A nuclear reactor having a penetration seal ring interposed between the reactor vessel flange and a mating flange on the reactor vessel head. Radial ports through the flange provide passage into the interior of the reactor vessel for utility conduits that can be used to convey signal cables, power cables or hydraulic lines to the components within the interior of the pressure vessel. A double o-ring seal is provided on both sides of the penetration flange and partial J-welds on the inside diameter of the flange between the flange and the utility conduits secure the pressure boundary.

A feed-through element for harsh environments is provided that includes a support body with at least one access opening, in which at least one functional element is arranged in an electrically insulating fixing material. The electrically insulating fixing material contains a glass or a glass ceramic with a volume resistivity of greater than 1.010.sup.10 cm at the temperature of 350 C. The glass or a glass ceramic has a defined composition range in the system SiO.sub.2B.sub.2O.sub.3-MO.

A reactor in-core instrument handling system in which the signal leads are routed from the instrument sensors through an outer sheath through the upper reactor internals and out of and around the sheath in a substantially tightly wound spiral before exiting the reactor vessel.

A reactor in-core instrument handling system in which the signal leads are routed from the instrument sensors through an outer sheath through the upper reactor internals and out of and around the sheath in a substantially tightly wound spiral before exiting the reactor vessel.

The invention relates to the field of electrical engineering, and specifically to sealed inlets of electrical circuits into a sealed area of a multi-layered containment shell of a nuclear power station. This design can be used in passages through an external and an internal wall which are subject to relative mutual displacement as a consequence of a seismic phenomenon or thermal expansion of the walls and passage. The problem addressed by the present invention is that of increasing the operating reliability of a sealed cable inlet when high-voltage electrical conductors which have little bending capacity are used. The problem addressed is achieved in that the sealed cable inlet through an external and an internal wall of a containment shell of a nuclear power station comprises an embedded pipe (3) which is arranged in the internal wall (1), with an inlet section (44) of a cable (2) fixed rigidly within said pipe. A means for compensating for a relative movement between the cable (2) and the external wall (11) is mounted in the external wall (11) coaxially with respect to the pipe (3). The compensating means has a tube (19) with a bellows (24) on the external end plane (20) and with a second analogous bellows (25) which is mounted symmetrically on the opposite end plane (21) of the tube (19) at the internal surface (18) of the external wall (11). The free ends (30) and (31) of the two bellows (24) and (25) are of conical design and have internal surfaces (28) and (29) which are support elements for an outlet section (46) of the cable (2), which is arranged freely in the tube (19) with a gap (47) relative to the internal surface (49) of the tube (19). The gap (47) between the braiding (48) along the external surface of the cable (2) and the internal surface (49) of the tube (19) is selected using a design calculation. The gap (47) must not be less than the value of maximum orthogonal thermo-seismic movement in one plane of the internal wall (1) relative to the external wall (11) and change in the coaxial position of the cable (2) in the tube (19).

A method for providing a neutron radiation shield includes a step (a) of providing a wall having an opening; and a step (b) of at least partially filling a space in the opening with a neutron moderator. Step (b) includes blast-injecting plastic granules into the opening with a blower device to form the neutron moderator.

A method for providing a neutron radiation shield includes a step (a) of providing a wall having an opening; and a step (b) of at least partially filling a space in the opening with a neutron moderator. Step (b) includes blast-injecting plastic granules into the opening with a blower device to form the neutron moderator.

A feed-through element for harsh environments is provided that includes a support body with at least one access opening, in which at least one functional element is arranged in an electrically insulating fixing material. The electrically insulating fixing material contains a glass or a glass ceramic with a volume resistivity of greater than 1.010.sup.10 cm at the temperature of 350 C. The glass or a glass ceramic has a defined composition range in the system SiO.sub.2B.sub.2O.sub.3-MO.

A feedthrough for shielding against radioactive radiation includes electrical feedthrough conductors, a tubular metal housing, a connecting conductor, and shielding bodies. The tubular metal housing includes ends and seals, the ends including a seals so that an interior is formed in the tubular housing between the seals. The seals include an insulating body through which an electrical feedthrough conductor is fed so that the electrical feedthrough conductor is fixed in the seals while electrically insulated from the tubular housing. The connecting conductor extends in the interior and connects an electrical feedthrough conductor at one of the seals to an electrical feedthrough conductor at another of the seals. The shielding bodies, which are respectively interrupted by at least one opening therein, are arranged successively in an axial direction of the tubular housing, the connecting conductor being fed through the opening. The shielding bodies shield against radioactive radiation by way of shielding material.

A feedthrough for shielding against radioactive radiation includes electrical feedthrough conductors, a tubular metal housing, a connecting conductor, and shielding bodies. The tubular metal housing includes ends and seals, the ends including a seals so that an interior is formed in the tubular housing between the seals. The seals include an insulating body through which an electrical feedthrough conductor is fed so that the electrical feedthrough conductor is fixed in the seals while electrically insulated from the tubular housing. The connecting conductor extends in the interior and connects an electrical feedthrough conductor at one of the seals to an electrical feedthrough conductor at another of the seals. The shielding bodies, which are respectively interrupted by at least one opening therein, are arranged successively in an axial direction of the tubular housing, the connecting conductor being fed through the opening. The shielding bodies shield against radioactive radiation by way of shielding material.