Abstract
In a cooperation between Brunsbüttel NPP (KKB) and Studsvik Nuclear AB, a post-irradiation examination (PIE) project is carried out on 13 Special Fuel Rods at the Studsvik Hot Cell Laboratory. The research project includes three focus areas; Basic PIE and characterization of the conditions of the Special Fuel Rods, a study of the drying process for defect rods and determination of the residual moisture content, and a study of hydride reorientation during dry storage (reported in another paper).
The set of 13 Special Fuel Rods is composed of rods of different fuel rod designs and manufactured by different vendors, which is representative of the fuel used in KKB over its operational life. Twelve defect rods represent a wide range of several important failure mechanisms, including classical pellet cladding interaction (PCI), PCI with secondary degradation, fretting and fretting with secondary degradation. The defects observed are tight cladding breakthroughs, small penetrations, axial cracks and circular cracks. Two rods have also experienced significant fuel loss, one at a transversal break of the rod and another with a large loss of cladding which exposed the fuel to the coolant.
The 13 Special Fuel Rods were shipped to Studsvik Hot Cell Laboratory in February 2018. Handling and preparations for transport from KKB is described in [1]. This reference also includes basic data on the rods and an overview of the PIE program. The early stage of the project included basic PIE, non-destructive and some destructive characterization of the fuel rods and of the failure sites. Selected parts of this work was reported in a 2019 TopFuel paper [2]. The PIE project has since progressed, and more detailed destructive characterization examinations have been performed including hydrogen measurements, mechanical bend testing, dewpoint measurements and loss-on-drying tests. This paper presents selected results obtained from examinations and tests performed since 2019.
The set of 13 Special Fuel Rods is composed of rods of different fuel rod designs and manufactured by different vendors, which is representative of the fuel used in KKB over its operational life. Twelve defect rods represent a wide range of several important failure mechanisms, including classical pellet cladding interaction (PCI), PCI with secondary degradation, fretting and fretting with secondary degradation. The defects observed are tight cladding breakthroughs, small penetrations, axial cracks and circular cracks. Two rods have also experienced significant fuel loss, one at a transversal break of the rod and another with a large loss of cladding which exposed the fuel to the coolant.
The 13 Special Fuel Rods were shipped to Studsvik Hot Cell Laboratory in February 2018. Handling and preparations for transport from KKB is described in [1]. This reference also includes basic data on the rods and an overview of the PIE program. The early stage of the project included basic PIE, non-destructive and some destructive characterization of the fuel rods and of the failure sites. Selected parts of this work was reported in a 2019 TopFuel paper [2]. The PIE project has since progressed, and more detailed destructive characterization examinations have been performed including hydrogen measurements, mechanical bend testing, dewpoint measurements and loss-on-drying tests. This paper presents selected results obtained from examinations and tests performed since 2019.
| Original language | English |
|---|---|
| Title of host publication | 2021 TopFuel conference proceedings |
| Publisher | European Nuclear Society (ENS) |
| ISBN (Electronic) | 978-92-95064-35-5 |
| Publication status | Published - 2021 |
| MoE publication type | A4 Article in a conference publication |
| Event | TopFuel conference 2021 - Santander, Spain Duration: 24 Oct 2021 → 28 Oct 2021 |
Conference
| Conference | TopFuel conference 2021 |
|---|---|
| Country/Territory | Spain |
| City | Santander |
| Period | 24/10/21 → 28/10/21 |