Pressurizer stability at the Mochovce NPP

The stability of the pressurizer was analyzed as part of the LBB concept applied to the primary coolant circuit of the Mochovce NPP. The scenario encompasses an indirect LOCA, assuming that after the seismic event dies out, damage of the suspension or anchoring elements can induce various additional loads on the pipes and, consequently, loss of their integrity. The pressurizer anchoring was analyzed by using mathematical models. It is concluded that if four GERB 100 dampers are installed, the condition of HCLPF > 0.1 g for the maximum design earthquake (MDE) of 6 deg on the MSK 64 scale at PGA =3D 0.1 g is satisfied (HCLPF is the High Confidence of Low Probability of Failure); the load-bearing capacity of the dampers is higher than the acting force, and the displacement on the dampers is below the permissible limit. In the existing design, however, the pressurizer body would lose its stability and the above condition would not be satisfied for each of the bedding elements. 1 tab., 10 figs, 9 refs