Model 9975 Shipping Package: Impact of Caplug Removal on Fiberboard Moisture Level

摘要

Two 9975 shipping packages were removed from KAC and provided to SRNL for test purposes, after both packages were found to exceed the 1 inch maximum criterion for the axial gap at the top of the package. Package 9975-01818 was found with an axial gap of 1.437 inch, and an estimated 2.5 liters of excess moisture in the lower fiberboard layers. Package 9975-02287 was found with an axial gap of 1.008 inch, and only slightly elevated moisture levels relative to typical packages. Prior data from the 9975 Surveillance Program has shown that the 9975 drum provides a degree of isolation, and will tend to preserve fiberboard moisture levels for an extended period of time. Both packages were provided to SRNL to identify whether removal of the 4 caplugs in each package would allow moisture to escape the package. Following testing with the caplugs removed for approximately 1 year, this report documents the findings from this effort. Two 9975 shipping packages removed from service in K-Area Complex (KAC) due to an excessive axial gap have been tested in SRNL to determine if caplug removal would facilitate the reduction of excess fiberboard moisture. An additional question to be answered through this testing was whether the resulting moisture loss would reduce the axial gap, reversing the effect seen during storage with excess moisture present. These packages have completed approximately 1 year in test, during which time the weight of each package has steadily decreased as a result of moisture migration out of the package. However, elevated moisture levels still remain in the packages. During this test period, the bottom fiberboard layers of package 9975-01818 (which contained the greater amount of excess moisture) experienced further compaction, and the axial gap of both packages has increased. This effort has shown that removal of the caplugs may not be a sufficient measure to rehabilitate packages with excess moisture or excess axial gaps in a timely manner. However, this measure might make a meaningful contribution in combination with other actions (to be determined). It is recommended that the caplug removal tests in SRNL be discontinued at this time.