Control modes for PWR (Pressurized Water Reactor) core of nuclear power plant

Abstract

The invention discloses control modes for a PWR core of a nuclear power plant. Two control rod groups, i.e., a T rod group and a D rod group, which are controlled independently are arranged. In the load tracking mode, a reactor is controlled in the manner that the average temperature of a coolant is controlled by the independent T rod group, reactive change of the core is controlled, the axial power distribution shape is controlled by the independent D rod group, soluble boron is adjusted periodically, and the control rod groups are recovered to an operation range. In other modes except the load tracking mode, the reactor is controlled in the manner that the average temperature of a coolant is controlled by the independent D rod group, the D rod group is also used to adjust the axial power shape and slight reactive change of the core. The control modes of the invention have the advantages that the control rod is used to reactive control of the core in the load tracking mode, so that burden of operators is greatly reduced; and generated wasted boron solution is reduced, the operation cost as well as the wasted solution processing cost is reduced, and the environment is protected.

Description

technical field [0001] The present invention relates to the technical field of nuclear power plant control, and in particular relates to a core control mode of a pressurized water reactor nuclear power plant. Background technique [0002] There are two main means of power regulation in the PWR core: 1) adjusting the boron concentration in the primary coolant to change the reactivity of the boron solution to the reactor; 2) adjusting the position of the control rods in the core to change the Core reactivity. The first means of adjusting the power of the reactor requires that the chemical capacity control system inject water or high-concentration boron solution into the primary circuit to dilute or borate the coolant. Since the primary coolant needs a certain amount of time to mix uniformly after each dilution or boronization, the boron concentration of the primary coolant changes slowly, and the power of the reactor is also slow to be adjusted. In addition, the stack power ...

AI Technical Summary

Problems solved by technology

The second way to adjust the reactor power is to adjust the reactor power through the movement of the control rods in the core, and its speed is relatively fast; but in operation, the movement of the control rods in the core will cause the axial power distribution of the core to be unbalanced , which will also cause problems such as unbalanced nuclear fuel consumption in the axial direction of the core, so there are also a series of constraints on the use of control rods to adjust the power of the reactor

[0005] In summary, the Mode-A control mode cannot quickly adjust the reactor power; both Mode-A and Mode-G control modes require the participation of the boron adjustment system; load following requires frequent dilution and boronization of the primary coolant, and the boron adjustment brings down The deficiencies stated:

[0006] 1) A large amount of boron solution to be recovered is generated, making it difficult for the boron recovery system to cope;

[0007] 2) At the end of the service life, boron adjustment is used to compensate for the change in reactivity during the load following process, which will generate many times more waste liquid than at the beginning of the service life, making the waste liquid treatment system of the nuclear power plant unable to bear and lose the load following ability;

[0008] 3) Boron adjustment will generate a large amount of radioactive waste liquid, which will increase the operating cost, and these additional radioactive waste liquid will enter the environment, posing a potential threat to environmental protection;

[0009] 4) The boron adjustment operation is relatively frequent and manually implemented, which increases the burden on the operator

However, when operating at base load, two sets of control rods are inserted into the core, which brings adverse effects such as fuel burnup shadow, control rod fluence increase, absorber burnup, and control rod drive mechanism load increase.

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