Fast Defect Detection on Primary Pump Pipe for RSG-GAS Reactor Using Acoustics Emission Techniques

Abstract

RSG-GAS reactor is one of the research reactors owned by National Nuclear Energy Agency of Indonesia (BATAN) which has been operated since 1987 and utilized its neutrons for radioisotope production and other research activities, and heat caused by nuclear fission reactions is discharged into the environment. To remove the heat is required coolant pumps taking heat from the reactor core to the environment. The RSG-GAS coolant pump consists of a primary coolant and secondary coolant with a heat transfer capacity of 33,000 kW and 5,500 kW respectively. The primary coolant pump takes heat directly from the core and the heat is then transported to the secondary coolant pump system as it passes through the heat exchanger. It then discharges the environment by the cooling system secondary on the cooling tower by blowing using a blower that works counter flow to the direction of the coolant flow. The drainage from the reactor core into the environment requires pipeline from the component system to other components at the pump. Since RSG-GAS reactor has reached 30 years, the RSG-GAS reactor coolant system has aging experienced and decrease of its performance. The occurrence of sound and vibration in the cooling primary pipe indicated a defect location or cavitation due to hard impact of water flow and exposure of gamma radiation on the pipe wall continuously during reactor operation. To ensure the occurrence of defect location, it is necessary to conduct research and testing on the material structure of the cooling pump pipe. Testing and research on the structure of the cooling pipe material can not be done by disassembling the pipes because it is installed firmly and is at risk of high exposure gamma radiation. It is, therefore, nondestructive test method (NDT), one of them using acoustic emission method, should be applied. The experiments to detect the location defect on pipe of primary cooling pump of RSG-GAS reactor have been conducted. The results on this research showed primary cooling pump pipe degradation and low cavitation existence.