Ensuring Data Quality for Environmental Fatigue: INCEFA-PLUS Testing Procedure and Data Evaluation

Abstract

INCEFA-PLUS stands for INcreasing safety in nuclear power plants by Covering gaps in Environmental Fatigue Assessment. It is a five year project supported by the European Commission HORIZON2020 program that commenced in mid-2015 and in which sixteen organizations from across Europe participate. Specifically, the effects of mean strain/stress, hold time, strain amplitude and surface finish on fatigue life of austenitic stainless steels in light water reactor environments are being studied, these being issues of common interest to all participants. The project will develop proposals for improvements to methods for environmental fatigue assessment of nuclear plant components. Therefore, extensive testing capacity is being solicited in various laboratories across Europe in order to add to the existing amount of published data on environmentally assisted fatigue. Since there currently is no standard on environmental fatigue testing, it was imperative to come up with and agree upon a testing procedure within the consortium to minimize lab-to-lab variations in test results. This was done prior to the first phase of testing, but an update of the procedure was required after review of initial results, when additional potential lab-to-lab differences were identified. The current status of the so-called test protocol, and the key areas of difference found between different testing facilities, will be discussed. Due to the large test matrix within INCEFA-PLUS, distributed amongst various test laboratories, it has been necessary to develop a method to assign a data quality level to each test result, and a minimum data quality requirement for results that will be included in the project’s datasets used for analysis. Furthermore, the project has triggered international interest in facilitating mutual data access, and this requires data is gathered in a common database with data quality ratings applied. Ways to address the evaluation of data quality will be discussed. In a way, both activities, on a test protocol and on data review, jointly contribute to data quality by, respectively, ensuring a pre-test, common test procedure and a post-test, harmonized data evaluation. The large number of participants in the INCEFA-PLUS project presents a unique opportunity to gain consensus on light water reactor environment fatigue testing procedures and data quality assessment from experts working in a range of different organizations. The test protocol and data quality ratings developed within the INCEFA-PLUS project could be adopted by other organizations, or possibly used as the basis for future testing standards documents to harmonize approaches across the nuclear industry.

Lessons Learnt from Engineering Science Projects Participating in the Horizon 2020 Open Research Data Pilot

“…In the context of EC-funded projects where the JRC has participated in a data management role, the appointment of a Data Committee has proven particularly effective in engaging researchers in data management activities [38,39]. Perhaps most importantly, the collective responsibility for authoring and maintaining the DMP ensures that the larger proportion of the project partners are familiar with and supportive of the data policy of the project.…”

Characterization of Austenitic Stainless Steels with Regard to Environmentally Assisted Fatigue in Simulated Light Water Reactor Conditions

“…In the absence of a dedicated standard for EAF tests in LWR conditions, the tests were performed as much as possible according to ISO 12106:2017, the standard for strain controlled fatigue testing [21] with additional guidance taken from other relevant standards such as ASTM E606 [22], ISO 11782-1 [23], BS7270:2006 [24] and AFNORA03-403 [25]. To reduce the scatter caused by differences in testing practices between the different laboratories, further guidelines were developed that provide more detailed guidance than is normally included in a testing standard [26]. All test data were uploaded in a dedicated materials database operated by the European Commission (MatDB) and have received digital object identifiers (DOIs) to ensure long-term storage and traceability.…”

“…As an additional quality assurance measure, each test was validated by a panel of fatigue experts from within the project and rated with regard to the quality of the test and the completeness of the information in the database. The test quality was determined on the basis of data like the cyclic stress amplitudes and hysteresis curves [26]. Where necessary, this information was complemented by microstructural characterization of the specimens [27].…”

Incefa-Plus (Increasing Safety in Npps by Covering Gaps in Environmental Fatigue Assessment

“…The tests have been performed in accordance with a "Test Protocol" (Vankeerberghen et al (2018)), developed by the consortium, that determines the specimen size, the temperature, humidity level and pressures during the tests and the procedures to identify and store the specimens, among others. An expert panel has been created with the aim of reviewing all data generated by the project to ensure high data quality.…”