Work Package 8: Seismic Studies

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1 Progress Status of the FP 7 ESNII plus Project March 18, 2015 ESNII Biennial Conference, Brussels44 Center, Boulevard du Jardin Botanique 44, Brussels Work Package 8: Seismic Studies Massimo FORNI ENEA Head, Seismic Engineering Technical Unit (UTSISM) Bologna, Italy

2 Task 8.1 Input data It aims at providing the input data (general layout of the buildings and main structures, mass distribution and position of the centre of gravity, seismic input and natural frequency of the most critical components), needed for the analyses of Tasks 8.2, 8.3 and 8.4 STATUS: COMPLETED ALFRED: data have been provided by ANSALDO and EA. ASTRID: data have been provided by CEA. Deliverable 8.1.1: Issued at month 18.

ALFRED: Finite Element Model implemented by ENEA Mass (Kg) Building 5.5377x10 7 Concrete 5.5182 x10 7 Steel 1.

3 ALFRED: Finite Element Model implemented by ENEA Mass (Kg) Building x10 7 Concrete x10 7 Steel 1.94 x10 5 Reactor Pressure Vessel (RPV) 5.217x10 6 Water (Pools) x10 6 Crane 1.00 x10 5 Dynamic Live Load x10 6 TOTAL ALFRED MASS x10 7

4 Finite Element Model of ASTRID implemented by NUMERIA

Acceleration Spectra INPUT DATA also included the seismic inputs for both ALFRED and ASTRID ALFRED 3 2.

5 Acceleration Spectra INPUT DATA also included the seismic inputs for both ALFRED and ASTRID ALFRED Acc_TH1 Acc_TH14 Acc_TH15 Acc_TH16 Acc_TH17 Acc_TH18 Acc_TH19 Design_Acc_Spectra ASTRID Period (s) a g =0.3s

6 Task 8.2 Isolation system design and testing STATUS: IN PROGRESS ALFRED: the design of the isolation system has been completed (100 High Damping Rubber Bearings) ASTRID: the design of the isolation system will be concluded in few weeks (neoprene bearings + lead core). Prototypes will be manufactured and tested by partner NUVIA in the second part of the project. Inputs will be provide to Task 8.4 (Fragility Analysis) scheduled for the last part of the project.

7 Task 8.3 Dynamic analyses STATUS: IN PROGRESS ALFRED: the design of the isolators has been already completed. After parametrical analyses, it was decided to use a regular grid 10X10 HDRBs (4.1 m distance) having 1.1 m diameter and 0.21 m rubber height.

The isolator designed for ALFRED is similar (a little bit smaller) to that developed for ELSY in the SILER Project, which was subjected to a full (and successfully)

8 The isolator designed for ALFRED is similar (a little bit smaller) to that developed for ELSY in the SILER Project, which was subjected to a full (and successfully) qualification experimental campaign. Thus, it can be considered as already qualified (experimental activities in task 8.2 are addressed to the ASTRID isolator only).

9 ALFRED ISOLATOR (HDRB) 10% damping 1.4 MPa shear modulus 1100 mm diameter 210 mm rubber height 100% shear strain at the design displacement 2.5 safety factor against failure in case of unexpected events years expected life (no need of replacement during the service life)

10 Acceleration x-dir. (m/s 2 ) ALFRED: acceleration at the vessel support: comparison between isolated and conventionally founded configuration 7 5 A1_Vessel_NO_Isolated A1_Vessel_Isolated Time (s)

11 Acceleration spectrum x-dir. (m/s 2 ) ALFRED: horizontal acceleration calculated at the vessel supports is dramatically reduced in case of seismic isolation A1_Vessel_NO_Isolated A1_Vessel_Isolated Frequency (Hz)

acceleration time-history compatible with EuroCode 8 (Maximum displacement lower than 20 cm) 2.

12 Displacement x-dir. (m) ALFRED: horizontal displacement of the corner isolators calculated with a threedirectional acceleration time-history compatible with EuroCode 8 (Maximum displacement lower than 20 cm) 2.5E E E E E E E E E E E-01 U1_1(SO) U1_10(SE) U1_91(NO) U1_100(NE) Time (s)

13 Acceleration x-dir. (m/s 2 ) ALFRED: horizontal accelerations in different vertical positions A1_Dome A1_Floor_ A1_Floor_ A1_Floor_ A1_Floor_+0 A1_Floor_-6000 A1_Floor_ Time (s)

A1_Floor_+23000 A1_Floor_+15500 A1_Floor_+10600

14 Acceleration spectrum (m/s2) ALFRED: horizontal acceleration response spectra A1_Dome A1_Floor_ A1_Floor_ A1_Floor_ A1_Floor_+0 A1_Floor_-6000 A1_Floor_ Frequency (Hz)

15 ALFRED: vertical forces on the isolators are always positive and below the design limit (also with a regular grid disposition and only one size isolator)

16 ALFRED: next activities will include the effects of the soil-structure interaction

17 ASTRID: activities similar to those performed on ALFRED are in progress

18 BASE ISOLATION SYSTEM LAYOUT 1 type of isolators CASE STUDY 1 ISOLATOR TYPE IS-A -horizontal stiffness, K h = 11,0 kn/mm -vertical stiffness, K v = 1.100,0 kn/mm -equivalent viscous damping, x esi = 10% and 20% CASE STUDY 2 ISOLATOR TYPE IS-B -horizontal stiffness, K h = 11,0 kn/mm -vertical stiffness, K v = ,0 kn/mm -equivalent viscous damping, x esi = 10% and 20%

19 BASE ISOLATION SYSTEM 2 types of isolators CASE STUDY 3 ISOLATOR TYPE IS1 -horizontal stiffness, K h = 9,0 kn/mm -vertical stiffness, K v = kn/mm -equivalent viscous damping, x esi = 10% and 20% ISOLATOR TYPE IS2 -horizontal stiffness, K h = 15,0 kn/mm -vertical stiffness, K v = kn/mm -equivalent viscous damping, x esi = 10% and 20% CASE STUDY 4 ISOLATOR TYPE IS3 -horizontal stiffness, K h = 9,0 kn/mm -vertical stiffness, K v = kn/mm -equivalent viscous damping, x esi = 10% and 20% ISOLATOR TYPE IS4 -horizontal stiffness, K h = 15,0 kn/mm -vertical stiffness, K v = kn/mm -equivalent viscous damping, x esi = 10% and 20%

20 Task 8.4 Fragility analysis of the ASTRID isolators STATUS: just started The fragility analysis (up to beyond design conditions) of the ASTRID isolator will be carried out in the second part of the project, based on the output of the analyses of Task 8.3 and the results of the experimental campaign of Task 8.2.

21 CONCLUSIONS Activities of WP8 are regularly in progress for ALFRED and ASTRID. For both reactors, the obtained results are very positive and confirm that seismic isolation can be considered the most promising technology to provide full protection to the whole nuclear island in case of earthquake, even for unexpected events (beyond design): - Provides a strong reduction of the horizontal accelerations ( rigid body motion of the superstructure); - Allows for the standardization of the antiseismic design of the reactor

22 Thanks for the attention

PROJECT OVERVIEW M. Forni, S. De Grandis SILER Training Course, Verona, May 21-24, 2012

PROJECT OVERVIEW M. Forni, S. De Grandis SILER Training Course, Verona, May 21-24, 2012 PROJECT OVERVIEW PROJECT AIM SILER Seismic-Initiated events risk mitigation in LEad-cooled Reactors is a Project aimed at evaluating the risk associated to seismic initiated events in Generation IV Heavy