WPNCS Expert Group on Criticality Excursions Analyses (CEA)
The Expert Group on Criticality Excursions Analyses was created with the aim of providing scientific
knowledge on criticality excursions (accidents, experiments and simulation).
Under the guidance of the Working Party on Nuclear Criticality Safety,
the major assignments of the Expert Group include:
Identifying and compiling criticality transient data from experimental programmes and from accident data
Evaluating the main transient experimental programmes and creating a database to store and disseminate the data
Identifying and highlighting experimental needs for criticality accidents analyses
Identifying and compiling available models and computer codes for transient analyses
Defining benchmark exercises to compare the computer codes used for criticality accidents analyses
Identifying modelling needs
Current programme of work
The expert group's work currently addresses the following areas:
The evaluation of criticality excursion experiments.
A draft format
was designed by extending and adapting the International Criticality Safety Benchmark Evaluation Project evaluation format.
The organisation of inter-code comparison exercises. Benchmark proposals based on experiments
performed in SILENE and
solution reactors have been prepared.
A report on these benchmark exercises is currently being finalised.
A further four phases of this exercise are envisaged.
The expert group is examining preliminary results from the second phase of the benchmark exercise,
which covers slow transients from the TRACY experimental reactor.
A third phase will study code performances to simulate long-duration experiments,
whilst a fourth phase will examine the dilute Pu-solution.
A final fifth phase will be a detailed analysis of postulated accident conditions.
The development of a
web-based information resource on
criticality excursions (experimental programmes, existing modelling capabilities, criticality accidents).
Phase I report discusses the performances of four transient codes: AGNES, CRITEX, INCTAC,
and TRACE to simulate experimental results from two experimental facilities SILENE and TRACY
(final report is on publication).
For more information on CEA activities please contact