SENSITIVITY AND UNCERTAINTY ANALYSIS OF J INTEGRAL CALCULATION OF THE RELIABILITY ASSESSMENT OF REACTOR PRESSURE VESSEL (Entin Hartini, Roziq Himawan, Abdul Hafid, Deswandri, Geni Rina Sunaryo)

ABSTRACT
SENSITIVITY AND UNCERTAINTY ANALYSIS OF J INTEGRAL CALCULATION OF THE
RELIABILITY ASSESSMENT OF REACTOR PRESSURE VESSEL. The structural
reliability of the reactor pressure vessel (RPV) is one aspect that must be considered in the
safety analysis of the reactor. J integral calculation was conducted for structure reliability due
to the cracks presence. In understanding the uncertainties that affect the output of the
analysis, the evaluation of the uncertainty and sensitivity of the input variables need to be
done. In the calculation of J integral input uncertainties variable involving physical variables
for the loading condition that the internal pressure and material properties. The purpose of
this study is to conduct a sensitivity analysis then to compare influence of the uncertainty of
the outcome variable to output. RPV J integral calculation in 2D with initial crack modeled
using MSC MARC. The calculation of input uncertainty was used simulation-based
probabilistic density function (PDF). Then a sensitivity analysis using a variant of the
conditional expectation was performed. The obtained results are stress intensity factor (SIF)
to include the uncertainty of the load input will first reach the limit value of the fracture
toughness (100 MPa m0.5) compared with the input uncertainty elasticity modulus. Based on
the evaluation of the sensitivity value, the uncertainty of the load input heavily influence the
integral J by 93.86% compared to the uncertainty of input on elasticity modulus.
Keywords: Uncertainty, sensitivity, J integral, MSC MARC