The owner of Paks NPP, Hungary’s nuclear generating facility, is aiming at adjusting the ISI program to meet ASME Code requirements. The objective is to achieve an internationally acceptable level in structural integrity assessment of long-lived and passive components, and to create the basis for a proper ageing management program for the operations period beyond design life of the units. Apart from this, it would allow to extend the current four-year inspection interval for Class 1 components up to an eight-year one, which would contribute to a more cost-efficient operation and maintenance. Hungarian nuclear regulatory regime gives an opportunity for this because the nuclear safety regulation does not determine explicitly the applicable codes neither for the design nor for the ISI. First, the basic regulatory principles related to ASME adaptation will be summarized. They focus on aspects of maintaining the current licensing basis as well as on the necessity to demonstrate the compliance with Section III requirements. The substantial part of the work is the construction review of selected Class 1 and 2 components. Then, the results of comparison of the current ISI program, mainly based on Russian normative documents, and the Section XI based one will be shown. These comparative studies have justified the feasibility of the project. The licensing of the ASME based ISI program is under way, and the regulator’s position will be presented as well.
Fatigue Crack Initiation and Propagation Behavior of a Nickel Alloy ; A Study of Structural Integrity Assessment Method Based on Polycrystalline FE Analysis