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Title: Humidity Data for 9975 Shipping Packages with Softwood Fiberboard

Abstract

The 9975 surveillance program is developing a technical basis to support extending the storage period of 9975 packages in K-Area Complex beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Direct measurements of humidity and fiberboard moisture content have been made on two test packages with softwood fiberboard and varying internal heat levels from 0 up to 19W. Comparable measurements with cane fiberboard have been reported previously. With an internal heat load, a temperature gradient in the fiberboard assembly leads to varying relative humidity in the air around the fiberboard. However, the absolute humidity tends to remain approximately constant throughout the package, especially at lower heat loads.

Authors:
 [1]
  1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Publication Date:
Research Org.:
Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Sponsoring Org.:
USDOE Office of Environmental Management (EM)
OSTI Identifier:
1340199
Report Number(s):
SRNL-STI-2017-00009
TRN: US1701502
DOE Contract Number:
AC09-08SR22470
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; HUMIDITY; HEATING LOAD; STORAGE; TEMPERATURE GRADIENTS; MONITORING; CONTAINERS; SAVANNAH RIVER PLANT; CELLULOSE; DECOMPOSITION; SERVICE LIFE; POWER RANGE 01-10 W; POWER RANGE 10-100 W; K-Area; Fiberboard

Citation Formats

Daugherty, W. L.. Humidity Data for 9975 Shipping Packages with Softwood Fiberboard. United States: N. p., 2017. Web. doi:10.2172/1340199.
Daugherty, W. L.. Humidity Data for 9975 Shipping Packages with Softwood Fiberboard. United States. doi:10.2172/1340199.
Daugherty, W. L.. Thu . "Humidity Data for 9975 Shipping Packages with Softwood Fiberboard". United States. doi:10.2172/1340199. https://www.osti.gov/servlets/purl/1340199.
@article{osti_1340199,
title = {Humidity Data for 9975 Shipping Packages with Softwood Fiberboard},
author = {Daugherty, W. L.},
abstractNote = {The 9975 surveillance program is developing a technical basis to support extending the storage period of 9975 packages in K-Area Complex beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Direct measurements of humidity and fiberboard moisture content have been made on two test packages with softwood fiberboard and varying internal heat levels from 0 up to 19W. Comparable measurements with cane fiberboard have been reported previously. With an internal heat load, a temperature gradient in the fiberboard assembly leads to varying relative humidity in the air around the fiberboard. However, the absolute humidity tends to remain approximately constant throughout the package, especially at lower heat loads.},
doi = {10.2172/1340199},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 12 00:00:00 EST 2017},
month = {Thu Jan 12 00:00:00 EST 2017}
}

Technical Report:

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  • The 9975 surveillance program is identifying a technical basis to support extending the storage period of 9975 packages in KAC beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis.Two efforts have been undertaken to better understand the levels and behavior of moisture within the fiberboard assemblies of the 9975 shipping package. In the first effort, an initial survey of humidity andmore » temperature in the upper air space of 26 packages stored in KAC was made. The data collected within this first effort help to illustrate how the upper air space humidity varies with the local ambient temperature and package heat load. In the second effort, direct measurements of two test packages are providing a correlation between humidity and fiberboard moisture levels within the package, and variations in moisture throughout the fiberboard assembly. This effort has examined packages with cane fiberboard and internal heat levels of 5 and 10W to date. Additional testing is expected to include 15 and 19W heat levels, and then repeat the same four heat levels with softwood fiberboard assemblies. This report documents the data collected to date within these two efforts.« less
  • The 9975 surveillance program is identifying a technical basis to support extending the storage period of 9975 packages in KAC beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis.Two efforts have been undertaken to better understand the levels and behavior of moisture within the fiberboard assemblies of the 9975 shipping package. In the first effort, an initial survey of humidity andmore » temperature in the upper air space of 26 packages stored in KAC was made. The data collected within this first effort help to illustrate how the upper air space humidity varies with the local ambient temperature and package heat load. In the second effort, direct measurements of two test packages are providing a correlation between humidity and fiberboard moisture levels within the package, and variations in moisture throughout the fiberboard assembly. This effort has examined packages with cane fiberboard and internal heat levels of 5 and 10W to date. Additional testing is expected to include 15 and 19W heat levels, and then repeat the same four heat levels with softwood fiberboard assemblies. This report documents the data collected to date within these two efforts.« less
  • The 9975 surveillance program is identifying a technical basis to support extending the storage period of 9975 packages in KAC beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Two efforts have been undertaken to better understand the levels and behavior of moisture within the fiberboard assemblies of the 9975 shipping package. In the first effort, an initial survey of humiditymore » and temperature in the upper air space of 26 packages stored in KAC was made. The data collected within this first effort help to illustrate how the upper air space humidity varies with the local ambient temperature and package heat load. In the second effort, direct measurements of two test packages are providing a correlation between humidity and fiberboard moisture levels within the package, and variations in moisture throughout the fiberboard assembly. This effort has examined packages with cane fiberboard and internal heat levels of 5 and 10W to date. Additional testing is expected to include 15 and 19W heat levels, and then repeat the same four heat levels with softwood fiberboard assemblies. This report documents the data collected to date within these two efforts« less
  • The 9975 surveillance program is developing a technical basis to support extending the storage period of 9975 packages in K-Area Complex beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Direct measurements of humidity and fiberboard moisture content have been made on two test packages with cane fiberboard and varying internal heat levels from 0 up to 19W. With an internalmore » heat load, a temperature gradient in the fiberboard assembly leads to varying relative humidity in the air around the fiberboard. However, the absolute humidity tends to remain approximately constant throughout the package. The moisture content of fiberboard varies under the influence of several phenomena. Changes in local fiberboard temperature (from an internal heat load) can cause fiberboard moisture changes through absorption or evaporation. Fiberboard degradation at elevated temperature will produce water as a byproduct. And the moisture level within the package is constantly seeking equilibrium with that of the surrounding room air, which varies on a daily and seasonal basis. One indicator of the moisture condition within a 9975 package might be obtained by measuring the relative humidity in the upper air space, by inserting a humidity probe through a caplug hole. However, the data indicate that for the higher internal heat loads (15 and 19 watts), a large variation in internal moisture conditions produces little or no variation in the air space relative humidity. Therefore, this approach does not appear to be sensitive to fiberboard moisture variations at the higher heat loads which are of most interest to maintaining fiberboard integrity.« less
  • Samples have been prepared from a softwood fiberboard lower subassembly. Physical, mechanical and thermal properties have been measured following varying periods of conditioning in each of several environments. These tests have been conducted in the same manner as previous testing on cane fiberboard samples. Overall, similar aging trends are observed for softwood and cane fiberboard samples. Some of the observed differences result from the limited exposure periods of the softwood fiberboard samples, and the impact of seasonal humidity levels. Testing following additional conditioning will continue and should eliminate this bias. Post-conditioning data have been measured on a single softwood fiberboardmore » assembly, and baseline data are also available from a limited number of vendor-provided samples. This provides minimal information on the possible sample-to-sample variation exhibited by softwood fiberboard. Data to date are generally consistent with the range seen in cane fiberboard, but much of the compression strength data tends toward the lower end of that range. Further understanding of the variability of softwood fiberboard properties will require testing of additional material. Cane fiberboard wall sheathing is specified for thermal insulation and impact resistance in 9975 shipping packages. Softwood fiberboard manufactured by Knight-Celotex was approved as an acceptable substitute for transportation in 2008. Data in the literature [1] show a consistent trend in thermal properties of fiberboard as a function of temperature, density and/or moisture content regardless of material source. Thermal and mechanical properties were measured for un-aged softwood fiberboard samples, and found to be sufficiently similar to those of un-aged cane fiberboard to support the acceptance of 9975 packages with softwood fiberboard overpack into KAMS for storage. The continued acceptability of aged softwood fiberboard to meet KAMS storage requirements was the subject of subsequent activities. This is an interim status report for experiments carried out per Task Technical Plan WSRC-TR-2008-00024 [2], which is part of the comprehensive 9975 package surveillance program [3]. The primary goal of this task is to validate the preliminary assessment that Knight-Celotex softwood fiberboard is an acceptable substitute for cane fiberboard in the 9975 shipping package overpack, and that the long-term performance of these two materials in a storage environment is comparable.« less