Periodic Reporting for period 1 - McSAFER (High-Performance Advanced Methods and Experimental Investigations for the Safety Evaluation of Generic Small Modular Reactors)
Período documentado: 2020-09-01 hasta 2022-02-28
The interest in the development and deployment of Small Modular Reactors (SMR) has increased in the last years in Europe and worldwide. SMRs have a great potential for safe, flexible and CO2-free power generation, salt-water desalination, and process heat generation. They are considered in various countries as alternative to large NPPs and as part of the future energy-mix to achieve the low-carbon power generation goals with low risk and cost in a competitive energy market. However, the new small core design, the integral concept, the innovative heat exchangers, passive heat removal systems, and novel containment designs represent new challenges for the safety demonstration in the frame of a licensing process. The design peculiarities of SMR-cores also challenges the prediction capability and accuracy of legacy core analysis tools. Instead, the use of multi-dimensional numerical tools and novel approaches is needed. The validation of these numerical simulation tools is very important for their acceptability and their use by regulators, and industry.
McSAFER aims at advancing SMR-safety research by combining thermal hydraulic experiments and numerical simulations of different multiscale/multi-physics approaches. The numerical investigations are focused on four SMR-designs such as CAREM, SMART, F-SMR and NuScale. The experimental program builds on European facilities such as COSMOS-H, HWAT, and MOTEL that will provide data for code validation. This project will demonstrate the complementarity of legacy codes with advanced and high fidelity simulations when use in licensing processes.
The overall objectives of the McSAFER are hereafter summarized:
• Increase the level of knowledge about thermal hydraulic phenomena in SMR-concepts to support the licensing process.
• Improve and optimize multiscale thermal hydraulic codes and neutron physics approaches for more precise simulations supporting the safety evaluations of SMRs.
• Consolidate the application of high-fidelity tools based on multi-scale /multi-physics for the safety evaluations of SMRs.
McSAFER aims at advancing SMR-safety research by combining thermal hydraulic experiments and numerical simulations of different multiscale/multi-physics approaches. The numerical investigations are focused on four SMR-designs such as CAREM, SMART, F-SMR and NuScale. The experimental program builds on European facilities such as COSMOS-H, HWAT, and MOTEL that will provide data for code validation. This project will demonstrate the complementarity of legacy codes with advanced and high fidelity simulations when use in licensing processes.
The overall objectives of the McSAFER are hereafter summarized:
• Increase the level of knowledge about thermal hydraulic phenomena in SMR-concepts to support the licensing process.
• Improve and optimize multiscale thermal hydraulic codes and neutron physics approaches for more precise simulations supporting the safety evaluations of SMRs.
• Consolidate the application of high-fidelity tools based on multi-scale /multi-physics for the safety evaluations of SMRs.
During the first 18 months, three facilities were extended, modified, and equipped with measurement techniques needed for the foreseen tests. Several pre-tests were needed at each facility to assure leak-tightness, sensor calibration, check heat loses, and to demonstrate the functionality of data acquisition/process systems.
Tests to study the behaviour of the helical coil heat exchanger of MOTEL-facility were done obtaining unique data for code validation, Figure 1 and 2. Other tests are under preparation to investigate the transversal flow.
Pre-tests at HWAT aimed at verification of the functionality of the measurement devices, the quantification of the uncertainties of sensors, and calibration. Static tests under forced circulation (in total 24) are planned for the near future. They cover heat transfer in relevant regimes e.g. single phase flow, subcooled boiling, CHF, onset of flow instabilities. The HWAT-setup for the second test series was also checked, where key test parameter for the natural convection e.g. pressures, mass flow rates, heat fluxes, degree of sub-cooling, heated lengths, etc. are considered, see Figure 3. The COSMOS-H facility was successfully set-up. Respective tests were performed to check functionality of the sensors, data acquisition and processing system, security checking due to high-pressure level. The preparation of the first test series with one tube is advanced. The validation of the different thermal hydraulic codes is foreseen for the second half of the project; the development of the respective inputs has been started.
The analysis of four SMR-core designs using different methods for REA, Cold Water Injection are progressing as expected. Needed data was collected, XS-data generated, core models (N, TH) developed. The REA and CWI transient were analysed with different codes. The comparison of selected REA-parameters showed that the different codes predict similar trends. One of the reasons for the expected discrepancies are related to the physical modelling approaches of the neutronics and thermal hydraulic solvers. Based on the obtained results by the different codes for NuScale, it can be stated that all steady state integral parameters are in reasonable agreement. All codes show consistent agreement in prediction of key parameters, Figure 4. The CAREM-core was analysed with PARCS/SCF/ICoCo and CONDOR/SCF. The main differences are stemming from the different approaches for the generation of condensed nodal XS (Serpent, HUEMUL), Figure 5. The SMART and F-SMR core are analysed with Serpent/PARCS/SCF/ICoCo and APOLLO3/C3PO/FLICA, respectively. The Analysis of the SMR-cores with coupled transport/subchannel TH codes is in advanced stage. The specifications for the ATF-core are done. Heat deposition models for the ANTS and the transient decay heat model for Serpent are implemented and tested.
The multiscale analysis of 3D-TH inside the RPV of SMART/NuScale has advanced as scheduled. The analysis of ATWS Boron Dilution was performed using 1D and 3D TH-codes, Figure 6, Figure 7 and Figure 8. The results obtained for SMART/NuScale showed that the different codes are predicting similar trends if they are using the same approach i.e. 1D/3D-TH models. It became evident that the results of the 1D and 3D simulations for sequences without strong spatial distortions are similar. Investigations of the SMR-plant behaviour is focus on SLB-sequence. The first option is the use of 1D TH with point kinetics and 1D/3D codes coupled with 3D-diffusion solvers. The numerical analysis for it are completed and reports written. The different solutions are compared to each other, especially for NuScale plant analysed by many institutions, Figure 10. The analysis of a Steam Line transient for both SMR-designs will follow in the second half of the project.
Tests to study the behaviour of the helical coil heat exchanger of MOTEL-facility were done obtaining unique data for code validation, Figure 1 and 2. Other tests are under preparation to investigate the transversal flow.
Pre-tests at HWAT aimed at verification of the functionality of the measurement devices, the quantification of the uncertainties of sensors, and calibration. Static tests under forced circulation (in total 24) are planned for the near future. They cover heat transfer in relevant regimes e.g. single phase flow, subcooled boiling, CHF, onset of flow instabilities. The HWAT-setup for the second test series was also checked, where key test parameter for the natural convection e.g. pressures, mass flow rates, heat fluxes, degree of sub-cooling, heated lengths, etc. are considered, see Figure 3. The COSMOS-H facility was successfully set-up. Respective tests were performed to check functionality of the sensors, data acquisition and processing system, security checking due to high-pressure level. The preparation of the first test series with one tube is advanced. The validation of the different thermal hydraulic codes is foreseen for the second half of the project; the development of the respective inputs has been started.
The analysis of four SMR-core designs using different methods for REA, Cold Water Injection are progressing as expected. Needed data was collected, XS-data generated, core models (N, TH) developed. The REA and CWI transient were analysed with different codes. The comparison of selected REA-parameters showed that the different codes predict similar trends. One of the reasons for the expected discrepancies are related to the physical modelling approaches of the neutronics and thermal hydraulic solvers. Based on the obtained results by the different codes for NuScale, it can be stated that all steady state integral parameters are in reasonable agreement. All codes show consistent agreement in prediction of key parameters, Figure 4. The CAREM-core was analysed with PARCS/SCF/ICoCo and CONDOR/SCF. The main differences are stemming from the different approaches for the generation of condensed nodal XS (Serpent, HUEMUL), Figure 5. The SMART and F-SMR core are analysed with Serpent/PARCS/SCF/ICoCo and APOLLO3/C3PO/FLICA, respectively. The Analysis of the SMR-cores with coupled transport/subchannel TH codes is in advanced stage. The specifications for the ATF-core are done. Heat deposition models for the ANTS and the transient decay heat model for Serpent are implemented and tested.
The multiscale analysis of 3D-TH inside the RPV of SMART/NuScale has advanced as scheduled. The analysis of ATWS Boron Dilution was performed using 1D and 3D TH-codes, Figure 6, Figure 7 and Figure 8. The results obtained for SMART/NuScale showed that the different codes are predicting similar trends if they are using the same approach i.e. 1D/3D-TH models. It became evident that the results of the 1D and 3D simulations for sequences without strong spatial distortions are similar. Investigations of the SMR-plant behaviour is focus on SLB-sequence. The first option is the use of 1D TH with point kinetics and 1D/3D codes coupled with 3D-diffusion solvers. The numerical analysis for it are completed and reports written. The different solutions are compared to each other, especially for NuScale plant analysed by many institutions, Figure 10. The analysis of a Steam Line transient for both SMR-designs will follow in the second half of the project.
- Unique experimental data for the thermal hydraulic behaviour of the helical heat exchanger at the MOTEL facility under SMR-conditions
- Increased knowledge about key-TH phenomena of SMRs e.g. boiling, CHF, natural circulation, transition from forced-to-natural circulation, cross-flow in the core, TH of helical HX, etc.)
- Validation of different thermal hydraulic codes using McSAFER experimental data
- Novel multi-physics analysis of SMR-cores under REA and Cold Water Injection conditions
- Novel multiscale simulation approaches for the analysis of 3d effects in RPV during selected transients (ATWS, Boron dilution)
- Novel multi-scale/multi-physics computational tools for the analysis of the a Steam Line Break accident of SMART und NuScale
Potential socio-economic impact:
- Increase of the competitiveness of the European stakeholders using the advanced validated tools
- Provide novel safety analysis methodologies to perform more realistic safety analysis of SMRs
- Pave the way for more accurate prediction of the safety margins
- Defining the state-of-the-art of safety analysis tools within Europe
- Novel multi-scale and –physical tools for design optimization of SMR to improve competitiveness of stakeholders
Potential societal-implications:
- Contribution to increase the acceptability of more precise methods for safety by national regulators
- Increased knowledge about key-TH phenomena of SMRs e.g. boiling, CHF, natural circulation, transition from forced-to-natural circulation, cross-flow in the core, TH of helical HX, etc.)
- Validation of different thermal hydraulic codes using McSAFER experimental data
- Novel multi-physics analysis of SMR-cores under REA and Cold Water Injection conditions
- Novel multiscale simulation approaches for the analysis of 3d effects in RPV during selected transients (ATWS, Boron dilution)
- Novel multi-scale/multi-physics computational tools for the analysis of the a Steam Line Break accident of SMART und NuScale
Potential socio-economic impact:
- Increase of the competitiveness of the European stakeholders using the advanced validated tools
- Provide novel safety analysis methodologies to perform more realistic safety analysis of SMRs
- Pave the way for more accurate prediction of the safety margins
- Defining the state-of-the-art of safety analysis tools within Europe
- Novel multi-scale and –physical tools for design optimization of SMR to improve competitiveness of stakeholders
Potential societal-implications:
- Contribution to increase the acceptability of more precise methods for safety by national regulators