Nuclear reactor, reactor internals, and method for designing same

A nuclear reactor, comprising:

• a pressure vessel, and a fuel assembly and reactor internals both arranged inside the pressure vessel, wherein
• the reactor internals comprise a core upper plate, a guide cylinder assembly and a supporting column assembly;
• a plurality of flow holes through which fluids are enabled to pass are provided in the core upper plate, and the plurality of flow holes comprise a first circular flow hole, a second circular flow hole and a square flow hole, the guide cylinder assembly being arranged above the square flow hole, and the supporting column assembly being installed above the first circular flow hole;
• and
• an upper tube seat of the fuel assembly is arranged below the core upper plate, and the fuel assembly is arranged below the upper tube seat of the fuel assembly.

A method for designing reactor internals of a nuclear reactor, wherein the nuclear reactor comprises a pressure vessel and a fuel assembly and reactor internals both arranged inside the pressure vessel, and the reactor internals comprise a core upper plate, a guide cylinder assembly, and a supporting column assembly;

• a plurality of flow holes through which fluids are enabled to pass are provided in the core upper plate, and the plurality of flow holes comprise a first circular flow hole, a second circular flow hole and a square flow hole, the guide cylinder assembly being arranged above the square flow hole, and the supporting column assembly being installed above the first circular flow hole;
• and
• an upper tube seat of the fuel assembly is arranged below the core upper plate, and the fuel assembly is arranged below the upper tube seat of the fuel assembly,
• the method for designing the reactor internals of a nuclear reactor comprising the following steps:
• step S1, calculating a resistance coefficient of each flow hole according to a flow area of each flow hole;
• step S2, calculating a flow distribution factor of each flow hole according to the calculated resistance coefficient and the flow area;
• step S3, iteratively adjusting a size of each flow hole until a requirement for the flow distribution factor is met;
• step S4, establishing a three-dimensional computational fluid dynamics analysis model based on each flow hole, the guide cylinder assembly and the supporting column assembly;
• step S5, performing flow field calculation for the three-dimensional computational fluid dynamics analysis model to obtain a flow distribution factor of each flow hole and a cross flow rate of a region at the upper tube seat of the fuel assembly;
• and
• step S6, iteratively adjusting the size of each flow hole and a structure of the supporting column assembly until the flow distribution factor and the cross flow rate of the region at the upper tube seat of the fuel assembly meet design requirements.