Reactor Safety Systems

         Briefly  a nuclear reactor is a device designed to controling the self-sustained fission chain reaction. The most common use of nuclear reactors is for the generation of electrical power in most country around the world and some of it use for the power in some ships like submarines.In most common of the time, the heat generated from the nuclear reaction are used to power steam turbines.

         After two major reactor accidents in the history of civil nuclear power which was happened at Three Mile Island and Chernobyl.  There has been a strong awareness of the potential hazard of both nuclear criticality and release of radioactive materials. 

       
        When asking what do peoples think about nuclear power plants, many people having the mind set of nuclear power plant is a giant bomb and may explode anytime. For information, Nuclear reactors cannot explode like atomic bombs because they are much more fundamentally very different devices. As we seen, bombs require highly concentrated U-235 or plutonium to be rapidly assembled into supercritical congfiguration. The concentration of fuel is far much dilute to allow any explosive reaction to take place.

        Nowadays, nuclear reactors are designed using the concept of multiple barriers in order to  prevent the escape of radioactivity. These barriers acts as obstacles to block the passage of radioactive atoms from the fuel to the surrounding population.

   
        Besides, the fissile and fissionable materials is been located within solid fuel elements or in dilute alloy of a structural materials such as aluminium, stainless steel or zirconium. These structural material are used to manufacture cladding because it able to prevent the fission product gases from escaping and to confine fission fragments emitted near the surface of the fuel which is surrounded by the cladding layer. In Pressurised Water Reactor (PWR) and Boiling Water Reactor(BWR), there is hollow metal tubes in the cladding which the fuel pellets are located.

      In most of modern nuclear reactors they had installed with closed coolant system. This system, those espaced fission products can be confined within the coolant system. Fission products and other radioactive atoms are removed throughout the coolant purification system.

    
      Reactor Vessel represent an obvious barrier to release of radioactivity. It is essential to be designed, manufactured and be tested to make sure it meets the highest standards of quality and reliability.The vessel must meets the requirements of the Section III of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code(ASTM). Besides, all reactors are required to be entirely enclosed by a structure to contain radioactivity from the coolant system or from the reactor vessel itself.

     Aboves, were all the safety system are well designed to ensure the nuclear reactors safely to be operated for a long period. I would like to end my sharing today with a hope that, we all have a better understanding about the safety systems been implemented.

So, now do we all feel nuclear reactor safe? ^_^

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