Figure 1-4 is the schematic diagram of the boiling water reactor nuclear power plant. Boiling water reactor and pressurized water reactor belong to light water reactor, which use the same fuel, moderator and coolant. This is doomed to the low thermal efficiency of boiling water reactor. However, compared with PWR nuclear power plant, boiling water reactor nuclear power plant has the following different characteristics:

First, direct circulation:

The steam generated by the reactor is directly introduced into the steam turbine to drive the steam turbine generator set to generate electricity. This is the biggest difference between boiling water reactor nuclear power plant and pressurized water reactor nuclear power plant. Boiling water reactor nuclear power plant lacks a loop, so there is no need for expensive steam generators and regulators that are prone to accidents in pressurized water reactor nuclear power plant, and a large number of loop equipment is reduced.

Second, it can reduce the core work pressure:

The technical scheme that the cooling water boils in the core and directly drives the steam turbine can effectively reduce the working pressure of the core. In order to obtain the same steam temperature as PWR, the core of boiling water reactor only needs to be pressurized to about 7 MPa, which is reduced to half of the working pressure of PWR core, which greatly simplifies the system and significantly reduces the investment.

Third, cavitation occurred in the core:

Compared with PWR, the biggest feature of boiling water reactor is that there are bubbles in the reactor and the core is in a two-phase flow state. Under any working condition, the reaction cavitation coefficient of moderator is negative, which can make the reactor run more stably, automatically flatten the radial power distribution and have good control and regulation performance.

Fourth, the power density is low:

After water boils, the density decreases and the moderating ability weakens, so the boiling water reactor needs more nuclear fuel than the pressurized water reactor with the same power, and the core and pressure shell are also larger than the pressurized water reactor with the same power. For example, the inner diameters of the pressure shells of the improved boiling water reactor nuclear power plant (ABWR) and the economical simplified boiling water reactor nuclear power plant (ESBWR), which belong to the third generation nuclear energy system, both reach 7. 1 m, which is almost twice the inner diameter of the pressure shell of the same power pressurized water reactor (3.99 m), resulting in lower power density than the pressurized water reactor. This is one of the main disadvantages of boiling water reactor nuclear power plant.

Fifth, radiation protection and waste disposal are more complicated.