Advancements in the Helium-Cooled Pebble Bed Breeding Blanket for the EU DEMO: Holistic Design Approach and Lessons Learned

Hernández, Francisco A.; Pereslavtsev, P.; Zhou, Guangming; Kiss, Béla; Kang, Qinlan; Neuberger, Heiko; Chakin, V.; Gaisin, Ramil; Vladimirov, P.; Boccaccini, L.V.; Spagnuolo, Gandolfo Alessandro; D’Amico, Salvatore; Moscato, I.

doi:10.1080/15361055.2019.1607695

Cited by 57 publications

(16 citation statements)

References 20 publications

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“…Thus, we decided to use the helium cooled pebble bed (HCPB) breeding blanket concept as a reference for the mock-up design. Detailed outlines of the design is given, for example, in [24][25][26] and references therein.…”

Section: Designmentioning

confidence: 99%

“…After joining, the combined block was milled to the final outer dimensions of 208 mm × 160 mm × 23.5 mm, reducing the thickness of the ODS steel plate to 3 mm in the process. Then the part was sent to KRÜGER ERODIERTECHNIK for electro-discharge wire-cutting the cooling channels according to the drawing in figure 4 (more details are given in [24][25][26]). This commercial fabrication step can also be performed on real-size components up to 3 m length.…”

Section: Machining the Cooling Channelsmentioning

confidence: 99%

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Fabrication routes for advanced first wall design alternatives

et al. 2021

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In future nuclear fusion reactors, plasma facing components have to sustain specific neutron damage. While the majority of irradiation data provides a relatively clear picture of the displacement damage, the effect of helium transmutation is not yet explored in detail. Nevertheless, available results from simulation experiments indicate that 9%-chromium steels will reach their operating limit as soon as the growing helium bubbles extent a critical size. At that point, the material would most probably fail due to grain boundary embrittlement. In this contribution, we present a strategy for the mitigation of the before-mentioned problem using the following facts. (1) The neutron dose and related transmutation rate decreases quickly inside the first wall of the breeding blankets, that is, only a plasma-near area is extremely loaded. (2) Nanostructured oxide dispersion strengthened (ODS) steels may have an enormous trapping effect on helium, which would suppress the formation of large helium bubbles for a much longer period. (3) Compared to conventional steels, ODS steels also provide improved irradiation tensile ductility and creep strength. Therefore, a design, based on the fabrication of the plasma facing and highly neutron and heat loaded parts of blankets by an ODS steel, while using EUROFER97 for everything else, would extend the operating time and enable a higher heat flux. Consequently, we (i) developed and produced 14%Cr ferritic ODS steel plates and (ii) optimized and demonstrated a scalable industrial production route. (iii) We fabricated a mock-up with five cooling channels and a plated first wall of ODS steel, using the same production processes as for a real component. (iv) Finally, we performed high heat flux tests in the Helium Loop Karlsruhe, applying a few hundred short and a few 2 h long pulses, in which the operating temperature limit for EUROFER97 (i.e. 550 • C) was finally exceeded by 100 K. (v) Thereafter, microstructure and defect analyses did not reveal critical defects or recognizable damage. Only a heat affected zone in the EUROFER/ODS steel interface could

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Section: Designmentioning

confidence: 99%

Section: Machining the Cooling Channelsmentioning

confidence: 99%

Fabrication routes for advanced first wall design alternatives

et al. 2021

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“…Other methods require diffusion bonding of complex shaped parts, which are also produced by wire-cut EDM. An overview and more details are given in [34][35][36] and references therein.…”

Section: Wire-cut Electro Discharge Machining (Edm)mentioning

confidence: 99%

“…Thus, we decided to use the Helium-Cooled Pebble Bed (HCPB) breeding blanket concept as a reference for the mock-up design. Detailed outlines of the design are given, for example, in [34][35][36] and references therein.…”

Section: Designmentioning

confidence: 99%

Technological Processes for Steel Applications in Nuclear Fusion

et al. 2021

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Plasma facing components for energy conversion in future nuclear fusion reactors require a broad variety of different fabrication processes. We present, along a series of studies, the general effects and the mutual impact of these processes on the properties of the EUROFER97 steel. We also consider robust fabrication routes, which fit the demands for industrial environments. This includes heat treatment, fusion welding, machining, and solid-state bonding. Introducing and following a new design strategy, we apply the results to the fabrication of a first-wall mock-up, using the same production steps and processes as for real components. Finally, we perform high heat flux tests in the Helium Loop Karlsruhe, applying a few hundred short pulses, in which the maximum operating temperature of 550 °C for EUROFER97 is finally exceeded by 100 K. Microstructure analyses do not reveal critical defects or recognizable damage. A distinct ferrite zone at the EUROFER/ODS steel interface is detected. The main conclusions are that future breeding blankets can be successfully fabricated by available industrial processes. The use of ODS steel could make a decisive difference in the performance of breeding blankets, and the first wall should be completely fabricated from ODS steel or plated by an ODS carbon steel.

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“…In 2018, a realignment of the European TBM (Test Blanket Module) Programme with the development of the European DEMO Breeding Blanket (BB) took place, in order to take the maximum benefit from the first and unique opportunity to test in ITER the response of representative component mock-ups at relevant operating conditions in an actual fusion environment. This decision was driven by the selection as driver blankets of two BB concepts, namely the Water Cooled Lithium Lead (WCLL) [1] and Helium Cooled Pebble Bed (HCPB) [2]. Consequently, a change of the European TBM options to be tested in ITER has taken place, [3], [4].…”

Section: Introductionmentioning

confidence: 99%