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The light-water reactor (LWR) is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator; furthermore a solid form of fissile elements is used as fuel. Thermal-neutron reactors are the most common type of nuclear reactor, and light-water reactors are the most common type of ...
Heavy water is less dissociated than light water at given temperature, and the true concentration of D + ions is less than H + ions would be for light water at the same temperature. The same is true of OD − vs. OH − ions. For heavy water Kw D 2 O (25.0 °C) = 1.35 × 10 −15, and [D + ] must equal [OD − ] for neutral water
The heavy water coolant is kept under pressure to avoid boiling, allowing it to reach higher temperature (mostly) without forming steam bubbles, exactly as for a pressurized water reactor (PWR). While heavy water is very expensive to isolate from ordinary water (often referred to as light water in contrast to heavy water), its low absorption of ...
Deuterium nuclei (in heavy water) absorb kinetic energy less well than do light hydrogen nuclei, but they are much less likely to absorb the impacting neutron. Water or heavy water have the advantage of being transparent liquids , so that, in addition to shielding and moderating a reactor core, they permit direct viewing of the core in ...
A pressurized water reactor (PWR) is a type of light-water nuclear reactor. PWRs constitute the large majority of the world's nuclear power plants (with notable exceptions being the UK, Japan, India and Canada). In a PWR, water is used both as a neutron moderator and as coolant fluid for the reactor core.
Water (sometimes called "light water" in this context) is the most commonly used moderator (roughly 75% of the world's reactors). Solid graphite (20% of reactors) and heavy water (5% of reactors) are the main alternatives. [1] Beryllium has also been used in some experimental types, and hydrocarbons have been suggested as another possibility.
Heavy Water Secondary coolant material Light Water Moderator material Heavy Water Reactor operating pressure, kg/cm 2 (g) 87 100 100 Active core height, cm 508.5 594 594 Equivalent core diameter, cm 451 – 638.4 Average fuel power density 9.24 KW/KgU 235 MW/m 3: Average core power density, MW/m 3: 10.13 12.1 Fuel Sintered Natural UO 2 pellets
The Advanced CANDU Reactor is a hybrid CANDU design that retains the heavy water moderator but replaces the heavy water coolant with conventional light water coolant, significantly reducing heavy water costs compared to traditional CANDU designs but losing the characteristic CANDU capability of using unenriched natural uranium as fuel. BARC ...