Radioactive Waste Management of Fusion Power Plants

This chapter outlines the attractive environmental features of nuclear fusion, presents an integral scheme to manage fusion activated materials during operation and after decommissioning, compares the volume of fusion and fission waste, covers the recycling, clearance, and disposal concepts and their official radiological limits, and concludes with a section summarizing the newly developed strategy for fusion power plant

New linear plasma devices in the trilateral euregio cluster for an integrated approach to plasma surface interactions in fusion reactors

New linear plasma devices are currently being constructed or planned in the Trilateral Euregio Cluster (TEC) to meet the challenges with respect to plasma surface interactions in DEMO and ITER: i) MAGNUM-PSI (FOM), a high particle and power flux device with super-conducting magnetic field coils which will reach ITER-like divertor conditions at high magnetic field, ii) the newly proposed linear plasma device JULE-PSI (FZJ), which will allow to expose toxic and neutron activated target samples to ITER-like fluences and ion energies including in vacuo analysis of neutron activated samples, and iii) the plasmatron VISION I. a compact plasma device which will be operated inside the tritium lab at SCK-CEN Mol, capable to investigate tritium plasmas and moderately activated wall materials. This contribution shows the capabilities of the new devices and their forerunner experiments (Pilot-PSI at FOM and PSI-2 Julich at FZJ) in view of the main objectives of the new TEC program on plasma surface interactions. (C) 2011 Forschungszentrum Julich, Institut fur Energieforschung-Plasmaphysik. Published by Elsevier B.V. All rights reserved

Thorough Chemical Decontamination with the MEDOC Process : Batch Treatment of Dismantled Pieces or Loop Treatment of Large Components Such as the BR3 Steam Generator and Pressurizer

The dismantling of the BR3-PWR reactor leads to the production of large masses of contaminated metallic pieces, including structural materials, primary pipings, tanks and heat exchangers. One of our main objectives is to demonstrate that we can minimize the volume of radioactive waste in an economical way, by the use of alternative waste routes, such as the clearance of materials after thorough decontamination. The SCKoCEN uses its own developed chemical decontamination process, so-called MEDOC (Metal Decontamination by Oxidation with Cerium), based on the use of cerium IV as strong oxidant in sulphuric acid with continuous regeneration using ozone. An industrial installation has been designed and constructed in close collaboration with Framatome-ANP (France). This installation started operation in September 1999 for the treatment of the metallic pieces arising from the dismantling of the BR3 reactor. Since then, more than 25 tons of contaminated material including primary pipes have been treated batchwise with success. 75 % of material could be directly cleared after treatment (Activity lower than 0.1 Bq/g for 60Co) and the other 25% free released after melting activity. The SCKoCEN performed in April 2002 the closed loop decontamination of the BR3 Steam Generator by connection of the MEDOC plant after few adaptations. The decontamination was done within 30 cycles in 3 weeks with consecutive steps like decontamination steps (injection of the solution into the SG) and regeneration steps with ozone. In total, 60 hours of decontamination at 70 C and 130 hours of regeneration were needed to reach the objectives. The tube bundle (600 m2) was attacked and about 10 {micro}m representing more than 41 kg of stainless steel and 2.06 GBq of 60Co was dissolved into the solution. The residual contamination measurements made directly into the water box are still going on, however it seems that the objective to reach the free release criteria after melting is achieved. The next decontamination operations of large components concern the primary pumps (*2) and the pressurizer and are foreseen in October 2002. The decontamination studies of large components take into account the technical aspects, the radiological and classical safety aspects, as well as the financial aspect

Critical Issues for Disposal, Recycling, and Clearance of Fusion Radioactive Materials: the European Viewpoint

In order to maximize the environmental benefits of fusion power generation, it is important to clearly define the parameters governing the back-end of the materials cycle. A fusion-specific approach is necessary. Recycling of materials and clearance (i.e. declassification to non-radioactive material) are the two recommended options for reducing the amount of fusion waste, while the disposal as low-level waste could be an alternative route for specific materials and components. Most fusion materials could potentially be recycled or cleared, providing the necessary studies and developments are carried out. To enhance prospects for a successful waste management scheme, we identified the key issues and challenges for disposal, recycling, and clearance, focusing on the EU studie

Numerical simulations of the IPPE target geometry flows

A high speed water and liquid lithium (Li) flow is computed over the IPPE geometry to evaluate the performance of different turbulence models in 2D and 3D simulations. Results reported are the thickness of the liquid jet, irregularities in the surface, transient phenomena at the wall which can affect fluid surface and effect of the variation in bulk velocity on these quantities. All models show good near wall resolution of the boundary layer and expected profiles for the free surface flow. Predicted turbulent kinetic energy compare well with published data. Fluctuations of the flow surface at the control location (center of the curved section) and elsewhere are well within 1 mm for all models. However it was observed that the predictions are strongly dependent on the model used. Overall, the predictions of RANS models are close to each other whereas predictions of laminar simulations are close to those obtained with LES models. (C) 2013 Elsevier B.V. All rights reserved

The role of clearance in the management of future fusion reactor radioactive materials

Under the framework of the European Power Plant Conceptual Study (PPCS), studies were carried out on the radioactive material management from future commercial fusion power plants, including among others: clearance and recycling, tritiated waste, waste categorisation, interim storage and final disposal. The present paper is focused on the important role that clearance will have in the management of such material flows. From different studies, performed inside the European Fusion Technology Programme, it is evident that fusion radioactive materials will be characterised by the following specific aspects: • Large volumes; • Mostly solid activated and contaminated material; • Reduced radioactivity in the medium term (< 100 y), no radioactivity in the long term, due to a careful selection of materials; • Low heat generation density and low radiotoxicity; • No transuranic elements beyond trace levels; • No proliferation concerns. These aspects will ensure that fusion materials can be managed so as to leave reduced or even no burden to future generations. The only significant management issue is the relatively large quantities of radioactive materials calculated to be produced. The possibility of drastically reducing this amount is based on the clearance and recycling of material arising from a fusion power plant. While clearance is based on the residual content of radioactivity, recycling involves also a mixture of socio-economic and environmental issues that are being investigated. The present paper will be mostly focused on the important role that might be played by well-defined and harmonised clearance criteria on fusion material management. A categorisation based on the neutron transport and activation calculations carried out on the four different PPCS models has revealed the importance that might be played by the clearance process on the reduction of the amount of material requiring disposal. The four investigated PPCS models span a range from relatively near term, based on limited plasma physics and technology extrapolations, to a rather advanced concept. The technological issues are determined by the different combinations of materials such as armour, structural material, coolant, breeder and neutron multiplier. The activation of the materials in all four Models decays relatively rapidly - very rapidly at first and broadly by a factor ten thousand over a hundred years. For much of this material, after an adequate decay time, the activity falls to levels so low that it could be "cleared" from regulatory control. The estimated share of clearable material ranges up to about 50% of the total mass after 100 years. Exploiting to a full extent the possibility to carry out recycling would reduce to a very limited quantity the amount of material to be disposed o