CSNI Workshop

MASCA Seminar 2004

Hosted by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN)

Aix-en-Provence, France
10-11 June 2004

The NEA has, since 1994, sponsored collaborative projects on severe accidents carried out at the RRC KI in Russia. These projects, entitled the RASPLAV and the MASCA Projects, consisted of a programme of experiments and analyses intended to address the conditions under which molten core material can be retained inside the reactor pressure vessel (RPV) by cooling of the vessel from outside. The results have been of wider applicability in that they have provided new insights as to the behaviour of molten corium pools and consequent heat load on the lower head of the reactor pressure vessel. These results are important since the thermal conditions affect the lower head failure mode (and the consequent pouring and spreading of the melt).

The RASPLAV Project demonstrated that the corium melt behaved comparably to the simulant material in its natural circulation, therefore previous evaluations based on simulant material data could be scaled to prototypic reactor conditions. However, two of the four RASPLAV tests exhibited an unexpected behaviour.
Sufficient knowledge of fission product spatial and chemical distributions in the melt pool is lacking. Well-designed experiments obtained with corium compositions prototypical of power reactors was supposed to provide the technical support for assessments of the in-vessel melt pool retention strategy as well as of ex-vessel phenomena. The MASCA tests covered this accident management need.

This goal was achieved through corium tests of different scale, including pre- and post-test analyses and development of computational models. Additional measurements of thermo-physical properties of the melts such as density, thermal conductivity and liquidus-solidus temperatures considerably expanded the material properties database obtained in the RASPLAV Project.

The objectives of the MAterial SCAling (MASCA) project were to:

The CSNI decided to hold a seminar where the major outcome of the MASCA Project could be presented and discussed also in the context of other experienced activities on severe accidents.
The objectives of the seminar were to:

Related links

Seminar programme

NEA Committee on the Safety of Nuclear Installations (CSNI)

RASPLAV project

MASCA project

Institut de Radioprotection et de Sûreté Nucléaire (IRSN)

Organising committee (restricted access)