NSUF 18-1163: Evaluation of Irradiated Cr Coatings on Zirconium Alloys
The Westinghouse Accident Tolerant Fuel (ATF) utilizes 20 to 30 micron thick cold sprayed coatings of Cr on zirconium alloys for cladding containing >94% of theoretical density U3Si2 pellets. Areas of interest in evaluating the post-irradiated Cr-coated cladding are: 1. Evaluation of oxidation of Cr-coating on zirconium base metal; 2. Characterization of changes in coating structure/porosity; 3. Hydrogen pickup analysis of the underlying zirconium cladding; and 4. Tensile strength changes due to irradiation. Scanning electron microscope (SEM) testing will be used to investigate items 1 and 2. About 1" of the irradiated 4.69" sample will be removed from each tube. A small portion of each will be mounted (in conductive Bakelite) cross-sectionally and longitudinally in the hot cell for metallographic examination using a SEM. Two mounts will be made for each tube, each containing 1 or 2 cross-sectional and transverse specimens. In addition, a small piece of the cladding (no bigger than 3/16"x 3/16") will be retained for SEM topographic characterization. The samples will also be examined to get a qualitative feel for changes in surface features, for instance, growth of dimples when exposed to PWR water. PAXIT or similar software will be used for image analysis. These SEMs will also be provided to the University of Wisconsin to be compared to samples that have been ion irradiated. This comparison will serve as a baseline to evaluate advanced coatings that have also been exposed to ion irradiation.Areas of interest are places where a loss of coating integrity could cause a path from the coolant to the zirconium underneath, and blind porosity where there are dimples and small voids on the surface that possibly get bigger over time due to corrosion of Cr, but have not yet extended through the coating. Also planned is hydrogen analysis of the zirconium tube right under the coating and on the inside diameter of the tube using our hydrogen analyzer to answer item #3. For item #4, tensile testing, dog bones will be made from a 1.5”-long section of the irradiated tubes (two dog bones per tube section) and tensile testing will be performed in our hot cell tensile load frame. This work will be performed from March 1, 2018 to September 30, 2018. This work will provide the first known post-irradiation examination of the Cr cold-sprayed coatings on zirconium and provide insights into the behavior of such coatings in PWR conditions.
Additional Info
| Field | Value |
|---|---|
| Abstract | The Westinghouse Accident Tolerant Fuel (ATF) utilizes 20 to 30 micron thick cold sprayed coatings of Cr on zirconium alloys for cladding containing >94% of theoretical density U3Si2 pellets. Areas of interest in evaluating the post-irradiated Cr-coated cladding are: 1. Evaluation of oxidation of Cr-coating on zirconium base metal; 2. Characterization of changes in coating structure/porosity; 3. Hydrogen pickup analysis of the underlying zirconium cladding; and 4. Tensile strength changes due to irradiation. Scanning electron microscope (SEM) testing will be used to investigate items 1 and 2. About 1" of the irradiated 4.69" sample will be removed from each tube. A small portion of each will be mounted (in conductive Bakelite) cross-sectionally and longitudinally in the hot cell for metallographic examination using a SEM. Two mounts will be made for each tube, each containing 1 or 2 cross-sectional and transverse specimens. In addition, a small piece of the cladding (no bigger than 3/16"x 3/16") will be retained for SEM topographic characterization. The samples will also be examined to get a qualitative feel for changes in surface features, for instance, growth of dimples when exposed to PWR water. PAXIT or similar software will be used for image analysis. These SEMs will also be provided to the University of Wisconsin to be compared to samples that have been ion irradiated. This comparison will serve as a baseline to evaluate advanced coatings that have also been exposed to ion irradiation.Areas of interest are places where a loss of coating integrity could cause a path from the coolant to the zirconium underneath, and blind porosity where there are dimples and small voids on the surface that possibly get bigger over time due to corrosion of Cr, but have not yet extended through the coating. Also planned is hydrogen analysis of the zirconium tube right under the coating and on the inside diameter of the tube using our hydrogen analyzer to answer item #3. For item #4, tensile testing, dog bones will be made from a 1.5”-long section of the irradiated tubes (two dog bones per tube section) and tensile testing will be performed in our hot cell tensile load frame. This work will be performed from March 1, 2018 to September 30, 2018. This work will provide the first known post-irradiation examination of the Cr cold-sprayed coatings on zirconium and provide insights into the behavior of such coatings in PWR conditions. |
| Award Announced Date | 2018-02-01T14:11:57.07 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Catou Cmar |
| Irradiation Facility | None |
| PI | Edward Lahoda |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1163 |