear industry employees is 20 millisieverts/year. (Not clear if this is in the US or world-wide, but it is presumably ICRP recommended).

No, natural gas and nuclear energy are two different sources of energy. Natural gas is a fossil fuel that is primarily composed of methane, while nuclear energy is generated through the process of nuclear fission in a nuclear reactor.

To calculate the energy required to heat the steam, you need to use the formula: Q = mcΔT, where Q is the energy, m is the mass of the steam, c is the specific heat, and ΔT is the change in temperature. Given that the specific heat of steam is 2.01 J/g°C and the temperature change is 14.0°C, you would need to know the mass of the steam in order to calculate the total energy required.

An artificial nuclear reactor is a device that initiates and controls a sustained nuclear chain reaction. This reaction produces heat, which is used to produce electricity in nuclear power plants. The fission process in these reactors generates energy by splitting atomic nuclei.

Fission by-products are the radioactive materials produced during the splitting of atomic nuclei in nuclear reactions. These by-products can vary but typically include isotopes of elements such as cesium, strontium, iodine, and xenon. Proper handling and disposal of fission by-products are essential to prevent environmental contamination and health risks.

Most power stations use steam to drive turbines connected to generators.

Most fuels can be burnt, to provide the heat to generate steam.

Choose two out of these:-

1. Oil

2. Gas

3. Coal

4. Peat

5. Bio mass (shredded wood)

Strontium-90 and cesium-137 and a whole lot more.

Nuclear fission involves splitting heavy atoms, like uranium, which releases energy. This process is easier to initiate because it requires less extreme conditions, such as lower temperatures and pressures, compared to nuclear fusion. Fusion involves merging light atoms, like hydrogen isotopes, which requires much higher temperatures and pressures to overcome the electrostatic repulsion between the positively charged nuclei.

Fusion reactions occur in the cores of stars, including our Sun, where temperatures are extremely high, on the order of millions of degrees Celsius. No other location in the solar system has temperatures high enough to sustain fusion reactions.

A nuclear fission power plant does this, there are 104 operating in the US. These are all light water moderated ones, PWR or BWR. These are the most used types in the world, but there are also heavy water reactors (Candu) and AGR gas cooled reactors.

Fossil fuels were originally either prehistoric zooplankton and algae (which became petroleum) or plant material (which generally became coal). In either case, the living organisms converted the energy of sunlight into their structures. By using the energy of the fossil fuel, we use the energy the original organisms captured, and that's the connection to sunlight.

There are two primary safety features in nuclear power plants. One is some kind of containment structure for the primary system, and the other is some kind of emergency cooling system to cool the nuclear core if things go sideways. The containment structure is designed to keep primary coolant from a major leak in the primary coolant system (and the colant will be radioactive to some degree) from escaping. As bad as that is, the primary mission of containment is to keep nuclear material, which may have broken free of the fuel elements in the core during a meltdown, from getting out into the environment. The clever engineering design and the strength of the reinforced concrete structure are supposed to keep things "under wraps" if it all goes to heck in a handbasket and the primary system is breached. The emergency cooling (XC) systems are designed to cool the fuel elements in the event of a major loss of coolant accident (LOCA). Failure of the primary cooling system could mean a meltdown. We need a way to pump lots of clean, cool water into the reactor vessel to directly cool the fuel if primary coolant is lost. High pressure pumps and a large volume of stored water are needed. Now that we've touched on the containment structure and the emergency cooling system, let's back up a bit. In a reactor, the primary useful product is heat, and we use the primary coolant to carry the heat off to generate steam in a secondary system. When a reactor is shut down after having operated at high power for more than a modest length of time, the fuel in the core still generates an immense amount of heat, and will do so for days after shutdown. The amount of heat is so great that without cooling following a rapid shutdown from extended high power use, the fuel will effortlessly generate enough heat to melt the fuel and the metal inside which it is clad. (That why we need the XC system - to cut this off.) Failure of the fuel cladding will spill the fission products, which are highly radioactive and remain so for many decades or even centuries, into the core. And without cooling, this material will literally "burn through" the reactor vessel itself and end up outside the metal barriers provided by the reactor vessel and all the heavy piping through which the primary coolant flows. If this stuff escapes confinement in the primary system's plumbing, it is hoped that containment inside a "dome" or "blockhouse" of sufficient volume and made of thick, reinforced concrete will hold it. And that's why we have those big, heavy structures in place. The two "biggies" out of the way, we'll need lots of reactor monitoring equipment to keep track of all aspects of the system. There will be temperature and pressure monitoring equipment, and a ton of indicators as to what is open or shut, running or off, high in level or low in level, and more. This equipment will need to be well maintained and will need to work around the clock. We will need radiation monitoring equipment, and we'll need chemical analysis on site to check the status of the coolant and primary plant chemistry on a continuous basis. We will need a well-trained staff who are intimately familiar with all the (well written) operating and contingency procedures for the plant. All the safety features designed into a system and incorporated during construction go for naught if faulty equipment fools operators, or if the operators don't appreciate what their instruments are telling them and act (or react) incorrectly during any evolution of "excursion" they are involved in. Let's all hope everyone does everything right and that everything works correctly. And all of that at all times.

Yes U235 is the fissionable isotope of Uranium. Natural Uranium contains only about 0.7 percent U235, which is enough to produce fission only with a good moderator such as graphite or heavy water. In light water reactors the Uranium has to be enriched to about 4 percent U 235.

There are (at least) four methods for production of hydrogen.

(1) The cheapest method is steam reforming of methane:

CH4 + H2O --> CO + 3 H2

(2) An environmentally friendly, but not very efficient method is electrolysis of water, using a dilute sulfuric acid electrolyte:

4 H2O + 4 e- --> 2 H2 + 4 OH- ; 2 H2O --> O2 + 4 H+ + 4 e-

(3) The original Cavendish method of hydrogen production involves reaction of red-hot iron with steam.

(4) A convenient method for producing a small amount of hydrogen as economically as possible is the reaction of iron with dilute sulfuric acid.

Uranium is a radioactive element commonly used in nuclear power stations. It undergoes nuclear reactions to produce heat, which is then used to generate electricity.

Low and intermediate level waste from Koeberg is transported by road in steel and concrete containers to a remote disposal site at Vaalputs, 600km away in the Kalahari Desert. However high level waste (the spent fuel) is stored on site.

The spent Uranium 235 rods are currently stored on high-density racks submerged in a reactor pool. The rods take 100 000 years to decay, and between 30 and 50 years to cool down to reach the boiling point of water

Nuclear reactors can be as small as a single room. There are many reactors that are less then 30 MW (a typical reactor is around 1,000 MW), and consider that a normal car engine is about 200 KW (or .2 MW) so some reactors produce the power of only about 100 cars.

The smallest that are standardly used, other then for research, are found on submarines.