Periodic Reporting for period 2 - ECC-SMART (Joint European Canadian Chinese development of Small Modular Reactor Technology)
Reporting period: 2022-03-01 to 2023-08-31
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 a supercritical water-cooled small modular reactor (SCW-SMR) that is one of the best options to supply clean energy by means of high efficiency and secure nuclear processes. SMRs 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.
The crucial aspect of the ECC-SMART project is a mutual cooperation, which has been effectively supported by regular in-person project meetings that boosted the discussion and project evolution after the delayed beginning due to the pandemic outbreak. More students and young researchers were involved in the project activities under close cooperation with the ENEN2plus project. Significant progress has been achieved in technical work packages. The pre-normative research proved the high corrosion resistance of selected materials (310S and 800H) perspective as a fuel cladding for future SMR and provided data for numerical and experimental investigations in the WP3. However, the effect of the environment becomes more detrimental at higher temperatures (500 °C) in terms of sensitivity to stress corrosion cracking. Most of the data are stored in the MatDB database extended also by the data from electrochemistry. The trial test obtained promising results, suggesting the possibility of mitigating the effects of radiolysis.
The pre-conceptual design of SCW-SMR has been further developed and analysed based on the established iterative procedure between WP3, WP4 and WP2. The reference database has been extended by two benchmarking activities that contributed to further improvement and validation of system-, subchannel- and CFD-codes. The core layout and passive safety concept of the SCW-SMR as well as Canadian and Chinese design concepts have been developed. These codes are subsequently applied for detailed reactor physics and system thermal hydraulics analysis of suggested design concepts.
Thus, the Serpent reactor model was upgraded to produce more realistic power, temperature, and density profiles, essential for current and future calculations. The model involves several variables e.g. different uranium enrichment, the geometry of fuel assembly, temperature of moderator, application of neutron reflectors, and effect of burnable absorber that needs to be considered. Reactivity feedback coefficients regarding the coolant, moderator and fuel temperatures were determined for the whole reactor model (globally) and each heat-up stage (locally). The temperature coefficients were negative which serves the inherent safety of the reactor. Reactivity feedback coefficients are vital for predicting reactor behavior during incidents, necessitating model adjustments for safe and reliable operation.
Furthermore, coupled APROS-SERPENT calculations were carried out to determine certain parameters, especially the peak cladding temperature. The preliminary core optimisation process has been continued with further calculations regarding reactivity control and power distribution improvement. Calculated parameters and their responses to model changes or burnup scenarios offer valuable insights for future model development. Monte Carlo reactor core models, optimized for neutronics, thermal-hydraulics, safety, and economics, are continually examined and improved.
The selected data and experiences from technical WPs have been used for establishing of Phenomena Identification and Ranking Table (PIRT). The PIRT analysis will supplement a pre-licensing study which is also being developed based on the identified regulations. In addition, PIRT will provide a good indication of key obstacles to licensing and will be useful in the next steps of design, analyses and safety assessment of ECC-SMART. The progress of the project is further described in 12 published peer-reviewed open-access scientific papers. An intensive involvement of the Advisory Board members provides the consortium with constructive feedback and support.
The pre-conceptual design of SCW-SMR has been further developed and analysed based on the established iterative procedure between WP3, WP4 and WP2. The reference database has been extended by two benchmarking activities that contributed to further improvement and validation of system-, subchannel- and CFD-codes. The core layout and passive safety concept of the SCW-SMR as well as Canadian and Chinese design concepts have been developed. These codes are subsequently applied for detailed reactor physics and system thermal hydraulics analysis of suggested design concepts.
Thus, the Serpent reactor model was upgraded to produce more realistic power, temperature, and density profiles, essential for current and future calculations. The model involves several variables e.g. different uranium enrichment, the geometry of fuel assembly, temperature of moderator, application of neutron reflectors, and effect of burnable absorber that needs to be considered. Reactivity feedback coefficients regarding the coolant, moderator and fuel temperatures were determined for the whole reactor model (globally) and each heat-up stage (locally). The temperature coefficients were negative which serves the inherent safety of the reactor. Reactivity feedback coefficients are vital for predicting reactor behavior during incidents, necessitating model adjustments for safe and reliable operation.
Furthermore, coupled APROS-SERPENT calculations were carried out to determine certain parameters, especially the peak cladding temperature. The preliminary core optimisation process has been continued with further calculations regarding reactivity control and power distribution improvement. Calculated parameters and their responses to model changes or burnup scenarios offer valuable insights for future model development. Monte Carlo reactor core models, optimized for neutronics, thermal-hydraulics, safety, and economics, are continually examined and improved.
The selected data and experiences from technical WPs have been used for establishing of Phenomena Identification and Ranking Table (PIRT). The PIRT analysis will supplement a pre-licensing study which is also being developed based on the identified regulations. In addition, PIRT will provide a good indication of key obstacles to licensing and will be useful in the next steps of design, analyses and safety assessment of ECC-SMART. The progress of the project is further described in 12 published peer-reviewed open-access scientific papers. An intensive involvement of the Advisory Board members provides the consortium with constructive feedback and support.
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.