Uncertainty and Sensitivity Analysis at Low Value of Determination Coefficient of Regression Analysis: Case of I-129 Release from RBMK-1500 SNF under Disposal Conditions

Minerals

Povilas Poskas¹  Darius Justinavicius¹  Asta Narkuniene¹ 

[1] Nuclear Engineering Laboratory, Lithuanian Energy Institute, 3 Breslaujos str., LT-44403 Kaunas, Lithuania;

关键词: RBMK-1500 spent nuclear fuel;    deep geological repository;    uncertainty and sensitivity;    CSM;    CSV;    radionuclide migration;   

DOI  :  10.3390/min9090521

来源: DOAJ

【 摘 要 】

As in other nuclear countries, the operation of the Ignalina nuclear power plant in Lithuania has led to the accumulation of around 22 thousand assemblies of spent nuclear fuel (SNF). The development of geological disposal program involves an iterative assessment of the system safety supported by scientific research on radionuclides migration and related processes. This study focused on the application of Contribution to the Sample Mean (CSM) and Contribution to Sample Variance (CSV) methods to complement the uncertainty and sensitivity analyses of the time-dependent flux of I-129 from the engineered barriers of a conceptual disposal facility for RBMK-1500 SNF (RBMK is abbreviation of “High Power Channel-type Reactor” (in Russian)). The analysis was performed using a MATLAB platform (8.0.0.783 (R2012b), MathWorks, MA, USA). The mean and variance ratios derived from CSM and CSV plots were applied to estimate the effect of reduced uncertainty range on mean flux and its variance, and the uncertainty analysis was also complimented. Increasing the lower bounding value of defect size enlargement time range to 4.6 × 10⁴ years would lead to a lower mean flux until 5 × 10⁴ years after repository closure. Later on (up to 1 million years after repository closure), the only reduction of the upper bounding value of the SNF dissolution rate range would affect a decreased mean flux.

【 授权许可】

Unknown