Investigations of Structural Integrity at AREVA

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2 Investigations of Structural Integrity at AREVA Elisabeth Keim AREVA GmbH, Dept. PTCMF-G Erlangen, Germany NUCLEAR 2013 Conference, May Pitesti, Romania

3 Content Company Presentation: The AREVA Group in the world and in Germany Structural Integrity assessment, examples Conclusion - AREVA GmbH Proprietary - AREVA NP - p.3

4 AREVA Company Structure 100% 100% 100% 100% AREVA Renewables AREVA NC AREVA NP AREVA Mining - AREVA GmbH Proprietary - AREVA NP - p.4

5 AREVA across the globe Bolster our market leadership Develop a balanced presence in Europe, North and South America, and Asia Offer à la carte solutions to each customer 45.4 billion backlog 9.3 billion sales (IFRS) 48,000 employees März AREVA GmbH Proprietary - AREVA NP - p.5

6 Executive Board & Committee Front-End Division AREVA Business Groups Nuclear BG Mining BG Front-End BG Reactors & Services BG Back-End BG Renewable Energies Uranium mines exploration and operation activities Conversion and enrichment of the uranium and design of the fuel for the nuclear reactors Design and construction of nuclear reactors Maintenance and modernization of the nuclear power plants Recycling of the used fuel and provider of clean-up and dismantling services Development of wind energy, bio-energy, solar power and hydrogen power solutions Engineering & Projects (E&P) Organization - AREVA GmbH Proprietary - AREVA NP - p.6

7 Reactors & Service Business Group Reactors & Services AREVA: a global key player in the Reactors & Services 2012 Sales: 3,452 M (37% of AREVA Sales) Design and construction of nuclear reactors Maintenance and modernization of the nuclear power plants 16,000 employees - AREVA GmbH Proprietary - AREVA NP - p.7

8 Renewable Energies Business Group Renewable Energies Worldwide leader in Biomass Emerging player in the offshore wind and solar sectors 2012 Sales: 572 M (6% of AREVA Sales) Development of wind energy, bioenergy, solar power and hydrogen power solutions 1,300 employees - AREVA GmbH Proprietary - AREVA NP - p.8

9 Workforce AREVA in Germany Renewable Energies Nuclear AREVA GmbH Proprietary - AREVA NP - p.9

10 AREVA s Nuclear Sector German Region: Locations, Main Activities and Employees Employees Lingen, Fuel assembly (FA) manufacturing Duisburg, Tube manufacturing Karlstein FA components Karlstein Service Center Technical Center intelligendt Offenbach, P&E BWR, I & C, Services Erlangen P&E PWR, I & C, Services, Fuel Sales & Engineering Technical Center, intelligendt Location Employees Lingen 321 Duisburg 170 Offenbach 770 Karlstein 315 Erlangen 3516 Total 5092 (*) Foreign markets: ca. 51 % Revenues 2011: 947 Mio (HGB) ANF AREVA GmbH, intelligendt ( * ) Status December AREVA GmbH Proprietary - AREVA NP - p.10

11 Corrosion and Wear Materials Laboratories Metallography PTCM-G Materials, Plant-Life Management Fracture Mechanics Safety Analyses Electron Microscopy and x-ray- Analyses Ageing & Plant Life Management Materials Engineering Materials Technology Root- cause Analysis - AREVA GmbH Proprietary - AREVA NP - p.11

12 1943 failure of Liberty ship Structural Integrity 1975 burst tests of components 2005 highly sophisticated numerical methods - AREVA GmbH Proprietary - AREVA NP - p.12

13 Structural Integrity and Fracture Mechanics The characteristic fracture mechanics parameter is the toughness, in this case the fracture toughness, which depends on: Loading Geometry (component and crack) Material Temperature Load rate FT = f (L, G, a) - AREVA GmbH Proprietary - AREVA NP - p.13

14 Fracture Toughness K (stress intensity factor) stress-based U J (the J-integral) energy-based J = a CTOD (crack-tip opening displacement) strain-based K = σ πa f ( g) - AREVA GmbH Proprietary - AREVA NP - p.14

15 Brittle Fracture Mechanics, experiment Load F in N ,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 1,60 Load line displacement LLD in mm K JC in MPa m T 0 = -49 C Temperatur in C AREVA GmbH Proprietary - AREVA NP - p.15

16 Ductile Fracture Mechanics, experiment - AREVA GmbH Proprietary - AREVA NP - p.16

17 Fracture toughness specimens reconstitution technique - AREVA GmbH Proprietary - AREVA NP - p.17

18 Fracture toughness specimens reconstitution technique Scheme Preparation before welding Specimen after welding Final 3PB - specimen - AREVA GmbH Proprietary - AREVA NP - p.18

19 Structural Integrity RPV safety analysis RPV integrity is a design principle for safe inclusion of the activity inventory to be maintained during operation Requirement of both RPV monitoring and structural mechanical analyses 1 RPV 2 13 Steam generator heat tubes Main coolant lines 13 - AREVA GmbH Proprietary - AREVA NP - p.19

20 Structural Integrity deterministic RPV safety analysis σ Material Fracture Toughness K IC and Stress Intensity factor K I in MPa m a Loading σ a Temperature in C Fracture toughness resists fracture - AREVA GmbH Proprietary - AREVA NP - p.20

21 Irradiation behavior, hot cell testing Hot Cells Material Testing Metallographic Examinations Manufacture of Specimens Transport Container - AREVA GmbH Proprietary - AREVA NP - p.21

22 Structural Integrity deterministic RPV safety analysis Konvoi, cold leg injection, hot leg leak, core region, flaw size 10x60mm², K I from J as a function of crack tip temperature KI from J [MPa m] KIc(RTNDT (Tang.)= 86 C) KIc(RTNDT (Max.)= 109 C) KJ 100h ke_core_k 2SEP KJ 400h 4SEP KJ 200h 4SEP KJ 100h 4SEP KJ 50h 4SEP to be correlated with material properties leading transient crack tip temperature [ C] - AREVA GmbH Proprietary - AREVA NP - p.22

23 Probabilistic fracture mechanics: PTS Screening criteria for RT NDT RPV geometry: -Inner radius: 2500 mm -Wall thickness (without cladding): 250 mm -Cladding thickness: 6 mm -Height of forging Ring II : 2288 mm -Height of forging Ring III : 2644 mm -Height of circ. Weld Corenaht : 87 mm RPV of NPP Emsland RPV material: -Base material: 22 NiMoCr 37 -Cladding material: X10CrNiNb189 -Welding material: NiMoCr1-UP - AREVA GmbH Proprietary - AREVA NP - p.23

24 Probabilistic fracture mechanics: PTS Screening criteria for RT NDT RTNDT,max (Ring II, Ring III) [ C] max. allowable RPV failure frequency = 1.0E E-07 (192E19 n/cm 2 ) 1.39E-07 (164E19 n/cm 2 ) 7.89E-08 (148E19 n/cm 2 ) 4.97E-08 (137E19 n/cm 2 ) 1.31E-08 (110E19 n/cm 2 ) 6.93E-09 (99E19 n/cm 2 ) 1.92E-09 (82E19 n/cm 2 ) 4.06E-10 (66E19 n/cm 2 ) 1.48E-10 (55E19 n/cm 2 ) 1.47E-11 (44E19 n/cm 2 ) RT NDT,m ax (Corenaht) [ C] PTS Screening Criteria to qualify deterministic analyses: deterministic PTS analysis for the NPP Emsland gives an allowable RTNDT of 90 C for the circumferential weld Corenaht value of 90 C correlates with a failure frequency of , which is a factor of less than the allowable failure frequency of used to define the PTS Screening Criteria large inherent safety margin - AREVA GmbH Proprietary - AREVA NP - p.24

25 Chain of transferability: consideration of constraint From the standard specimen to the component - AREVA GmbH Proprietary - AREVA NP - p.25

26 Fracture Toughness K JC (1T) [MPa m 0.5 ] Chain of transferability: consideration of constraint Note: Constraint is depending on the level of loading! Shallow Crack Effect Biaxial Effect Temperature T [ C] - AREVA GmbH Proprietary - AREVA NP - p.26

27 Application to the RPV - AREVA GmbH Proprietary - AREVA NP - p.27

28 Application of the LA model to predict the component failure with surface crack Safety margin between failure curve of standard specimen and component with surface flaw is T=80K 250 Stutzenfehler Pf=50% Belastung Stutzenfehler Bruchzähigkeit KJ bzw. KIC/KJC [MPa m] S = T 0 = 80 K KIC RTTo Bauteil KIC mit RTTo PCCV a/w 0.5 Master Curve 50% Vorhersage LA Stutzen, T0 = 0 C 5 % Fraktile Vorhersage LA Stutzen Master Curve 50% PCCV a/w 0.5, T0 = 80 C 5% Fraktile PCCV a/w Temperatur [ C] - AREVA GmbH Proprietary - AREVA NP - p.28

29 Conclusion By means of fracture mechanics (FM) methods structural integrity of NPP components and structures can be proven Fracture mechanics methods are used in the brittle and ductile material regime of the materials Deterministic as well as probabilistic approaches are applied Specific effects like crack tip constraint and advanced methods, like micromechanical modelling can be considered in structural integrity analyses - AREVA GmbH Proprietary - AREVA NP - p.29

30 Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its content is prohibited unless Company Name has provided its prior and written consent. This document and any information it contains shall not be used for any other purpose than the one for which they were provided. Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations. - AREVA GmbH Proprietary - AREVA NP - p.30

31 End of presentation Investigations of Structural Integrity at AREVA