additionally, the central location is reserved for instrumentation. The remaining locations contain fuel rods. Fuel rods are formed by UO2 fuel pellets clad in Zr-based cladding. The outside cladding diameter is 0.374", the clad thickness is 0.0225", and the diametral gap is 0.0065". (This is the gap between the clad and pellet; note that the diametral gap is twice the radial gap.) Axially, the fuel pellet stack (so-called active core) is 14 feet tall. Pellets are made of UO2 sintered to 95.5% of its theoretical density which is 10.96 g/cm3. Dishing and chamfering amount to 1% of the pellet volume. Assume that fuel enrichment is 4 wt%. The thermal power of AP 1000 is 3,400 MW-th. a. Calculate the total heavy metal loading, i.e., the total uranium weight in the cycle 1 fresh core. [Justify all assumptions.] b. Calculate specific power expressed in W/gU. Also, calculate specific power expressed in MW/tU. c. Assume that the reactor has an annual refueling cycle composed of 15 days of shutdown for refueling, and the remaining -11.5 months of operation at power. Further assume that the average capacity factor, when operating at power, is 98%. What is the average burnup that fuel receives each year? You may express burnup in MWd/tU or GWd/tU or MWd/kgU. [Note that "t" will always denote metric tons, i.e., 1,000 kg, unless very specifically stated otherwise. Also, U in burnup units refers to the initial mass of uranium (ALL uranium, not just U235).
Fig: 1