Mounting arrangement for protecting shipboard nuclear reactors against collision damage

摘要

A mounting arrangement for protecting shipboard nuclear reactors against collision damage comprises a polygonally-shaped shield which has a plurality of wall portions surrounding the lateral sides of a reactor which is located in the interior of a ship's hull. The shield has two opposite converging pairs of wall portions which are fixedly anchored to the hull, and each of the pairs forms an angle whose bisectrix is normal to a line which extends lengthwise of the hull.PP BACKGROUND OF THE INVENTIONPPThe present invention relates to a mounting arrangement for protecting nuclear reactors aboard ships, and more particularly for protecting the nuclear reactors from the effects of a collision.PPIt has been proposed in the prior art to protect nuclear reactors on board ship against damage due to collision with other ships, foreign objects in the sea, or such stationary structures as piers, by providing the rammed ship with resilient material which is intended to absorb the force of collision as a function of its resilience characteristics.PP Experimental and statistical tests have been conducted of the largest anticipated collision force and the expected range of amplitudes of collision ramming forces and their associated direction or ramming angles which are to be anticipated in a typical sea collision situation. A report summarizing the test results is published in the German publication "Hansa", Volume 12, 1964, pages 1-11. In the most frequent collision situation, a ramming ship will engage a rammed ship broadside, i.e., more or less substantially normal to the line or axis which extends lengthwise of the hull.PPThe prior art has attempted to deal with this aforementioned ramming situation by reinforcing the outer hull plating with heavy steel plates and by providing a plurality of protective decks having walls which extend longitudinally of the axis of the ship, i.e., longitudinal bulkheads, and walls which extend tranversely to the axis of the ship, i.e., cross-bulkheads.P PThe many decks are constructed of heavy metal material and the spaces between them are generally filled with resilient materials so as to aid in absorbing the collision forces. The prior art suffers from the disadvantage that the construction of building a plurality of steel decks is not only expensive and complex, but it contributes to a very heavy deadweight for the ship. Thus, the prior art has been found to be unsatisfactory for shielding nuclear reactors which are located in the interior of the ship's hull.PPSUMMARY OF THE INVENTION PP Accordingly, it is the general object of the present invention to overcome the disadvantages of the prior art.P PMore particularly, it is an object of the present invention to protect and shield a nuclear reactor located within the interior of the hull of a ship from the effected collision forces.PP Another object of the present invention is to shield the reactor in the most effective manner so that it is able to withstand broadside collision forces which act more or less substantially in the normal direction as considered with respect to the axis of a ship.PPAn additional object of the present invention is to divert from the collision force so that it is transmitted away from the point of collision and distributed throughout the hull of the ship.P P In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention is to provide a rigid polygonally-shaped shield which has a plurality of planar wall portions which surround the lateral sides of a reactor to be protected. The shield has two opposite converging pairs of wall portions which are fixedly anchored to the hull of the ship. Each wall portion pair forms an angle whose bisectrix is substantially normal to a line or axis which extends along the length of the hull.PPPreferably, the shield will have four wall portions and take on a quadrilateral configuration. In the quadrilateral embodiment, the reactor is positioned inside the shield so that the vertical axis of the reactor lies at the intersection of the axis of the ship with the bisectrix.PP The ship's hull is comprised of an outer hull portion and longitudinal bulkheads which are located on opposite sides of the axial line of the ship and which are inwardly spaced of the outer hull portion. Cross- bulkheads which are transverse or perpendicular to the longitudinal bulkheads are also comprised in the ship's hull. Thus, the shield may be secured to the hull at either of these locations.PP Specifically, if the shield has a quadrilateral shape and if the two opposite pairs of wall portions are respectively secured to the cross- bulkheads and the longitudinal bulkheads then the shield will take a rectangular or square shape depending upon the spacing of the bulkheads relative to each other. Alternately, if the two opposite pair of wall portions are respectively secured to the outer hull and the cross- bulkheads, then the shield will take on a parallelogram or rhombus-like shape, again depending upon the spacing of the bulkheads and the outer hull relative to each other.PP This mounting arrangement simply and effectively overcomes the aforementioned prior art disadvantages associated with using resilient material and requiring a plurality of decks. The nuclear reactor which is provided within the shield is kept free from the effects of a collision inasmuch as the force is distributed by the shield throughout the hull of the ship and not allowed to act only at the area or point of collision. The rigidity and the orientation of the shield permit the shield to withstand all anticipated collision forces without substantially elastically or plastically deforming.PPAnother feature of the present invention is that the shield may further comprise additional wall portions to enclose the upper and lower sides of the reactor, thereby completely enclosing the latter. The lower side is protected by a reinforced planar platform which has support legs embedded therein. For example, the platform may be formed of any crush-resistant material, such as concrete and may be reinforced by metal rods or the like. The legs support the reactor and effectively aid in isolating all collision forces. PPThe novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.