At Forsmark nuclear power plant the rather old-fashioned software COPTA is used in containment safety analysis. There exists a desire within the organisation to introduce a more modern software with ability to more detailed modeling and increased usability. The goal of this thesis was to evaluate the software APROS in containment safety analysis. APROS models describing one of the containments at Forsmark NPP have been developed. Two simulations of typical containment incidents, one of them a large pipe break, have been made where containment safety parameters such as pressure and temperature are studied. Results are analyzed and verified against results from corresponding COPTA models. The other part of the evaluation includes a listing of detected possibilities and limitations with APROS regarding containment modeling in general. Overall the developed APROS models show a good agreement with results from corresponding COPTA models. Observed differences can in most cases be explained by minor differences in model choices, mostly concerning flow patterns and heat transfer. APROS has many similarities with COPTA regarding the main calculation and modeling methods but APROS can in most cases be seen as the more sophisticated software with more possibilities regarding modeling complexity. The general conclusion is that APROS shows good potential to be used in containment safety analysis.

Nuclear power is an important part of Sweden's energy system and contributes with about 30 % of the supplied electric energy. Interest in new construction is currently high and one type of reactor that may be built is small modular reactors, SMRs. A method that is used to evaluate the safety of a traditional nuclear power plant is the so called probabilistic safety assessment (PSA). An important question is if PSA is applicable to SMRs. This thesis examines differences between a BWRX-300 type SMR and a generic boiling water reactor to investigate if the traditional PSA method is applicable to SMRs and what characteristics that may affect the results.  To investigate the topic, a simplified PSA analysis is carried out at level 1 for five different initiating events: extreme snowfall, loss of cooling accident, loss of main feedwater, loss of offsite power supply and transient. These are then compared to a model of a generic BWR reactor.  The conclusions that emerge from the analysis are that the traditional PSA method can be applied for SMRs of the BWRX-300 type. The features that distinguish the BWRX-300 compared to a generic BWR are mainly that the SMR is smaller in size and power and the influence of the passive safety systems. This results in a lower core damage frequency. Some the areas where the PSA method could be developed for SMRs are the analysis of passive components and passive functions.

This master thesis examines the possibility of performing asimplified uncertainty analysis on a probabilistic safety assessment(PSA) of the Oskarshamn 3 nuclear power plant. The aim of the thesiswas divided in two parts, first to examine the uncertainty parametersof a PSA-model for Oskarshamn 3 and the second part was to developand examine a simplified method of uncertainty analysis as comparedto a more regular method of Monte Carlo-simulation. The thesis ismostly concerned with examining the core damage frequency. Theexamination of uncertainty parameters showed that many parameterswere missing from the model and thus further investigation areneeded, if a full Monte Carlo is to be performed. The simplifiedmethod for uncertainty analysis that was developed consisted ofassuming a lognormal distribution for the frequency of basic eventsand then using the minimal cutset-list to calculate an approximationto the end distribution. The simplified method was then compared tothe Monte Carlo-analysis for Oskarshamn 2 for different MCS-lists anda preliminary uncertainty analysis was performed for Oskarshamn 3.

The scope of this project is to investigate if the software Ecolego is suitable for creating models in accordance with level 3 PSA, with the goal of creating a model calculating the possible outcomes for the radiological impact at 20 km distance resulting from a fictional severe nuclear accident at the Forsmark Nuclear Power Plant. This report aims to answer the questions “What is the concentration on the ground (kBq/m2), at a distance of 20 km, 30 days and 10 years after the fictional severe nuclear accident, with and without filtered venting” and “Is Ecolego a suitable software for level 3 PSA models?” The source term for the fictional severe nuclear accident is made to resemble the actual source term from the Fukushima Daiichi accident including the radionuclides Cs-134, Cs-136, Cs-137, I-131, I-132, I-133 and Te-132. In the model, three source terms are created and tested. Two source terms in which the total emissions are released in 24 hours, for which one contains the total emissions from the Fukushima Daiichi accident and one containing 1 percent of the emissions from the Fukushima Daiichi accident due to reduction of emissions when passing the filtered venting. The thirdsource term is made to resemble the time-dependent emissions for the Fukushima Daiichi accident, with emissions varying in intensity over 50 days. The transport of the radionuclide concentration is only due to atmospheric dispersion in the model, for which the Gaussian Plume Model (GPM) is applied under undisturbed condition where only the concentrations in the centerline of the plume are calculated. Probabilistic variation is performed with Monte Carlo simulations where probability density functions (PDFs) are assigned to wind speed andprecipitation, with 5000 iterations. Simulation of the model with one of the two source terms which has the release period of 24 hours gives reasonable results. However, to run the simulation with the time varying source term the model needs to be developed to generate reasonable results, for which necessary development actions are presented. The calculations of the resulting concentration on the ground 30 days and 10 years after the fictional accident shows that there are multiple possible outcomes, which makes it impossible to give a single answer to the expected concentration on the ground. Due to their short half-lives, there will be no concentrations of I-132 and I-133 on the ground at the distance 20 km after 30 days or 10 years. For the remaining radionuclides, the ranges of the possible outcomes for the concentration on ground are presented. It is concluded that Ecolego is suitable for PSA level 3 with the risk metric of environmental impact based on the results of the investigation. However, due to the time limit of the investigation, the applicability of creating an Ecolego model with the risk metrics health effects and economic impact are not investigated. But the report discusses suitable development of the model to contain the risk metric health effects in accordance with level 3 PSA. With such development the conclusion is that Ecolego is suitable for level 3 PSA.

Syfte. Avhandlingen syftar till att bidra med ökad kunskap om faktorer som kan antas påverka patientsäkerheten dels på system-, dels på individnivå. Metod.Det nationella rapporteringssystemet Lex Maria analyserades före och efter Socialstyrelsens regionalisering av tillsynsorganisationen 1990/91. I en av de två studierna analyserades särskilt ärenden som överförts till HSAN för prövning av disciplinär påföljd. I tre empiriska studier analyserades kompletterande metoder till rapportering för att få information om risker i hälso- och sjukvården. Personal har intervjuats om deras uppfattning av potentiella risker som skulle kunna hota patienternas säkerhet. Vårdbiträdens och undersköterskors kunskaper om diabetes undersöktes i en enkätstudie. Eventuella samband mellan vårdbiträdens och undersköterskors kunskapsnivå och medicinskt ansvariga sjuksköterskors uppfattning om säkerhetsrelaterade frågor undersöktes i en uppföljande enkätstudie. I en kvalitativ studie undersöktes flygets metoder för säkerhetsrelaterat arbete vilket jämfördes med motsvarande arbete inom hälso- och sjukvården. Resultat.Lex Maria-rapporteringen ökade efter regionaliseringen av tillsyns-verksamheten och en minskad andel ärenden överfördes till HSAN för disciplinär prövning. De kompletterande metoder för att identifiera risker som undersökts visade sig vara värdefulla tillägg till traditionell rapportering. Intervjuerna inom barnsjukvården uppvisade en annan riskbild än den som fås genom rapporteringssystemet Lex Maria. Enkäten till vårdbiträden och undersköterskor visade ett tydligt samband mellan bristande kunskap om diabetes och en ökad risk att vidta en riskfylld åtgärd. Studien indikerade brister på systemnivå, vilket bekräftades av resultaten från enkätstudien till medicinskt ansvariga sjuksköterskor i motsvarande kommuner. Studien visade på behovet av ökad uppmärksamhet på hur sjukvårdens stödsystem påverkar yrkesutövarna i frontlinjen. Jämförelsen mellan flyget och hälso- och sjukvården visade att flyget hade ett mera proaktivt och bredare förhållningssätt till säkerhet än vad hälso- och sjukvården uppvisade. Slutsatser. Studien har visat att yrkesutövare som befinner sig i frontlinjen och möter den enskilde vårdtagaren är särskilt sårbara när hälso- och sjukvårdens stödsystem uppvisar brister. Förebyggande säkerhetsanalyser som komplement till rapportering visade sig ge värdefull information för det förebyggande säkerhetsarbetet. En sammanhållen strategi baserad på aktuell säkerhetsforskning kan bidra till att utveckla hälso- och sjukvårdens säkerhetsarbete. Nyckelord: Patientsäkerhet, rapportering, prevention, händelseanalys, säkerhetsanalys, Lex Maria, ansvarsärenden, disciplinära åtgärder

There are more and more parents that are considering to purchase smart watches for their kids. The children’s smart watches on the market are usually equipped with many practical functions like the GPS positioning, the camera and the messaging. Among all the smart watches for children, the ones that can be connected via a mobile application called SeTracker are popular for the acceptable prices. These smart watches may have different brands although they come from the same manufacturer company and share the common service and database. The security of the mobile application is essential to the security of the products. But are they designed in a secure way? There were reports about vulnerabilities of the products previously. Unfortunately, the security requirements do not stop upon solving those vulnerabilities. In this project, it was found that the parents can track the kids and communicate with them through the mobile application, but their accounts might be logged on the attacker’s phone at the same time. And it is surprisingly easy to get the password of the users because it is stored in a local file using simple substitution cipher. There are other examples of insecure design in the products. Among them are the unlimited attempts to send and enter verification codes used for changing the password. It seems that the server does not have a complete logging and monitoring mechanism to prevent abnormal behaviors. The security analysis and penetration testing of this project would provide an example of the mobile hacking, and it will also raise a warning on the security of smart devices. / Det finns fler och fler föräldrar som funderar på att köpa smarta klockor till sina barn. De smarta barnklockorna på marknaden är vanligtvis utrustade med många praktiska funktioner som GPS, kamera och meddelanden. Bland alla smarta klockor för barn är de som kan kopplas upp via en mobilapplikation som heter SeTracker populära för de acceptabla priserna. Dessa smarta klockor kan ha olika märken även om de kommer från samma tillverkarföretag och delar den gemensamma tjänsten och databasen. Säkerheten för den mobila applikationen är väsentlig för produkternas säkerhet. Men är de designade på ett säkert sätt? Det fanns rapporter om sårbarheter i produkterna tidigare. Tyvärr slutar inte säkerhetskraven när man löser dessa sårbarheter. I det här projektet fann man att föräldrarna kan spåra barnen och kommunicera med dem via mobilapplikationen, men deras konton kan vara inloggade på angriparens telefon samtidigt. Och det är förvånansvärt lätt att få användarnas lösenord eftersom det lagras i en lokal fil med hjälp av enkla ersättnings-chiffer. Det finns andra exempel på osäker design i produkterna. Bland dem är de obegränsade försöken att skicka och ange verifieringskoder som används för att ändra lösenordet. Det verkar som om servern inte har en fullständig loggnings- och övervakningsmekanism för att förhindra onormalt beteende. Säkerhetsanalysen och penetrationstesten av detta projekt skulle ge ett exempel på mobilhackning, och det kommer också att väcka en varning om säkerheten för smarta enheter.

Disturbances in the supply of electric power can have serious implications for everyday life as well as for national (homeland) security. A power outage can be initiated by natural disasters, adverse weather, technical failures, human errors, sabotage, terrorism, and acts of war. The vulnerability of a system is described as a sensitivity to threats and hazards, and is measured by P (Q(t) > q), i.e. the probability of at least one disturbance with negative societal consequences Q larger than some critical value q, during a given period of time (0,t]. The aim of the thesis is to present methods for quantitative vulnerability analysis of electric power delivery networks to enable effective strategies for prevention, mitigation, response, and recovery to be developed. Paper I provides a framework for vulnerability assessment of infrastructure systems. The paper discusses concepts and perspectives for developing a methodology for vulnerability analysis, and gives examples related to power systems. Paper II analyzes the vulnerability of power delivery systems by means of statistical analysis of Swedish disturbance data. It is demonstrated that the size of large disturbances follows a power law, and that the occurrence of disturbances can be modeled as a Poisson process. Paper III models electric power delivery systems as graphs. Statistical measures for characterizing the structure of two empirical transmission systems are calculated, and a structural vulnerability analysis is performed, i.e. a study of the connectivity of the graph when vertices and edges are disabled. Paper IV discusses the origin of power laws in complex systems in terms of their structure and the dynamics of disturbance propagation. A branching process is used to model the structure of a power distribution system, and it is shown that the disturbance size in this analytical network model follows a power law. Paper V shows how the interaction between an antagonist and the defender of a power system can be modeled as a game. A numerical example is presented, and it is studied if there exists a dominant defense strategy, and if there is an optimal allocation of resources between protection of components, and recovery. / QC 20100831

In human-robot collaborative (HRC) scenarios where humans and robots work together sharing the same workspace, there is a risk of potential hazard that may occur. In this work, an AI-based risk analysis solution has been developed to identify any condition that may harm a robot and its environment. The information from the risk analysis is used in a risk mitigation module to reduce the possibility of being in a hazardous situation. The goal is to develop safety for HRC scenarios using different AI algorithms and to check the possibilities of improving efficiency of the system without any compromise on the safety. This report presents risk mitigation strategies that were built on top of the robot’s control system and based on the ISO 15066 standard. Each of them used semantic information (scene graph) about the robot’s environment and changed the robot’s movement by scaling speed. The first implementation of risk mitigation strategy used Fuzzy Logic System. This system analyzed the riskiest object’s properties to adjust the speed of the robot accordingly. The second implementation used Reinforcement Learning and considered every object’s properties. Three networks (fully connected network, convolutional neural network, and hybrid network) were implemented to estimate the Qvalue function. Additionally, local and edge computation architecture wereimplemented to measure the computational performance on the real robot. Each model was evaluated by measuring the safety aspect and the performance of the robot in a simulated warehouse scenario. All risk mitigation modules were able to reduce the risk of potential hazard. The fuzzy logic system was able to increase the safety aspect with the least efficiency reduction. The reinforcement learning model had safer operation but showed a more compromised efficiency than the fuzzy logic system. Generally, the fuzzy logic system performed up to 28% faster than reinforcement learning but compromised up to 23% in terms of safety (mean risk speed value). In terms of computational performance, edge computation was performed faster than local computation. The bottleneck of the process was the scene graph generation which analyzed an image to produce information for safety analysis. It took approximately 15 seconds to run the scene graph generation on the robot’s CPU and 0.3 seconds on an edge device. The risk mitigation module can be selected depending on KPIs of the warehouse operation while the edge architecture must be implemented to achieve a realistic performance. / I HRC-scenarier mellan människor och robotar där människor och robotar arbetar tillsammans och delar samma arbetsyta finns det risk för potentiell fara som kan uppstå. I detta arbete har en AI-baserad lösning för riskanalys utvecklats för att identifiera alla tillstånd som kan skada en robot och dess miljö. Informationen från riskanalys används i en riskreduceringsmodul för att minska risken för att vara i en farlig situation. Målet är att utveckla säkerhet för HRC-scenarier med olika AI-algoritmer och att kontrollera möjligheterna att förbättra systemets effektivitet utan att kompromissa med säkerheten.Denna rapport presenterar strategier för riskreducering som byggdes ovanpå robotens styrsystem och baserade på ISO 15066-standarden. Var och en av dem använder semantisk information (scendiagram) om robotens miljö och förändrar robotens rörelse genom skalning av hastighet. Den första implementetationen av riskreducerande strategi använder Fuzzy Logic System. Detta system analyserade de mest riskabla objektens egenskaper för att justera robotens hastighet i enlighet därmed. Den andra implementeringen använder förstärkningslärande och betraktade varje objekts egenskaper. Tre nätverk (fully connected network, convolutional neural network, and hybrid network) implementeras för att uppskatta Q-värde-funktionen. Dessutom implementerade vi också lokaloch edge-arkitektur för att beräkna beräkningsprestanda på den verkliga roboten. Varje modell utvärderas genom att mäta säkerhetsaspekten och robotens prestanda i ett simulerat lagerscenario. Alla riskreduceringsmoduler kunde minska risken för potentiell fara. Fuzzy logicsystem kunde öka säkerhetsaspekten med minsta effektivitetsminskning. Förstärkningsinlärningsmodellen har säkrare drift men har en mer begränsad effektivitet än det fuzzy logiska systemet. I allmänhet fungerar fuzzy logicsystem upp till 28 % snabbare än förstärkningslärande men komprometterar upp till 23 % när det gäller säkerhet (medelrisk hastighetsvärde). När det gäller beräkningsprestanda utfördes kantberäkningen snabbare än lokal beräkning. Flaskhalsen för processen var scengrafgenerering som analyserade en bild för att producera information för säkerhetsanalys. Det tog cirka 15 sekunder att köra scengrafgenerering på robotens CPU och 0,3 sekunder på en kantenhet. Modulen för riskreducering kan väljas beroende på KPI för lagerdriften medan edge-arkitekturen måste implementeras för att uppnå en realistisk prestanda.