Inverse Heat Conduction Problem in Estimating Nuclear Power Plant Piping Performance

Abstract

Most of today's operating nuclear plants that were originally designed for 30 or 40-year life are facing the long-term operation issues. Therefore, it is of meaningful importance to assess the time-dependent degradation and the ageing of the relevant nuclear systems, structures, and components (SSCs) because of resulting loss of structural capacity. In this framework, the inverse method is implemented starting from temperatures at an accessible boundary, which are measured through a monitoring system. The reconstruction technique uses the elaborated signal provided by the monitoring system to determine temperature at inaccessible surface: this is the so-called inverse heat transfer problem (IHTP). The inverse space marching method is applied. Analytical and numerical studies are performed taking into account thermal transient conditions in order to determine thermal loads. In particular, the developed code demonstrates to be able to reconstruct temperature and stress profiles in any section of the pipe with a good accuracy. In addition, the thermal loads obtained suggest that the investigated transient condition is not able to jeopardise the integrity of NPP, confirming the possibility of the plant extension of life.

Approaches to Sustainable Energy Management in Ensuring Safety of Power Equipment Operation

“…Some research [17][18][19] has addressed the safety concerns related to various aspects of nuclear power plant components and equipment, offering diverse methods and approaches for technical diagnostics and enhancing regulatory support for operational safety. In [20], the authors proposed equipment standardization to distinguish methods and models for evaluating the technical condition of pipeline systems subjected to different types of loads and coolant mediums. Furthermore, papers emphasized the importance of conducting a comprehensive assessment of power equipment, considering its operational characteristics, to predict changes in technical condition and service life beyond the design period.…”

“…Ensuring the safe operation of power plant equipment requires a comprehensive approach to assess its quality and technical condition. For instance, for pipelines, researchers have proposed a comprehensive technical diagnosis of energy equipment, which considers structural features, defects, and stress-strain state after a specific period of operation [13,[20][21][22]. The studies employ research methods like mathematical modeling, comparison of calculated and experimental results, identifying boundary parameters of the technical condition, predicting service life, and monitoring and controlling the mechanical properties of energy equipment during operation using non-destructive testing methods.…”