16.2 - Severe Accident Analysis (RRC-B) - EDF Hinkley Point

SUB-CHAPTER : 16.2PRE-CONSTRUCTION SAFETY REPORTCHAPTER 16: RISK REDUCTION AND SEVEREACCIDENT ANALYSESPAGE : 117 / 295Document ID.No.UKEPR-0002-162 Issue 04• Combustion temperatures are considerably lower in the cylindrical part of thecontainment where the penetrations for ducts, material hatch and personnel airlockare located.• Dynamic loads on the containment shell are benign. Pressurisation is bounded byAICC pressure. Although the flame accelerates in the SG tower, it decelerates in thedome, which results in small dynamic loads on the containment shell.There seems to be no restriction for the activation of the spray system with regard to hydrogenrisk. The positive effect of mixing the atmosphere by the spray system compensates thenegative effect of increasing the relative hydrogen concentration due to steam condensation.