NDTnet 1998 Aug, Vol.3 No.8

Full-Text - Abstract

By innovation of the ultrasonic examination technology with the new UT instrument SAPHIR in connection with a new effective data base-and data evaluation system as well as by the high reliability and efficiency of the utilized equipment and manipulators it was possible during the last years, to cut down the critical path time for occupation of the reactor pool in German PWR nuclear power stations from 6 - 8 days to 3 - 4 days. As a result, the downtimes of the nuclear power stations could be shortened and also the costs of the examination performance itself could be reduced. Additional innovation steps, e. g. the use of advanced robot technique and the increasing application of Phased Array UT probes, are in progress to continue the optimization process of the reactor pressure vessel exam in PWR- as well as in BWR-nuclear power stations.

The UT instrument SAPHIR represents the first unique system, combining the conventional test technology with standard UT probe heads and on-line-data reduction with the advantages of the Phased Array technology. On the one hand by the high number of probe channels (max. 96) and on the other hand by the use of Phased Array probes, being able to cover several various examination tasks by their variable transmit and receive angles, the goal was reached to design a compact probe head assembly, which contains all the necessary probes for simultaneous exam of longitudinal and transverse discontinuities inside thick-wall pieces. Therefore only one single scan is sufficient in each area to be inspected. Especially the examination of geometric complicated objects is made easier and quicker by using Phased Array probe heads.

A newly developed manipulator for the outside examination of the reactor pressure vessel of BWR-nuclear power stations moves on vertical guide rails which are installed on the circumference of the RPV. Utilizing a robot swivel arm it can reach all the areas to be inspected without alterations of the mechanics. In connection with the new concept of the Phased Array probe head assembly, all longitudinal and circumferential welds as well as the nozzles inner radii can be examined very much faster than before, because there is no retrofitting of the probes or the manipulator necessary during the whole examination performance.

For the inside examination of the reactor pressure vessel in PWR-nuclear power stations, a new advanced inspection manipulator is being developed. Two robot arms are attached to a mobile underwater platform which is able to fix itself in the center of the RPV. In that way therobot arms can reach the complete circumference of the vessel wall without repositioning the platform. Therefore the examination performance is much more efficient than with comparable systems.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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