The Hongyanhe Nuclear Power Plant (HNPP) is located in Dong gang Town, Wafangdian, in the Liaoning Province of China. The first unit of the plant was connected to the grid in February 2013, and commissioned in June 2013.
Because the nuclear power plant needs a lot of cooling water when working, it is located on the east side of Liaodong Bay in Bohai Sea. The site is surrounded by the sea on three sides. Marine climatic conditions place high demands on the corrosion requirements of power station equipment. Corrosion influences more than just the fan appearance. If a small rivet on the fan impeller is corroded, it is possible to fly off the entire impeller during high-speed operation, and severely impact the safety of the fan and even the entire ventilation system. Therefore, nuclear power plants have strict requirements for the corrosion protection of the fan equipment used.
Due to factors such as the economical efficiency and nuclear radiation problems, the service life of fans is required to be relatively long, so the structural stability requirements of fans are relatively demanding. The service life of axial / centrifugal fans and auxiliary equipment shall be at least 10 years (except for wearing parts). The safe running time before the first overhaul should be no less than 18000h. The service life of roof fans and auxiliary equipment is at least 10 years. The safe running time before the first overhaul shall be no less than 12000 hours. The service life of explosion-proof fans and auxiliary equipment shall be at least 10 years, and the safe operation time before the first overhaul shall be not less than 13000 hours.
1. Anti-corrosion structure design:
a. Taking “multiple guarantees” as a design concept, important components and structures are strengthened, including the use of more fasteners, such as rivets on the fan impeller.
b. Take compensation measures for the corrosion loss and appropriately increase the thickness of the plate, such as the fan impeller.
c. Improve the degree of protection of each component, for example the motor adopts IP55 protection level.
d. Adopt an easy-to-replace structure: A bolted structure instead of a welded or riveted structure shall be used.
e. For important structures, INFINAIR has corresponding testing and protection measures. For example, an observation window or an access door is designed on the housing; a safety guard is installed at the inlet and outlet.
f. Corrosion-resistant materials: The main body of the fan is made of stainless steel or fiberglass reinforced plastic instead of carbon steel. Parts that have been treated for corrosion resistance are preferred, for example, nickel plating treatment, stainless steel 316 (or 304) material, etc. Surface spraying method is used and the surface is well treated before coating to improve the adhesion of the coating. High-performance coatings, epoxy antirust primers for nuclear power plants and epoxy topcoats for nuclear power plants.
2. For the structural stability of the fan:
a. Inadequate steel structure rigidity and connection stiffness can easily cause vibration, so all the basic components of INFINAIR fans have been strengthened, such as increasing the number of angle iron and mounting holes.
b. Before the design of the fan, the fluid analysis and structural strength analysis will be used to ensure the structural strength.