Heavy-Water Reactor

heavy-water reactor

[′hev·ē ¦wȯd·ər rē′ak·tər] (nucleonics) A nuclear reactor in which heavy water serves as moderator and sometimes also as coolant.

Heavy-Water Reactor

a thermal reactor in which heavy water (D₂0) serves as the moderator. Because heavy water has a small neutron capture cross section, a heavy-water reactor may contain an extremely large fraction of fuel in the process of being generated as the original fuel is burned; the ratio of the weight of newly produced fuel to that of the burned fuel may be as high as 0.9. Ordinary water, heavy water, and certain gases, for example, steam and carbon dioxide, are used as coolants in heavy-water reactors.

Table 4. Production of diesel engines in the USSR¹
	1940	1950	1970	1975
¹ Excluding motor-vehicle and tractor engines
General-purpose diesels:
units. . . . . . . . . . . . . . . . . . . . . .	12,140	54,322	59,627	65,235
total horsepower. . . . . . . . . . . . . . . . . . . . . .	469,900	8,830,700	16,158,000	18,230,600

Construction and operating costs of heavy-water reactors are high because of the price of heavy water. The reactors are therefore used in industry only in countries where heavy water can be produced relatively cheaply, such as in Canada, where the electric power supplied by the country’s hydroelectric power plants costs very little.