Energiewende – Complements to the Mainstream in the Media
Nuclear Safeguards in the EU
Analysis of Common Cause Failure Parameters
Upgrading the Charging Pump Mechanical Sealing System
Reprocessing and Recycling Services for Research Reactors
Since the Fukushima-Daiichi accident in 2011 few western countries have been building nuclear reactors. China, however, seems to be going on something of a spree, sensing a solution for pollution at home – and unprecedented commercial opportunities abroad. There might be a general feeling in the industry that nuclear energy is on the wane in the West, but the same industry is casting increasingly envious glances to the East. A minimum of 60 nuclear power reactors are expected to start up in China over the next decade. By 2050, nuclear power should exceed 350 GW in China, with about 400 new nuclear reactors and total nuclear investment of over a trillion dollars.
In 2015, German electricity consumers have again paid more than 23 billion Euros just for the electrical energy generated by renewables. The success of the “Energiewende” seems to be limited due to rising costs and CO2-emissions as well as the increasing vulnerability of the grid. Also the protagonists of the new technologies have severe economic problems. At the same time the German industry alerts on rising electricity generation costs endangering productivity. All these complaints are publicly available, but nevertheless, the public support remains widely unchallenged. The support for the Energiewende project relies on several mostly politically driven cornerstones.
Nuclear safeguards in the 28 Member States of the European Union are based on a complex structure of national, supranational and international legal acts: A first approach are the three “S” to be met: security, safety, safeguards. The EURATOM safeguards are based on two pillars: the control of nuclear material itself, as well as different types of international agreements: the first refers to “agreements with a third State”, the second on “agreement with an international organization”.
The shutdown of eight reactors in Germany in the wake of Fukushima 2011 and the scheduled phase-out of the remaining units in several steps ending 2022 has obviously triggered a wave of applications for decommissioning and dismantling licences. It would seem natural to strive for a harmonised handling of these processes, analogous to the 'convoi' concept which was successfully employed for licensing and construction of the three most recent German NPPs in the 1980s. However, a comparative analysis shows that the motivation of all players is much different from that of earlier times and that harmonisation of licensing processes for dismantling is not as crucial for operators, authorities and technical support organisations as it was for construction.
Baehyeuk Kwon and Moosung Jae
Probabilistic Safety Assessment (PSA) based applications and regulations are becoming more important in the field of nuclear energy. According to the results of a PSA in Korea, the common cause failure evaluates CDF (Core Damage Frequency) as one of the significant factors affecting redundancy of NPPs. The purpose of the study is to develop a COCAP (Common Cause Failure parameter Analysis for PSA) program for the accurate use of the alpha factor model parameter data provided by other countries and for obtaining the indigenous CCF data of NPPs in Korea through Bayesian updating.
Gerard van Loenhout, Peter Nilsson and Magnus Jehander
For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.
Pavel Kus, Šárka Bártová, Martin Skala, Katerina Vonková, Václav Zach and Roman Kopa
In nuclear power plants, drained primary coolant containing boric acid is currently treated in the system of evaporators and by ion exchangers. Replacement of the system of evaporators by membrane system (MS) will result in lower operating cost mainly due to lower operation temperature. In membrane systems the feed primary coolant is separated into two output streams: retentate and permeate. Retentate stream consists of the concentrated boric acid solution together with other components, while permeate stream consists of purified water. Results are presented achieved by testing a pilot-plant unit of reverse osmosis in nuclear power plant (NPP) Temelín.
Sandor Tözser, Frances M. Marshall, Pablo Adelfang, Edward Bradley, Madalina Elena Budu and Mustapha Chiguer
International activities in the back end of the research reactor (RR) fuel cycle have so far been dominated by the programmes of acceptance of highly-enriched uranium (HEU) spent nuclear fuel (SNF) by the country where it was originally enriched. In the future inventories of LEU SNF will continue to be created and the back end solution of RR SNF remains a critical issue. The IAEA, based on the experience gained during the decade of international cooperation in supporting the objectives of the HEU take-back programmes, drew up a report presenting available reprocessing and recycling services for RR SNF. This paper gives an overview of the report, which will address all aspects of reprocessing and recycling services for RR SNF.
Saleem Chaudry, Sophie Kuppler and Ulrich Smeddinck
Searching for solutions for solving environmental problems, dissolves the boundaries between the several scientific disciplines. The disposal of radioactive waste requires such interdisciplinary solutions. A problem is described, which generates new problems, if one is solved. The interdisciplinary cooperation for the evaluation of a disposal solution is described. The point of view is a theoretical approach and a transdisciplinary combination of science and the public.
The safe decommissioning of nuclear installations is technically feasible, but is also still a challenge for science, technology and industry. The expertise and know how for decommissioning must be ensured because it will be needed for further decades. Already in 2008 the Karlsruhe Institute of Technology (KIT) had identified this challenge that later emerged through the closure of nuclear power plants in Germany. The KIT opened the professorship Technology and Management of the Decommissioning of Nuclear Installations. In 2014, this section was extended through the dismantling of conventional installations.