How nuclear reactors are made

Nuclear reactors produced by AEM-Technologies, JSC have a long service life (60 years) and overhaul period (up to 8 years), and also meet the most stringent safety requirements. The manufacture of reactors requires close adherence to all process standards, the availability of unique machines and units, and strict control at each stage.

Production process

Metallurgical blanks

Head stamping

Welding, weld overlaying and heat treatment

Machining

Tests

Metallurgical blanks for the reactor pressure vessel are supplied from AEM-Special Steels Plant. Large-sized workpieces undergo incoming inspection, vertical lathe machine working of surfaces and edges for welding. After inspection job, the workpieces enter on the further process steps: assembly and welding.

A pearlitic steel slab is preheated in a furnace at a temperature of 1000 °C and then it is placed under max 15000 ton-force press, which forms a head of the slab. The double-acting hydraulic sheet-metal stamping press is unique and Russia’s only equipment that can stamp heads of a slab up to 380 mm thick.

Assembly and joining of two half-vessels and welding of the closing seam are one of the key stages of the reactor vessel manufacturing cycle. Welding and overlaying welding are carried out automatically using a special installation. Heat treatment of blanks is carried out in gas-flame chamber furnaces to obtain the highest performance characteristics of products.

Machining process involves the manufacture of threaded holes for studs of the reactor vessel main expansion joint, as well as general work on finish machining of surfaces, welds, nozzles, hole drilling in internals. Thread cutting is performed using a CNC milling and boring machine. Thread milling provides high speed and accuracy of work. The total fleet of machining production of the plants of AEM-Technologies JSC includes many dozens of pieces of equipment: screw-cutting lathes, vertical lathes, boring machines, milling machines, band saws, deep drilling machines, etc.

During the entire reactor manufacturing process, most of the time is devoted to quality control tests. X-ray control units are used to detect defects in thick-walled articles. Quality control of welded joints is ensured by the use liquid penetrant examination and ultrasonic flaw detection techniques. In a specially equipped underground stand - a caisson - hydraulic tests are carried out. A pressure of 25.7 MPa (262 atm) is injected into the body, in ten minutes the pressure should not fall below 24.5 MPa (250 atm).

In total, hundreds operations are carried out after jointing of the reactor half-vessels. Particular attention is paid to non-destructive testing methods.

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Quality control methods

768

total number of transactions

110

control tests

4900

witness samples

Shipment and delivery

The equipment is delivered to the factory berth by special vehicles. Self-propelled and tractor-driven modular multi-axle trawls are used, which are capable of withstanding a load of over 400 tons. Loading operations are carried out using two cranes with a lifting capacity of 650 tons each.

01

Large weight and large dimensions of the reactor vessel

02

Availability of infrastructure and specialized equipment for transportation

03

Drawing up the optimal land and water route

04

Multi-stage coordination of transportation at all stages

05

Security and escort of transported objects