The reactor pressure vessel of Three Mile Island

14-1 -6. The reactor pressure vessel of Three Mile Island 2 

It took ten years to understand the conditions in the damaged TMI core through a considerable international investment. The research program, TMI Vessel Investigation Program (VIP) lasted five years and cost 9 m, with contributions from ten countries besides the USA. 

A first conclusion on the condition of the vessel concerned the presence of a hot, almost circular, zone of about 1 m in diameter where the maximum temperature had reached 1373 K (1100°C) on the 

Concerning the rupture modes of the vessel (which was one of the issues in the VIP programme), it has been possible to exclude a rupture in the instrumentation tubes the formation of crusts and the favourable situation of thermal dispersion prevent the creation of holes corresponding with the instrumentation tubes. 

A very important factor in determining the possible interaction between molten masses and the vessel bottom is that the cooling of the molten mass was also due to convection from the upper part of the vessel and from conduction towards the vessel wall in the lower part. It is thought that water had 

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