Reactor Pressure Vessel under Severe Accident Loading (RPVSA) Final report

The mechanical behaviour of the reactor pressure vessel strongly influences the environmental consequences of a core melt-down accident. If unfavourable large-scale failure of the vessel could be ruled out, this accident would lose much of its catastrophic character. Therefore, thorough investigations of the most vulnerable parts of the reactor pressure vessel under severe accident loading have been carried out. In the 1"s"t section the lower vessel head is assumed to be heated intensely by contact with a corium pool. As a result the lower head will undergo a transient temperature rise with very non-uniform spatial distributions causing complex creep deformations and material damage. In the 2"n"d section the lower vessel melt-through failure was investigated by the CORVIS experiments, where a high temperature alumina/iron thermite as a corium substitute was poured on a thick steel plate simulating the lower head wall. In the 3"r"d section the lower head region mechanical processes during a postulated in-vessel steam explosion has been addressed. It will be studied by the model experiments BERDA II. In the 4"t"h section the upper head dynamic response during a postulated in-vessel steam explosion has been investigated by the model experiments BERDA I. In the 5"t"h section the mechanical material properties required for the lower and upper head problem, have been investigated by corresponding material test programs. Results related to the lower head problem indicated a material phase change between 690 and 825 C. (orig.)SIGLEAvailable from TIB Hannover: ZA 5141(6358 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekCommission of the European Communities (CEC), Brussels (Belgium)DEGerman