Developmental verification of the FRAP uncertainty analysis option. [BWR; PWR]

Technical Report · Mon Jan 01 04:00:00 EST 1979

DOI:https://doi.org/10.2172/6471510· OSTI ID:6471510

Peck, S. O.; Atwood, C. L.

The Fuel Rod Analysis Program--Transient code is a best-estimate code designed to calculate fuel rod response during transient conditions in the reactor. An automated uncertainty analysis option has been added to the FRAP-T5 code which allows the user to obtain estimates of the uncertainty in computed code outputs as functions of known input uncertainties. Developmental verification, the subject of this report, is an ongoing process whereby the uncertainty subcode is checked for programming correctness and for validity of analysis results. Three developmental verification studies were undertaken. (1) A benchmark calculation using a simple equation replacing FRAP-T5 was performed to check the correctness of the subcode programming. (2) The adequacy of the fit of the response equations to the data was evaluated using a statistical criteria to guard against over and under fitting and a visual examination of residuals. An uncertainty analysis of a LOCA was used as an example. (3) The ability of the response equations to predict the true response surface was determined by generating new data and comparing the predictions of the original equations with the new data. Results indicated that the majority of the responses were fit acceptably well by just a linear response equation. The fit for a few responses could be improved by continuing the analysis to include higher order terms. Recommendations for future versions of the uncertainty analysis option are to include methods for assessing the validity of the response equations as an automatic user feature.

• Research Organization: Idaho National Engineering Lab., Idaho Falls (USA)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-07-1570
• OSTI ID: 6471510
• Report Number(s): CDAP-TR-79-050
• Country of Publication: United States
• Language: English

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