Radiological impact mitigation of waste coming from the European fusion reactor DEMO with DCLL breeding blanket

During operation fusion reactor components will be exposed to long periods of neutron irradiation. As such, a reactor’s structural steels will become activated and need to be disposed of as radioactive waste. Previous studies have shown that such wastes can struggle to meet low level waste (LLW) requirements meaning that costly geological disposal may be required. In order to explore the waste expectations of steels from European DEMO-like fusion reactors, several radioactive waste management systems have been investigated. This includes their LLW criteria, currently available disposal sites and planned future developments. This information was used to analyse the results of DEMO-like inventory simulations of potential reactor steels. The simulations were performed with the inventory code FISPACT-II and the TENDL2017 nuclear data library. The results suggest that when steels are exposed to near plasma neutron fluxes they will struggle to meet the majority of LLW requirements. For lower neutron fluxes, typical of reactor containment vessels, the waste expectations can be more positive, with several steels able to meet some low level criteria. It can be concluded that steels should not be expected to be consistently internationally classified as LLW 100 years after reactor shut down. As all activated fusion waste cannot be disposed of in a single location, it is recommended that waste disposal strategies are included in any fusion reactor proposal before construction begins. These strategies need to align with the radioactive waste regulations the proposed reactor will be subject to.

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“…Cabril [32] to reach an authorised capacity of 130 000 m 3 for VLLW. • Japan plans to increase capacity at the Rokkasho waste facilities [29].…”

Section: • Spain Is Planning To Construct Two Additional Cells At Elmentioning

confidence: 99%

Waste expectations of fusion steels under current waste repository criteria

2021

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“…Limited fusion radioactive waste assessments have been performed previously for DEMO designs (e.g. [8,9]), other fusion experiments, such as the Joint European Torus (JET) [10] and ITER [11], and other concepts (e.g. for IFMIF [12]), but the present works are part of a coordinated effort within the European programme to perform assessments efficiently and continuously as the design of DEMO evolves.…”

Section: Introductionmentioning

confidence: 99%

“…for W [13]), at only specific reactor components (e.g. the blanket modules [9]), or at the prospects of a single DEMO concept (as in earlier European projects [8,9]). This flexible and rapid assessment objective has been further extended in the present work, whereby it is now straightforward to consider the relative waste disposal prospects of DEMO concepts under different regulatory systems and for different waste repositories.…”

Section: Introductionmentioning

confidence: 99%

Waste implications from minor impurities in European DEMO materials

et al. 2019

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Waste-production predictions for the future demonstration fusion power plant (DEMO) are necessary to produce an accurate picture of the likely environmental and economic costs of radioactive waste disposal at end-of-life. An integrated simulation process combining Monte-Carlo neutron transport simulations, inventory calculations, and extensive and reproducible post-processing algorithms has been used for the evolving European DEMO designs to quantify the time-varying mass inventories in different waste classes for individual regions and components of the reactor vessel, as well as for the reactor as a whole. Waste categories based on UK and French regulations reveal that minor impurities contained in structural steels, particularly Eurofer, as well as in functional materials such as tungsten, and beryllium, can have a significant impact on their waste classification prospects. Predictions for current European DEMO concepts suggest that there may be an issue in disposing of fusion structural-steel waste as low-level waste (LLW) in near-surface repositories. Detailed analysis of the subtleties of these predictions, particularly with regard to the production of long-lived radionuclides such as 14C and 94Nb, reveal that the threshold for acceptance as LLW is only just exceeded in some situations. Several mitigation approaches are discussed in this context. The computational framework developed for these assessments can be rapidly and continuously applied to the maturing DEMO design, helping to guide design choices to mitigate long-lived waste production and ensure that most waste becomes LLW or better within a few decades.

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“…Figure 4 a shows that the plasma-facing components in the blanket and divertor have higher specific radioactivity than other materials just after a shutdown. However, these decrease by 6–7 orders of magnitude within 100 years 21 , 47 – 49 . Similar substantial decreases are predicted for most of the materials.…”

Section: Prerequisites For Fusion Regulation: Identification Of Safet...mentioning

confidence: 99%

Preliminary assessment of the safety factors in K-DEMO for fusion compatible regulatory framework

Kim

Hong

Kim

2022

Sci Rep

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We open an avenue for discussing how we can pave the way for compliance with existing regulations is a far-reaching factor for settling nuclear fusion technology. Based on a model of the Korean Fusion Demonstration Reactor (K-DEMO) with a target fusion power of 2.2 GW, we assess the intrinsic safety determinants of internal energy sources, the expected radioactive waste, and the tritium management. Regarding these safety factors, we scrutinize the compatibility of the current legislative environment in Korea with K-DEMO and envisage foreseeable obstacles, such as licensing of the nuclear facilities and acceptability of the radioactive waste. Based on precedent licenses for the Korean Superconducting Tokamak Advanced Research (KSTAR) and lessons learned from the International Thermonuclear Experimental Reactor (ITER), we examine hazardous factors that would threaten regulatory compliance of K-DEMO. This approach can help shape a fusion-compatible framework for consolidating the necessary technical provisions and regulatory baselines reflecting social acceptance with a sense of safety. Fusion-compatible aspects in the regulatory environment are discussed, from fusion philosophy to subordinate administrative and technical guidelines, facility classification, and detailed methods guaranteeing integrity and safety. This paper will contribute to the timely settlement of fusion demonstration facilities and subsequent commercial plants.

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Radiological impact mitigation of waste coming from the European fusion reactor DEMO with DCLL breeding blanket

Cited by 10 publications

References 13 publications

Waste expectations of fusion steels under current waste repository criteria

Waste expectations of fusion steels under current waste repository criteria

Waste implications from minor impurities in European DEMO materials

Preliminary assessment of the safety factors in K-DEMO for fusion compatible regulatory framework

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