Feasibility study on the seismic isolation of pool-type LMFBR. Pt. 1

Feasibilities and effectivenesses of a horizontal seismic isolation applied to the NIB of an LMFBR have been evaluated. The results are summarized as follows: (1) Seismic responses of seismically isolated NIBs and the reactor structure are characterized by a large sway motion displacement as a rigid body with low acceleration. The maximum response acceleration is reduced to 1/3-1/10 for the NIB and reactor structure when isolated. (2) Structural integrity of a seismically isolated NIB is shown by the study not withstanding nearly 50% of the weight has been reduced compared to the non-isolated building. (3) As for the reactor structure, the seismic isolation can result in reduced wall thicknesses down to about 20 mm or, around 20% in weight. (4) The stability and structural margin of the building and the reactor yet increase in spite of the above-mentioned weight reduction of the structures. (orig./HP)