Thursday, October 28, 2010

The Crucibles

What is so special about Japanese steel crucibles?

At the recently concluded India-Japan summit meeting, one of the top items on the table was the issue of nuclear cooperation between Japan and India. Since India refuses to sign the NPT, Japan has been cagey about allowing its companies to participate in what is being billed as the biggest emerging N-energy market in the world.

One would imagine that if Japanese companies are unable to enter this market, well, too bad for them...companies from USA, France, Germany or Canada would be glad to do the honors in a market that was worth GBP 150 billion in 2008. However, for some reason, nearly all  transnational firms in this business depend on one company in Japan - Japan Steel Works (JSW), Hokkaido - for the most critical component of their nuclear power stations: the nuclear-reactor cores.

The JSW reactor-cores are common to all four 3rd generation nuclear-power-plant designs:
  1. ACR 1000 (CANDU II) of Atomic Energy Canada Ltd. (AECL)
  2. European Pressurized Water Reactor (EPR) built by EDF/Areva
  3. ES Boiling Water Reactor (ESBWR) by General Electric/Hitachi
  4. AP 1000 of Westinghouse/Toshiba

JSW has between 80 to 100 per cent market share for its large reactor components in countries where they are sold. Nearly all of 237 nuclear reactors planned worldwide till 2030 depend on this one company. Why? What is so special about these cores or crucibles?

The 40-year-old way (still used in China) of making these crucibles is to weld together two smaller forgings using explosive techniques. The `new` JSW crucibles are forged from a single 600 ton steel ingot; they are 12 inches thick with a stainless steel cladding.  The forgings are uniformly strong with their metal crystal lattices (grain) perfectly alighed (in a normal casting process, would get randomly jumbled).

The process is said to be `partly art and partly science`, involving at least the following steps:
  1. Scrap steel is heated in giant electric furnaces to 2,000 degrees Celsius (3,600 F)
  2. Five giant ladles are filled with 120 tons of orange-hot molten metal
  3. Argon gas in injected to eliminate impurities, and manganese, chromium and nickel is added to make the steel stronger
  4. The mixture is poured into a casing to form ingots 4.2 meters wide, in the rough shape of a cylinder
  5. The ingots are then pressed, heated and re-pressed under 15,000 tons applied by a machine that rotates them gradually over a three-week period
Sounds like the perfect `secret recipe`...but how long will such a huge market continue depend on a single supplier for their most critical component?



Pressurized Water Reactors (Ragheb 2008) -

JSW - Product List-

Capacity crisis at Japan Steel Works threatens global nuclear power plant production (Times-UK 17, March 2008)-

A New Generation of Nuclear Power Stations (Fells, 2008) -

Economics of New Nuclear Power Plants (Wiki)

Nuclear Power Reactors: A Study In Technological Lock-in (Cowan 1990) -

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