Further development of moulding technology for underwater applications in nuclear reactors

• Main Author: Nygren, Hanna
• Format: Others
• Language: English
• Published: Uppsala universitet, Materialvetenskap 2010
• Subjects: moulding; non-destructive evaluation; nuclear; polymer compound; Engineering physics; Teknisk fysik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121268

To be able to ensure quality, efficiency and safety in nuclear reactors, non-destructive evaluations (NDE) are performed. The moulding technique, which has been studied in this project, is an NDE method used to verify surface breaking cracks at various objects in reactor vessels. The idea of moulding is to receive a copy of the replicated surface for microscopic analysis. Within forensic science the moulding technique is used at crime scenes to collect evidence and tie suspects to crimes. Underwater moulding, however, is a newly developed technique and WesDyne TRC is a pioneer in offering services within moulding for underwater purposes. This project was initiated by WesDyne TRC to further their knowledge within the moulding technology. In the project, studies have been made at three important parameters effect on cast quality using three different polymer compounds. Problems during moulding, such as crack detection failures and bubbles in the casts, raise the question whether the underwater moulding technique can be trusted to detect cracks. Results from the experiments led to a greater insight into the problem with receiving high quality casts during underwater moulding. Only if a satisfactory cast is made, the moulding method can be trusted to detect defects down to the detection target in both dry and wet environment. To increase the surface quality of underwater casts a suggestion for mould design and a recommended moulding method was developed. In addition, one of the polymer compounds approved for use, turned out not to be suitable for underwater moulding.