Experimental study of the behaviour of the prestressed concrete pressure vessel of the THTR-300 at severe accident temperatures

The risk of medium-sized High Temperature Reactors (HTR-500, THTR-300) with PCRV is dominated by the behavior of the vessel during a hypothetical core heat-up accident. Tests up to extremely high severe accident temperatures with representative models are carried out. The results of these tests are: During a core heat-up accident after total failure of afterheat removal systems the prestressed concrete reactor pressure vessel of the THTR-300 can also be cooled with only one train of the liner cooling system (LCS); refeed of the failed system is possible up to at least 650degC; insulation and liner will not fail during long-term outage of the LCS and do not aggravate the accident in the long run. (author)