discovered_01_2013

discovered 01.13 PORTRAIT WWW.Hzdr.DE accelerator is to supply the high energy protons to the spallation target acting as an external neutron source for the reactor core. Germany is involved in this global project as well. By 2024, construction of a new sodium-cooled fast reactor called ASTRID is scheduled to commence in the South of France. Emil Fridman's group will contribute to its safety evaluation in the framework of a recently approved EU project called ESNII+ (ESNII – European Sustainable Nuclear Industrial Initiative). At the same time, albeit far off the shores of Europe, high-temperature gas cooled reactors are currently being developed in the US. One of the main advantages of this reactor type is its capability to provide both electricity and high-grade heat for energy-intensive industrial processes. High-temperature gas cooled reactors are also one of the topics of a common project that is currently being conducted at HZDR and Technische Universität Dresden. Years ago, Germany, together with France, was a leader in Europe in fast reactor development. In fact, during the Seventies of the last century, a sodium-cooled research reactor was built at the Karlsruhe Nuclear Research Center, which in turn prompted construction of the first German sodium-cooled breeder reactor for generating power in Kalkar at the Lower Rhine. At the time, one of its most fervent supporters was Wolf Häfele who, later, following the German reunification became the Rossendorf Research Center's founding director. This "fast breeder," however, never began operations. A second innovative project was the high- temperature reactor in Hamm-Uentrop in the German state of North Rhine-Westphalia. The THTR-300 prototype began trial operations in 1983 and, in 1989, was permanently taken off the grid. Its job had been to optimize nuclear fuel utilization by breeding uranium from thorium. Potential use of thorium in existing reactors During the power production in light water reactors, a number of new isotopes are created from uranium including plutonium and other heavier actinides. Plutonium isotopes can be extracted from the spent nuclear fuel and used as new fuel for operating or future nuclear reactors. In some countries like France, spent fuel from light water reactors is routinely reprocessed to recover plutonium. Nowadays, large stockpiles of civil plutonium accumulated in the World have raised concerns associated with proliferation potential as well as the risk of environmental hazards. Keeping in mind that the massive deployment of commercial fast reactors is not foreseen in the near future, existing commercial power reactors are the only available facilities for plutonium recycling in the short to mid-term. Today’s practice of plutonium recycling is the utilization of uranium-plutonium mixed oxide (MOX) fuel in 40 light water reactors licensed for that very purpose. Several of them are operated in Germany. Yet, MOX fuel has limited plutonium destruction efficiency. On the other hand, the use of thorium-plutonium mixed oxide (TOX) fuel instead of “classical” MOX can dramatically increase plutonium destruction rates. This is due to the fact that the replacement of uranium with thorium eliminates the generation of new plutonium. Together with scientists from Italy, India, Canada, the US, and the Czech Republic, the Dresden junior research group is participating in IAEA’s coordinated research project entitled “Near Term and Promising Long Term Options for Deployment of Thorium Based Nuclear Energy.” The Dresden researchers are responsible for assessing the feasibility of plutonium recycling in light water reactors using TOX fuel. Other international collaboration activities of the junior reactor physicists are also related to computer codes. The US-based company Studsvik, for example, develops the most widely used industrial simulation tools for light water reactors. The Dresden scientists are currently in the process of testing one of them for use with fast reactors and their results will provide important clues for key methodological adjustments. Fast reactors are also what Fridman, together with the Swiss Paul Scherrer Institute (PSI) and Israel's Ben Gurion University, is working on. This shows his connections to his alma mater in Israel are still quite good. It is where he earned his Ph.D. and where one of his mentors first introduced him to the idea of weekly meetings. The fact is that Emil Fridman attaches great importance to having weekly group meetings where Ph.D. students Yurii Bilodid, Daniela Baldova, and Reuven Rachamin give updates on their research progress. This allows him to quickly intervene if one of the students needs help with solving a problem. Having weekly meetings also helps students be aware of the group's ongoing research activities and thus to expand their knowledge and expertise. By now, these update presentations make for an impressive archive, which prevents things from quickly fading into obscurity, and they are an exemplary starting point for conference presentations, journal publications, and even Ph.D. theses. By now, the meetings have become popular with other doctoral students in nuclear technology and reactor physics as well and even the head of the HZDR's Division of Reactor Safety likes to drop in on occasion. ContaCt _Reactor Physics Junior Research Group at HZDR Dr. Emil Fridman e.fridman@hzdr.de

discovered_01_2013

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