NEA Sesar Thermal-hydraulics (SETH) Project

The SESAR Thermal-Hydraulics (SETH) project covered two aspects of accident management:

The PKL tests investigated two PWR safety issues: boron dilution in loss-of-coolant-accidents and boron dilution during mid-loop operation (shutdown conditions). The first category of tests aimed to verify if the necessary conditions can arise for core reactivity insertion due to boron dilution during a small-break loss-of-coolant-accident with a natural circulation restart. Results received so far indicate that while boron dilution can occur under specific circumstances, safety is not impaired. The second test series will assess primary circuit accident management operations to prevent boron dilution as a consequence of loss of heat removal in mid-loop operation conditions. A final report on the results of the PKL tests was issued in 2004.

The (PSI) PANDA experiments aimed to provide data on containment three-dimensional gas flow and distribution issues that are important for code prediction capability improvements, accident management and the design of mitigating measures. These experiments were conducted on a large scale in multi-compartment geometries in order to provide data suitable for the improvement and validation of safety analysis codes.

The NEA Committee for the Safety of Nuclear Installations (CSNI) has been promoting international initiatives and collaboration to establish convincing experimental safety programmes around specific facilities. As a first step in this direction, the PKL (Pressurised Water Reactor) loop in Germany and the PANDA in Switzerland were requested to develop proposals consistent with the priorities indicated in the CSNI Senior Group of Experts on Safety Research (SESAR) report Nuclear Safety Research in OECD Countries: Summary Report of Major Facilities and Programmes at Risk. Their proposals, after discussions with member country experts, formed the basis for the SETH Project.

After an extensive preparation phase, the experimental series started in 2004 and continued in 2005. Due to the complexity of the PANDA experiments, some delays were encountered. The Project Board therefore decided to extend the programme’s time frame to the end of 2006.

Project data

SETH/PKL data abstract and SETH/PANDA data abstract are public.

Project participants

Belgium, Czech Republic, Finland, France, Germany, Hungary, Italy, Japan, Korea, Spain, Sweden, Switzerland, Turkey, the United Kingdom and the United States.

Project period

SETH/PKL: April 2001 to June 2005 (available to member countries)

SETH/PANDA: April 2001 to December 2006 (available to member countries in January 2010)


USD 4.7 million

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Last updated: 24 February 2014