원자력 발전소 폴라 크레인의 내진설계에 관한 연구

Abstract

The Polar Crane (PC) consists of two structural parts of bridge and trolley. The bridge structure is approximately 43 m long and 9 m wide and is primarily composed of one 36.8m deep wire rope area at the operating level. A trolley structure is mounted on wheels that roll on the rails of the containment building.

The analysis uses the seismic response curves (OBE, SSE) for plant that were reflected the revision to the seismic requirement of nuclear power plant. New curves contain higher amplitude than those of previous nuclear power plants in Korea. The structure was modeled using finite element techniques. Calculated stresses from finite element model are evaluated in accordance with design criteria of KEPIC MCN, 2000.

The objective of this paper is to evaluate the integrity of polar crane due to normal and earthquake loading, and to reduce the reaction force on the support. The response spectrum analysis is the most common technique used to determine the maximum structural response due to earthquake loading.

The analysis assumes that, for the seismic loading in the horizontal direction perpendicular to the crane girder (the lateral direction), slip of the end trucks along the runway rails occurs. The responses, for this condition, are conservatively combined with those due to vertical and longitudinal seismic loading.

It is shown that the crane is adequate to resist loads up to the Maximum Critical Load (MCL) under response to the Safe Shutdown Earthquake(SSE) loading given in the KEPCO. The seismic qualification has been carried out in accordance with KEPCO specification for the Nuclear Power Plant, containment polar crane.

The containment polar crane is classified as seismic category II equipment. It is required that the crane shall be capable of holding the loads upto the maximum critical load under response to an SSE loading without exceeding the allowable stresses for the crane materials to maintain its structural integrity during and after an SSE loading.

The reaction forces that transfered from crane support(wheel) to the rail are important loading data to design the containment building, because the rail of polar crane is located on the top of containment building. The method to reduce the reaction forces is proposed.