NUCLEAR WEAPON VS NUCLEAR REACTOR 2

As we all know nuclear bomb and nuclear reactor use the same fission method to produce large amount of energy in a short amount of period. So therefore what makes a nuclear reactor safe compared to the destructive force of the nuclear bomb? Well the answer lies in the ability of man to control this nuclear fission process various types of methods. The most widely used fission control technique is the use of moderator and the use of control rods.

 A moderator is a medium which is used to slow down the fast neutron to the thermal state (slow neutron state), by controlling the speed of the neutrons in the reactor core, eventually we can control the reaction rate or the reactivity. By controlling the reactivity we can ensure that the nuclear fission is taking place in a safe amount which is suitable for a nuclear reactor. Although there are many different types of moderator like the D2O (heavy water) and C2O (carbon dioxide) but the best moderator is pressured H2O or in simple word is the pressured water.

The efficiency of the reactor is called reactivity and the reactivity is measured using the k_eff. Moderator to fuel ratio is the amount of moderator in the reactor with respect to the fuel. In the modern reactors nowadays, they operate in the under moderated region. From the graph it shows that when the moderator to fuel ratio increases the k_eff  increases and if the moderator to fuel ratio decreases the k_eff decreases. This feature of the nuclear fission process is very useful when the reactivity of the nuclear fission start to reach the dangerous level so when we enter the control rod (such as graphite) the amount of moderator to fuel ratio decreases and according to the graph the k_eff also decreases and the reactor will reach a safe operating state.

This ability certainly ensures the reactor is safe and not hazardous to anyone. This use of moderators certainly gives us the ability to control the nuclear reactivity fission process; unlike the nuclear bomb whereby, the nuclear reactivity is uncontrollable and becomes destructive. This proves that the nuclear fission process is controllable for the use of power generation and it is also safe.