Integral fuel burnable absorber

No credit for fuel-relafed burnable absorbers, such as Gadolinia in BWR fuel and integral fuel burnable absorber (IFBA) rods or Erbia in PWR fuel. 

Fuel rods containing burnable absorber integral with the fuel may be used within some fuel assemblies one type uses a thin zirconium boride coating on the surface of the fuel pellets another type uses fuel pellets containing gadolinium oxide mixed with uranium dioxide. Combinations of the two types may be used within a reload. 

The bum-up reactivity swing is around 1% Ap, which is achieved by Gd integrated in fuel and separate burnable absorber rods (Fig. VI-3). 

To reduce the bum-up reactivity swing and the number of control rods required, all fuel assemblies contain integrated Gd-fuel rods. Separate burnable absorber rods are also used to reduce the reactivity swing. The RCC data is summarized in Table VI-2. 

The fuel assembly is placed in a zirconium casing of 144 mm turn-key size and contains 127 fuel elements, including 12 fuel elements in which Gd203 is integrated with UO2 as a burnable absorber. Each fuel assembly has six guide tubes for the absorber rods (AR) of the... 

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