Results 1 - 7 of 7
Results 1 - 7 of 7. Search took: 0.02 seconds
|Sort by: date | relevance|
[en] The long term-durability and the soundness of the plastic pipe have been sufficiently verified through use of the plastic pipe during the past several decades. Recently, as the pipe material have been constantly developed, the application of the plastic pipe is expanded to various industrial fields, such as an increase of a use pressure, the bigger diameter of the pipe, etc. In a nuclear power plant where a carbon steel pipe and a stainless steel pipe are mainly used as a safety class III buried pipe, safety in an operation is seriously threatened by abrasion, heat deterioration or the like, frequently generated in a metal pipe. Therefore, in order to provide an alternate to this problem there is a rising interest on using high-density polyethylene (HDPE) pipes which are known to provide much enhanced corrosion, abrasion and impact resistant properties. With polyethylene piping, one of the issue that is being looked into is the integrity of butt-fusion joint. At the present time the Referencing Code and Standard for the NDT technology of for butt fusion joint of the plastic pipe have not yet established. An optimum inspection parameters were determined according to the thickness of the HDPE pipe. It was also confirmed that most of the detection results of two techniques have matched with each other. In the PAUT, it is easy to distinguish signals with from the flaws made by the thin plate and the void. Also the resolving power of PAUT on the detection in the depth direction has been demonstrated to be satisfactory
[en] In-service inspection plays an important role to assure the integrity of nuclear power plants. A number of studies and experiences such as PISC and IGSCC detection and sizing of BWR brought new requirements of performance demonstration of nondestructive testing system. However, fulfilling the requirements needs huge cost as well as a long period of preparation. Therefore, an effective approach should be pursued not only from the viewpoint of plant safety but also from the viewpoint of cost aspects. The necessities of performance demonstration are acknowledged by all related organizations in Korea, but a lot of methodologies can exist as to how it can be accomplished. This paper presents the worldwide status of performance demonstration in Europe, US, and Korea. And also a Korean perspective on the performance demonstration is discussed.
[en] This study verifies the validation of microwave testing used in the efficient detection of cold fusion on the butt fusion joints of high density polyethylene(HDPE) pipes. The characteristics of HDPE materials, butt fusion joints, and cold fusion, as well as the principles of the microwave testing technique are all described in detail. The PE4710-based cold and sound fusion pipe specimens with diameters of 110mmare fabricated. After microwave technology testing for the specimens is conducted, destructive testing is performed and the test results are discussed
[en] Piping stress analysis has been performed using computer code ANSYS in order to find the stress profile considering thermal stratification phenomena. This kind of analysis can be a useful tool to assist inspection engineer to choose right method and area of inspection during in-service inspection of nuclear power plants. Mechanical fatigue cracks have been generated in order to improve detection reliability of defect ultrasonically since the defects that have been searched for are mostly related to fatigue cracks in pressurized water reactors. (Author)
[en] Like the phase array based ultrasonic system, complicated electronics has been used for real time signal processing in the magnetostrictive long-range ultrasonic testing(LRUT) system. This study shows that the software approach including the phase compensation, noise filtering and waveform transformation takes advantage rather than the previous hardware approach. Furthermore, it is possible for the software approach to be able more flexible and efficient realtime signal processing. These results will contribute to a cost-effective LRUT system and analysis of the inspection data.
[en] Highly Vulnerable area to crack generation has been chosen by calculating the stress and deformation using computer program ANSYS considering thermal stratification phenomena and for weld area, stress distribution has been investigated in order to perform the intensive ISI. The manufacturing of specimens with inside natural crack has been done and basic procedure to manufacture mechanical fatigue crack by implanting fatigue cracked specimen into parent metal has been set up and this will be a great distribution to meet the requirement of ASME code Sec.XI, App.VII and VIII (1989 Ed). (Author)
[en] In this study, a microwave reflection technique was used to detect an abnormal joint in a polyethylene pipe. The polyethylene pipe specimens were fabricated at different welding times; the outer diameter and length or the specimens were 350 mm and 245 mm, respectively. Experimental microwave equipment was organized to transmit and receive the microwave signals at the weld joint parts of polyethylene pipe specimens at frequencies ranging from 12.4 to 18 GHz. The abnormal joint of polyethylene pipe specimens could be fully separated at 13.1 GHz and a linear relationship between the width of bead at polyethylene pipe and microwave reflection signal was found. Consequently, non-contact evaluation of the weld joint part of polyethylene pipes can be possible using the proposed microwave reflection technique