Experimental Thermal Hydraulics for Analysis, Research and Innovations in NUclear Safety (ETHARINUS) Project
Joint project

PKL facility. Photo: FRAMATOME, Germany

The Experimental Thermal Hydraulics for Analysis, Research and Innovations in Nuclear Safety (ETHARINUS) project serves the objectives of investigating phenomena where the knowledge base for safety assessment is not sufficiently developed and of providing qualified data for thermal-hydraulics code model development and validation for the analysis of key safety issues. The project scope also facilitates a common database to contribute to the experimental verification of cool down procedures, operation modes and systems (including passive ones) for different transients. An enhanced focus of the investigations is on studies related to loss of coolant accident (LOCA) addressing design extension conditions (DEC) for small break LOCA (SB-LOCA) scenarios and two-phase flow thermal-hydraulic phenomena for Intermediate break LOCA (IB-LOCA) scenarios, on studies related to core cooling performance under partial core blockage, on studies related to effectiveness of passive heat removal systems and on studies related to cool down procedures after a multiple steam generator tube rupture (M-SGTR) scenario. ETHARINUS experiments are highly relevant to the improvement and validation of thermal-hydraulics safety codes and their use, as well as to the maintainance of competence and expertise in this field which is an important goal for the NEA member countries. 

The ETHARINUS project involves experimentation in the modified PKL facility (PKL stands for Primärkreislauf-Versuchsanlage [Primary Coolant Loop Test Facility]) at Framatome GmbH, Germany, in the PACTEL facility at the Lappeenranta-Lahti University of Technology, LUT University, Finland, and in the PSB-VVER facility at the Electrogorsk Research and Development Center for Nuclear Power Plants Safety, JSC ENIC, Russian Federation. It is supported by 24 organisations from 14 countries. ETHARINUS will extend the large database resulting from the PKL project series which started in early 2004 and ended in October 2020. The ETHARINUS and the ATLAS phase 3 (2021-2024) projects have been designed to be complementary in both scope and testing.

ETHARINUS Members' area  (password protected | reminder)


Belgium, China, Czechia, Finland, France, Germany, Hungary, Japan, Korea, Russia (suspended), Spain, Sweden, Switzerland, United States

Project period

October 2020 - September 2024


EUR 4.9 million