08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Post Mortem Investigations of the NPP Greifswald WWER-440 Reactor Pressure Vessels Hans-Werner Viehrig, Udo Rindelhardt and Jan Schuhknecht Forschungszentrum Dresden-Rossendorf e.V. Institute for Safety Research P.O.Box Dresden, Germany 19th International Conference on Structural Mechanics in Reactor Technology August 12 – 17, Toronto, Canada

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Outline Introduction Trepanning of the Greifswald WWER-440 (230) Reactor Pressure Vessels (RPV) Material and Specimens Testing and Evaluation Test Results of the RPV Core Welding Seam Summary and Conclusions

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Introduction NPP North Greifswald located at the Baltic Sea in the north eastern part of Germany 4 Units WWER-440 (230) operated from 1974 to Units WWER-440 (213) were under construction

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community unitcyclesoperation period effective days annealed in azimuthal maximum of  E>1MeV in units of n/cm 2 inner wall axial maximum inner wall weld 4 outer wall axial maximum outer wall weld * not Operation Characteristics and Expected Maximum Neutron Fluencies of Greifswald WWER-440 (230) Units 1 to 4 * re-irradiated water inlet temperature: 265°C recovery annealing: 475°C/152h

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Trepanning of the Greifswald WWER-440 (230) Reactor Pressure Vessels (RPV) milling head lead plug marker extractor fan Trepanning Device

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Location of the Trepanning Device at the RPV

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community RPV Steels, Irradiation and Annealing Conditions of the Trepans Sampled from Greifswald Unit 1 trepanRPV-Materialcondition RPV-wall inside Fluence in n/cm 2 (E>0.5 MeV) temperature during recovery annealing in °C 1-1.1weld metal SN0.1.4.IAI weld metal SN0.1.4.IAI weld metal SN0.1.4.IAI base metal shell IAI base metal shell U>0.11<300 I: irradiated A: recovery annealed U: unirradiated reactor core

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Chemical Composition in mass % Unit/ Trepan materialCSiMnPSCrNiMoCuVRef. %%%%% 1weld SN [1] 1-1 *1 weld SN [2] 1-1 *2 weld SN [2] 1shell [1] 1-1 *1 shell [2] *1 inner RPV wall *2 110 from the inner RPV wall [1] mean values from TACIS Report [2] measured (wet chemistry) on trepan 1.1

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Handling of the Trepans within the Hot Cell

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Welding Seam SN over the RPV Wall Longitudinal Section 2.5 mm from the RPV inner wall mm from the RPV inner wall Welding root

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Trepan 1-1 With the Location of the Welding Seam and Cutting Scheme

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Orientation of WWER-440 (213) RPV Surveillance Specimens Producer SKODA* Base metal:tensile specimens:L Charpy-V and COD:LT weld metal:tensile specimens :L Charpy-V and COD:TL HAZ:tensile specimens :T Charpy-V and COD:TS Producer Russia** base metal:tensile specimens :L Charpy-V and COD:LS weld metal:tensile specimens :L Charpy-V and COD:TS HAZ:tensile specimens :T Charpy-V and COD:TS * Information Dr. Brynda SKODA Nuclear ** Information D. Erak RRC Kurchatov Institute

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Orientation of Weld Metal Specimens 5 mm S T SE(B) specimen weld metal TL

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Location of the Investigated Discs Within Trepan 1-1, Neutron Fluences, MC Test Results According to ASTM E and Charpy-V Parameter code disc distance from inner surface (centre disc) neutron fluence in n/cm 2 (E>1MeV) ASTM E SINTAPCharpy-V before*after*totalT0T0 σT 0 T 0 SINTAP TT 41J USE mm°CK J SE(B) specimen orientation: TS * Recovery annealing

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community K Jc Values Measured on Charpy Size SE(B) Specimens Versus the Test Temperatures Normalised to T 0 of the Individual Discs, and Master Curves

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Location of the Investigated Discs Within Trepan 1-1, Neutron Fluences, MC Test Results According to ASTM E and Charpy-V Parameter code disc distance from inner surface (centre disc) neutron fluence in n/cm 2 (E>1MeV) ASTM E SINTAPCharpy-V before*after*totalT0T0 σT 0 T 0 SINTAP TT 41J USE mm°CK J SE(B) specimen orientation: TS * Recovery annealing SINTAP – Structural Integrity Assessment Procedures for European Industry

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Course of the Reference Temperatures T 0 and T 0 SINTAP Through the Welding Seam SN0.1.4.

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Location of the Investigated Discs Within Trepan 1-1, Neutron Fluences, MC Test Results According to ASTM E and Charpy-V Parameter code disc distance from inner surface (centre disc) neutron fluence in n/cm 2 (E>1MeV) ASTM E SINTAPCharpy-V before*after*totalT0T0 σT 0 T 0 SINTAP TT 41J USE mm°CK J SE(B) specimen orientation: TS * Recovery annealing

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community K Jc(1T) values versus the test temperature normalised to RTT 0 of the different discs of trepan 1-1 and VERLIFE lower bound curve VERLIFE – Unified Procedure for Lifetime Assessment of Components and Piping in WWER NPP’s

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community K Jc(1T) values versus the test temperature normalised to RTT 0 (SINTAP) of the different discs of trepan 1-1 and VERLIFE lower bound curve

08/ Institute for Safety Research Hans-Werner Viehrig Member of the Leibniz Community Summary and Conclusions -The recovery annealing could be confirmed with the test results. -K Jc values generally follow the course of the MC with a remarkable scatter. -There is a big variation of the evaluated T 0 through the thickness of the RPV wall. -The highest T 0 was about 50°C at a distance of 22 mm from the inner surface of the weld. It is 40 K higher compared with T 0 at the inner surface. -The measured K Jc values are not enveloped by the RTT 0 indexed VERLIFE lower bound curve. However, the VERLIFE lower bound curve indexed with the SINTAP reference temperature RTT 0 SINTAP envelops the K Jc values. Trepans were taken from the core weld SN0.1.4 and base metal of the Greifswald Unit 1 RPV. Charpy size SE(B) specimens from 5 locations through the thickness of the welding seam were tested and evaluated according to the MC approach as adopted in ASTM E Results of the welding seam SN (trepan 1-1) in the irradiated, recovery annealed and re- irradiated condition: