Assessment of thermal damage to polymeric materials by hydrogen deflagration in the reactor building

Thermal damage to susceptible material in accessible regions of the reactor building was distributed in nonuniform patterns. No clear explanation for nonuniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, the authors assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. Simple hydrogen-fire-exposure tests and heat transfer calculations duplicate the degree of damage found on inspected materials from the containment building. These data support estimated 8% pre-fire hydrogen concentration predictions based on various hydrogen production mechanisms