Question

What r nutrinos???? With what would they react..

Answer 1

Neutrinos can be created in several ways, including in beta decay of atomic nuclei or hadrons, nuclear reactions such as those that take place in the core of a star, supernovae, and when accelerated particle beams or cosmic rays hit atoms.

Answer 2

A neutrino is a fermion that interacts only via the weak subatomic force and gravity. The mass of the neutrino is much smaller than that of the other known elementary particles. 
neutrinos interact weakly with each other through the Z boson. However, these interactions are so rare and weak that they have never been observed, and most of the literature I looked through is basically analyzing astrophysical data to see any evidence of their interaction, and using its non-observation to constrain the cross-section for neutrino interaction.