Abstract: Element placement optimizing method and apparatus for determining an optimum placement of constituent elements for an LSI or the like. A parallel processing type computer system including a plurality of CPUs is used. An initial element placement is established and a number of paired element candidates for position exchange are selected from the initial placement, the number being equal to that of CPUS. A cost improvement value resulting from the exchange is determined for each of the paired candidates by the associated CPU. The exchange of the elements is performed for the paired element candidates for which the cost improvement value is maximum of those determined by the CPUs. By repeating the exchange, an optimum element placement is determined.

Abstract: A nuclear reactor facility including a primary containment vessel, a reactor pressure vessel installed in the primary containment vessel and accommodating a reactor core in a lower part thereof, and a vertical cylindrical wall disposed in a lower part of the primary containment vessel around and spaced from the reactor pressure vessel so as to delimit an annular space therebetween. The vertical cylindrical wall has an upper end disposed at a position higher than an upper end of the reactor core and a diaphragm extends substantially horizontally between the upper end of the vertical cylindrical wall and an inner wall of the primary containment vessel for cooperating with the vertical cylindrical wall to separate a space in the primary containment vessel around the reactor pressure vessel into a pressure suppression chamber and a drywell which includes annular space.