Abstract
NDE investigations using ultrasonic inspections were
performed on core basket bolts at a VVER 440 unit. Bolts
with indications were replaced. Destructive
investigations were performed on three bolts with
indications. These investigations comprised of
microstructural investigations using optical microscopy,
hardness measurements and scanning electron microscopy of
fracture surfaces. The bolts are M12 bolt manufactured
from solution annealed Ti-stabilized stainless steel.
Only one bolt had suffered from cracking. The washer of
this bolt had been welded to the shielding plate, which
had resulted in unintentionally high stresses. The
observed cracking is regarded to be a result of
intergranular stress corrosion cracking, enhanced by
irradiation. The reason for the NDE indications in the
other bolts were incomplete filling of the flat slot of
the bolt head when the bolt was welded to the washer to
prevent unscrewing of the bolt during operation.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of the 15th international Conference on Environmental Degradation of Materials in Nuclear power Systems - Water reactors |
| Editors | Jeremy T. Busby, Gabriel Ilevbare, Peter L. Andresen |
| Publisher | Wiley |
| Pages | 2067-2078 |
| ISBN (Electronic) | 978-1-1184-5683-5 |
| ISBN (Print) | 978-1-1181-3241-8 |
| DOIs | |
| Publication status | Published - 2011 |
| MoE publication type | A4 Article in a conference publication |
| Event | 15th international Conference on Environmental Degradation of Materials in Nuclear power Systems - Water reactors - Colorado Springs, CO, United States Duration: 7 Aug 2011 → 11 Aug 2011 |
Conference
| Conference | 15th international Conference on Environmental Degradation of Materials in Nuclear power Systems - Water reactors |
|---|---|
| Country/Territory | United States |
| City | Colorado Springs, CO |
| Period | 7/08/11 → 11/08/11 |
Keywords
- stainless steel
- irradiated assisted stress corrosion cracking
- failure analysis