The company “AtomSeismicProject” has done strength and seismic resistance calculations of fans of the “Radiway” type, designed and manufactured by “INNOVENT”, LLC.
Fans of the “Radiway” type are standard radial fans and are commonly used at nuclear stations for ventilation and air cleaning of contaminated area, belongs to the equipment of the I category of seismic resistance and to the systems important for nuclear and radiation safety.
For calculated estimation there have been chosen fans of the “Radiway” type with the worst operation factors from seismic loadings (the biggest engine power, the worst alternator’s supports etc.)
There have been considered variants of set-up and installation on different types of vibro isolators (rubber antivibration mount and spring antivibration mount)
During calculations, there has been done an estimation of:
· Hull, bed frame and body of fans strength;
· Strength of fans mounting hardware to foundation;
· Strength of holt-down bolts to the body of fans;
· Fan wheel strength.
In the calculations there have been considered seismic loads, inertial and aerodynamic loads of the runner rotation, static loads due to own weight.
Week points in the construction of fans according to the results of calculations were vibro isolators and bed frames:
1. Subsidence of issues spring antivibration mount according to the results of calculations exceed maximum possible..
2. Obtained exertions on issued rubber antivibration mounts exceeded than maximum possible.
3. Tension in the bed frame and body of the biggest fans of this type were exceeded maximum possible.
According to the results of calculations in cooperation with the manufacturer, there were developed mitigations of earthquake damage of fans:
· For biggest fans there were found cross-sections for production of the bed frame and the body.
· For all these fans there were done recommendations on choosing vibro isolators and theirs amount.
Developed actions did not need complicated modifications and changing constructions of fans and its realization did not require large economic expenses or designing difficult technical decisions.
According to the results of effective cooperative work with “INNOVENT”, LLC we decided to continue cooperation on developing seismic resistance constructions of fans and other equipment used at nuclear stations.