Monday, November 1, 2010

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Nuclear Safety


Yes, I believe Nuclear is safe and our best solution for Malaysia for the future energy sources.




First, we take a look why nuclear power plant should be close to oceans. Nuclear power plants should be close to oceans, or sea water to get the required cooling capacity for the steam condensate that is passing through the condenser. This condensate, after being cooled down, is recirculated back to the steam generators (in a closed circuit where is turned again into steam that passes over the steam turbines). Once the water is cycled through the cooling system, it would be sent to a cooling tower where it would cool off and be used again. Some water is lost through evaporation in the closed cooling system, so the cooling system would still have to intake some water. The closed cooling system would cut water usage by up to ninety-five percent and significantly reduce damage to the ecosystem and of course not affect the fish.
Exposure to the outside world can bring danger such as earthquakes. With the safety the first priority for nuclear plants, it is incumbent upon nuclear installation designer and builders to prepare for the worst that nature can bring to bear.


Usually nuclear plants have very compact sites of 500 to 1000 acres including the exclusion area around the plant. 
Containment - a building designed to sustain pressures of about 50 pounds per square inch. Normally houses the reactor and the related cooling system that contains highly radioactive fluids. Building is of steel construction. Sometimes the building is surrounded by a concrete structure that is designed for much lower pressures (3 pounds per square inch). The area between the steel and concrete building is called the annulus. Designs vary. At one facility there are 4 1/2 foot thick concrete walls reinforced with steel. The dome is 2 1/2 feet thick and the base 12 feet thick. The containment is the 3rd fission product barrier. In BWRs, the drywell is located in the reactor building.

Reactor Building- a building separate from the containment that houses much of the support equipment that may contain radioactive liquids and gases. Emergency equipment is also normally located in this building.

Turbine Building - a building that houses the turbine, generator, condenser, condensate and feedwater systems.

Intake Structure - a building that houses the circulating water pumps used to pump water from the river, lake, sea for cooling the condenser. Trash racks and traveling screens also remove debris to clean the water so that it can pass through the condenser tubes.

Fuel Building - a building separate from the containment that is used to spent fuel assemblies in steel racks in a large 40 foot deep storage pool. Casks for shipping or onsite dry storage of spent fuel assemblies will be loaded (or unloaded in this pool). A new fuel storage area is provided for receipt of new assemblies and storage prior to going into the containment and subsequently into the reactor during a refueling.

Diesel Generator Building - a building used to house the diesel generators and supporting systems (air, water, radiator fans, fuel oil, lubricating oil, air conditioning, and ventilation). In some cases, related electrical switchgear for distributing electrical power produced by the diesel generator. The Diesel generators that provide backup electrical power to safety and non-safety systems.

In some plants separate buildings or areas within the buildings mentioned above may house the following:
  • Water treatment systems used to purify water so that it can be used in the power plant.
  • Radioactive waste treatment systems used to purify and store radioactive liquids and gases.
  • Cooling tower pumps used to pump water to cooling towers. Cooling towers are often used for power plants located on rivers and small lakes so that impact of temperature of discharged water on fish is minimized.
  • Control Room  related electrical cabling, and ventilation systems (sometimes called the Control Building)
  • Administration Building
  • Security


Defense in depth.

Defense in Depth philosophy requires that nuclear facilities shall be provided with multiple defenses in depth to assure safety of nuclear facilities so that any single failure of SSC does not cause severe consequences. The risking formed defense-in-depth approach and the procedures however do not seem to have been sufficiently developed for seismic design of nuclear power plants.
Q

Defense-in-depth measures for nuclear power plants (NPP) consist of the following steps:

Level 1: Prevent occurrence of abnormal events
Level 2: Prevent propagation of abnormal events to accidents
Level 3: Mitigate consequence of accidents
Level 4: Severe accident management (AM)
Level 5: Off-site emergency response


Why a Nuclear Power plant CAN NOT Explode like a Nuclear Bomb!!!!!!!!!!!!!!

 Bombs are completely different from reactors. There is nothing similar about them except that they both need fissile materials. But they need DIFFERENT fissile materials and they use them very differently. A nuclear bomb "compresses" pure or nearly pure fissile material into a small space. There is no other material in The volume containing the nuclear explosive. The fissile material is either the uranium isotope 235 or plutonium. If it is uranium, it is at least 90% uranium 235 and 10% or less uranium 238. There is no isotope separation problem if the fissile material is plutonium. These fissile materials are metals and very difficult to compress. Because they are difficult to compress, a high explosive [high speed explosive] is required to compress them. Pieces of the fissile material have to slam into each other hard for the nuclear reactions to take place. A nuclear reactor, such as the ones used for power generation, does not have any pure fissile material. The fuel may be 2% uranium 235 mixed with uranium 238. A mixture of 2% uranium 235 mixed with uranium 238 cannot be made to explode no matter how hard you try. A small amount of plutonium mixed in with the uranium can not change this. Reactor fuel still cannot be made to explode like a nuclear bomb no matter how hard you try. There has never been a nuclear explosion in a reactor And there never will be. [Uranium and plutonium are flammable, but a fire isn't an explosion.] The fuel is further diluted by being divided and sealed into many small steel capsules. The fuel is further diluted by the need for coolant to flow around the capsules and through the core so that heat can be transported to a Place where heat energy can be converted to electrical energy. A reactor does not contain any high speed [or any other speed] chemical explosive as a bomb must have. A reactor does not have any explosive materials at all. As is obvious from the above descriptions, there is no possible way that a reactor could ever explode like a nuclear bomb. Reactors and bombs are very different. Reactors and bombs are really not even related to each other.

 Nuclear power is the safest kind and it just got safer.





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