PROBLEM SET HINTS

1. Determine the SWU value using the equation given in class; look up the latest spot prices for uranium ore and enrichment services online; and calculate the price of enrichment.

2. All required information appears in the figure provided as part of the problem. Note
that burnup is usually calculated as MWd⁄MTHM (Metric Ton of Heavy Metal),
which includes uranium and plutonium (if present) in the fresh fuel. Thermal energy is assumed (MWt).

The numbers appearing in the figure and its accompanying table are in units of kg, which is assumed to be the annual mass flow that generates 0.75 GWe (electric). Therefore, the mass flow can be re-expressed in units of kg⁄MWd (where d is days). The questions relate to mass balances around the fuel fabrication and reactor portions of the flow diagram.

BOC refers to the beginning of refueling cycle and EOC to the end of cycle. When fuel is inserted into the core, its fissile content (uranium-235) corresponds to the BOC. When it is discharged from the core three years later its fissile content (U-235 and Pu) corresponds to EOC.

PROBLEM SET #2

1. For the problem discussed in Tutorial 2, calculate the cost of the enriched uranium ($/ton) using the results from part (a) and the latest UxC® nuclear fuel price indicators as given at http://www.uxc.com/review/UxCPrices.aspx.
Note that prices are quoted in US dollars and are mostly per kg, except for yellow cake which is per US pound.

2. Referring to the nominal LWR fuel cycle shown below, calculate the following:

(a) the specific burnup of the fuel in MWd/t;

(b) the 235U enrichment of the fresh fuel;

(c) the enrichment of the spent fuel;

(d) the fraction of power originating from fissions in 235U and plutonium. Assume that the reactor operates at an overall efficiency of 33.4%.