Could I turn into a nuclear bomb? Just out of curiousity, could the nuclei of our atoms split via quantum tunnelling, thereby leading to nuclear reactions and ultimately turning us into atomic bombs? I know that this is near-impossible, but wondering if it was technically possible.
 A: The thing is, we're made of mostly stable matter of low atomic number. In a nuclear bomb, unstable nuclei split, releasing a number of energetic neutrons which strike other unstable nuclei, and the reactions chain uncontrollably. Splitting a small nucleus actually costs energy, so even if a carbon atom in your body did split, it would only split into smaller, still low-energy atoms, which would interact normally with other atoms in your body. A couple extra lithium or helium atoms isn't going to do anything drastic.
A: Quantum tunneling keeps the energy of the tunneling particle the same as it had within the potential .

As you will find, putting realistic numbers for nuclear penetration in the calculator of the link the probabilities come out zero.
So spontaneous "turn into a nuclear bomb " is out.
Lets took "technically" : A human exposed to MeV radiation can he/she turn into a bomb?
If this were possible, there would have been a chain reaction  in Hiroshima and Nagasaki, of people turning into new bombs , instead of dying or getting radiation burns. So, experimentally the answer is No. 
Humans are made up of atoms that belong to the left side of the binding energy curve, this means fusion not fission, which needs high temperatures and pressures to even start.A careful choice of nuclei and initial conditions  are necessary for a fusion nuclear explosion/bomb to be constructed.
