ICONE15-10547 A COMPARISON OF HVAC SYSTEMS BETWEEN CONFINEMENT AND CONTAINMENT

In the pressurized-water reactor (PWR) and the boiling water reactor (BWR) power plant, The anticipated transients without scram (ATWS) accident does possibly happen, so the containment (pressure-resistant airtight space) is used as an important safety barrier. At the same time, for assuring the structure integrity of containment in a severe accident, a filtered vented containment system (FVCS) is usually mounted. But in the high temperature gas-cooled reactor (HTR) power plant, the functions of spherical fuel elements have been equivalent to two barriers, the first is the coated particles, the second is the graphite shell. The pressure vessel (pressure-resistant airtight space) is the third safety barrier. In addition, the ATWS accident will not occur in HTR, so the vented confinement is adopted instead of the containment. For the heating, ventilating and air conditioning (HVAC) systems in a reactor, the containment of Qinshan Phase I nuclear power plant includes five sub-systems and the configuration is complex, but the confinement of HTR-10 built in Tsinghua University has only the safety class negative pressure exhaust system rather than the supply air system. By comparison, the vented confinement design brings to a great advance and simple in designing and building HTR.