Study on the passive safe technology for the prevention of air ingress during the primary-pipe rupture accident of HTGR

A primary-pipe rupture accident is one of the design-basis accidents of a h igh-temperature gas-cooled reactor (HTGR). When the primary-pipe rupture ac cident occurs, air is expected to enter the reactor core from the breach an d oxidize in-core graphite structures. This study is to investigate the air ingress phenomena and to develop the passive safe technology for the preve ntion of air ingress and of graphite corrosion. This paper describes the me thod for the prevention of air ingress into the reactor during the primary- pipe rupture accident. It is found that a safe cooling rate of the reactor core exists for the prevention of air ingress. The experimental results sho w that the natural circulation flow of air during the accident can be contr olled by the method of helium gas injection into the reactor pressure vesse l. (C) 2000 Elsevier Science S.A. All rights reserved.