SCALE 5.1 Predictions of PWR Spent Nuclear Fuel Isotopic Compositions

Propagation of Isotopic Bias and Uncertainty to Criticality Safety Analyses of PWR Waste Packages

“…3 for 118 PWR fuel samples with initial enrichment ranging from 2.453 to 4.657 wt % 235 U and burnup ranging from 7.2 to 70.4 GWd/MTU. The isotopic bias and bias uncertainty for each burnup-credit isotope were determined in this calculation as the sample mean and the sample standard deviation, respectively, of the M/C isotopic concentration values (see Sect.…”

“…3 The SCALE 44GROUPNDF5 cross section library is based on the Evaluated Nuclear Data File/B Version V (ENDF/B-V) library. The criticality calculation code for disposal criticality analysis employing burnup credit is General Monte Carlo N-Particle (MCNP) Transport Code.…”

“…7.2) using the isotopic validation data in Ref. 3, which consist of the values of the ratio of measured-tocalculated (M/C) fuel isotopic concentrations for the evaluated burnup credit isotopes. The random variable , j i X defined as shown in Eq.…”

“…For instance, the measurement uncertainties for the uranium and plutonium isotopes in the Takahama fuel samples and in the TMI-1 fuel samples (from assembly NJ05YU) measured at Argonne National Laboratory vary from 0.1 to 2% and from 3.7 to 7.9%, respectively. 3 Sources of potential modeling uncertainties have been identified for some of the evaluated fuel samples (e.g., the measured samples in the Obrigheim assemblies BE124 and BE210) (Ref. 3).…”

Developing Spent Fuel Assembly for Advanced NDA Instrument Calibration - NGSI Spent Fuel Project

“…• destructive radiochemical analysis of fuel samples for direct measurement of a subset of nuclide compositions [3], • nondestructive measurements, such as gamma spectrometry or neutron counting, to measure a subset of nuclide compositions or infer fuel properties [4], and • fuel burnup simulations performed using assembly design and reactor operating information acquired from the operator [5], or a combination of the above techniques. Destructive radiochemical assay (DA) analysis of the spent fuel (usually on the scale of a fuel pellet) represents a high-accuracy method for spent fuel characterization, in which the fuel contents are measured directly, independent of any operator information.…”