1. MATTINO* Activities on Nuclear Materials Research *MATerials performance assessmenT for safety and Innovative Nuclear reactOrs Karl-Fredrik Nilsson

2. Standardisation Basic research into materials performance characterisation Modelling & Simulation Safety reference Our Main mission is Materials and components related safety issues for present and future reactors Increased emphasis

3.  NUGENIA: Maintain safety and competitiveness of today’s technologies  NC2I: Enlarge nuclear fission portfolio beyond electricity production (heat)  ESNII/EERA JPNM: Develop Gen IV Fast Reactors with closed fuel cycle to enhance sustainability and to minimize waste NUGENIA NC2I ESNII, EERA JPNM SNETP: The 3 Pillars SNETP is central for our activities

4. Examples of Activities 1.Experimental Activities Stress corrosion cracking Small Punch Test 2.Experimental and modelling Thermal Fatigue of pipes Residual stresses in welds 3.Model development Multi-scale and physics based models Simulation of fuel cladding in accident scenario 4.Codes, Standards & Harmonization European Design Codes Materials Database MatDB

5. Stress Corrosion Cracking (AMALIA) damage interaction irradiation damage thermo-mech. loading chemical attack  need for environmental testing incl. in-pile experiments, collaboration with VTT, ITU, NRG, CV Rez Under construction: Liquid lead recirculation loop for -Corrosion -Erosion -Stress corrosion cracking At T max = 700°C, v max = 5 m/s 3 recirculation loops with full water chemistry control, equipped for environmental mechanical tests at p max = 360 bar, T max = 650°C: => BWR, PWR, SCWR conditions Why? Stress corrosion cracking is one of the major failure mechanism in power plants

6. Possibility to obtain creep resistance data from small amounts of material Characterization of material response to multi-axial loading Characterization of anisotropy in mechanical properties Main principle of small punch test SP test specimen, 8mm diameter, 0.5 mm thickness SP creep tests were carried out in accord with the CWA 15627 Code of Practice, at 650°C in an Ar atmosphere. Small Punch Test Why? Need for fast “semi non-destructive ” test method for small specimen

7. INTEGRITY of repair welds Project BM - Base material WM - Weld material HAZ material: (FG Fine grained, CG Coarse grained) SE - Service exposed* INTEGRITY Pipe Application to P91 weld 4-point bend (75.89 kN) + internal pressure (160 bar) at 600 °C for 5000 h * Service exposed conditions: 60kh at 565 o C under pressure of 250 bar

8. Application to P91 weld SP stress rupture results for all weldment zones The weakest zone is clearly the fine grain HAZ where type IV cracking often occurs in plant components

9. Thermal Fatigue in Nuclear Components Why? Thermal fatigue is one of the major degradation mechanisms. Complex loadings is a main issue. Procedures for thermal fatigue initiation (NESC) and propagation (NUGENIA) by replacing the load spectrum with the single frequency load that gives the shortest life Experimental Programme to simulate thermal fatigue damage through cyclic down shocks

10. Axial loading train Water quenching lines Thermal loads: Induction Heating and cooling by water Mechanical Load: Axial load (0, 50, 100 kN) Experimental set-up for Thermal fatigue tests

11. Computed and measured crack depth vs # of cycles for 300°C and 550°C The initiation of cracking and depth of cracks is monitored by NDT Time-of-Flight Diffraction for crack sizing Replica technique for crack initiation (surface cracking) Thermal Fatigue in Nuclear Components

12. Residual Stresses in welds Measured vs. computed Initial Refined In MATTINO we perform: Residual stress measurements with neutron diffraction and synchrotron diffraction Analyses with different levels of refinement Spiral slit technique in synchrotron diffraction stress measurement: Why? Welds are weak spots in components. For assessment we need to know: Residual stresses Material variability and defects

13. Research Front: Multi-scale Models (Crystal plasticity models) Fatigue initiation and short crack growth Dislocation patterning Why? Material degradation occurs at different “length and size scales” Necessary to extrapolate form accelerated tests to operational conditions Basis for development of new materials (e.g. nano materials)

14. 28 April 201514 Experimental data University of Manchester: http://dx.doi.org/10.1016/j.commatsci.2010.12.014http://dx.doi.org/10.1016/j.commatsci.2010.12.014 IGSCC-Multiscale modelling Surface reconstruction  Real grain topology  Simplification Conformal meshing:  Surfaces  Volumes Constitutive models:  Grains: AE+CP  Grain boundaries: cohesive zone

15. Model development New Model development & implementation in Codes Strain gradient effects Non-convex free energy (leads to instabilities) Grain boundary model 10 -3 10 10 -1 Patterning from non-convexity Computed variation in stress-strain curves for different loading rates caused by dislocation patterning

16. Fuel pellet clad interaction (sub-assembly blockage) 28 April 201516 Assessment of the behaviour of fuel pin sub-assembly blockage (GFR) Two-step analysis: CFD  temperature transients FEM fuel-pin (cracked fuel and cladding) Computed hoop strain cladding Computed K vs. crack depth (different crack aspect ratios) Von Mises stress distribution in fuel and cladding Why? Fuel cladding is the first safety barrier. Safety assessment requires modelling of the fuel and cladding for relevant loads

17. Contribution to Codes & Standards Code of Practice Small punch test (CEN/CENEL) European Procedure High- Cycle Thermal Fatigue (NESC/NULIFE) Design & Construction Code for mechanical Equipment of innovative nuclear installations (CEN/CELEC) Feasibility Study to develop standardized rules for the design and construction of Gen IV reactors (DG-ENER) Examples:

18. MATTER Project 7 th Framework EURATOM project Development of Test procedures and Design Rules in support of Design & Construction of ESNII Reactors Three Domains D1: Screening Test procedures and material characterization tests for MYRRHA D2: Design Rules for ASTRID, Gr 91 steel (creep-fatigue, ratchetting, negligible creep, welding, thermal ageing..) D3: Management of EERA JPNM

19. Workshop on Env. Degradation effects & Design Codes for heavy liquid metal reactors In the MATTER Description of Work Original idea: presentation of progress in MATTER Design Code related Work Packages (WP 4 – 6) (high-temperature issues) More urgent need to discuss Design Rules for heavy liquid metal alloys (CEN WS/64 Feasibility Study) When; Second Quarter 2013 Where: Petten Duration 1,5 days

20. MATTER WS HLM Env. Degradation & Design Codes Design and material and component requirements for ALFRED and MYRRHA (partly already covered by MATTER Deliverable and last year's Workshop) Degradation mechanisms for lead and lead-bismuth Mitigation mechanisms (coatings, environment control, etc) Requirements/needs for environmental degradation sections in Design Code (RCC-MRx as basis) (e.g. priorities of specific data) Proposal for outline of Design Factors and structure of Design Code for HLM environmental effects Topics to be addressed:

21. Who should attend? Experts in environmental degradation HLM Reactor Designers User and developers of Codes Generalists in environmental effects & Design Codes Confirmed participation (ALFRED/MYRRHA Development ESNII): ENEA, KIT, KTH, SCKCEN, JRC, NRG?, ANSALDO? Confirmed participation (Design Code): RCC-MRX/AREVA Confirmed participation: D. Tice (AMEC, ASME and LWR) Invitation sent: (IPPE/Obninsk) Exact Dates not fixed: main reason waiting for response from IPPE

22. MatDB is an online database application for preserving and exchanging engineering alloys data The facility is based on an enduring data model established more than 30 years ago through the joint efforts of NIMS, NIST, and the JRC MatDB—Overview Material entity Chemical composition Designation & production Characterisation Isotropic grain size Duplex grain size Directionally solidified grain size Hardness Microstructure Phase Physical constants Thermo-mechanical heat treatment Customer internals

23. MatDB—Purpose Support to nuclear safety policy IAEA embrittlement data Safeguard data Data relevant to MYRRHA from former FBR and HTR research programmes Support to Euratom indirect actions Data management Data exchange Reuse Development of new testing Standards, such as creep-fatigue and small punch Validation of models

24. MatDB—Activities I-NERI Materials Database Interoperability project Enable data transfer between MatDB and the GenIV Handbook hosted at ORNL Migration of the IAEA Surveillance Database Transfer more than 40.000 data sets to the IET materials database Development of ICT Standards for database interoperability Enable systems interoperability in the engineering materials sector by developing Standard messaging formats for data transfer Work performed in the framework of the European Committee for Standardization (CEN), IET awarded lead role in CEN/WS SERES, a 2-year CEN Workshop on Standards for electronic reporting in the engineering sector Data citation Data cite DOIs assigned to individual data sets to allow citation and reuse