caloporteur

Traductions

• anglais

  Auteur : Office québécois de la langue française, 1993

  Note :

  The amount of heat given off per second per unit volume of a reactor core (the "power density" of a reactor) varies: from 1.1 kilowatt per litre in the Magnox reactor to 49 kilowatts per litre in the boiling water reactor; 102 in the pressurized water reactor (PWR); and, in the liquid metal-cooled fast breeder reactor (LMFBR), 646 kilowatts per litre. In reactors with low power densities the coolant may be a gas, carbon dioxide or helium, which has many advantages but relatively poor thermal conductivity, though this is improved if the gas is pressurized. In a reactor with higher power density a coolant with prime heat removal abilities is vital; the PWRs use water, the LMFBRs molten metal (sodium or sodium-potassium alloy). Failure of the coolant in a nuclear reactor leads to overheating which can in turn lead to melt-down of the reactor core: the engineering of the cooling systems of reactos must be to the highest standards. Some reactors have an open-ended cooling system, pumping water from a river through the reactor core and back to the river, or ordinary air from the atmosphere and back again. This means that the radioactivity picked up by the coolant in the reactor pollutes the neighbourhood around it. Alternatively, reactors can have one or two closed circuits which recycle the coolant. Closed circuits can be pressurized which improves the heat transfer properties of some coolants; dangerous or expensive coolants, such as molten sodium, helium or heavy water can be used in them; and they can be constructed to check the leakage of radioactive substances out of the reactor.

  Termes :

  1. coolant
  2. reactor coolant