Don't be scared about...the challenges concerning containing a "small" star in the earth are intrinsically safe. If any of the parameters needed for the Fusion reaction is not met the "star" will not appear. Actually,our goal is to maintain long enough those conditions (UltraHigh Vaccumm and ultra high temperature) in order to sustain a self-estiguishable "star", so, enough "fusion" pulse in order to be capable to process the energy of this "small" star (around 5 minutes), do you understand?

Fusion is Safe by nature, Fision is Riskier because it is based on Controlling the parameters to avoid a chain-reaction impossible to estiguish once you reach that point