How Low-Carbon Heat Requirements for Direct Air Capture of CO2 Can Enable the Expansion of Firm Low-Carbon Electricity Generation Resources

A rapid build-out of direct air capture (DAC), deployed in order to mitigate climate change, will require significant amounts of both low-carbon thermal and electrical energy. Firm low-carbon power resources, including nuclear, geothermal, or natural gas with carbon capture, which also will become more highly valued as variable renewable energy penetration increases, would be able to provide both heat and electricity for DAC. In this study, we examined the techno-economic synergy between a hypothetical DAC plant in the year 2030 and a nuclear small modular reactor, and determined two avenues for which this relationship could benefit the nuclear plant. First, we demonstrated that, under certain assumptions, selling a portion of its energy to a DAC facility allows the nuclear plant to take in 21% less revenue from selling electricity to wholesale markets than its projected levelized cost, and still break even. Second, after estimating a potential revenue stream, we showed that an integration with DAC allows for the nuclear plant's capital costs to be up to 35% higher than what would be required if only selling electricity to wholesale markets. This could enable the nuclear plant to operate economically even in the face of variable and decreasing wholesale electricity prices, and also could offer developers more financial certainty when planning a new project. Ultimately, this study shows that the need for low-carbon energy for DAC plants might incentivize the development of advanced nuclear plants and firm low-carbon resources more broadly.

Health status and cancer related mortality among nuclear plant workers exposed to ionizing radiation

BackgroundThe investigation of potential adverse health effects of occupational exposures to ionizing radiation, on nuclear plant workers, is an important area of research. In this study, we aimed to calculate the incidence and risk of cancer development and mortality during last five years (2015-2019).Material and Methods456 nuclear industry workers were included into this study (39 cancer patients and 417 healthy. For this cohort, the cancer mortality has been assessed by data obtained from national health registry excluded for the probability of known causes of death. The associations between cumulative occupational radiation exposures (radon, gamma radiation and long-lived radionuclides) and cancer mortality were calculated.ResultsRadon and Gamma exposure was significantly higher among workers who developed cancer [8.4 (0; 3,224.5) vs 19.7 (0; 128.4), p=0.03] and [12.0 (2.1; 110.0) vs 24.5 (0; 470.1), p=0.02]. However, no significant association was found between long-lived radionuclides and risk of cancer (p=0.07).ConclusionIn conclusion, significant association has been observed between the risk of cancer development and radon and gamma exposure among nuclear industry workers, but no association was found between cancer and long-live nucleoids exposure.

Safety Justification Strategy for the Implementation of Additive Manufacture Small-Bore Globe Valves for Nuclear Plant

The Additive Manufacture (AM) of nuclear plant components, such as small-bore globe valves, offers opportunities to reduce costs and improve production lead-times. Cost reductions can be achieved by reducing raw material quantities, removing machining operations, and eliminating the welding of sub-assemblies. Furthermore, there is the opportunity to reduce production lead-times by simplifying the supply chain, e.g. reducing the number of parts to be sourced and eliminating special operations. Such opportunities are important against a backdrop of industry striving to reduce the cost of nuclear power generation in order to ensure viability with other forms of power generation. However, AM is a relatively new and innovative manufacturing technology, and although now seeing greater use in industry, there are still very few examples of where the technology has been applied to components used in safety critical applications. Furthermore, it is not covered by the American Society of Mechanical Engineers (ASME), Section III, nuclear design code. For nuclear plant applications, it is imperative a robust safety justification is provided. This paper presents Rolls-Royce’s approach to provision of a high integrity safety justification to enable the implementation of AM small-bore globe valves, up to a nominal bore size of 2” to nuclear plant. The material of construction is AM Laser Powder Bed Fusion (LPBF) 316LN stainless steel, with a Hot Isostatic Press (HIP) bonded LPBF Tristelle 5183 low cobalt hard facing seat. The paper describes the structure of the safety justification, which follows a multi-legged approach. It provides an overview of the innovative manufacturing process, which is, to the best of Rolls-Royce’s knowledge, the first of a kind application on nuclear pressure boundary components. The paper provides a summary of the suite of materials testing and metallurgical examinations conducted, and majors on prototype functional and performance testing where comparisons are made with the previous forged form. Pressure testing is covered which includes ultimate pressure testing to 2,000 bar, as well as: functional cyclic testing, hard facing bond strength tests, dynamic loading (shock), and cyclic thermal tests. In all cases the additive manufactured small-bore globe valves performed as well, and in some cases better than the forged material equivalent.

Fishy SPS Measures? The WTO's Korea-Radionuclides Dispute

The Korea–Radionuclides case addresses Korean SPS measures imposed on Japanese fishery products after the Fukushima Dai-ichi nuclear plant meltdown in 2011. Japan challenged these measures as more restrictive than necessary under the SPS Agreement. The panel agreed with Japan, but this ruling was largely reversed by the Appellate Body. Korea's victory at the Appellate Body was based on procedure. The panel accepted Korea's appropriate level of protection (ALOP), which included both quantitative and qualitative elements. However, the Appellate Body found that the panel only addressed the quantitative aspect of Korea's ALOP and reversed on that basis. The Appellate Body's ruling did not affirmatively find that Korea's SPS measures were legal under WTO rules. Instead, the Appellate Body found that panel had not sufficiently addressed Korea's arguments and, thereby, the panel could not determine that the SPS measures were more restrictive than necessary. The case highlights the need for the Appellate Body to be able to conduct its own factual analysis, a power it could be given if the dispute settlement system is reformed. Without independent fact-finding power, the Appellate Body cannot correct panels’ mistakes, and respondents can prevail based on panel error.

Utilization of SCC Technology for Large Placements in New Nuclear Construction: A Study On SCC Stability and Constructability

This paper discusses the use of Self Consolidating Concrete (SCC), in a large scale placement during new nuclear plant construction. SCC has provided cost and labor savings and construction process improvements. Use of SCC has been effective in schedule acceleration by reducing placement durations and early curing termination with rapid strength gain. Self-consolidating properties were particularly of value at placements of poor access as internal vibrators were not effective and large surface area made form vibrators ineffective beyond the perimeter. This paper provides a discussion of technical challenges encountered in development of a properly functioning SCC mixture, and testing performed to overcome these challenges. The paper discusses the engineering considerations and laboratory and field trials preparing for a 3950 cubic meter placement for the basemat of a nuclear plant. The placement was anticipated to take 35 hours at 110 m3/hour batch plant output. Overview of mix design specifications and mix development is provided. The mixture satisfied the laboratory test parameters including SCC tests; stability and column segregation. However, the mixture had to undergo rounds of constructability testing beyond laboratory development prior to the large placement. The placement was completed successfully in 35 hours over multiple shifts.