Filtered generated 401 hits.
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2008:10 User’s manual for Ecolego Toolbox and the Discretization Block
The CLIMB modelling team (Catchment LInked Models of radiological effects in the Biosphere) was instituted in 2004 to provide SSI with an independent modelling capability when reviewing SKB’s assessment of long-term safety for a geological repository. Modelling in CLIMB covers all aspects of performance assessment (PA) from near-field releases to radiological consequences in the surface...
Content type: Publications -
2012:02 Evaluation of activity build-up experiments
This project aims to understand how the water chemistry affects the activity build-up on surfaces in different systems in Swedish nuclear power plants, which in turn provides information on conditions required to reduce the radiation exposure to power plant staff. The study was done to obtain knowledge about water chemistry conditions preferred to minimize the activity build-up. A number of...
Content type: Publications -
2020:15e Protective Actions in Nuclear or Radiological Emergencies - Planning Basis for Events in Emergency Preparedness Category IV
In this report, the Swedish Radiation Safety Authority (SSM) presents planning basis for protective actions in the event of nuclear or radiological emergencies in connection with activities and acts in emergency preparedness category IV. Activities and acts encompass events in activities with ionizing radiation that are not conducted in a specifically defined location as well as antagonistic...
Content type: Publications -
2020:02 Models for axial gas flow and mixing in LWR fuel rods
SSM perspective Background Fission gases inside a fuel rod plays an important role in the behaviour of the fuel, both during normal operation and during events and accidents. Fission gases are released from inside the fuel pellets to the gap between the pellet and the cladding tube and then flow to the plenum volume at the top of the fuel rod. In high burnup fuel, this axial flow to the...
Content type: Publications -
2021:04 Calibration of models for cladding tube high-temperature creep and rupture in the FRAPTRAN-QT-1.5 program
SSM perspective Background In Swedish Light Water Reactors (LWR), stress corrosion cracking of reactor components and welds occurs from time to time. As the nuclear power plants are ageing, it is essential to study and further understand the mechanism for environmentally induced sensitization. Natural cracking is a phenomenon that is difficult to predict and very hard to study since it occurs...
Content type: Publications -
2021:10 Establishment and use of attention values in environmental fatigue assessments
SSM perspective Background As Swedish NPPs reach their original technical design life, re-assessment of the fatigue life of structural components is needed for safe long term operation (LTO). In these re-assessments one must consider that new knowledge has shown that environmental effects on fatigue life must be considered. One common method to verify the fatigue life of structural components...
Content type: Publications -
2021:20 Effects of additives on UO2 fuel behavior: expanded edition
SSM perspective Background The Swedish Radiation Safety Authority (SSM) follows the development of nuclear fuel closely. Fuel with additives like chromia and gadolinia is used in Swedish reactors and fuel with even better thermal and mechanical properties is under development. This project is an in-depth study of data and models regarding the impact of additives on the properties of uranium...
Content type: Publications -
2021:09 Mechanisms important for material modelling in weld residual stress analysis
SSM perspective Background The prediction of weld residual stresses (WRS) is very complex as many mechanisms and phenomena influence the development of WRS during welding. For accurate prediction, the constitutive material models used are essential and must be able to describe the material response of the weldment constituents. For example, selection of a material model should only depend on...
Content type: Publications -
2022:04 Warm Pre-Stressing mechanisms
SSM perspective Background Swedish nuclear power plants (NPP) were originally designed and analyzed with an assumed operating period of approximately 40 years. As Swedish NPPs reach their original technical design life the safety of the additional operating time has to be verified. With increased operating time, the shift in the fracture toughness curve of the reactor pressure vessel (RPV)...
Content type: Publications -
2022:09 Assessment of modelling approaches for axial gas flow inside LWR fuel rods
SSM perspective Background The fuel rod analysis program SCANAIR has been developed by IRSN (Institut de Radioprotection et de Sûreté Nucléaire) for analysis of reactivity initiated accidents (RIA) in light water reactors. The Swedish Radiation Safety Authority (SSM) has access to SCANAIR in exchange for annual contributions for its further development. The development and administration...
Content type: Publications