This java applet simulates a nuclear reaction in which 235U is the fissile isotope. The chain reaction can be controlled by moving the "neutron absorbers" slider up and down. This slider dynamically changes the number of neutron absorbers present as the applet is running, just like an operator at a nuclear power plant lowers and raises the control rods. When a neutron hits the fissile 235U, an average of 2.5 neutrons are released; sometimes 2, sometimes 3. You can also specify the inital amount of 235U; but you must hit the RESET button for this change to take effect.

Start - Starts the reaction

Stop - Pauses the reaction

Reset - Reconfigures reaction

Enable Sound - Actives sound which occurrs everytime a U235 atom fissions (the simulation may not produce the sound 100% of time due to large amount of atoms). This option may slow down the speed of the applet.

NOTE: When the applet is paused (STOP or RESET has been hit), moving the slider up and down does not have its desired effect. You can move it while the reaction is running. In addition, you must hit RESET for the change in initial 235U amount to take effect.