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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
  • 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
  • 2023:11 Study of degradation of spent fuel’s structural material and core components under long-term wet storage

    SSM perspective Background Sweden is managing the spent nuclear fuel and core components from its commercial nuclear reactors with a national strategic plan. The fuel and core components are initially stored at the reactor site. After an on-site storage period to comply with transportation limits on decay heat and radiation, these materials are shipped to the Clab (Central Interim Storage...

    Content type: Publications
  • 2023:14 Effect of gamma-irradiation on the redox states of the structural iron in bentonite clay

    SSM perspective Background Bentonite clay is used as buffer and backfill material which form engineered barrier in the spent fuel repository. The buffer material surrounding the copper canister will be exposed to gamma and neutron radiations, especially during the first few hundred years after closure of the repository. The redox states of the structural iron in montmorillonite, the dominant...

    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
  • 2017:19 Numerical simulations of headed anchors break in reinforced and non-reinforced concrete structures, Phase 2

    Background In the design of anchorage equipment in concrete structures the beneficial effects of reinforcement are, in most cases, not considered. The American ASCI 349-06 code opens up for a more detailed analysis where the beneficial impact of reinforcement on anchor capacity can be taken into account. How this analysis can be done is, however, not explicitly described in the code. The...

    Content type: Publications
  • 2022:14 Weld residual stress and strain measurements on a mock-up with single layer strip cladding common in reactor pressure vessels

    Summary Residual stress and strain measurements were performed on a mock-up consisting of a 160 mm thick low-alloy ferritic steel plate of type SA-508 Class 3 with a single layer weld deposited strip cladding of austenitic stainless steel E308L. The cladding was manufactured with submerged arc strip welding adapted to a procedure used for reactor pressure vessels in the 1970s. Comprehensive...

    Content type: Publications