EVOGY - Evolving the Fennoscandian GMPEs

WP4 focused on international cooperation. In 2018 COMRADE workshop was organized in Forsmark, Sweden by Forsmark NPP. The two-day meeting was held at the Forsmark NPP during 4^th and 5^th of December. The first day concluded from lectures given by various instances from NPPs, regulator, polymer industries with topics relevant to ageing of polymer components in nuclear power plants. The second day focused presenting the project results, discussions and presenting the future research project proposal. In addition, visits to the local final repository site were organized.

Deliverables in 2018

• Development of condition monitoring technique for O-rings used in NPP applications (presentation at Fontevraud 9 conference)

• Development of FEM model and test run using data from T1.1 (RISE-research report)

• Conduct workshops on each powerplant to discuss results and how to use them (minutes of the meeting)

• Material acquisition from plants and description how to include the materials in project work (RISE-research report)

• Scientific publication on the molecular dynamics modelling efforts to understand the reverse temperature effect (peer reviewed publication)

• Development of ToF SIMS technique in determination of oxidation gradient on EDPM (conference publication in Fontevraud 9)

• Application of semi-empirical ageing techniques on EPDM and Lipalon cable jacketing materials (VTT-Research report)

• COMRADE Workshop/seminar on polymer ageing issues at NPPs (minutes of the meeting)

Specific goals in 2018

In Task1 the goal was to create a homogeneous dataset of earthquake recordings for the calibration of the GMPE. We carried out quality control of the recorded data by making old and newly added data more uniform in terms of their format. ISUH and VTT worked together within this task, creating synergy and internal review to the process. We created seven consecutive updates of the dataset, gradually improving the procedures of data processing. The dataset contains recordings of Fennoscandian earthquakes with magnitude above 2. Task1 provided a uniformly processed earthquake dataset of the measurements for Fennoscandian earthquakes up to 2017, data to be released as Deliverable 1 of EVOGY.

The goal of Task2 was to implement a calculation procedure for spectra calculation and link it to the earthquake data. ISUH and VTT have agreed on the data interfaces, and the spectral calculation procedure is automated. Hence, additional ground motion data can easily be accommodated and the spectra re-calculated. An independent checking protocol was implemented to test the steps of the automated routines, to assure the correctness of the spectra calculations.

The automated methodology developed in Task2 was used to obtain the database of the spectra for all the collected ground motions, practically all Fennoscandian earthquakes with magnitude above 2. The spectra database will be released in excel format by the project as Deliverable 2 and 3.

Finally, we used these spectra to calibrate the constants of the proposed GMPE. The calibration constants and measures of the prediction’s error margins are reported in the Final report of the EVOGY project (Deliverable 4a) and a manuscript in preparation (Deliverable 4b).

Some examples of fit between the GMPE prediction and selected Fennoscandian earthquake recordings are given in Figure 2.49.

Figure 2.49. Comparison with selected spectra from the Fennoscandian dataset a) from a 9/27/2008 event with depth=17.3km, b) from the Gulf of Bothnia event of 2016-03-19 with

depth=23.5km

As an embedded activity to the SAFIR/EVOGY, in the NKS/SYTAGMA project we used our hybrid modelling method¹ to generate larger datasets of synthetic ground motions. The fit of

1 Fülöp, Ludovic, Vilho Jussila, Björn Lund, Billy Fälth, Peter Voss, Jari Puttonen, and Jouni Saari. 2017. Model- ling as a Tool to Augment Ground Motion Data in Regions of Diffuse Seismicity - Final Report. NKS Nordic Nuclear Safety Research.

0.00001 0.0001 0.001 0.01 0.1 1 10

0.1 1 10 100 1000

PSA/PGA

f(hz)

M2.4, R_hyp~19km

FennG-16 (19km) 19.3222

0.0001 0.001 0.01 0.1 1 10

0.1 1 10 100 1000

PSA/PGA

f(hz)

M4.1, R_hyp~95km

FennG-16 (95km) 104.5382 104.5224 95.218

the synthetic data to the near-field of the GMPE prediction is shown in Figure 2.50, while the displacement field of the earthquake is shown in Figure 2.51.

At this point we formulated the GMPE only using natural earthquake recordings, we only accepted the synthetic recordings to indicatively guide the short distance tale of the GMPE. In this range, there are no natural recordings, so it is debatable how the spectra evolve very close to the fault. However, we plan to check the developed GMPE with merged natural-synthetic data sets.

Figure 2.50. Comparison of spectra in black from the simulated synthetic ground-motion and the GMPE in red. The plot corresponds to Mw=5.0.

Figure 2.51. Displacements (mm) on the ground surface from an Mw=5.0 earthquake, occurring on a fault dipping 45 degrees, in the case of oblique faulting. The rows in the figure

are time slices at 4.1 and 5.9 s. The columns in the figure are the radial from epicentre, transverse and vertical components of the displacement. The depth of the hypocentre is 10

km.

Deliverables in 2018

• Integrated data-sets of earthquake recordings. Ready – will be delivered to power companies and STUK on an EVOGY HDD/DVD.

• Calculation of spectral and new intensity measures. The calculated spectra is in EXCEL worksheet and will be delivered on an EVOGY HDD/DVD

• The code was used to calculate the spectra and it is written in Python.

• Research paper draft, with a shortened version to become final Report for the SAFIR book was delivered 08.02.2019 for review to Fennovoima (Juho Helander)

• NKS report draft ready. Still in review with authors. Agreed to be sent to STUK (Pekka Välikangas / Simon Burck).