【Haichuan New Energy】 High-temperature steam electrolysis (SOEC) technology

It’s tough in the scorching summer heat! Keep up with heat prevention and cooling! Clarify the key tasks! Safety analysis must not be neglected! ----------------------------------------------The past decade has been a period of rapid development in China’s chemical industry, with the emergence of many new processes, products, and equipment. China’s chemical processing equipment has also seen significant progress, which has contributed to the swift advancement of the petrochemical sector. Here, we have compiled some of the achievements and breakthroughs made by Chinese equipment manufacturers in terms of larger-scale production and increased use of domestic equipment. We invite everyone to share their insights and discuss these topics together; let’s cheer for Made in China and support the development of chemical processing equipment! ------------------------------------------------------ 【Ministry of Emergency Management’s Special Inspection 2022】Summary Edition – Feel free to participate in discussions and self-inspections! ! ! ! https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=3418729 (Source: Huahai Chuanliu – Haichuan Network) Summary post for the 【Major Chemical Equipment in China】 series; being updated. https://bbs.hcbbs.com/thread-3366481-1-1.html (Source: Huahai Chuanliu – Haichuan Network)

In addition to the current mainstream large and medium-sized nuclear power plants, small pressurized water reactors are also expected to be put into practical use as carbon-free power sources, which are mainly used in small power grids such as those in emerging ** countries and areas with underdeveloped power grids. Furthermore, small pressurized water reactors are also highly anticipated as compact mobile power sources for remote islands, island areas, and disaster-stricken regions, with the goal of achieving a low output power of around 300,000 kWe in line with these applications. Small pressurized water reactors are characterized by: ① a low output level, which gives them inherent safety; based on this, the nuclear reactor cooling safety system in the event of an accident is simplified ； ②Modular design is used for factory production, which reduces on-site construction work and similar tasks. To date, Mitsubishi Heavy Industries has been involved in the construction and maintenance of 24 PWRs (Pressurized Water Reactors) in Japan. While actively pursuing technological development to enhance safety and reliability and ensure long-term operation, it is also committed to developing various innovative nuclear energy technologies, including small reactors. Among them, the development of small reactors preceded the introduction of pressurized water reactors; the first nuclear-powered ship, the \"Mutsu,\" was developed (1967–1972) ； The power reactor developed by the Japan Nuclear Ship Development Organization, and subsequently efforts were made to develop the Integrated Modular Reactor IMR (Integrated Modular Water Reactor). Not only was a conceptual design created, but empirical tests were also conducted on the key basic technologies of small integrated reactors, thereby accumulating relevant development knowledge. Based on this development knowledge, while making full use of the proven characteristics of PWRs, safety designs and modular designs unique to small reactors are adopted according to their intended use. As a result, they can not only serve as power sources for small power grids but also meet the needs of supplying power to remote isolated areas or islands with very limited power infrastructure, as well as for emergency power in disaster zones and as ship propulsion. Therefore, Mitsubishi Heavy Industries is working on developing a modular pressurized water reactor (a reactor for use on ships). Figure 1 shows a conceptual diagram of the development of small pressurized water reactors.

As a general concept for small pressurized water reactors used for power generation and mobile small pressurized water reactors, an integrated nuclear reactor is employed, one that integrates the primary coolant loop (large-diameter pipes) of conventional PWRs along with the main equipment of the primary system (steam generators, primary coolant pumps, pressurizers, etc.) into the nuclear reactor vessel. Thus, the risk of accidents such as coolant loss caused by a rupture in the primary coolant pipes is eliminated in principle. Furthermore, safety and reliability can be improved by incorporating safety measures that can utilize the low-output characteristics of small reactors to stabilize accidents and cool the nuclear reactor. Furthermore, learning from the lessons of the Fu-1 accident, Japan has established updated regulatory standards. In line with these standards, and based on the experience of restarting existing facilities in Japan, this design also takes into account strict seismic requirements, measures to deal with natural disasters such as tsunamis and tornadoes (external hazards), as well as measures to address terrorism and aircraft collisions. On the basis of ensuring these safety aspects, storage containers can be made smaller by using as simple a system configuration and device design as possible. Moreover, by employing module designs based on the latest technologies and advanced construction methods, the construction process can be streamlined and the construction period shortened, thereby significantly reducing construction costs. The output capacity of mobile small pressurized water reactors is half that of small pressurized water reactors used for power generation, and by further reducing the size of the nuclear reactor vessel, they can be installed on ships. Leveraging the advantages of PWR, it can operate stably even under environmental conditions such as rocking/inclination typical of offshore operations. Furthermore, in order to maximize the usability as a power bank, Mitsubishi Heavy Industries aims to minimize the frequency of replacing large-scale equipment as well as the number of maintenance tasks required in remote and islandous areas, and to enable the fuel to remain unused for extended periods of time. As mentioned above, the small pressurized water reactor developed by Mitsubishi Heavy Industries can be used not only for power generation in small grids and areas without power transmission networks, but also as a mobile power source for shipboard reactors and as marine propulsion, providing carbon-free nuclear energy for various future needs and applications.

High-temperature gas-cooled reactors (2): High-temperature gas-cooled reactors are characterized by an inherent safety feature that prevents core melting, and they are capable of generating heat at temperatures above 900°C. They can be used for conventional power generation as well as as carbon-free high-temperature heat sources, which can be applied in processes such as hydrogen production, with a stable supply of heat. To achieve decarbonization, Japan has set a long-term goal of reducing greenhouse gas emissions by 80% by 2050, requiring a reduction in carbon dioxide emissions not only in the electricity sector but also in the industrial sector. For example, in Japan’s steel industry, the “Development of Innovative Ironmaking Process Technologies (COURSE50: CO2, Ultimate Reduction in Steelmaking Processes by Innovative Technology for Cool Earth 50)” has been proposed, with the goal of achieving practical application by 2030. Additionally, hydrogen-based ironmaking is a cutting-edge technology that enables zero-carbon production; therefore, the goal for the future is to transition to this method. To realize the practical application of hydrogen-based iron reduction in the future, nuclear energy for hydrogen production is highly anticipated from the perspectives of mass production, low cost, and stable supply. Regarding the development of high-temperature gas-cooled reactors in Japan, research and investigation on such reactors were initiated under the leadership of the Japan Atomic Energy Agency (JAEA: Japan Atomic Energy Agency) (formerly the Japan Atomic Energy Research Institute). In 1991, construction began on Japan’s first high-temperature engineering test reactor (HTTR: High Temperature Engineering Test Reactor); it reached criticality in 1998. In 2004, it operated at full capacity with helium gas exiting the reactor at a temperature of 950°C, and further safety verification tests were conducted to confirm the high-temperature nuclear heat generation capability of these reactors as well as their inherent safety features. Mitsubishi Heavy Industries has been involved in the research and development for the construction of HTTR from the very beginning. In the construction of HTTR, it served as the lead contractor, responsible for coordinating four design companies to design and manufacture the complete equipment for HTTR, including the reactor vessel, major cooling system components, and high-temperature pipes. Thereafter, as part of the development of basic technologies for practical high-temperature gas-cooled reactors, efforts were also made in the development of ultra-dense plate-fin heat exchangers and high-temperature isolation valves, as well as in the design studies of high-temperature gas-cooled reactor gas turbine power generation systems (GTHTR300: Gas Turbine High Temperature Reactor of 300 MWe) in collaboration with JAEA, all aimed at advancing the development of basic technologies for practical high-temperature gas-cooled reactors. Furthermore, in terms of hydrogen production systems, Mitsubishi Heavy Industries has extensive experience in the design research of hydrogen production systems connected to the HTTR at JAEA. Building on these accumulated technologies and experience, Mitsubishi Heavy Industries is currently developing a high-temperature gas-cooled reactor cogeneration plant that offers excellent economic efficiency and flexibility, enabling it to meet the needs of various future societies such as those focused on decarbonization and hydrogen energy. Figure 2 shows a diagram of a cogeneration plant for high-temperature gas-cooled reactors. This plant uses technology developed at HTTR to set the reactor outlet temperature at 950°C for combined heat and power generation of hydrogen and electricity. Generally speaking, although the fuel cost for nuclear power plants is low, the initial costs associated with construction are high. Therefore, in order to recoup the investment costs, it is necessary to increase the utilization rate of the equipment, and nuclear reactors should operate at their rated output. This cogeneration plant balances power generation/hydrogen production in response to changes in hydrogen or electricity demand, while maintaining a constant output from the nuclear reactor; this approach improves equipment utilization rates while taking into account coexistence with renewable energy sources. Furthermore, by setting the reactor outlet temperature at 950°C, high efficiency can be achieved in both hydrogen production and power generation. Especially in power generation, Mitsubishi Heavy Industries aims to achieve higher efficiency than the Rankine cycle using steam turbines by directly employing helium turbines in the primary system. In terms of safety, based on the inherent safety proven by HTTR, original fuel/core design and structural studies are conducted, and safety is verified through analysis, thereby maintaining the same inherent safety even when increasing the output capacity of the nuclear reactor.

In hydrogen production technology, the steam reforming method is first applied to demonstrate nuclear hydrogen production, with the goal of establishing a plant capable of steadily producing large quantities of low-carbon hydrogen based on the hydrogen production demonstrations using HTTR. The goal of this plant is to produce 120,000 Nm3/h of hydrogen using approximately 220 MWt of heat (over 900 million Nm3 per year). Furthermore, it is assumed that after 2050, carbon-free hydrogen production methods such as high-temperature water vapor electrolysis and the IS method will be put into practical use, with the goal of achieving large-scale, stable production of carbon-free hydrogen through cogeneration plants equipped with high-temperature gas-cooled reactors that connect these hydrogen production facilities. Furthermore, in terms of cost efficiency, the goals are to achieve low-cost hydrogen production using nuclear energy while ensuring high power generation efficiency. This is accomplished by simplifying and optimizing safety systems based on inherent safety, adopting a simple system structure with helium turbines in the primary system, utilizing the high efficiency of high-temperature helium for power generation, and reducing construction costs through modularization. As mentioned above, Mitsubishi will collaborate with users in the steel industry who aim to transition to hydrogen-based iron production, and while coordinating with industry efforts such as policy-driven decarbonization and the creation of a hydrogen society, it will conduct research and development aimed at the practical application of heat and power generation plants using high-temperature gas-cooled reactors.

【HaiChuan New Energy】Construction of a 100% ammonia direct combustion power plant on Jurong Island, Singapore https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=3479092 (Source: HaiChuan Network – Transforming the Currents of Chemistry)