In fast neutron nuclear reactors, the heat produced by the core of the reactor is usually conveyed to the steam generators by liquid sodium flowing in the secondary circuit of the reactor. This sodium is at elevated temperature, on the order of 500.degree. C., and this temperature is capable of undergoing relatively large variations during the operation of the reactor. The sodium of the secondary circuit is at low pressure, on the order of a few bars, and flows in the piping of large diameter whose thickness is relatively small relative to its diameter. This piping has, for example, diameters exceeding 1 meter while its thickness is only a few millimeters and at the most 20 mm. This permits a reduction in the amount of stainless steel required to produce the secondary circuit which encloses the sodium whose super-pressure relative to atmospheric pressure is low, and a reduction in the stresses of thermal origin.
The main stresses undergone by the pipes of the secondary circuit are due to thermal shocks which may be considerable upon rapid variations in the temperature of the liquid sodium, vibrations in the secondary circuit during the operation of the reactor or even, in the case of earthquakes, cyclic forces of large amplitude.
Such pipes of large diameter and small thickness have a low resistance to crushing and may undergo large variations in diameter resulting from variations in the temperature of the sodium conveyed therein. The vibrations or other cyclic forces to which these pipes are subjected may result, in particular in the region of the anchoring points in the installation, in more or less large deteriorations in the pipe and even in the destruction of the latter.
Consequently, the supporting of such pipes in a nuclear station poses a technical problem difficult to resolve.
There has been proposed in British Patent application No. 84-01184, filed Jan. 26, 1984 filed by the assignee of the present invention, a supporting device comprising a rigid collar surrounding the pipe and defining an annular space around the latter, and elastically yieldable and deformable annular sectors interposed between the collar and the outer surface of the pipe. This device results in an effective maintenance of the pipe while it enables the latter to expand without producing high stresses in its wall. However, such a device does not permit an absorption of the vibrations or other cyclic stresses which are transmitted without attenuation by the elastically yieldable annular sectors.