Patent Number: 045335133
Section: summary

The present invention relates to an enclosing means for a nuclear reactor core. The enclosing means comprises an elongated concrete body and a pressure chamber within the concrete body. The pressure chamber is substantially defined by a surface of revolution corresponding to a longitudinal axis of revolution. The pressure chamber has an axially directed opening as well as a cover disposed at said opening for pressure-tight sealing of the pressure chamber. More particularly, the invention relates to a concrete pressure vessel designed for a pressure of 20-120 bar and intended to accomodate equipment requiring maintenance. In such a pressure vessel of conventional design, the handling of the cover requires a great deal of work and is very time-consuming, among other things because of the great handling weight of the cover. This is true particularly if the concrete pressure vessel is intended to accomodate equipment which is so space demanding that the inlet opening has to be made with a relatively large cross-sectional area. An enclosing means according to the invention is particularly intended for such cases where the pressure chamber is designed for the accomodation of a reactor core with associated heat exchangers and has an inner diameter of 8-16 m and an upwardly facing opening constituting at least 70% of the largest cross-section diameter of the pressure chamber. In such cases a cover of steel or concrete--retained in a conventional manner--will have such a large weight that the handling is connected with very considerable inconveniences. The task that is sought to be solved by the invention is to construct and arrange--in an enclosing means of the type described in the introduction--the means of attachment of the cover in such a way that, due to a particularly favourable distribution of the clamping forces, the cover can be dimensioned weaker and be made with considerably lower weight than with a corresponding conventional enclosing means, and in such a way that clamping members of a simple design and with a particularly short mounting and dismantling time can be used. What characterizes the invention will become clear from the appended claims .