Filtered generated 403 hits.
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2009:15 Improvement and Validation of Weld Residual Stress Modelling Procedure
Weld residual stresses have a large influence on the behavior of cracks growing under normal operation loads and on the leakage-flow from a through-wall crack. Accurate prediction of these events is important in order to arrive at proper conclusions when assessing detected flaws, for inspection planning and for assessment of leak-before-break margins. Therefore, it is very important to have...
Content type: Publications -
2010:16 Guidance to Risk-Informed Evaluation of Technical Specifications using PSA
No guidance documents for risk-informed analysis and assessment of changes in Limiting Conditions for Operation (LCO:s) in TS (Technical Specifications) have been available in the Nordic countries. In the U.S. several guidance documents, primarily developed by the owners groups for PWRs and BWRs, exist. Guidance for analysis of TS changes in this report generally follows the U.S. Regulatory...
Content type: Publications -
2011:19 Experimental evaluation of influence from residual stresses on crack initiation and ductile crack growth at high primary loads
Cracked components are usually subjected to loads causing both primary and secondary stresses, e.g. welding components. Engineering assessment approaches, such as the ASME XI code and the R6 procedure, are commonly used to conduct integrity assessment of such components. There has been an ongoing debate how to treat secondary stresses using engineering assessment methods. The nature of these...
Content type: Publications -
2010:42 Using the EPRI Risk-Informed ISI Methodology on Piping Systems in Forsmark 3
In the SSM regulation SSMFS 2008:13, it is stated that the selection of locations for inspection of mechanical components shall be based upon the risk for core damage or the risk of release of radioactive substances. Both qualitative and quantitative measures of the relative risk are allowed to be used. So far only the PWRs in Sweden are using a quantitative procedure to evaluate the risk...
Content type: Publications -
2009:13e 2009 assessment of radiation safety in the Swedish nuclear power plants
This report has been prepared by order of the Swedish government in accordance with the “Governmental directive for the financial year 2009 regarding the Swedish Radiation Safety Authority”. The Swedish Radiation Safety Authority has through its supervision ensured a comprehensive basis for this overall assessment of radiation safety. The overall conclusion is that the radiation safety,...
Content type: Publications -
2011:17 Structural Health Monitoring of Piping in Nuclear Power Plants – A Review of Efficiency of Existing Methods
SSM needs to acquire knowledge about new applied Non-Destructive Engineering (NDE) techniques and their efficiency. One area that is discussed more frequently is Structural Health Monitoring (SHM). SSM needs to investigate the international experiences of SHM from the nuclear industry. SSM also wants to have more information about the capabilities and the limitations of NDE methods The first...
Content type: Publications -
2009:27 Analysis Strategy for Fracture Assessment of Defects in Ductile Materials
SSM has supported research for investigating the role of secondary stresses when fracture assessments are performed for cracked structures made of ductile materials. There are evidences that indicate that some secondary stresses, such as weld residual stresses, are not as important as primary stresses for estimating the safety margin against rupture (measured by the J-integral) for the type...
Content type: Publications -
2005:61 Review and Assessment of SCC Experiments with RPV Steels in Oskarshamn 2 and 3 (ABB Report SBR 99-020)
Although the extent of cracking was rather surprising for a bolt-loaded specimen, the average stress corrosion crack growth rate of 0.5 mm/year over the five-year testing period does not represent an immediate concern. The overwhelming part of crack growth can have occurred during a 20 day chloride transient during the third year of exposure because of a condenser leakage after an outage. The...
Content type: Publications -
99:10 Verification and Validation of HumanFactors Issues in Control RoomDesign and Upgrades
Systems, facilities and equipment are periodically updated during a power plant's lifetime. This has human factors implications, especially if the central control room is involved. Human factors work may therefore be required. There is an extensive literature on human factors itself, but not so much on how it is verified and validated. Therefore, HRP and the Swedish Nuclear Power Inspectorate...
Content type: Publications -
2004:16e Statement of the Situation Concerning Safety and Radiation Protection at Swedish Nuclear Plants in 2003
The safety philosophy upon which the Swedish Nuclear Power Inspectorate’s (SKI) supervisory and regulatory activities are based assumes that multiple physical barriers will exist and that a plant-specific defence-in-depth system will be implemented at each plant. The physical barriers are situated between the radioactive material and the plant personnel and surroundings. In the case of...
Content type: Publications