The Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF) Project was established in 2012. The objective of the project was to improve severe accident (SA) codes and to analyse the accident progression and current status of units 1 to 3 of the Fukushima Daiichi nuclear power plant (NPP), providing useful information for the decommissioning of these units.

It was hosted by the Institute of Applied Energy (IAE) in Japan, in collaboration with other Japanese institutions such as Japan Atomic Energy Agency (JAEA), Nuclear Regulatory Authority (NRA) and Central Research Institute of Electric Power Industry (CRIEPI). It was additionally supported by the Tokyo Electric Power Company (TEPCO), the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF) and other Japanese industry partners. The project brought together international experts to advance the understanding of severe accident phenomena specific to the Fukushima Daiichi nuclear power plant (NPP) accident while also improving the methods and codes for modelling such severe accidents.

A phased approach was applied in the NEA benchmark exercise.

BSAF phases

First phase (2012-2015)

The first phase of the BSAF project closed in 2015, and focused on the thermal-hydraulics in reactor pressure vessels (RPVs) and primary containment vessels (PCVs) for the first six days of the accident. The summary report is available below.

Second phase (2016-2018)

The second phase of the project expanded the work scope to include fission product behaviour outside PCVs, lengthening the time span for analyses of accident events to about three weeks after the occurrence of the earthquake. During phase 2, several workshops will be held to allow project participants to discuss their calculation results with other experts and to compare them with other information, such as measured data and investigation results from the Fukushima Daiichi nuclear power plant, for better understanding of the current status of the plant and the progression of the accident.

BSAF-2 members' area (password-protected | reminder)