This paper mainly deals with the improvement in the post test accident analysis results prediction for the test no. 2, “Total loss of feed water with failure of HPIS pumps and operator actions on primary and secondary circuit depressurization”, carried-out on PSB integral test facility in May 2005. This is one the most complicated test conducted in PSB test facility. The prime objective of this test is to provide support for the verification of the accident management strategies for NPPs and also to verify the correctness of some safety systems operating only during accident. The objective of this analysis is to assess the capability to reproduce the phenomena occurring during the selected tests and to quantify the accuracy of the code calculation qualitatively and quantitatively for the best estimate code Relap5/mod3.3 by systematically applying all the procedures lead by Uncertainty Methodology based on Accuracy Extrapolation (UMAE), developed at University of Pisa. In order to achieve these objectives test facility nodalisation qualification for both ‘steady state level’ and ‘on transient level’ are demonstrated. For the ‘steady state level’ qualification compliance to acceptance criteria established in UMAE has been checked for geometrical details and thermal hydraulic parameters. The following steps have been performed for evaluation of qualitative qualification of ‘on transient level’: visual comparisons between experimental and calculated relevant parameters time trends; list of comparison between experimental and code calculation resulting time sequence of significant events; identification/verification of CSNI phenomena validation matrix; use of the Phenomenological Windows (PhW), identification of Key Phenomena and Relevant Thermal- hydraulic Aspects (RTA). A successful application of the qualitative process constitutes a prerequisite to the application of the quantitative analysis. For quantitative accuracy of code prediction Fast Fourier Transform Based Method (FFTBM) has been used. It is concluded that most of the phenomena occurred in experiment are reproduced by code calculation and overall qualitative and quantitative accuracy of code prediction are acceptable as per UMAE.
Improvement in post-test accident analysis results prediction for the test no 2 in PSB test facility by applying UMAE methodology
D'AURIA, FRANCESCO SAVERIO
2006-01-01
Abstract
This paper mainly deals with the improvement in the post test accident analysis results prediction for the test no. 2, “Total loss of feed water with failure of HPIS pumps and operator actions on primary and secondary circuit depressurization”, carried-out on PSB integral test facility in May 2005. This is one the most complicated test conducted in PSB test facility. The prime objective of this test is to provide support for the verification of the accident management strategies for NPPs and also to verify the correctness of some safety systems operating only during accident. The objective of this analysis is to assess the capability to reproduce the phenomena occurring during the selected tests and to quantify the accuracy of the code calculation qualitatively and quantitatively for the best estimate code Relap5/mod3.3 by systematically applying all the procedures lead by Uncertainty Methodology based on Accuracy Extrapolation (UMAE), developed at University of Pisa. In order to achieve these objectives test facility nodalisation qualification for both ‘steady state level’ and ‘on transient level’ are demonstrated. For the ‘steady state level’ qualification compliance to acceptance criteria established in UMAE has been checked for geometrical details and thermal hydraulic parameters. The following steps have been performed for evaluation of qualitative qualification of ‘on transient level’: visual comparisons between experimental and calculated relevant parameters time trends; list of comparison between experimental and code calculation resulting time sequence of significant events; identification/verification of CSNI phenomena validation matrix; use of the Phenomenological Windows (PhW), identification of Key Phenomena and Relevant Thermal- hydraulic Aspects (RTA). A successful application of the qualitative process constitutes a prerequisite to the application of the quantitative analysis. For quantitative accuracy of code prediction Fast Fourier Transform Based Method (FFTBM) has been used. It is concluded that most of the phenomena occurred in experiment are reproduced by code calculation and overall qualitative and quantitative accuracy of code prediction are acceptable as per UMAE.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
