FRACTESUS Project: General Framework of Materials Selection and Testing Processes

Abstract

The H2020 project entitled “Fracture mechanics testing of irradiated RPV steels by means of sub-sized specimens (FRACTESUS)” started on the 1st October 2020. The aim of this project is to demonstrate the applicability of miniaturized compact tension specimens in fracture toughness testing of the reactor pressure vessel steels under hot cell conditions. Validation of this method in an industrially-relevant environment will be an important step towards achieving its acceptance by the nuclear authorities, and finally, to induce its prospective usage by the nuclear power plant operators. Successful implementation of a miniaturized specimens testing technique will result, among others, in the optimization of surveillance material usage and savings in irradiated materials testing. The general project overview showing its structure, partners involved and main deliverables was published elsewhere. Here, we focus on some technical aspects being of the utmost importance in the initial stage of the project and which will have a crucial impact on its overall progress. The general consideration on the selection of the best available materials for testing are discussed on the examples of 73W weld, A533B LUS and the WWER-440 base metal 15Kh2MFAA. Moreover, the general scheme of the testing process, which is planned within the project, is briefly presented as well as the basic assumptions about the numerical modeling task aimed for rationalizing experimental findings.

Increase of nuclear installations safety by better understanding of materials performance and new testing techniques development (MEACTOS, INCEFA-SCALE, and FRACTESUS H2020 projects)

“…The successful implementation of the FRACTESUS project is possible only if all the stakeholders' concerns have been considered at the very beginning of the project. Although miniature specimen usage is permitted even in the current MC standard [25], there are still many concerns related to the reli-ability of the results, briefly described in [26], and the current Technology Readiness Level (TRL) of MCT testing is estimated to 5. The first results of inter-laboratory trials show successful implementation of MCT specimens [27,28].…”

“…The general assumptions of the FRACTESUS material selection and testing processes are described in [26]. The main part of the testing campaign is focused on the round robin (RR) exercise, where seven selected materials will be tested.…”