Periodic Reporting for period 1 - ECC-SMART (Joint European Canadian Chinese development of Small Modular Reactor Technology) Reporting period: 2020-09-01 to 2022-02-28 Summary of the context and overall objectives of the project As a result of concerns about fossil fuel resources availability and environmental issues, interest in nuclear power technologies is growing. After a period when large units were developed and privileged, there is now a revival of interest concerning the small modular reactors (SMRs). SMR technologies using various concepts are being developed worldwide. The water-cooled one is believed as the most promising as it inherits experience gained by most of the power reactors operating worldwide. In this frame, the supercritical water (SCW) technology can play an important role, representing a natural evolution of current advanced water-cooled nuclear reactor technologies, while integrating much of the advances in SCW technology used in modern conventional fossil power plants. The scope of the ECC SMART project is an SCW-SMR that is one of the best options to supply clean energy by means of high efficiency and secure nuclear processes. The Small Modular Reactors offer many advantages, such as relatively small physical footprints, reduced capital investment and the ability to be sited in locations not possible for larger nuclear plants. It is expected that SCW-SMR will improve the standard of living and technological development not only in cities but also in remote areas and small towns. As the project deals with all important aspects such as structural material withstanding high temperature and pressure, thermal-hydraulic, neutron physics as well as safety requirements and pre-licensing process, its outputs and progress are, thus, crucial not only from the scientific but also from the societal point of view. One of the main challenges of the ECC-SMART project is to demonstrate the feasibility of the supercritical water-cooled reactor (SCWR) concept as one of the six advanced nuclear reactors of the future Generation IV. The project consortium benefiting from the European, Chinese, Canadian and Ukraine synergies plans to develop generic and specific safety criteria and requirements for the SCW-SMR concept, by following and further developing the science-based recommendations by IAEA and GIF for SMRs, in particular the concept of defense-in-depth, physical protection and security and non-proliferation principles. Those will be then used to identify and characterize the main safety-related findings and conclusions in other work packages. This will facilitate the development of the pre-licensing study, which will summarize both the already fulfilled safety criteria and the potential gaps to be further investigated in future research projects. Finally, the guidelines for the demonstration of safety in the further development stages of the SCW-SMR concept will be developed to support the deployment of SCW-SMR in the future. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far The work to be performed within the ECC-SMART project is divided into six work packages (WPs). The first focused on overall coordination and the last on dissemination, communication, and nuclear education, are both addressing general processes helping to manage and disseminate the project. WP2 covers material testing. For this purpose, the test matrix was established including more than 700 specimens. The focus is devoted to stainless steel 310S and alloy 800H, which have been selected as the most prospective material for fuel cladding for SCWR based on previous research and recommendations. In addition, experimental material such as AFA (Alumina Forming Austenitic alloy) was supplied by colleagues from China to support the progress in the SCWR and SCW-SMR field and international collaboration. Most of the above-mentioned tested specimens have been manufactured from the tubes to get closer to the real conditions as the corrosion resistance of the cladding tube was indicated as a crucial issue for further development. The conditions for tests were based on relevant calculations done in cooperation with the Canadian partner. Challenging tasks connected with electrochemical measurements and irradiation by a neutron in relation to corrosion behaviour of candidate material have been started. Up to now, the first results mainly from the exposure tests are being evaluated. Within WP3 on thermal-hydraulics and safety of the SCW-SMR, an innovative design concept of a small modular reactor cooled by SCW has been proposed based on a high-pressure light water reactor (HPLWR) including the experiences of Canada and China. The first results have been published at relevant conferences and through scientific papers. The extension of the reference database has been started based on the data provided by the project partners. Two benchmarking activities are defined, and the work is in progress to improve codes (system, subchannel and CFD) with a focus on the SCW-SMR concept. At the same time, coupling of analysis as well as improvement of application of codes are ongoing. In addition, the experiments dealing with the effect of corroded surfaces on thermal-hydraulic were implemented. Neutronic optimization of the SCW-SMR design is based on reactor physics calculations carried out by WP4. One of the main goals is to achieve a 2-year-long burnup cycle. For this purpose, the number and design of fuel assemblies (FA), including the geometry, assembly gaps and number of fuel rods are modified. In addition, the type and enrichment of fuel such as UO2 and MOX are also necessary to balance and make relevant calculations on this. The first results revealed that MOX fuel can be successfully used in combination with the higher enrichment of UO2. However, additional analyses are planned to reach the appropriate core layout. Changes proposed based on the neutron physics (WP4) have to be feasible from the thermohydraulic (WP3) and material (WP2) point of view. Thus, the ongoing close cooperation within the project is crucial. The outputs and progress performed in technical WPs would propose a consistent set of the main safety-related findings which should be further completed and used by WP5 with a focus on pre-licencing and safety, security and safeguards documentation. Up to now, the review report on safety criteria and requirements for the SCW-SMR concept was completed. The entanglement of the safety in the early design of the SCW-SMR is at the core of the WP5 and the entire ECC-SMART project. As briefly described, the project is well on track and all activities are performed and headed towards objective completion. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) The ECC-SMART project is an important contributor to the new type of reactor, the SMR. It reunites specialists from three continents with the scope of working on safety features on SCW-SMR. This type of reactor represents the attest development in the field of nuclear power, and it is widely addressed by the research community. Advancements in technology will allow the deployment of power sources in formerly inaccessible areas while ensuring economically available ways. In addition, passively safe operation is one of the most important principles on which the concept of this type of reactor is designed. As the usage of SCW can be found in additional industrial processes, some of the anticipated results from the ECC-SMART can promote the progress in these technologies. Above all, the support of young scientists and students and an increase in their interest in the nuclear field remains one of the main goals and relevant events and internships are planned to be organized in the following implementation of the project period. ecc-logo.png
