Actual status of the research alliances “Condensation Induced Water Hammer” and “Boiling processes in Pressurized Water Reactors”

The German Nuclear Society (KTG) is a non-profit scientific technical association with more than 2500 members. KTG strives for the development and dissemination of the stateof-the-art in nuclear science and technology to promote the peaceful use of nuclear energy and related disciplines. The technical work of the KTG members is performed within the framework of currently 9 topical sections, which, for instance, jointly organize the KTG Annual Meetings, topical meetings devoted to selected subjects and several other activities. In recent years, the topical sections Reactor Safety, Thermal and Fluid Dynamics, as well as Reactor Physics and Computational Methods, have successfully established a series of meetings on \Topical Issues of Reactor Safety Research in Germany". These meetings represent a forum for authorities, operators, technical support organizations, universities and vendors. A Technical Program Committee (TPC) consisting from members of the participating topical sections is responsible for selecting the issues to be addressed at the meeting. The acceptance and success of this series of meetings is mainly due to the current subjects dealt with. In addition to the presentation of scientific and technical research results, this forum offers the chance for a free exchange of opinions outside licensing and supervisory procedures. A balance is presented between survey papers on the background and the state of the art in the related field, specific technical presentations, and outlook papers. The participants are provided with a general overview on the area addressed and with new ideas, and impetus for their future work. In order to further promote these conference series, the TPC has initiated co-operation with the journal KERNTECHNIK. The cooperation started in 2011 with a very successful edition of the topic \Requirements for the demonstration of effective emergency core cooling during loss-ofcoolant accidents involving the release of insulation material and other substances". Two contributions of this special issue were among the top five downloads in the period 2010 up to 2011 of KERNTECHNIK. The 2012 meeting on \Topical Issues of Reactor Safety Research in Germany" was held at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) on 11–12 October 2012, hosted by the Institute of Fluid Dynamics of HZDR and the TUV NORD SysTec GmbH & Co. KG and the section Thermal and Fluid Dynamics of the German Nuclear Society (KTG). At the meeting selected results of the two research alliances \Condensation induced water hammer – CIWA" and \Boiling processes in PWR" were presented. Both research alliances are sponsored by the Federal Ministry of Education and Research within the "Basic Energy Research 2020+" concept. Even though Germany is phasing out of domestic power generation from nuclear energy, it should be noted that the Federal Ministry of Education and Research continues to fund further scientific and technological R&D in support of safe operation of existing nuclear reactors. One of the most effective paths for ensuring high quality basic and applied research programs is to provide funding of multi-organizational, multi-disciplinary research alliances. In addition, special attention should be paid to the support of young scientists and researchers, and to the dissemination and transfer of research findings to industry. The selection of the main topics \Condensation Induced Water Hammer" and \Boiling processes in PWR" at the actual topical meeting was made by the following background: Pressure surges are still a cause of serious damages in both nuclear and conventional power generation plants. Understanding the mechanisms and underlying physics, as well as developing measures to prevent and/or mitigate their initiations are still challenging tasks for utilities and technical support organizations. Boiling processes play an important role in energy generating facilities were energy transfer is essential. The deeper understanding of the mechanisms not only increases the safety of the facility but also enables to enhance the effective operation. In the past the development of promising Computational Fluid Dynamics (CFD) models stagnated not least due to missing of CFD grade experiments. The research alliance \Boiling processes in PWR" contributed in both directions: Small and large scale experiments and model development. For enhanced dissemination of the state-of-theart, selected papers of the meeting are published in this special issue of KERNTECHNIK. Both, the topical meeting as well as the now presented special issue of KERNTECHNIK is certainly an impressive proof that the strategic objectives of the Basic Energy Research 2020+" concept can be achieved. EDITORIAL