RU2753924C2 - Melting unit for induction remelting of metal radioactive waste - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to a melting unit for processing highly active metal waste used in a plant of induction slag remelting of metal radioactive waste MRAW, placed in a radioprotective hot chamber equipped with manipulators. The melting unit contains a crucible with electrically isolated metal sections with cooling channels located without a gap along the longitudinal axis of the crucible along its perimeter, fastened in the upper and lower parts with welded upper and lower rings, wherein a funnel is rigidly fixed on the upper ring with a metal ring clamp, lugs for turning the crucible around the axis are welded to the funnel, and coupling with external thread is rigidly attached to the lower ring, by means of which the crucible is installed in a socket by rotational movement, wherein, at the same time, the crucible, with a quick-release connection fitting rigidly mounted on an inlet collector and drain pipes of sections brought to one side, sections of which lie in the same plane and are connected to quick-release connection fittings using flexible steel bellows tubes connected to stationary sockets of quick-release connections, is placed in an inductor located in the upper part of the crucible equipped with a metal water-cooled pallet moving along the inner surface of the crucible in a zone from lower inductor coils to a gap, formed by the lower end of the crucible and the upper end of an ingot being melted, wherein the upper surface of the pallet is made in the form of a dovetail, using which the ingot being melted is fixed on the pallet.

EFFECT: acceleration of service operations carried out with the crucible, the reduction of labor costs and the negative economic effect associated with long downtime is ensured.

1 cl, 2 dwg

Description

SUBSTANCE: invention relates to melting units used as part of MPAO induction remelting units, placed in radiation-shielding chambers.

Known MPAO remelting devices containing a crucible transparent to electromagnetic fields, assembled from water-cooled metal sections with drainage devices and having no design features aimed at simplifying service operations (US 20130294473 A1, 02.02.16; JP 4348460 B2, 21.10.09; WO 2014174489 , 30.10.14).

It is also known a device for the production of metals and alloys, processing of metal and solid mixed radioactive waste, as well as irradiated fuel elements and fuel assemblies containing spent nuclear fuel, consisting of a metal melting cooled crucible, transparent to the electromagnetic field and a metal refrigerated pan with a drain device. One or more drain devices in the form of metal sectioned cooled crucibles, transparent to the electromagnetic field, with inductors located around the crucibles (RU 2177132, 19.10.2000) (prototype) are placed in the pallet and / or the side wall.

The disadvantages of this device are the need to use additional molds to obtain ingots of the required configuration and the lack of adaptation to service operations using manipulators in radiochemical production.

The objectives of the invention are to reduce the number of technological methods for processing MP AO and reduce labor costs for service operations associated with the replacement of the melter in HLW processing units located in hot chambers.

This is achieved by the fact that, in contrast to the known technical solution, the melting unit has a movable water-cooled pallet with a dovetail groove, movable along the axis of the apparatus, has a threaded sleeve in the lower part of the crucible, connected during installation with a stationary threaded socket, and ears on the loading the funnel serve as points of application of force when screwing in, the drain pipes of the sections are brought out to one side, their sections lie in the same plane and are connected to the fittings of the quick-release couplings by flexible connections from a steel bellows tube, the cooling water is inlet through an inlet manifold with a rigidly installed quick-disconnect coupling.

FIG. 1 shows a drawing of the melting unit, FIG. 2 - three-dimensional model of the melting unit

The melting unit contains a crucible (1), made up of insulated water-cooled sections located along the crucible axis without a gap, having a threaded sleeve (2) in the lower part and a loading funnel (3) with ears for slinging (4) in the upper part; inductor (5) located in the upper part of the crucible; stationary socket with female thread (6); metal pallet with a dovetail groove (7), moved by means of a rod (8) from the lower coil of the inductor; drains from sections (9) in the upper part of the crucible, brought out to one side in such a way that their cuts lie in the same plane and are connected by means of flexible steel bellows tubes (10) with fittings of quick-disconnect couplings (BRS) (11), intended for docking with stationary nests of the water cooling system; BRS fitting (12) rigidly mounted on the crucible inlet manifold (13).

Before installing the crucible (1) with the help of manipulators, slings of the intra-chamber lifting mechanism (PMM) are attached to the ears (4) of the loading funnel (3). After that, the assembly is moved and placed coaxially with the coils of the inductor (5). Then, by means of a directed force action on the ears (4) of the loading funnel (3), the crucible is screwed into a stationary socket (6). After that, with the help of manipulators, docking of a large input quick coupler (12) with an input hose (not shown) and fixed on bellows connections (10) quick couplers drains from the crucible sections (9). When dismantling the assembly, the sequence is reversed. Thus, during installation and dismantling, only intra-chamber manipulators and PMG are involved.

The device works as follows. At the first stage, the initial components are loaded into the crucible. In the case of simple remelting, only scrap metal is charged in order to compact. In the case of electroslag remelting, for the purpose of decontamination refining of metal, the flux is first loaded, and the top is contaminated with scrap metal.

After filling the crucible with the starting material to the required level, cooling water is supplied and power is supplied to the inductor, eddy currents arise in the metal material and its warming up.

After melting the first portion of the starting materials, the metal ingot is cooled down by increasing the flow rate of water supplied to the copper sump. Further, the metal is continuously dosed with simultaneous pulling of the ingot from the melting zone.

Upon completion of the compacting remelting, the resulting ingot is completely removed from the crucible, removed from the pallet and sent for long-term storage or burial. In the case of electroslag remelting for the purpose of refining and decontamination, the resulting two-phase block of smelting products, consisting of metal phases, is sent to the slag separation.

Claims (1)

A melting unit for induction melting of metal radioactive waste, containing a crucible with electrically insulated metal sections with drain branch pipes in the upper part of the crucible and with cooling channels located without a gap along the longitudinal axis of the crucible along its perimeter, a cooling system, a movable metal water-cooled pan , an inductor, a rigidly fixed loading funnel, characterized in that it is equipped with a threaded coupling rigidly attached in the lower part of the crucible for connection with a stationary threaded socket during installation, an inlet manifold for cooling water inlet with a quick-disconnect fitting rigidly mounted on it, while the loading funnel is made with ears welded to it to ensure that the crucible can be rotated around its axis, the drain pipes of the sections are brought out to one side, while their sections lie in the same plane with the possibility of connecting with the fittings of the quick-release couplings using flexible steel bellows tubes, butted with stationary sockets of quick-release couplings, the inductor is placed in the upper part of the crucible, the mentioned metal water-cooled pallet is made with the possibility of moving along the inner surface of the crucible in the zone from the lower turns of the inductor to the gap formed by the lower end of the crucible and the upper end of the ingot being melted , and the upper surface of the pallet is made with a groove in the form of a dovetail, with which the ingot being melted is fixed on the pallet.

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