1. 1 FRAPCON Statistical Package FRAPCON/FRAPTRAN Users Group Meeting September 7, 2012 Paul Clifford Division of Safety Systems Office of Nuclear Reactor Regulation

2. 2 Statistical Package FRAPCON-3.4 designed to provide best-estimate predictions. NRC needed ability to perform independent fuel rod design calculations. FRAPCON statistical package performs the following tasks: –randomly samples among specified distributions of manufacturing tolerances, modeling uncertainties, and rod power uncertainties, –creates multiple FRAPCON input decks, –executes each of these unique cases, and –compiles the results (e.g., plots, 95/95 UTL, data files). Statistical package also allows introduction of a power ramp to existing rod power history. –User specifies ramp magnitude (KW/ft), time duration, and burnup time step.

3. 3 Statistical Package (cont.)

4. 4 Manufacturing Tolerances Manufacturing tolerances may be defined as a variety of distributions including uniform and normal.

5. 5 Modeling Uncertainties FRAPCON calibration modeling uncertainties defined in NUREG/CR-7022, Volume 2.

6. 6 Usage NRC using FRAPCON statistical package to perform independent fuel rod design calculations. –End-of-life rod internal pressure. –LOCA initialization (stored energy). –AOO overpower cladding strain. –AOO overpower fuel power-to-melt. FRAPCON confirmatory calculations may support review of a variety of licensing applications. –New fuel rod designs. –Fuel vendor transitions. –Power uprates. –Condition reporting (e.g., fuel thermal conductivity degradation). –Review of new fuel performance models/methods.

7. 7 PWR 16x16 – UO2 Rod 1 Calculated end-of-life rod internal pressure (500 cases): Nominal = 1676 psia 95/95 with sampled TOL = 1847 psia 95/95 with sampled TOL + FGR = 1873 psia 95/95 with sampled TOL + FGR + POW= 2015 psia

8. 8 PWR 16x16 – UO2 Rod 2 Calculated end-of-life rod internal pressure (500 cases): Nominal = 1809 psia 95/95 with sampled TOL = 1977 psia 95/95 with sampled TOL + FGR = 2088 psia 95/95 with sampled TOL + FGR + POW= 2332 psia

9. 9 PWR 14x14 – UGdO2 Rod Calculated end-of-life rod internal pressure (500 cases): Nominal = 1319 psia 95/95 with sampled TOL = 1463 psia 95/95 with sampled TOL + FGR = 1785 psia 95/95 with sampled TOL + FGR + POW= 1820 psia

10. 10 Conclusions FRAPCON statistical package provides a robust tool for performing independent fuel rod design calculations. During the past 12 months, NRC has completed confirmatory calculations to support the following licensing actions: –Calvert Cliffs Units 1 &2 fuel transition (CE 14x14). –Turkey Point Units 3 & 4 extended power uprate (W 15x15). –St. Lucie Unit 1 extended power uprate (CE 14x14). –St. Lucie Unit 2 extended power uprate (CE 16x16). NRC will continue to utilize statistical package to support licensing actions.