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Management of Commercially Generated Radioactive Waste - U.S. ...

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7.2 METHOD OF ANALYSIS FOR SYSTEM IMPACTS<br />

7.6<br />

The information flow in the computer simulation used for this analysis is presented in<br />

Figure 7.2.1. The first two modules <strong>of</strong> this computer model (i.e., ORIGEN and ENFORM) were<br />

adaptations <strong>of</strong> existing programs (Bell 1973, Heeb et al. 1979), while the last two modules<br />

were developed specifically for this simulation.<br />

The computer code ORIGEN (Bell 1973) was used to define spent fuel composition. The<br />

ORIGEN code calculates the average composition <strong>of</strong> the spent fuel discharged from a nuclear<br />

reactor based on a set <strong>of</strong> input parameters that characterize the irradiation conditions.<br />

The set <strong>of</strong> input parameters (i.e., neutron cross sections and spectral indices) used had<br />

been calibrated to match results <strong>of</strong> empirically measured spent fuel compositions. Isotopic<br />

data were calculated for 175 nuclides, including all significant fission products, activa-<br />

tion products and actinides.<br />

Twenty-eight ORIGEN cases representing both PWR and BWR fuel irradiations were used to<br />

describe the spent fuel compositions for all <strong>of</strong> the fuel cycle alternatives. These cases<br />

(see DOE/ET-0028, Sec. 10.1) include separate cases for each enrichment zone <strong>of</strong> the initial<br />

cores, a first reload and equilibrium reload fuel batch and three recycle fuel batches for<br />

both uranium and plutonium recycle. In addition, the low exposure fuel batches remaining<br />

when a plant is shut down for decommissioning are described. Whether recycling is used or<br />

not, all plants start up and shut down without recycle fuel in the core. Recycle <strong>of</strong> both<br />

uranium and plutonium is limited to equilibrium fuel reloads, and the amount <strong>of</strong> either<br />

recycle fuel in any year is limited to 50% <strong>of</strong> the equilibrium reload fuel.<br />

INPUT SYSTEM MODULE OUTPUT<br />

REERENCE<br />

PWR & BWR<br />

L<br />

IRRADIE YATION<br />

ISOTOPIC<br />

ST O<br />

ENFORMN SPENT FLCYCE<br />

PARAMETERS CALCULATIONS ND COMPOSITION<br />

CASE LOGISTICS STREA FLOWS-<br />

PARAMETERS CALCULATIONS ANCOOSONS<br />

WASTE WASTRAC WASTE STREAM<br />

PROCESSING WASTE LOGISTICS PROCESSING C.POSITI.S FLOWS AND<br />

PARAMETERS<br />

CALCULATI S COMPOSITIONS<br />

IMPACT<br />

ANNUAL AND<br />

UNIT WASTE A IMPACTS, COSTS<br />

AND COST --- CUMULATIVE AND<br />

FACTORS IMPACTS AND DATA TABLES<br />

AG1.S COST CALC'S<br />

FIGURE 7.2.1. System Simulation Information Flow

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