A partial low-leakage loading and refueling method suitable for modular small reactors

Abstract

The invention discloses a partial low-leakage loading and refueling method suitable for small modular stacks, which solves the problem that the prior art cannot take into account the balance between fuel economy and power flattening characteristics. The present invention includes (1) adopting the high-leakage loading form in which U-235 enrichment decreases sequentially from the outside to the inside to construct the core of the first cycle; the core contains a plurality of square fuel assemblies, and the fuel assemblies include gadolinium-loaded fuel rods ; (2) After entering the balance cycle through the transition cycle, the fuel assemblies in the core are replaced in three batches in the form of partial low-leakage loading; The fuel assemblies include non-gadolinium-loaded fuel assemblies and gadolinium-loaded fuel assemblies. The invention realizes the 24-month refueling target, improves the fuel utilization rate to a level close to that of a large commercial reactor, and simultaneously ensures the core power flattening characteristic.

Description

technical field [0001] The invention relates to the technical field of modular small reactors, in particular to a partial low-leakage loading and refueling method suitable for modular small reactors. Background technique [0002] Typical core refueling schemes include four types: "inner-outer refueling", "outer-inner refueling", "outer-inner partition exchange refueling", and "low leakage refueling". The leakage loading method has the advantages of high fuel utilization rate and low neutron fluence of the pressure vessel. The second and third types belong to the high leakage loading method, which is conducive to radial power flattening and provides a large safety margin. The advantages and disadvantages of leakage and low-leakage loading are complementary; in today's mainstream core refueling design, the first cycle usually uses high-leakage loading to meet safety requirements, and the balance cycle usually uses low-leakage loading to improve fuel economy and reduce equipmen...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is that the existing technology cannot balance the fuel economy and power flattening characteristics, and the purpose is to provide a partial low-leakage loading and refueling method suitable for small modular reactors. Arrange a certain number of new fuel assemblies and used fuel assemblies to achieve a proper balance between fuel economy and power flattening characteristics, so as to meet the design goals of modular small reactors with both safety and economy

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