Materials Assessment of Insulating Foam in the 9977 Shipping Package for Long-Term Storage - Annual Report

McWilliams, A. J.¹ 

[1] Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

关键词: 9977 shipping package;    rigid foam;    aging;    degradation;    high temperature;   

DOI  :  10.2172/1305134
RP-ID  :  SRNL-RP--2016-00445
PID  :  OSTI ID: 1305134

学科分类：材料科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

The 9977 shipping package is being evaluated for long-term storage applications in the K-Area Complex (KAC) with specific focus on the packaging foam material. A rigid closed cell polyurethane foam, LAST-A-FOAM?? FR-3716, produced by General Plastics Manufacturing Company is sprayed and expands to fill the void between the inner container and the outer shell of the package. The foam is sealed in this annular space and is not accessible. During shipping and storage, the foam experiences higher than ambient temperatures from the heat generated by nuclear material within the package creating the potential for degradation of the foam. A series of experiments is underway to determine the extent of foam degradation. Foam samples of three densities have been aging at elevated temperatures 160 ?��F, 160 ?��F + 50% relative humidity (RH), 185 ?��F, 215 ?��F, and 250 ?��F since 2014. Samples were periodically removed and tested. After approximately 80 weeks, samples conditioned at 160 ?��F, 160 ?��F + 50% RH, and 185 ?��F have retained initial property values while samples conditioned at 215 ?��F have reduced intumescence. Samples conditioned at 250 ?��F have shown the most degradation, loss of volume, mass, absorbed energy under compression, intumescence, and increased flammability. Based on the initial data, temperatures up to 185 ?��F have not yet shown an adverse effect on the foam properties and it is recommended that exposure of FR-3716 foam to temperatures in excess of 250 ?��F be avoided or minimized. Testing will continue beyond the 96 week mark. This will provide additional data to help define the long-term behavior for the lower temperature conditions. Additional testing will be pursued in an attempt to identify transition points (threshold times and temperatures) at the higher temperatures of interest, as well as possible benefits of aging within the relatively oxygen-free environment the foam experiences inside the 9977 shipping package.