Thermo-economic assessment of flexible nuclear power plants in the UK’s future low-carbon electricity system: role of thermal energy storage

Nuclear power plants are commonly operated as baseload units due to their low variable costs, high investment costs and limited ability to modulate their output. The increasing penetration of intermittent renewable power will require additional flexibility from conventional generation units, in order to follow the fluctuating renewable output while guaranteeing security of energy supply. In this context, coupling nuclear reactors with thermal energy storage could ensure a more continuous and efficient operation of nuclear power plants, while at other times allowing their operation to become more flexible and cost-effective. This study considers options for upgrading a 1610-MWel nuclear power plant with the addition of a thermal energy storage system and secondary power generators. The analysed configuration allows the plant to generate up to 2130 MWel during peak load, representing an increase of 32% in nominal rated power. The gross whole-system benefits of operating the proposed configuration are quantified over several scenarios for the UK’s low-carbon electricity system. Replacing conventional with flexible nuclear plant configuration is found to generate system cost savings that are between £24.3m/yr and £88.9m/yr, with the highest benefit achieved when stored heat is fully discharged in 0.5 hours (the default case is 1 hour). At an estimated cost of added flexibility of £42.7m/yr, the proposed flexibility upgrade to a nuclear power plant appears to be economically justified for a wide range of low-carbon scenarios, provided that the number of flexible nuclear units in the system is small

Role of Coronary CT Angiography in the Evaluation of Acute Chest Pain and Suspected or Confirmed Acute Coronary Syndrome

Advances in CT technology have resulted in improved imaging of the coronary anatomy in patients with stable coronary artery disease, using coronary CT angiography (CCTA). Recent data suggest that CCTA may play a role in higher risk patients, such as those evaluated in the emergency room with acute chest pain. Data thus far support the use of CCTA in low-risk patients with acute chest pain. Recent literature suggests that CCTA may play a role in the risk stratification of selected intermediate-risk patients. In this review, the authors discuss the emerging role of CCTA in higher risk patients, such as those with suspected or confirmed acute coronary syndrome (ACS). The excellent accuracy of CCTA in detecting obstructive coronary artery disease in patients with ACS is detailed, along with a highlighting of the safety of using CCTA in this setting. The authors also discuss the role for CCTA atheromatous plaque characterization, which is being increasingly recognized as an important predictor of clinical outcomes

System-driven design of flexible nuclear power plant configurations with thermal energy storage

Nuclear power plants are expected to make an important contribution to the decarbonisation of electricity supply alongside variable renewable generation, especially if their operational flexibility is enhanced by coupling them with thermal energy storage. This paper presents a system modelling approach to identifying configurations of flexible nuclear plants that minimise the investment and operation costs in a decarbonised energy system, effectively proposing a system-driven design of flexible nuclear technology. Case studies presented in the paper explore the impact of system features on plant configuration choices. The results suggest that cost-efficient flexible nuclear configurations should adapt to the system they are located in. In the main low-carbon scenarios and assuming standard-size nuclear power plants (1,610 MWel), the lowest-cost system configuration included around 500 MWel of additional secondary generation capacity coupled to the nuclear power plants, with 4.5 GWhth of thermal storage capacity and a discharging duration of 2.2 h. Net system benefits per unit of flexible nuclear generation for the main scenarios were quantified at £29-33 m/yr for a wind-dominated system and £19-20 m/yr for a solar-dominated system

System-driven design of flexible nuclear power plant configurations with thermal energy storage

The media from SDEWES 2022 are available at: https://www.paphos2022.sdewes.org/media .A later version of this paper was published by Elsevier - Aunedi, M. et al. (2023) 'System-driven design of flexible nuclear power plant configurations with thermal energy storage', Energy Conversion and Management, 291, 117257, pp. 1 - 14. doi: 10.1016/j.enconman.2023.117257.Nuclear power plants are expected to make an important contribution to the decarbonisation of electricity supply, together with variable renewable generation. Previous work by the authors identified significant potential benefits of coupling nuclear reactors with thermal energy storage (TES) and secondary power generation cycle systems to improve the plant operational flexibility. This paper presents a system modelling approach to identifying configurations of flexible nuclear plants that minimise the investment and operation cost in a decarbonised energy system, effectively proposing a system-driven design of flexible nuclear technology. Case studies presented in the paper explore the impact of system features on plant configuration choices. The results suggest that cost-efficient flexible nuclear configurations should adapt to the system they are located in. In the main low-carbon and net-zero carbon scenarios and for a standard-size nuclear unit, it was found to be cost-efficient to install around 500 MWel of secondary generation capacity and 4.5 GWhth of TES capacity, resulting in an equivalent TES duration of 2.2 hours. Enhancing the nuclear plant flexibility was found to be less attractive when applied to a large number of nuclear units or when exposed to high interest rates, but more attractive if battery storage cost was higher or there was no option to invest in carbon offsetting technologies. Net system benefits per unit of flexible nuclear generation for the main scenarios were quantified at £29-33m/yr for a wind-dominated system and £19-20m/yr for a solar-dominated system.UK Engineering and Physical Sciences Research Council (EPSRC) [grant number EP/R045518/1] (IDLES Programme)

System-driven design of flexible nuclear power plant configurations with thermal energy storage

Data availability: Data will be made available on request.A shorter version of this paper has been presented during the 17th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) held in Paphos, Cyprus, 6-10 November 2022.Copyright © 2023 The Author(s).. Nuclear power plants are expected to make an important contribution to the decarbonisation of electricity supply alongside variable renewable generation, especially if their operational flexibility is enhanced by coupling them with thermal energy storage. This paper presents a system modelling approach to identifying configurations of flexible nuclear plants that minimise the investment and operation costs in a decarbonised energy system, effectively proposing a system-driven design of flexible nuclear technology. Case studies presented in the paper explore the impact of system features on plant configuration choices. The results suggest that cost-efficient flexible nuclear configurations should adapt to the system they are located in. In the main low-carbon scenarios and assuming standard-size nuclear power plants (1,610 MWel), the lowest-cost system configuration included around 500 MWel of additional secondary generation capacity coupled to the nuclear power plants, with 4.5 GWhth of thermal storage capacity and a discharging duration of 2.2 h. Net system benefits per unit of flexible nuclear generation for the main scenarios were quantified at £29-33 m/yr for a wind-dominated system and £19-20 m/yr for a solar-dominated system.UK Engineering and Physical Sciences Research Council (EPSRC) [grant number EP/R045518/1] (IDLES Programme)

Outcomes of Durable Mechanical Circulatory Support in Myocarditis: Analysis of the International Society for Heart and Lung Transplantation Registry for Mechanically Assisted Circulatory Support Registry

Myocarditis can be refractory to medical therapy and require durable mechanical circulatory support (MCS). The characteristics and outcomes of these patients are not known. We identified all patients with clinically-diagnosed or pathology-proven myocarditis who underwent mechanical circulatory support in the International Society for Heart and Lung Transplantation Registry for Mechanically Assisted Circulatory Support registry (2013-2016). The characteristics and outcomes of these patients were compared to those of patients with nonischemic cardiomyopathy (NICM). Out of 14,062 patients in the registry, 180 (1.2%) had myocarditis and 6,602 (46.9%) had NICM. Among patients with myocarditis, duration of heart failure was22%, 1-12 months in 22.6%, and \u3e1 year in 55.4%. Compared with NICM, patients with myocarditis were younger (45 vs. 52 years, P \u3c 0.001) and were more often implanted with Interagency Registry for Mechanically Assisted Circulatory Support profile 1 (30% vs. 15%, P \u3c 0.001). Biventricular mechanical support ( biventricular ventricular assist device [BIVAD] or total artificial heart) was implanted more frequently in myocarditis (18% vs. 6.7%, P \u3c 0.001). Overall postimplant survival was not different between myocarditis and NICM (left ventricular assist device: P = 0.27, BIVAD: P = 0.50). The proportion of myocarditis patients that have recovered by 12 months postimplant was significantly higher in myocarditis compared to that of NICM (5% vs. 1.7%, P = 0.0003). Adverse events (bleeding, infection, and neurologic dysfunction) were all lower in the myocarditis than NICM. In conclusion, although myocarditis patients who receive durable MCS are sicker preoperatively with higher needs for biventricular MCS, their overall MCS survival is noninferior to NICM. Patients who received MCS for myocarditis are more likely than NICM to have MCS explanted due to recovery, however, the absolute rates of recovery were low

Cardiovascular adverse events associated with BRAF versus BRAF/MEK inhibitor: Cross-sectional and longitudinal analysis using two large national registries

BACKGROUND: Cardiovascular adverse events (CVAEs) associated with BRAF inhibitors alone versus combination BRAF/MEK inhibitors are not fully understood. METHODS: This study included all adult patients who received BRAF inhibitors (vemurafenib, dabrafenib, encorafenib) or combinations BRAF/MEK inhibitors (vemurafenib/cobimetinib; dabrafenib/trametinib; encorafenib/binimetinib). We utilized the cross-sectional FDA\u27s Adverse Events Reporting System (FAERS) and longitudinal Truven Health Analytics/IBM MarketScan database from 2011 to 2018. Various CVAEs, including arterial hypertension, heart failure (HF), and venous thromboembolism (VTE), were studied using adjusted regression techniques. RESULTS: In FAERS, 7752 AEs were reported (40% BRAF and 60% BRAF/MEK). Median age was 60 (IQR 49-69) years with 45% females and 97% with melanoma. Among these, 567 (7.4%) were cardiovascular adverse events (mortality rate 19%). Compared with monotherapy, combination therapy was associated with increased risk for HF (reporting odds ratio [ROR] = 1.62 (CI = 1.14-2.30); p = 0.007), arterial hypertension (ROR = 1.75 (CI = 1.12-2.89); p = 0.02) and VTE (ROR = 1.80 (CI = 1.12-2.89); p = 0.02). Marketscan had 657 patients with median age of 53 years (IQR 46-60), 39.3% female, and 88.7% with melanoma. There were 26.2% CVAEs (CI: 14.8%-36%) within 6 months of medication start in those receiving combination therapy versus 16.7% CVAEs (CI: 13.1%-20.2%) among those receiving monotherapy. Combination therapy was associated with CVAEs compared to monotherapy (adjusted HR: 1.56 (CI: 1.01-2.42); p = 0.045). CONCLUSIONS AND RELEVANCE: In two independent real-world cohorts, combination BRAF/MEK inhibitors were associated with increased CVAEs compared to monotherapy, especially HF, and hypertension

Automated analysis of fibrous cap in intravascular optical coherence tomography images of coronary arteries

Thin-cap fibroatheroma (TCFA) and plaque rupture have been recognized as the most frequent risk factor for thrombosis and acute coronary syndrome. Intravascular optical coherence tomography (IVOCT) can identify TCFA and assess cap thickness, which provides an opportunity to assess plaque vulnerability. We developed an automated method that can detect lipidous plaque and assess fibrous cap thickness in IVOCT images. This study analyzed a total of 4,360 IVOCT image frames of 77 lesions among 41 patients. To improve segmentation performance, preprocessing included lumen segmentation, pixel-shifting, and noise filtering on the raw polar (r, theta) IVOCT images. We used the DeepLab-v3 plus deep learning model to classify lipidous plaque pixels. After lipid detection, we automatically detected the outer border of the fibrous cap using a special dynamic programming algorithm and assessed the cap thickness. Our method provided excellent discriminability of lipid plaque with a sensitivity of 85.8% and A-line Dice coefficient of 0.837. By comparing lipid angle measurements between two analysts following editing of our automated software, we found good agreement by Bland-Altman analysis (difference 6.7+/-17 degree; mean 196 degree). Our method accurately detected the fibrous cap from the detected lipid plaque. Automated analysis required a significant modification for only 5.5% frames. Furthermore, our method showed a good agreement of fibrous cap thickness between two analysts with Bland-Altman analysis (4.2+/-14.6 micron; mean 175 micron), indicating little bias between users and good reproducibility of the measurement. We developed a fully automated method for fibrous cap quantification in IVOCT images, resulting in good agreement with determinations by analysts. The method has great potential to enable highly automated, repeatable, and comprehensive evaluations of TCFAs.Comment: 18 pages, 9 figure