NDTsi 2001 Session: Structural Integrity and NDE I-II
Role of NDE in Integrity Assessment of Steam Generator Tubes
M. Behravesh, EPRI, USA
ABSTRACT
Periodic evaluation of steam generator tube integrity in US PWR plants is governed by the Nuclear Energy Institute (NEI) Initiative 97-06. This evaluation takes place at each refueling outage and its aim is to ensure that the steam generator performance criteria are met. The two elements of this evaluation, at each refueling outage, are condition monitoring and operational assessment. Condition monitoring is a backward look in time to establish that performance criteria were not violated during the previous operating cycle. This is typically done via NDE techniques to find if the tubes contain any defects exceeding structural limit. Operational assessment is a forward look in time to determine that the steam generator tubes can operate another cycle without violating performance criteria, and that also uses NDE data as input to establish beginning of cycle conditions. Requirements for steam generator integrity assessments dictate the particular inspections that must be conducted and NDE data that needs to be generated. This data ranges from identification of various degradation forms, probability of detection statistics, sizing measurements, and NDE variability and uncertainties associated with techniques, analysts, and overall inspection systems. This paper discusses the specific NDE needs of the SG integrity assessments and how they are being met for the US PWR plants.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
