Load following of Small Modular Reactors (SMR) by cogeneration of hydrogen: A techno-economic analysis

Load following is the possibility for a power plant to adjust its power output according to the demand and electricity price fluctuation throughout the day. In nuclear power plants, the adjustment is usually done by inserting control rods into the reactor pressure vessel. This operation is inherently inefficient as nuclear power cost structure is composed almost entirely of sunk or fixed costs; therefore, lowering the power output, does not significantly reduce operating expenses and the plant is thermo-mechanical stressed. A more attractive option is to maintain the primary circuit at full power and use the excess power for cogeneration. This paper aims to present the techno-economic feasibility of nuclear power plants load following by cogenerating hydrogen. The paper assesses Small Modular nuclear Reactors (SMRs) coupled with: alkaline water electrolysis, high-temperature steam electrolysis, sulphur-iodine cycle. The analysis shows that in the medium term hydrogen from alkaline water electrolysis can be produced at competitive prices. High-temperature steam electrolysis and even more the sulphur-iodine cycle proved to be attractive because of their capability to produce hydrogen with higher efficiency. However, the coupling of SMRs and hydrogen facilities working at high temperature (about 800 °C) still requires substantial R&D to reach commercialisation

JUNO Conceptual Design Report

The Jiangmen Underground Neutrino Observatory (JUNO) is proposed to determine the neutrino mass hierarchy using an underground liquid scintillator detector. It is located 53 km away from both Yangjiang and Taishan Nuclear Power Plants in Guangdong, China. The experimental hall, spanning more than 50 meters, is under a granite mountain of over 700 m overburden. Within six years of running, the detection of reactor antineutrinos can resolve the neutrino mass hierarchy at a confidence level of 3-4$\sigma$, and determine neutrino oscillation parameters $\sin^2\theta_{12}$, $\Delta m^2_{21}$, and $|\Delta m^2_{ee}|$ to an accuracy of better than 1%. The JUNO detector can be also used to study terrestrial and extra-terrestrial neutrinos and new physics beyond the Standard Model. The central detector contains 20,000 tons liquid scintillator with an acrylic sphere of 35 m in diameter. $\sim$17,000 508-mm diameter PMTs with high quantum efficiency provide $\sim$75% optical coverage. The current choice of the liquid scintillator is: linear alkyl benzene (LAB) as the solvent, plus PPO as the scintillation fluor and a wavelength-shifter (Bis-MSB). The number of detected photoelectrons per MeV is larger than 1,100 and the energy resolution is expected to be 3% at 1 MeV. The calibration system is designed to deploy multiple sources to cover the entire energy range of reactor antineutrinos, and to achieve a full-volume position coverage inside the detector. The veto system is used for muon detection, muon induced background study and reduction. It consists of a Water Cherenkov detector and a Top Tracker system. The readout system, the detector control system and the offline system insure efficient and stable data acquisition and processing.Comment: 328 pages, 211 figure

Are SMR a Reasonable Choice for Switzerland? An Application of the INCAS Model

Small countries can represent a suitable market for Small Medium Reactors (SMR). Among them Switzerland is one the more interesting since already hosts five commercial nuclear reactors; three of them are SMR (about 370 MWe) and two are large units (985 and 1165 MWe). Since the oldest units are about 40 year-old the Swiss utilities wereplanning to replace them while adding new nuclear power capacity to the portfolio mix.. Most recently, a radical re-thinking of the country energy policy is taking place as a Fukushima accident’s aftermath. Debate is about abandoning nuclear power and replacing it with renewable new capacity and import. “Economiesuisse, the umbrella organisation for Swiss business, considers a premature abandonment of atomic energy . Without valid alternatives, Economiesuisse warns, abandoning the nuclear option will have serious consequences for Swiss industry”. Also “the environmental organisationsrecognise that the discussion on energy policy — which will really heat up with the parliamentary debate in June — is not solely an ideological one. Financial and economic considerations are likely to make all the difference” (L.Jorio, “What price a future without nuclear energy?”, www.swissinfo.ch, May 17, 2011).An objective and unbiased estimation of the cost of new nuclear power is essential to Policy Makers and a focus on SMR economic potential is a further contribution to the debate. SMR advanced passive safety features may cope with public concerns about safety, which has become a priority. Polimi’s INCAS model has been developed to compare the investment in SMR respect to LR and is able to assess the financial/economic indicators arising from these two alternative investment options. In particular the INCAS model provides the value of IRR (Internal Rate of Return), NPV (Net Present Value), Upfront investment, etc. A stochastic approach to the data elaboration and the implementation of a Montecarlo analysis provide the evaluation of the investment risk profile. Results show that investment returns are comparable for LR and SMR; however SMR require a lower upfront investment, thus representing lower sunk costs and more affordable and scalable investment option than monolithic LR

Italy Re-Opening the Nuclear Option: Are SMR a Suitable Choice? An Application of the INCAS Model

The Italian strategic plan for the energy policy targets 25% of the national generation mix covered by nuclear technology by 2030. Considering a demand for electric power of 340 TWh in 2010 and assuming an annual rate of increase between 2,5% and 1,0%, the national plan would require to build some 8–10 large nuclear power plants, at least. The new generation capacity may be covered by EPR or AP1000 technology or, alternatively, by multiple SMR (i.e. 300–150 MWe), or even a mix of LR and SMR. The original intent, prior to the stop imposed by the dramatic earthquake and tsunami in Japan, was to have the first plant deployed by 2020. Today the Italian strategy to re-open the nuclear option is undergoing hard criticism and its fate is currently uncertain. In this context, this paper might contribute to the debate, by exploring the economics of the nuclear option with a focus on the opportunity to invest in large NPP category rather than in multiple, modular SMR. The latter have features that may compensate the dis-economy of scale and improve their cost-effectiveness, while granting investors with a lower up-front investment and a higher capability of project self-financing. The analysis is run through the Polimi’s proprietary “INtegrated model for the Competitiveness Analysis of Small modular reactors” (INCAS).Even if some specific inputs are related to the Italian scenario (e.g. the Electricity price) the results can be generalized to countries or utilities that are planning to install more than 10 GWe of nuclear capacity

Investment in different sized SMRs: economic evaluation of stochasticscenarios by INCAS code

Small Modular LWR concepts are being developed and proposed to investors worldwide. They capitalize on operating track record of GEN II LWR, while introducing innovative design enhancements allowed by smaller size and additional benefits from the higher degree of modularization and from deployment of multiple units on the same site. (i.e. “Economy of Multiple” paradigm) Nevertheless Small Modular Reactors pay for a dis-economy of scale that represents a relevant penalty on a capital intensive investment. Investors in the nuclear power generation industry face a very high financial risk, due to high capital commitment and exceptionally long pay-back time. Investment risk arise from uncertainty that affects scenario conditions over such a long time horizon. Risk aversion is increased by current adverse conditions of financial markets and general economic downturn, as is the case nowadays. This work investigates both the investment profitability and risk of alternative investments in a single Large Reactor or in multiple SMR of different sizes drawing information from project’s Internal Rate of Return stochastic distribution. multiple SMR deployment on a single site with total power installed. equivalent to a single LR. Uncertain scenario conditions and stochastic input assumptions are included in the analysis, representing investment uncertainty and risk. Results show that, despite the combination of much larger number of stochastic variables in SMR fleets, uncertainty of project profitability is not increased, as compared to LR: SMR have features able to smooth IRR variance and control investment risk. Despite dis-economy of scale, SMR represent a limited capital commitment and a scalable investment option that meet investors’ interest, even in developed and mature markets, that are traditional marketplace for LR

Load following by cogeneration: options for small modular reactors, Gen IV reactor and traditional large plants

Nuclear Power Plants (NPPs) has been historically deployed to cover the base-load of the electric power demand. Nowadays this scenario is changing and some NPPs are requested to perform daily load cycling operation (i.e. load following) between 50% and 100% of their rated power. The traditional methods to perform the load following are by inserting negative or positive reactivity into the core, moving the control rods. This strategy reduces the produced thermal power and in turn the electric power output with respect to the base-load strategy. From a technical standpoint this strategy submits the primary circuit to thermodynamic transients, which causes thermomechanical stresses on some components. From an economic standpoint this operation is very inefficient since, in NPPs, costs are mainly fixed and sunk, and there is a negligible cost saving (if any) in reducing the power of the reactor. A more efficient alternative might be doing the “Load Following by Cogeneration”, i.e. performing the Load Following by diverting the excess of power to an Auxiliary Plant. This paper assesses the technical feasibility of the coupling between a NPP and hypothetical cogenerate plants producing: diesel-like fuels from plastic pyrolysis, or desalinated water, or pellets from waste wood, or hydrogen from water splitting

Financial Case Studies on Small- and Medium-Size Modular Reactors

Nowadays interest in small- to medium-size modular reactors (SMRs) is growing in several countries, including those economically and infrastructurally developed. Such reactors are also called "deliberately small reactors" since the reduced size is exploited from the design phase to reach valuable benefits in safety, operational flexibility, and economics. A rough evaluation based only on the economies of scale could label these reactors as economically unattractive, but that approach is incomplete and misleading. An economic model (INCAS - INtegrated model for the Competitiveness Assessment of SMRs) is currently being developed by Politecnico di Milano university within an international effort on SMR competitiveness fostered by the International Atomic Energy Agency, suitable to compare the economic performance of SMRs with respect to large reactors (LRs). INCAS performs an investment project simulation and assessment of SMR and LR deployment scenarios, providing monetary indicators (e.g., internal rate of return, levelized cost of electricity, total equity employed) and nonmonetary indicators (e.g., design robustness, required spinning reserve). This paper presents the general features and purpose of the INCAS model, detailing the input required, and points out the main differences with other simulation codes. INCAS is applied to evaluate the financial attractiveness of an investment in four SMRs with respect to a single LR with the same power generation capacity installed, in different deployment scenarios. Then, a sensitivity analysis highlights the degree of elasticity of the key output parameters for the investors, with respect to the most sensitive input parameters. Given the uncertainties of the main input parameters, INCAS results are affected by uncertainties as well. However, the financial output parameters provide a general understanding on the investment economics: INCAS shows that the economy of scale is not the only cost driver, because the economies of multiples may compensate for most of the gap in the economic performance of the SMRs. The uncertainties that affect the input data and the model do not allow declaration of a straightforward and neat economic performance superiority of SMRs versus LRs, or vice versa. Nevertheless, some trends have been highlighted. In particular, in "supported" market scenarios, where overnight construction costs have the highest incidence and the market conditions are less volatile, the most suitable strategy is to pursue the economies of scale. In contrast, SMRs behave better in "merchant" scenarios, where the cost of financing is higher and financial risk is sensitive. A "modular" investing strategy with a step-by-step power block deployment process allows lower financial exposure and less capital at risk and may mitigate the impact of scenario uncertainties on a project's profitability