Abstract
In this work, the transmissibility of gas through the pellet stack of full-length pressurized water reactor (PWR) high burnup (HBU) spent nuclear fuel (SNF) rods is measured at room temperature and correlated to a permeability. Gas transmission and depressurization testing of eight high burn-up fuel rods revealed that gas communication from one end of the pellet stack to the other is unobstructed, but slow, at room temperature. Two traditional flow models, Darcy's Law and Muskat's application of Poiseuille's Law to compressible gas flow through porous media are explored. The derived permeability values for the two methods are compared and are considered in conjunction with rod cladding type and various indicators of rod operation such as burnup, High Duty Core Index (HDCI), and average fuel temperature. The derived permeability appears to be correlated to fuel temperature and maximum HDCI, but not to rod average burnup. Three of the HBU rods were heat-treated to simulate dry storage vacuum drying conditions prior to the measurements and the heat-treatments may have resulted in increased permeability.
| Original language | English |
|---|---|
| Pages (from-to) | 206-215 |
| Number of pages | 10 |
| Journal | Journal of Nuclear Materials |
| Volume | 523 |
| DOIs | |
| State | Published - Sep 2019 |
Funding
The authors wish to thank the staff of the Oak Ridge National Laboratory Irradiated Fuel Examination Laboratory for their help in conducting these demanding tests and the general conduct of operating of the hot cells. We also wish to thank John Scaglione and Bruce Bevard for their support. We also wish to thank the reviewers for their useful comments and in particular for the comments about the physical nature of the appropriate pressure driving function to use. This work is part of a collaborative effort between Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Sandia National Laboratory, and Argonne National Laboratory, funded by the US DOE Office of Nuclear Energy .
Keywords
- Depressurization
- Gas permeability
- Gas transmission
- High burnup
- Pellet stack