Investigation study for inspection technique and flame of code for inspection

Plant economics is one of important items in FBR development. In present FBR design, large design factor provided in design standards is considered to be one of restriction for the improvement of FBR economics. From such a background, FBR Integrity System Code (FISC), which is for settlement of appropriate design margin, is now under development. Aim of this study is to contribute to the development of this code, and investigation study on inspection technique and flame of code for inspection has been performed. The results of this study are as follows. (1) Study of position of code for inspection. The present code, and standard for inspection and evaluation examples for risk assessment, which is one of method for margin exchange, have been investigated, and inspection accuracy, inspection interval, type of inspection and inspection procedure etc. have been extracted as the standardization item. In these items, first two items, in particular, have a large contribution to rationalization. (2) Investigation of inspection technique. Because the inspection accuracy is one of important item from study item (1), present status of Ultrasonic Testing (UT) technique, which is the one of the method used for ISI, has been investigated. And, monitoring technique, which is effective for rationalization of inspection, has been also investigated. Concerning UT, estimation of detection limit is difficult, but it is considered that detection of 1-2 mm depth crack can be detected by present UT technique. On monitoring technique, fatigue or crack monitoring can contribute to maintenance schedule. (3) Study of flame of code for inspection. Based on the above study results, the standardization items in code for inspection have been extracted, and area and flame of this code have been studied. Because FISC is considered to provide the concrete design procedures, present code and guideline such JEAC and JEAG is considered to be covered in this code. Material inspection included in design code is also included. Route for margin exchange between another code has been studied using the extracted standardization items, and flame of code for inspection has been settled preliminarily. (author)