We make a model for an outburst occurred in the Halley Comet during March 23-25, 1986. With radio and UV observations we detected an increase in the production rate of gas by a factor of 2.5 in one day. Taking into account the evolution of four bursts in the 1667 MHz line of OH, we proposed a model for the dissociation of this radical. We calculate the photo-chemical lifetime of the OH and H₂O. The lifetimes calculated for the OH in the Halley at 1 A.U. from the Sun, change between 2.3x10⁵ and 4.7x10⁵ sec. for heliocentric radial velocities which range between -27 km/sec and +27 km/sec.