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LNF: Tecnologías de Litio críticas para IFMIF-DONES: Difference between revisions
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LNF: Tecnologías de Litio críticas para IFMIF-DONES (view source)
Revision as of 10:00, 29 October 2024
, 29 October 2024→Description of the project
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IFMIF-DONES is the facility that will be used to irradiate candidate materials for the construction of DEMO and Fusion reactors. Its concept is based on the neutronic radiation produced by the nuclear stripping reaction between 40 MeV deuterons and lithium. The resulting radiation field will produce a damage in materials similar to the one expected in fusion reactors in terms of ratio of gases production (H and He) to displacements. It will be also intense enough to irradiate materials to levels comparable to the conditions foreseen in DEMO. The IFMIF-DONES facility will be composed by three main systems: the accelerator systems, able to produce the 40 Mev deuteron beam, the lithium systems able to provide a liquid lithium target for the deuteron beam, and the irradiation area were the material samples will be irradiated. | IFMIF-DONES is the facility that will be used to irradiate candidate materials for the construction of DEMO and Fusion reactors. Its concept is based on the neutronic radiation produced by the nuclear stripping reaction between 40 MeV deuterons and lithium. The resulting radiation field will produce a damage in materials similar to the one expected in fusion reactors in terms of ratio of gases production (H and He) to displacements. It will be also intense enough to irradiate materials to levels comparable to the conditions foreseen in DEMO. The IFMIF-DONES facility will be composed by three main systems: the accelerator systems, able to produce the 40 Mev deuteron beam, the lithium systems able to provide a liquid lithium target for the deuteron beam, and the irradiation area were the material samples will be irradiated. | ||
The fulfillment of the requirements for the lithium target to be provided by the Li-systems challenges the knowledge on Li technologies. The impurities in lithium may enhance the potential corrosion of Li in the stainless steel pipes. Corrosion increases, in its turn, the amount of impurities in the liquid metal, giving rise to a runaway process. In addition, impurities may be activated due to the presence of radiation fields in the facility, particularly in the target area. Radioactive transmutation products may be also produced due to the neutron irradiation of Li; this is the case of tritium and 7Be, which will circulate with the liquid lithium and have implications for nuclear safety. In addition, impurities can affect the free surface stability of the lithium target. The presence of gases and solid elements might favor nucleation of boiling processes. An Impurity Control System (ICS) is, therefore, required in the plant to monitor and to keep the impurities content below specific limits. | <br> The fulfillment of the requirements for the lithium target to be provided by the Li-systems challenges the knowledge on Li technologies. The impurities in lithium may enhance the potential corrosion of Li in the stainless steel pipes. Corrosion increases, in its turn, the amount of impurities in the liquid metal, giving rise to a runaway process. In addition, impurities may be activated due to the presence of radiation fields in the facility, particularly in the target area. Radioactive transmutation products may be also produced due to the neutron irradiation of Li; this is the case of tritium and 7Be, which will circulate with the liquid lithium and have implications for nuclear safety. In addition, impurities can affect the free surface stability of the lithium target. The presence of gases and solid elements might favor nucleation of boiling processes. An Impurity Control System (ICS) is, therefore, required in the plant to monitor and to keep the impurities content below specific limits. | ||
Lithium may also react with gases present in the atmosphere, in particular with water, oxygen and nitrogen. During the normal operation, the Li loop will be operated under inert atmosphere, for which the presence of N, O and water will be controlled. A leakage of lithium out of the loop may evolve into a fire if the inert conditions are partially or totally lost due to an accident scenario. Therefore, the fire risk must be minimized in any situation during the lifetime of the facility. | <br> Lithium may also react with gases present in the atmosphere, in particular with water, oxygen and nitrogen. During the normal operation, the Li loop will be operated under inert atmosphere, for which the presence of N, O and water will be controlled. A leakage of lithium out of the loop may evolve into a fire if the inert conditions are partially or totally lost due to an accident scenario. Therefore, the fire risk must be minimized in any situation during the lifetime of the facility. | ||
The systems for controlling and monitoring impurities, traps and sensors, are not completely defined, and research activities on different areas are still required. Also, since the definition of the maximum tolerable values for humidity, oxygen or nitrogen in the inert gas is uncertain, conservative values are presently used. Most of the experience on liquid metals was extrapolated from sodium loops since only a few experiments were done with Li. This project aims to develop several technologies and requirements related with the use of liquid lithium considered critical for the development of the IFMIF-DONES project, particularly regrading the ICS (including traps and sensors) and safety issues associated to the reactivity of Li with gases in the atmosphere. Four work packages will be developed in parallel: | <br> The systems for controlling and monitoring impurities, traps and sensors, are not completely defined, and research activities on different areas are still required. Also, since the definition of the maximum tolerable values for humidity, oxygen or nitrogen in the inert gas is uncertain, conservative values are presently used. Most of the experience on liquid metals was extrapolated from sodium loops since only a few experiments were done with Li. | ||
WP1: Development of techniques and procedures to measure the impurity content in Li | <br> This project aims to develop several technologies and requirements related with the use of liquid lithium considered critical for the development of the IFMIF-DONES project, particularly regrading the ICS (including traps and sensors) and safety issues associated to the reactivity of Li with gases in the atmosphere. Four work packages will be developed in parallel: | ||
WP2: Basic research to understand the behavior of H in the Li-Y-H system | <br> - '''WP1''': Development of techniques and procedures to measure the impurity content in Li | ||
WP3: Experiments in a small Li loop to study experimentally the trapping and monitoring of impurities | <br> - '''WP2''': Basic research to understand the behavior of H in the Li-Y-H system | ||
WP4: Experiments to analyze the reactivity of Li under controlled gas atmospheres | <br> - '''WP3''': Experiments in a small Li loop to study experimentally the trapping and monitoring of impurities | ||
These WP’s will not be executed independently, but they are very much interrelated. WP1 will provide with some support to the other three WP’s. Knowledge generated in WP2 will be very useful to understand the results from WP3. It is also possible that some procedures used in WP2 will be used in WP3 for the determination of H content in Li and Y. Finally, experience gained in WP4 will give some confidence from the safety point of view which will be beneficial for all of the experiments to be performed with liquid lithium. | <br> - '''WP4''': Experiments to analyze the reactivity of Li under controlled gas atmospheres | ||
<br>These WP’s will not be executed independently, but they are very much interrelated. WP1 will provide with some support to the other three WP’s. Knowledge generated in WP2 will be very useful to understand the results from WP3. It is also possible that some procedures used in WP2 will be used in WP3 for the determination of H content in Li and Y. Finally, experience gained in WP4 will give some confidence from the safety point of view which will be beneficial for all of the experiments to be performed with liquid lithium. | |||
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== References == | == References == | ||
Knaster, J et al., The accomplishment of the Engineering Design Activities of IFMIF/EVEDA: The European–Japanese project towards a Li(d,xn) fusion relevant neutron source. Nuclear Fusion 2015, 55 (8), 086003. https://doi.org/10.1088/0029-5515/55/8/086003 | Knaster, J et al., The accomplishment of the Engineering Design Activities of IFMIF/EVEDA: The European–Japanese project towards a Li(d,xn) fusion relevant neutron source. Nuclear Fusion 2015, 55 (8), 086003. https://doi.org/10.1088/0029-5515/55/8/086003 | ||