The production of hydrogen due to the radiolysis of reactor containment spray solutions has been investigated. An experimental program was conducted to determine the extent of radiolytic hydrogen production in a laboratory system modeled after the nuclear plant systems. Radiolysis of the solution, as it would occur in the containment sump and in the reactor core, was studied. Experimental results indicate a conservative rate of hydrogen production due to sump solution radiolysis of 0.30 molecules/100 eV of energy absorbed by the solution. Experimental studies of core solution radiolysis have shown the extent of hydrogen production from this source is limited by the attainment of a steady-state hydrogen concentration in the solution passing through the core. Based on experimental data, an analytic model was derived which conservatively approximates the hydrogen production process as it would occur in the nuclear plant should a hypothetical design basis accident (DBA) occur. The significance of other sources of hydrogen in the post-accident environment is discussed also.