Heavy water reactor

The Heavy Water Reactor ( Heavy Water Reactor, HWR ) is a type of nuclear reactor in which heavy water ( D 2 O, 2H2O spelled differently ) is used as coolant and moderator. Heavy water is water that contains instead of ordinary hydrogen ( H) with mass number 1, the heavier hydrogen isotope deuterium (D or 2H) with mass number 2. Heavy water absorbs neutrons less than normal water. Therefore, this type of reactor can be operated as natural uranium reactor in contrast to light-water reactors with uranium in the natural isotopic composition.

The difference in the neutron absorption is exploited in danger of Reaktivitätsstörfalls: The reactor vessel is flooded with normal water H2O from the reserve cooling water basin. By greater neutron absorption of normal water, the reactivity is decreased, the pre- critical reactor is sub-critical, so that the chain reaction ceases. On this measure can be used in the case of a cooling leak or failure of the control rod system. The reactor can not be restarted without heavy water.

A disadvantage is that the production of heavy water is expensive. In addition, costs would increase by the larger dimensions and greater material requirements associated such reactors.

In heavy water reactors arises from the deuterium of heavy water by neutron tritium.

Heavy water reactors are operated mainly by countries with its own uranium deposits that do not have uranium enrichment plant. Of the different types of reactors is mainly developed in Canada called CANDU reactor ( pressure tube reactor ) has prevailed. As an economic flop proved the Siedeschwerwasserreaktor.

In India there are numerous pressure heavy water reactors.

Heavy water reactors in Germany

The only two heavy water reactors used for electricity generation in Germany were

  • The multi-purpose research reactor Karlsruhe (52 MW net, 57 MW gross), which was in operation from 1966 to 1984 and
  • The nuclear power plant Niederaichbach (100 MW net, 106 MW gross), which until 1974 was from 1973 into operation.

Documents

  • Type of reactor
Light water reactor Nuclear power in India
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