Statistical Modelling of Pressure Tube Diametral Creep
34th Annual CNS Conference - 2013 June 09-12

Presented at:
34th Annual CNS Conference
2013 June 09-12
Toronto, Canada
Session Title:
Chemistry & Materials

Mikko Jyrkama (University of Waterloo)
Grant Bickel (AECL)
Mahesh Pandey (University of Waterloo)


This paper presents the development of a weighted least squares (WLS) regression model for predicting pressure tube diametral creep over time, using in-service inspection data from 328 different pressure tubes from Bruce B and Darlington stations. The proposed model is linear in time as a function of flux and temperature, with a temperature dependent variance function.  The model predicts the shape of the observed diametral creep profiles very well, and is useful not only for prediction, but also for assessing tube-to-tube variability and manufacturing properties among the inspected tubes.

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