Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2024-03-15
Abstract： Abstract：In order to improve the reliability of neutronics simulation for space reactors, based on the criticality benchmark experiment for space reactors in the International Criticality Safety Handbook (HMF005 benchmark experiment), the Monte Carlo program is used to model the core arrangement in the HMF005 benchmark experiment, and the deviation of the keff calculated values from the experimental values under six core arrangements is calculated by combining the different evaluated nuclear databases and the ratios between the calculated and experimental values are analyzed in depth. mean, standard deviation, χ2 and root mean square error are analyzed in depth. It is found that the deviation of the core keff results from the experimental values calculated by the four types of evaluation nuclear databases, ENDF/B-VII.1, CENDL-3.2, ENDF/B-VIII.0 and JEFF-3.3, is within the triple uncertainty, with the calculated results of ENDF/B-VII.1 being the closest to the experimental values, and the deviation of CENDL-3.2 from the experiments being a little bit larger.The deviation of the calculated results from the experimental values of the CENDL-3.2 library is also shown in the table below. CENDL-3.2 library calculations deviate slightly from the experimental values mainly due to the molybdenum and beryllium nuclides in the evaluation library, and the isotope of molybdenum has the largest effect of 92Mo. Sensitivity analysis was also carried out, and the total reaction sensitivity coefficients of 92Mo and 9Be were mainly related to the elastic scattering sensitivity coefficient, and the difference in radiation capture sensitivity between CENDL-3.2 and 9Be in ENDF/B-VII.1 was large, and the deviation between the two could be up to 34.9%.
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2017-08-27
Abstract： The theory of spot pricing is the basis of power market design in many countries, but there are many problems in the practice of spot electricity market. Spot electricity price has two major drawbacks: one is that it is still based on the traditional hourly scheduling/dispatch model, ignores the crucial time continuity in electric power production and consumption and does not handle the intertemporal constraints seriously; the second is that it assumes that the electricity products are homogeneous in the same dispatch period and cannot distinguish the base, shoulder and peak load power with obviously different technical and economic characteristics. To overcome the shortcomings, this paper presents a continuous time commodity model of electricity, including spot pricing model and the model priced according to load duration. The market optimization models under the two pricing methods are established with the Riemann and Lebesgue integrals respectively and the functional optimization problem are solved by the Euler-Lagrange equation to obtain the market equilibria. The feasibility of pricing according to load duration is proved by strict mathematical derivation. The theory and methods proposed in this paper will provide new ideas and theoretical foundation for the development of electric power markets in China and all over the world.
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