Working Group on Analysis and Management of Accidents (WGAMA)

The main mission of this working group is to advance the current understanding of the physical processes and address the safety issues associated with the following areas:

Both current and advanced reactors are considered.



The Working Group on the Analysis and Management of Accidents (WGAMA) shall be responsible for activities related to potential accidental situations in nuclear power plants, including the following technical areas: reactor coolant system thermal-hydraulics; design-basis accident including ECCS strainer clogging; pre-core melt conditions and progression of accident and in-vessel phenomena; coolability of over-heated cores; ex-vessel corium interaction with concrete and coolant; in-containment combustible gas control; physical-chemical behavior of radioactive species in the containment; combustion phenomena. The activities will mainly focus on existing reactors, but will have application also for some advanced reactor designs. Priority setting will be based on established CSNI criteria and in particular on safety significance and risk and uncertainty considerations.


The WGAMA objective is to assess and where necessary strengthen the technical basis needed for the prevention, mitigation and management of potential accidents in nuclear power plants, and to facilitate international convergence on safety issues and accident management analyses and strategies.

In order to fulfil this objective, the working group shall:

The Working Group shall report to the Committee on the Safety of Nuclear Installations (CSNI) and assist that Committee with its work. The programme will be carried out by small task groups, each set up for performing a specific programme activity under the WGAMA supervision. The output of the working group will consist of state-of-the-art reports and other technical reports, workshops and related proceedings, benchmarking exercises and joint research proposals.

The working group will aim to provide answers as requested by CNRA, CSNI and member countries and will co-ordinate its work with other working groups, notably with WGRISK for priority setting, WGOE for emerging issues and WGIAGE for ageing and structure integrity evaluation. WGAMA will also work in co-ordination with the NEA/NSC on scientific items such as advanced neutronic and thermal-hydraulic methods. Interaction with joint projects will be strengthened as recommended in the CSNI Operating Plan.


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Last reviewed: 10 January 2017