Gas-cooled fast reactor (GFR) is considered as one of the six most promising advanced nuclear reactor technologies, supported worldwide by the Generation IV International Forum and ESNII in Europe. It excels in versatility, combining very high core outlet temperatures and the possibility to close the fuel cycle, allowing for very efficient and sustainable electricity and industrial heat production. The SafeG proposal presents a Research and Innovation action aiming at connecting developers of the ALLEGRO reactor (V4G4) with European and international experts having experience in GFR and HTR research, who will utilize their unique expertise, knowledge and experience, bringing fresh ideas to the GFR development to the SafeG project will bring the GFR research and development in Europe a major step forward. It is divided into 7 Work Packages, four of them dealing with open research and development problems of GFRs, namely the core safety and proliferation resistance (WP1), advanced materials and technologies (WP2), decay heat removal (WP3), standardization and codes (WP4). Additionally, a major part of the effort (15 % of the total budget) will be dedicated to education and training activities sheltered by WP5. Dissemination and outreach activities are included in WP6 while WP7 ensures smooth management and execution of the project. The main objectives of the SafeG project are: - To strengthen safety of the GFR demonstrator ALLEGRO - To review the GFR reference options in materials and technologies - To adapt GFR safety to changing needs in electricity production worldwide with increased and decentralized portion of nuclear electricity by study of various fuel cycles and their suitability from the safety and proliferation resistance points of view - To bring in students and young professionals, boosting interest in GFR research - To deepen the collaboration with international non-EU research teams, and relevant European and international bodies

Environmentally-Assisted cracking (EAC) is one of the major failure modes occurring in light water reactors (LWRs). The condition of surfaces exposed to the primary coolant plays a main role on the susceptibility of components to EAC. However, many national and international guidelines and standards do not address surface condition of critical components in nuclear power plants (NPP) The goal of the MEACTOS project is to improve the safety and reliability of Generation II and III of NPP by improving the resistance of critical locations, including welds, to EAC through the application of optimized surface machining and improved surface treatments. MEACTOS is proposed by a consortium of 16 partners from 11 EU member countries (Spain, France, Finland, Czech Republic, Belgium, Germany, Slovakia, Romania, UK, The Netherlands and Slovenia) plus Switzerland (associated country of Euratom), that comprises all the appropriate key players to ensure the availability of technologies, capabilities, technical and operational knowledge required for the goal of the project. Research laboratories (VTT, SCK-CEN, CVR, CIEMAT, PSI, JRC, RATEN), universities (UNIMAN, USFD, STUBA) nuclear components suppliers (The NAMRC of the University of Sheffield, ENSA, SA.),utilities (EdF), engineering companies (ZAG, AMEC) and plant designers (AREVA-NP) has been selected in order to complete the required capacities to cover all the expertise fields faced by the project. The Consortium members have differential but complementary skills and expertise in areas such as project management, manufacturing, technology transfer or dissemination, to name a few key areas. Pro-active material degradation programs outside Europe, particularly in Japan and in the United States, currently address, or plan to address, surface condition with respect to EAC. This European MEACTOS project will directly benefit Europe, engaging on an equal footing with these initiatives, maintaining a level of competitiveness for European industry in the global scenario.

INCEFA-PLUS delivers new experimental data and new guidelines for assessment of environmental fatigue damage to ensure safe operation of European nuclear power plants. Austenitic stainless steels will be tested for the effects of mean strain, hold time and material roughness on fatigue endurance. Testing will be in nuclear Light Water Reactor environments. The three experimental parameters were selected in the framework of an in-kind project during which the current state of the art for this technical area was developed. The data obtained will be collected and standardised in an online fatigue database with the objective of organising a CEN workshop on this aspect. The gaps in available fatigue data lead to uncertainty in current assessments. The gaps, will be targeted so that fatigue assessment procedures can address behaviour under conditions closer to normal plant operation than is currently possible. Increased safety can thus be assured. INCEFA-PLUS also develops and disseminates a modified procedure for estimating environmental fatigue degradation. This will take better account of the effects of mean strain, hold time and surface finish. This will enable better management of nuclear components, making possible the long term operation (LTO) of NPPs under safer conditions. INCEFA-PLUS is relevant to the NFRP1-2014 programme because: • Present guidance originates from NRC. In Europe various national programmes aim to develop counter proposals allowing greater operational efficiency with at least comparable safety assurance. INCEFA-PLUS brings these programmes together through which a strong EU response to the NRC methodology will be obtained with improved safety assurance through increased lifetime assessment reliability. • INCEFA-PLUS improves comparability of data from EU programmes because partner laboratories will do some tests on a common material under common conditions. Reduced assessment uncertainty will enable easier maintenance of safety

The objective is to continue work, advancing ability to predict lifetimes of Nuclear Plant components when subjected to Environmental Assisted Fatigue loading. Over the five years proposed for INCEFA-SCALE, EPRI in the USA is leading a series of component scale environmental fatigue tests. These are expected to advance data availability significantly; however, advances in addressing transferability of laboratory scale tests to real component geometries and loadings will still be constrained by limited test data. This knowledge gap is recognised worldwide as significant. INCEFA-SCALE will generate significantly increased understanding of the transferability of laboratory scale test data to component scale. The project strategy will be (1) the development of comprehensive mechanistic understanding developed through detailed examination of test specimens and MatDB data mining, and (2) testing focussed on particular aspects of component scale cyclic loading. Examples of tests possible include, uniaxial specimens with notches (to address complex loads), membrane tests (to address biaxiality), thermo-mechanical tests (to address thermal cycling and thermal gradient effects), and complex wave tests (to address real plant transient effects). The project will begin by “data mining” to extract maximum understanding from the vast amount of test data within JRC’s MatDB database (from the predecessor INCEFA-PLUS project, and from other external sources such as USNRC, EPRI, MHI and the AdFaM project). In parallel the test program needs will be agreed. Testing will commence after one year and run for 3 years. Finally, the project will deliver guidance on use of laboratory scale data for component scales. Industrial support, is demonstrated by over €3M matching funds and positive endorsements from EPRI, ENEN and NUGENIA. EC support will enable maximum consistency and coordination of testing and assessment.

NFRP 1: 2016-2017 notes that “A number of current Generation II reactors should continue operating for a few decades and Generation III should still be in operation one century from now.” This requires a systematic ageing management procedure for justifying their safe long term operation (LTO). One fundamental part in this process is to demonstrate the integrity of the nuclear power plant components. The required safety margins are determined by considering various degradation and ageing mechanisms and postulated defects. This project focuses on open technology gaps, identified in the NUGENIA road map, related to piping components, not covered by other ongoing projects. Specifically this project will focus on developing: o innovative quantitative methodologies to transfer laboratory material properties to assess the structural integrity of large piping components, o an enhanced treatment of weld residual stresses when subjected to long term operation, o advanced simulation tools based on fracture mechanics methods using physically based mechanistic models, o improved engineering methods to assess components under long term operation taking into account specific operational demands, o integrated probabilistic assessment methods to reveal uncertainties and justify safety margins. ATLAS+ will have a significant impact on the safety of operational Generation II and III nuclear power plants. The project will demonstrate and quantify inherent safety margins introduced by the conservative approaches used during design and dictated by codes and standards employed through-out the life of the plant. The outcomes from ATLAS+ will therefore support the long term operation of nuclear power plants. This will be achieved by using more advanced and realistic scientific methods to assess the integrity of piping. The project will provide evidence to support the methods by carrying out large scale tests using original piping materials.