Reactor shroud support device

In an improved BWR reactor, internal pumps are disposed between a reactor pressure vessel and a shroud for compulsorily recycling reactor water. A support structure is radially disposed horizontally between upper outer circumference in the vicinity of the upper end of the shroud which is an outer wall of the reactor core and the inner circumference of the pressure vessel for containing the shroud. The support structure supports the shroud slidably in radial and axial directions relative to the pressure vessel while restricting the circumferential displacement. An friction member is disposed at the sliding surface between the support structure of the shroud and the support structure of the pressure vessel. With such a constitution, displacement at the top of the shroud can be suppressed upon occurrence of earthquakes and, since the friction member is disposed to the support structures, excess stresses applied to the lower support of the shroud caused by bending moment can be moderated. Further, an operation space upon maintenance of the internal pumps can be ensured. (N.H.)