NDTsi 2001 Session: Advances in Non-Ultrasonic NDE Methods
Acoustic Emission Monitoring of Water- Cooling System of BWR Reactor
G. Muravin, B. Muravin, L. Lezvinsky, Margan Physical Diagnostics, Israel; R. Axelsson, L. Johansson, Oskarsham NPP, Sweden; J. Cwiefeld, AF Kontroll, Sweden
ABSTRACT
1. Acoustic Emission Monitoring System and Methodology was developed for inspecting and evaluating the operational safety of water-cooling system of BWR reactor in nuclear power station. The system makes it possible to:
Operate within the environmental condition of the containment area.
Determine the damage type and its danger level according to established criteria.
Evaluate the kinetics of defect development.
2. A complex of investigations was carried out for the reliable AE diagnosis of pipes in the environmental condition of the containment area. These required:
Creating specific thermally and radioactively stable sensors.
Determining the real lifetime of sensors and preamplifiers installed at different positions in the containment area with and without radioactive protection.
Finding AE indications (fingerprints) of cracks, stress corrosion cracks, etc. developing in the metal in its original condition as well as in metal subjected to stress corrosion.
Preparing AE criteria for evaluating the danger level of defects.
Determining the degree of background noise in pipes operating under different nuclear power station production loads.
Establishing the correct set-up for the accurate diagnosis of defect types and the evaluation of their danger level.
Estimating the capacity of the AE monitoring system to locate specific defects and evaluate their danger level.
3. AE monitoring of the operating loop was performed under conditions of normal operating load, of power reduction and of maximal load of the nuclear power station. The results of these measurements and their evaluation established:
The system and methodology that had been developed made possible the satisfactory diagnosis of defect types and evaluation of their danger level.
Stress corrosion development in several zones and determined the location of the defects and their J-integral value.
The results of the AE monitoring were checked by independent Non- Destructive Test methods.
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]
