Use of Forward Sensititvity Analysis Method to Improve Code Scaling, Applicability, and Uncertainty (CSAU) Methodology
Since the Code Scaling, Applicability, and Uncertainty (CSAU) methodology was proposed about two decades ago, it has been widely used for new reactor designs and existing LWRs power uprates. In spite of these huge successes, CSAU has been criticized for the need of further improvement, focusing on two main issues - lack of objectiveness and high cost. With the effort to develop next generation safety analysis codes, new opportunities appear to take advantage of new numerical methods, better physical models, and modern uncertainty qualification methods. Forward sensitivity analysis (FSA) directly solves the partial differential equations for parameter sensitivities. Moreover, our work shows that time and space steps can be treated as special sensitivity parameters so that numerical errors can be directly compared with physical uncertainties. When the FSA is implemented in a new advanced system analysis code, CSAU could be significantly improved by quantifying numerical errors and allowing a quantitative PIRT (Q-PIRT) to reduce subjective judgement and improving efficiency. This paper will review the issues related to the current CSAU implementations, introduce FSA, show a simple example to perform FSA, and discuss potential improvements on CSAU with FSA. Finally, the general research direction and requirements to use FSA in an advanced system analysis code will be discussed.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC07-05ID14517
- OSTI ID:
- 1043051
- Report Number(s):
- INL/JOU-11-21430; NEDEAU; TRN: US1202999
- Journal Information:
- Nuclear Engineering and Design, Vol. 249; ISSN 0029-5493
- Country of Publication:
- United States
- Language:
- English
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