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History of THERPRO

  With the explosive expansion of computer applications to design, analysis, simulation and process control, material properties data have become an essential and a crucial part in nuclear engineering and science. The evaluation of reactor performance under normal operation and severe accident conditions is vital for current and future water cooled reactors and requires accurate representations of thermo-physical properties under relevant temperature and neutron fluence conditions. Assuring that the needed thermo-physical properties are sufficiently accurate requires peer review, assessment, and evaluation of existing data and selective measurements of new data at conditions for which data are currently lacking or highly inadequate.

  From 1990 to 1994 the IAEA carried out a CRP on thermo-physical properties of materials for water cooled reactors with the aim to collect and systematize a database of thermo-physical properties for light and heavy water reactor materials. Data already existing at the participating institutes, and new data from some additional measurements carried out within the CRP, were collected. The data were then independently reviewed by Argonne National Laboratory and Atomic Energy of Canada Limited and this database was published in 1997. The data were stored in electronic format in the THERSYST system, which was maintained by the Institute for Nuclear Technology and Energy Systems, University of Stuttgart in Germany.

  Since the results of the work showed a large “spread” in some openly available thermo-physical properties data in use at that time, it was decided to establish a new IAEA CRP to critically assess and peer review selected property data and correlations, to extend the database to include properties at severe accident conditions, and to recommend the most appropriate data, if warranted. In particular, this new CRP took critical steps to establish recommended “most appropriate” data with known uncertainties, including peer review of the data, review of the measurement techniques, but also selected new measurements.

  Nine institutes from seven countries participated in this CRP: Atomic Energy of Canada Ltd (Canada); the Nuclear Power Institute of China (China); the University of West Bohemia (Czech Republic); the Institute of Physics and Power Engineering and the Institute of High Densities of the Russian Academy of Sciences (Russian Federation); the Bhabha Atomic Research Centre (India); Commissariat _a I'_Energie Atomique, Grenoble (France); and Hanyang University and Seoul National University (Rep. Of Korea). Significant contributions were also made by the Argonne National Laboratory (USA).

  The objective of second CRP was to establish an internationally available, peer reviewed database of properties at normal and severe accident conditions on the Internet. To accomplish that goal, new measurements of thermo-physical properties of Zirconium liquid, Hf, Zr-2.5% Nb and UO2-Gd2O3 were completed. In addition, the CRP carried out the assessment of thermo-physical properties of materials including Zircaloy, Zr-2.5%Nb, Zr-1% Nb, Zr liquid, ThO2-UO2, ThO2, UO2-Gd2O3, UO2, Russian steels, Hafnium, Corium, and Inconel.

  Along with the review, assessment and new measurement works, a feasibility study on the conversion of the THERSYST database into a web-based online database was proposed during the 2nd CRP. Given the positive results of this study, the old database was completely redesigned and reconstructed using a powerful relational DBMS (Database Management System) using contemporary information technologies (O/S: Linux, DB: MySQL).

  In the reconstruction of the database, the category scheme of THERSYST was preserved while all modular groups of materials were merged into one. For the input entry, the original format of the data set was kept as a standard and all the relevant information was converted into this standardized form to avoid input difficulties and to keep the consistency. New web-based database took the GUI (Graphic User Interface) approach, and thus all descriptors were laid out in the form of buttons in the pop-up windows, which make data selection, manipulation, and representation very user friendly.

  This whole task was carried out by Nuclear Materials Laboratory at Hanyang University in Seoul, Korea, with the financial support of the Ministry of Science and Technology of the Korean government (MOST, Now MEST: Ministry of Education, Science, and Technology). During the 3rd Research Coordination Meeting (RCM) for this CRP, held in Vienna in 2003, the new name THERPRO was given to this new web-based database.