The research projects are required to be of high scientific quality and their results are disseminated to the organizations involved in the Steering Committee. The research needs and challenges, as well as the organization of the program, are presented in the SAFIR2010 Framework Plan [1]. Below is a brief summary of the results of the individual projects (Chapter 2) and the general financial (Chapter 3) and administrative (Chapter 4) matters.
Organisation and human factors research area
Safety management and organizational learning (MANOR)
Expert Work in Safety Critical Environment (SafeExpertNet)
The modeling of the nuclear power community, its actors and their expertise builds a strong foundation for cooperation, exploitation of expertise and development of necessary knowledge in the future. In subtask 1.2, a questionnaire was developed: it includes questions relevant to the content of learning organizations, cooperation in the national nuclear expert community, aspects of the safety-critical environment are also taken into account. Thus, managerial measures can be taken to improve the utilization of the Finnish nuclear power network's knowledge resources.
Automation and control room research area
Model-based safety evaluation of automation systems (MODSAFE).12
However, the symbolic model checking techniques used in NuSMV scale much better as the number of input variables increases. In addition to step-by-step closure logic model modeling and checking, the project compared two security case notations, CAE (Claim Argument Evidence) and GSN (Goal Structuring Notation). Only branches where model checking could be used as evidence were investigated in the project.
Operator practices and human-system interfaces in computer-based
A final version of the literature review on the use of computer-based emergency operating procedures was also prepared. One of the main focuses has been investigating the practices of using HSI elements such as operational procedures and LSDs. Assessment form for the development of situational awareness showing the basic categories of the LSD concept.
Fuel and reactor physics
Development and Validation of Fuel Performance Codes (POKEVA)21
Preliminary simulations of one of the NUPEC (Nuclear Power Engineering Corporation) BFBT (BWR Full-size Fine-mesh Bundle Tests) benchmark steady-state exercises were. An article in the SAFIR2010 interim report summarizes the status of the development of the PORFLO model. New users have been trained in the use of the PARCS code and the sensitivity and uncertainty analysis tool.
Total reactor physics analysis system (TOPAS)
Development of a new Monte Carlo full-core reactor physics simulation code MORA has begun and the first code version will be made. Variance reduction methods in the Monte Carlo simulations, especially related to the use of MCNP code, need to be further investigated and a doctoral thesis will be written on the subject. Sensitivity and uncertainty analysis will be applied to characteristic code and the OECD UAM benchmark for uncertainty analysis in light water reactor modeling will be attended.
Thermal hydraulics research area
- Numerical modeling of condensation pool (NUMPOOL)
- Improved Thermal Hydraulic Analysis of Nuclear Reactor and
- CFD modelling of NPP horizontal and vertical steam generators
- Improvement of PACTEL Facility Simulation Environment (PACSIM)39
- Large Break Loss-of-Coolant Accident Test Rig (LABRIG)
The purpose of the test will be to study the degradation of heat transfer in the steam generator. Most of the heat transfer occurs on the hot side of the steam generator (nodes 1 - 7). Void fraction on the hot side (top) and on the cold side (bottom) of the horizontal steam generator.
Severe accidents research area
Release of Radioactive Materials from a Degrading Core (RADECO)47
In the calculated cases, the release of Ru from the core was 8 – 23% of the initial core supply. The aim of the project is to study the behavior of iodine in severe accident conditions. The aim of the study at VTT is to determine the iodine compounds released as a result of reactions on the surface of the tubes of the primary circuit.
Core Melt Stabilization (COMESTA)
The abstract "Behavior of ruthenium under air entrainment conditions: main achievements in the SARNET project" was published in the Proceedings of the Third European Review Meeting on Severe Accident Research (ERMSAR. Within the framework of the COMESTA project, Finland participates in the CSARP (Cooperative Severe Accident) Research Programme).At the conference ICAPP'08 published a joint paper with CEA on the HECLA and VULCANO experiments.
Hydrogen risk in containments and particle bed issues (HYRICI)
The STYX test facility was modified by installing downcomers that feed water to inlets near the bottom of the cylindrical test bed. The analysis of tests with different flow configurations continued from previous projects (2006 and 2007) with the WABE/MEWA 2D code. The STYX test facility was modified to include three downcomers that feed water from the pool above the test particle bed to the bottom of the bed.
Structural safety of reactor circuit research area
- Risk informed inspections of piping (PURISTA)
- Fatigue endurance of critical equipment (FATE)
- Water chemistry and oxidation in the primary circuit (WATCHEM)
- Monitoring of the structural integrity of reactor circuit (RAKEMON)
- Fracture assessment for reactor circuit (FRAS)
- Influence of material, environment and strain rate on environmentally
The limits of sub-modelling techniques were defined in the first part of the study. Calculations of the HDR experiment were performed using different geometries and meshes. The selected hydrogen content for the fracture toughness tests is higher (100 cc H2/kg H2O) than the typical hydrogen content of PWR primary water (~30 cc/kg H2O), that is, the selected environment for the fracture toughness tests is accelerated and will naturally be too conservative results compared to actual PWR environments.
Construction safety research area
Service Life Management System of Concrete Structures in Nuclear
The project manager is a steering committee member of the ICG-EAC (International Cooperative Group on Environmentally Assisted Cracking) and on the scientific board for the 13th Symposium on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors. The development and programming of the design algorithm for serviceability state design in accordance with Eurocode 2 in the code of the design program "IVODIM" and the execution of necessary tests for verification. Report on the methods and details of the risk analyzes for the corrosion of steel lining and prestressing tendons in containment buildings.
The databases are completed and connected to the service life management system framework. The main features of the system are shown in the publication 'Service life management system of concrete constructions in nuclear power stations'. The system includes an automatically performed condition analysis and a condition monitoring system for each module of the system.
An automatic LC cost analysis and environmental impact analysis was developed and combined with a management system condition analysis. The system automatically produces life-cycle action profiles (specification and timing of future maintenance and repair actions) for all device modules, and life-cycle costs and environmental impacts are calculated on both an action-based and a life-cycle basis. The reliability of the program was ensured by simple hand calculations for a limited number of shell and beam elements and loading conditions.
Literature survey on RF measurement method for the substrate for waterproofing and RF criteria is being prepared.
Impact of an aircraft against a structure (IMPACT 2010)
This was done by designing a new wider force plate and installing new and more accurate force transducers at the rear of the force plate. The detonation system has been improved by creating a new system to control the speed of the rocket in tests. This is done by building a new double vane system in front of the pressure accumulator, which will burst the vane according to the desired pressure value.
The frame was also designed to be suitable for fluid expansion testing when wet projectiles are used. The goal of Task 1 was to improve the test rig to be suitable for testing wider impact projectiles and prestressed walls. This was solved by increasing the wires on the piston capture frame and on the target surface.
The object of task 2 was to improve the data acquisition system and the number of sensors to obtain more accurate and reliable test results. The scope of task 4 in 2008 was to test prestressed concrete walls at different rates, prestressing levels and different reinforcements to obtain knowledge and data on prestressing. The speed of the rocket is successfully determined very accurately by the double blade system.
The ability to measure the rocket's speed and the force time function have been improved.
Structures Under Soft Impact (SUSI)
Even though the impulse is slightly higher in the dry missile test, the maximum deflection is clearly smaller than the one in the wet missile test in agreement with both the measurements and calculations. According to the calculations with the shell element model, the maximum deformation, by a clear margin, occurred in the horizontal reinforcement in the dry missile test. This is due to the fact that the wall loaded by the deformable empty missile acts like a wide bending beam.
In tests where the water missile was used, the calculated strain values in the vertical back surface reinforcement were almost as high as in the horizontal back surface reinforcement. This is due to the fact that the missile filled with water has a much higher maximum peak value in the loading time function at least according to the Riera method. However, the model was able to simulate the frequency of the global bending mode of the damaged wall quite well.
The rocket behaved similarly in both the tests and the corresponding simulations. The contact force between the rocket and the wall was close to that given by the Riera method that was used in simulations without a rocket. The connection between steel bars and concrete is an important part of the mechanical system of reinforced concrete.
The main parameters measured and documented were the liquid discharge velocity, the direction and shape of the liquid spray pattern, the propagation speed of the spray front, the accumulation of liquid on the floor and the size of the droplets deposited on the floor.
Probabilistic safety analysis (PSA) research area
CHAllenges in Risk-Informed Safety MAnagement (CHARISMA)
Develop an ARANO code for Level 3 PSA to allow the use of hourly weather data. Develop EU guidelines on best practice for the implementation of PSA level 2 methodologies with the aim of harmonization at the EU level and enable a meaningful and practical assessment of uncertainty in PSA level 2. In 2008, the needs of end users will be collected and combined, and the preparation of instructions will begin.
OECD/NEA Working Report on "Probabilistic Measures of Risk." Conference Papers in PSAM9, ESREL-2008, PSA Castle Meeting 2008. NPSAG Seminar on "Interpretation and Risk Assessment of Technical Specification Terms, Phase 1." First Phase Final Report and Conference Papers for PSAM9 and PSA Castle Meeting 2008. Notes on the development of an integrated analysis method in collaboration with the FIRAS project and in relation to the controllability of a cable room fire situation.
Work report of the second case in the international study of HRA methods (LOFW scenario). Participation in the evaluation work of the Halden HRA method (comparison of selected methods with simulator data). ARANO model for level 3 PSA has been adjusted, test calculations done, reports sent for review.
The end-user requirements document on performance and guidelines for level 2 PSA (EU project ASAMPSA2).
Implementation of Quantitative Fire Risk Assessment in PSA (FIRAS)87
A recalculation of the ENACCEF uniform hydrogen distribution test was carried out in the spring of 2008.
