Method for precisely calculating power distribution of fuel assembly rod

Abstract

The invention provides a method for precisely calculating power distribution of a fuel assembly rod. The method comprises the following steps of 1, performing resonance calculation and transportation calculation to obtain the multigroup microscopic capture cross section and microscopic fission cross section of each nuclide in each burn-up state and the netron-flux density of each calculation region; and 2, obtaining corresponding heat release energy through precise processing according to information provided by a burn-up library, and calculating the power distribution of a fuel assembly according to the obtained microscopic absorption cross section, the microscopic fission cross section, the netron-flux density and the heat release energy. The method provided by the invention has the advantage that the energy release in the fuel assembly, including energy release of fission reaction occurrence and energy release of radiation capture reaction occurrence is strictly considered, so that the precise single-rod power distribution is obtained.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor core design and safety, in particular to a method for accurately calculating the power distribution of fuel assembly rods. Background technique [0002] In the fuel management calculation process based on the two-step method, the component calculation needs to give the single-rod power distribution shape factor in the component, so as to carry out fine power reconstruction in the core calculation. It is therefore necessary to accurately calculate the rod power distribution within the fuel assembly. [0003] The calculation of the rod power of the fuel assembly mainly depends on the energy release in the reactor, and the energy release in the reactor mainly comes from the fission reaction of heavy nuclides, so the traditional energy release calculation in the fuel rod is carried out by the following formula: [0004] P m = V ...

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Problems solved by technology

[0040] In 1999, based on the WIMS-5B program, Persic et al. calculated the typical new and old fuel nuclide compositions of PWR and TRIGA research reactors, and verified the reference value proposed by James. The results showed that the numerical error of 6.1 MeV was very small, but in In the verification work of Persic et al., the material does not contain isotopes of gadolinium

In addition, Joel et al. mentioned in the article about CASMO-5 energy calculation that the reference value of 6.1MeV ignores the situation that a part of the radiation capture reaction occurs in the moderator, so for the fuel rod, 6.1MeV is too large of

[0041] Regarding the traditional power calculation method, on the one hand, the above two reference values ​​are not suitable for power calculation at the single rod or component level, because the calculation At the time, James and Tasaka et al. selected typical materials in the whole stack, and they were not necessarily targeted in such a small range of materials as fuel rods; on the other hand, from the verification process of 6.1MeV by Persic et al. It is pointed out that these reference values ​​do not specifically consider the capture energy of gadolinium isotope, and the facts also prove that this approach has a very large error in the power calculation of fuel rods containing gadolinium

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