LOCA analysis evaluation model with TRAC-PF1/NEM
- IBERDROLA Ingenieria y Consultoria, Avda. de Burgos, 8B, 28036 Madrid (Spain)
Nowadays regulatory rules and code models development are progressing on the goal of using best-estimate approximations in applications of license. Inside this framework, IBERDROLA is developing a PWR LOCA Analysis Methodology with one double slope, by a side the development of an Evaluation Model (upper-bounding model) that covers with conservative form the different aspects from the PWR LOCA phenomenology and on the other hand, a proposal of CSAU (Code Scaling Applicability and Uncertainty) type evaluation, methodology that strictly covers the 95/95 criterion in the Peak Cladding Temperature. A structured method is established, that basically involves the following steps: 1. Selection of the Large Break LOCA like accident to analyze and of TRAC-PF1/MOD2 V99.1 NEM (PSU version) computer code like analysis tool. 2. Code Assessment, identifying the most remarkable phenomena (PIRT, Phenomena Identification and Ranking Tabulation) and estimation of a possible code deviation (bias) and uncertainties associated to the specific models that control these phenomena (critical flow mass, heat transfer, countercurrent flow, etc...). 3. Evaluation of an overall PCT uncertainty, taking into account code uncertainty, reactor initial conditions, and accident boundary conditions. Uncertainties quantification requires an excellent experiments selection that allows to define a complete evaluation matrix, and the comparison of the simulations results with the experiments measured data, as well as in the relative to the scaling of these phenomena. To simulate these experiments it was necessary to modify the original code, because it was not able to reproduce, in a qualitative way, the expected phenomenology. It can be concluded that there is a good agreement between the TRAC-PF1/NEM results and the experimental data. Once average error ({epsilon}) and standard deviation ({sigma}) for those correlations under study are obtained, these factors could be used to correct in a conservative way code models in point, in order to meet requirements given in the Appendix K of 10CFR50.46. At last, a conservative evaluation model is proposed to cover conservatively the test results. A specific plant model development and validation is being developed, all aimed to a generic analysis of methodology application. For further applications, and based on performed uncertainties quantification, a methodology of CSAU type realistic approach will be considered in a nearby future. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21160806
- Resource Relation:
- Conference: ICAPP'04: 2004 international congress on advances in nuclear power plants, Pittsburgh, PA (United States), 13-17 Jun 2004; Other Information: Country of input: France; 5 refs; Related Information: In: Proceedings of the 2004 international congress on advances in nuclear power plants - ICAPP'04, 2338 pages.
- Country of Publication:
- United States
- Language:
- English
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