Cut-away view of the NPD-2 nuclear power station under construction at Rolphton on the Ottawa River. It will supply 20,000 kw and is due to be completed during 1961. Each major component being produced by Canadian metalworking firm will be covered in this series.

The metalworking behind our first nuclear power station

This first part of a series presents a broad view of the exciting challenge being met by Canadian firms

The metalworking industry is playing a major role in Canada's exciting bid to be one of the world's leading producers of atomic power stations. It has successfully dealt with some of the most formidable metalworking problems ever tackled in Canada in meeting the stringent demands of a program of immense national importance. The main manufacturing activity is at present centred round the production of components for the 20,000-kw

power station under construction at Rolphton, some 20 miles upstream along the Ottawa River from Atomic Energy of Canada Ltd.'s research centre at Chalk River. Construction of the station, known as Nuclear Power Demonstration 2, is well advanced and it should be supplying power into Ontario Hydro's distribution system during the second part of 1961.

Metalworking frontiers attacked in connection with development have ranged from powder metallurgy to welding and from gun drilling to component inspection. For example, at CGE's Carboloy Section in Toronto, methods have been developed for the production of uranium oxide fuel slugs in the form of high-density centreless ground powder metal compacts, while at Babcock & Wilcox and Goldie McCulloch tooling was developed for drilling 2,099 holes in 8-in.-thick heat exchanger plates in alloy and carbon steel. At the Peterborough plant of the Canadian General Electric Co., notable research and development has been devoted to methods of perfecting and inspecting large welded assemblies which, once the reactor is completed, will be virtually inaccessible for any form of repair.

Both the reactor vessel itself (known as the Calandria) and the moderator dump tank are all welded units which in operation will contain over $4,000,000, worth of heavy water controlled by a system employing some 2,100 cu ft of helium. The Calandria, which has a double wall, required over four miles of crucial weld passes in the fabrication of the inner shell alone. Each inch of this requires the utmost scrutiny from every form of non-destructive test. In establishing the welding procedures employed CGE worked in close collaboration with Air Reduction Canada and the Pandjiris Weldment Co. who built a massive fixture to enable rotation of the entire assembly at predetermined peripheral speeds.

Here's what each part does

Reactor vessel

This is where the heat is generated. Uranium fuel "burns" in horizontal tubes immersed in heavy water moderator. The level of the moderator determines the power developed. Heat is collected in heavy water pumped through the tubes.

Moderator dump tank

This receives or supplies the heavy water moderator according to the level required in the reactor. Moderator is supported on helium gas, the pressure of which determines its level

Fueling machines

These are two electro-hydraulically remotely controlled machines at each end of the reactor vessel. One inserts new fuel slugs into reactor tubes while other accepts and removes "spent" fuel from the opposite end of each tube.

Steam generator

This receives the circulating heavy water at about 530 F and transfers the heat to ordinary water for steam raising.

Moderator cooler

A heat exchange unit to transfer unwanted heat from the moderator to circulating river water.

- Part 1 page 1 -

Table of Contents

Part 1 page 2

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