Containment transport behavior

This paper addresses the containment vessel of a nuclear reactor, the last barrier against the release of radioactive material in the event of a severe accident. For light water reactors (LWRs), there are more than a half-dozen different types of containments. The risk significant differences among them are of geometry, size (volume), strength, and construction details. They vary in volume from the smallest (the boiling water reactor Mark-I) of about 4500 m3 to the largest (the FRG BIBLIS type) of about 72000 m3. The U.S. large-dry pressurized water reactors (PWRs) have a volume of about 5100 m3. Some containments are free standing steel structures (e.g., the BIBLIS type), while others derive their strength as concrete structures lined on the inside with steel for leak tightness. Some have special features designed to condense steam and/or to remove heat as a means of reducing the pressure loads produced by an accident. These features include: fan coolers in large-dry PWRs; ice beds in ice-condenser PWRs; suppression pools in BWRs; and sprays in PWRs and in the BWR Mark-III. Some of the reactor plants in Europe are equipped with the capability to vent through a filter system