A Jordanian PhD student, Ayman Ahed Abu Ghazal, studying in a Nuclear power installations specialty, including design, operation, decommissioning, at the Department of Instrument and Installation Design – Faculty of Physics and Technology, was engaged in the improvement of a new method of nondestructive testing and conducted the experiment at the Pulsed fast reactor IBR-2 in the Frank Laboratory of neutron physics, at the Joint Institute for nuclear research (JINR), Dubna-Russian Federation. The young scientist became the first and only representative of the Arab countries, who were allowed to work in the reactor.
The electrophysical method of nondestructive testing or the method of scanning contact potentiometry (SCP), developed in the Laboratory of functional electrophysical diagnostics and nondestructive testing (ElphysLAB) at the National Research Nuclear University MEPhI, provides an effective diagnostics of reactor equipment, ensuring the reliability of measurement results in operating conditions of nuclear power plants. It includes the reactor core, where other methods of diagnostics and control do not give a real picture, because of the direct dependence of the measurements accuracy on external factors, for example, surface purity, temperature, dose rate, while the SCP won’t be affected by these external factors.
One of the main advantages of the scanning contact potentiometry method is that the measuring system sensors have very small linear dimensions (of the order of 1-2 millimeters), therefore, can be placed in any inaccessible location virtually, including welded seams of butt joints. In addition, the use of new technology makes it possible to obtain information about the initial stages of nucleation and development of cracks, as well as other defects in reactor materials.
“By scanning contact potentiometry method, we can not only find the embryonic fatigue cracks in the reactor steel, but also predict where and when they can appear,” Ayman commented. “So, during the tests, we discovered an embryonic fatigue crack in reactor steel with a size up to 100 microns at a depth of 2 mm, three hours prior the sample destruction.”
The experiment proved a high efficiency of the new technology, according to the head of the sector of the Laboratory of Neutron Physics Gizo Bokuchava, where the unique method of neutron correlation time-of-flight diffractometery was developed for structural studies at the atomic level. No one else was engaged in scanning contact potentiometry in Russia, the MEPhI scientists were the first. The scientist is sure that the proposed method is very relevant and will find a wide application at nuclear power plants for qualitative diagnostics of reactor equipment.
The results of Ayman Abu Ghazal’s research were presented at the 13th International Scientific and Practical Conference “The Future of Atomic Energy - AtomFuture 2017”. His reports: “The application of scanning contact potentiometry method and diffraction of thermal neutrons at physico-mechanical tests of materials" and “Control quality of welded joints of the collector assembly to the branch pipe of steam generator pgv- 1000 by the method of scanning contact potentiometry” won a prize at the end of the conference.
According to the head of the ElphysLAB MEPhI, Associate Professor Vitaly Surin “enterprises of the nuclear industry has already shown interest to the method of scanning contact potentiometry, and the method was successfully tested at Rostov nuclear power plant.” Currently, preparations are under way for an international patent.
