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FP6

Pre-Test Calculations of the FPT3 Experiment Using the MELCOR, ATHLET-CD and ICARE2 Computer Codes (Comparative Study)

Funded under: FP6-JRC

Abstract

In the frame of an international co-operation, a computational a benchmark study was performed using the reference scenario where the initial and boundary conditions were provided by IRSN. The calculations, carried out by the severe accident codes MELCOR, ATHLET-CD and ICARE2, they focused on the fuel bundle degradation occurring in conditions of a typical PHEBUS FP test. Special effort was done to use the same nominal bundle power and materials properties.
In the FPT3 test, LWR-typical fuel elements are used and the chosen initial and boundary conditions are very similar to those in severe accidents. The test bundle consists of twenty, one-meter-long fuel rods comprising 10.5 kg of UO2 and it is heated by the driver core of PBEBUS reactor.
The comparison shows overall good agreement of results calculated by the three severe accident codes. Each calculation managed to predict the target value of the duration of steam starvation period (1300 s at 0.5 g/s steam inflow) and of the melted fuel mass (1 to 3 kg) set as the test objectives. The total mass of hydrogen produced in the transient and averaged over the calculations is 120 g.
The calculations also predicted that the fuel relocates and accumulates in the lower part of bundle between 0.10 m and 0.25 m at the end of test. The differences in the relocated masses are mainly attributed to different relocation (2500 - 2600 K) temperatures used in the calculations. The spread of oxidised boron carbide mass indicates that modelling efforts are still necessary in all the codes in this respect.

Additional information

Authors: TÓTH B, European Commission, Joint Research Centre, Institute for Energy, Petten (NL);MÜLLER K, European Commission, Joint Research Centre, Institute for Energy, Petten (NL);BIRCHLEY J, PSI, Paul Scherrer Institut, Villigen (CH);HOZUMI W, JNES, Japan Nuclear Energy Safety Organization (JP);JAMOND C, IRSN, Institut de Radioprotection et de Sûreté Nucléaire (FR);TRAMBAUER K, GRS, Gesellschaft für Anlagen- und Reaktorsicherheit (DE)
Bibliographic Reference: EUR 21555 EN (2006), 69 pp. Free of charge
Availability: Available from European Commission, JRC Knowledge Management Unit, Ispra (IT) Tel: +39 033278 9893 Fax: +39 033278 5409 E-mail: jrc-info@ec.europa.eu or Bruxelles (BE) Tel: +32 2 295 76 24 Fax: +32 2 299 63 22
Record Number: 200718895 / Last updated on: 2007-03-16
Category: PUBLICATION
Original language: en
Available languages: en