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Mechanistic Modeling of Porosity in Hanford 3013 Outer Container Welds

Description: One of the current priorities within the Department of Energy (DOE) complex is the stabilization, packaging and storage of plutonium-bearing materials. The packaging is key to the safe long-term handling and storage of these materials. Packaging consists of placing the stabilized materials into a set of two nested stainless steel containers. Each container is seal-welded, providing double containment of the plutonium materials. The outer container is designated as the primary barrier to the release of the materials to the environment. An initial, full scope diagnostic analysis of the equipment, welding materials / consumables and process conditions identified the primary cause of the porosity to be related to geometry at the root of the weld joint preparation. A volume of gas is trapped between the advancing weld puddle and the start of the weld, at weld tie-in, and incorporated into the weld during puddle solidification. Figure 5 illustrates the basic geometric conditions contributing to the porosity. This paper describes the efforts to analyze and understand / quantify the interaction between the weld-joint geometry and formation of porosity.
Date: November 26, 2002
Creator: Daugherty, W.L.
Partner: UNT Libraries Government Documents Department

A Study of Weld Porosity in Containers for the Storage of Plutonium Containing Materials

Description: An autogenous GTAW closure weld was developed for the Department of Energy's (DOE) primary container for the storage of plutonium-bearing materials. The occurrence of porosity at the tie-in point of the closure weld was investigated. The primary cause of the porosity was linked to the geometry at the root of the closure weld joint. This paper describes the mechanistic model that was developed to describe and predict the porosity.
Date: April 21, 2003
Creator: Daugherty, W.L.
Partner: UNT Libraries Government Documents Department

PROPERTIES OF FIBERBOARD OVERPACK MATERIAL IN THE 9975 SHIPPING PACKAGE FOLLOWING THERMAL AGING

Description: Many radioactive material shipping packages incorporate cane fiberboard overpacks for thermal insulation and impact resistance. Mechanical, thermal and physical properties have been measured on cane fiberboard following thermal aging in several temperature/humidity environments. Several of the measured properties change significantly over time in the more severe environments, while other properties are relatively constant. These properties continue to be tracked, with the goal of developing a model for predicting a service life under long-term storage conditions.
Date: January 10, 2007
Creator: Daugherty, W
Partner: UNT Libraries Government Documents Department

Status Report - Cane Fiberboard Properties and Degradation Rates for Storage of the 9975 Shipping Package in KAMS

Description: Thermal, mechanical and physical properties have been measured on cane fiberboard samples following accelerated aging for up to approximately 7 years. The aging environments have included elevated temperature < 250 ?F (the maximum allowed service temperature for fiberboard in 9975 packages) and elevated humidity. The results from this testing have been analyzed, and aging models fit to the data. Correlations relating several properties (thermal conductivity, energy absorption, weight loss and height decrease) to their rate of change in potential storage environments have been developed. Combined with an estimate of the actual conditions the fiberboard experiences in KAMS, these models allow development of service life predictions. Some of the predicted degradation rates presented in this report are relatively extreme. However, these relate to environments that do not exist within KAMS, or would be postulated only as upset conditions that would not likely persist for an extended period. For a typical package with ~10 watts internal heat load or less, and ambient temperatures below 90 ?F, the fiberboard experiences storage conditions less severe than any of the aging environments. Little or no degradation of the fiberboard is expected for typical storage conditions. It should be noted that the ultimate service life will be determined by the cumulative effect of degradation from all the conditions these packages might encounter. The assumptions and inputs behind the models in this report should be well understood before attempting to identify an actual service life in KAMS. Additional data continue to be collected to permit future refinements to the models and assumptions. For developing service life predictions, the ambient conditions within KAMS can be reasonably identified, and the temperature profiles within the various packages (with a range of heat loads and at varying locations within an array of packages) can be calculated. However, the humidity within the ...
Date: January 31, 2013
Creator: Daugherty, W. L.
Partner: UNT Libraries Government Documents Department

DESTRUCTIVE EXAMINATION OF SHIPPING PACKAGE 9975-00600

Description: The Savannah River Site (SRS) stores packages containing plutonium (Pu) materials in the K-Area Complex (KAC). The Pu materials are packaged per the DOE 3013 Standard and stored within Model 9975 shipping packages in KAC. The KAC facility DSA (Document Safety Analysis) [1] credits the Model 9975 package to perform several safety functions, including criticality, impact resistance, containment, and fire resistance to ensure the plutonium materials remain in a safe configuration during normal and accident conditions. The Model 9975 package is expected to perform its safety function for at least 12 years from initial packaging. The DSA recognizes the degradation potential for the materials of package construction over time in the KAC storage environment and requires an assessment of materials performance to validate the assumptions of the analysis and ultimately predict service life. As part of the comprehensive Model 9975 package surveillance program [2-3], destructive examination of package 9975-00600 was performed following field surveillance in accordance with Reference [4]. Field surveillance of the Model 9975 package in KAC included nondestructive examination of the drum, fiberboard, lead shield and containment vessels [5]. Results of the field surveillance are provided in Attachment 1. Destructive and non-destructive examinations have been performed on specified components of shipping package 9975-00600. For those attributes that were also measured during the field surveillance, no significant changes were observed. Three conditions were identified that do not meet inspection criteria. These conditions are subject to additional investigation and disposition by the Surveillance Program Authority. The conditions include: (1) The lead shield was covered with a white corrosion layer; (2) The lead shield height dimension exceeded drawing requirements; and (3) Fiberboard thermal conductivity in the axial direction exceeded the specified range. The Surveillance Program Authority was notified of these conditions. All other observations and test results met identified criteria, or ...
Date: October 29, 2007
Creator: Daugherty, W
Partner: UNT Libraries Government Documents Department

DESTRUCTIVE EXAMINATION OF SHIPPING PACKAGE 9975-02168

Description: The Savannah River Site (SRS) stores packages containing plutonium (Pu) materials in the K-Area Complex (KAC). The Pu materials are packaged per the DOE 3013 Standard and stored within Model 9975 shipping packages in KAC. The KAC facility DSA (Document Safety Analysis) credits the Model 9975 package to perform several safety functions, including criticality prevention, impact resistance, containment, and fire resistance to ensure the plutonium materials remain in a safe configuration during normal and accident conditions. The Model 9975 package is expected to perform its safety function for at least 12 years from initial packaging. The DSA recognizes the degradation potential for the materials of package construction over time in the KAC storage environment and requires an assessment of materials performance to validate the assumptions of the analysis and ultimately predict service life. As part of the comprehensive Model 9975 package surveillance program, destructive examination of package 9975-02028 was performed following field surveillance in accordance with Reference. Field surveillance of the Model 9975 package in KAC included nondestructive examination of the drum, fiberboard, lead shield and containment vessels. Results of the field surveillance are provided in Attachment 1. Destructive and non-destructive examinations have been performed on specified components of shipping package 9975-02168. For those attributes that were also measured during the field surveillance, no significant changes were observed. Two conditions were identified that do not meet inspection criteria. These conditions are subject to additional investigation and disposition by the Surveillance Program Authority. The conditions include: (1) The lead shield was covered with a white corrosion layer, and (2) Fiberboard thermal conductivity in the axial direction exceeded the specified range. The Surveillance Program Authority was notified of these conditions and will document the findings by surveillance report. All other observations and test results met identified criteria, or were collected for information ...
Date: November 18, 2010
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

DESTRUCTIVE EXAMINATION OF SHIPPING PACKAGE 9975-03431

Description: Destructive and non-destructive examinations have been performed on specified components of shipping package 9975-03431. For those attributes that were also measured during the field surveillance, no significant changes were observed. All observations and test results met identified criteria, or were collected for information and trending purposes. Except for modest corrosion of the lead shield (which is typical of these packages following several years service), no evidence of a degraded condition was found in this package. The Savannah River Site (SRS) stores packages containing plutonium (Pu) materials in the KArea Complex (KAC). The Pu materials are packaged per the DOE 3013 Standard and stored within Model 9975 shipping packages in KAC. The KAC facility DSA (Document Safety Analysis) credits the Model 9975 package to perform several safety functions, including criticality prevention, impact resistance, containment, and fire resistance to ensure the plutonium materials remain in a safe configuration during normal and accident conditions. The Model 9975 package is expected to perform its safety function for at least 12 years from initial packaging. The DSA recognizes the degradation potential for the materials of package construction over time in the KAC storage environment and requires an assessment of materials performance to validate the assumptions of the analysis and ultimately predict service life. As part of the comprehensive Model 9975 package surveillance program, destructive examination of package 9975-03431 was performed following field surveillance in accordance with Reference. Field surveillance of the Model 9975 package in KAC included nondestructive examination of the drum, fiberboard, lead shield and containment vessels. Results of the field surveillance are provided in Attachment 1.
Date: May 30, 2012
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

EXAMINATION OF FIBERBOARD FROM SHIPPING PACKAGE 9975-01819

Description: Upon opening package 9975-01819 following approximately 5.5 years storage in KAMS, it was observed that the fiberboard was moldy, and the total height of the fiberboard assemblies was less than normal. Observations and measurements have since been made on three subsequent occasions. The available information indicates that the package contained approximately 2.5 liters of water in excess of what would normally exist within the fiberboard. This excess moisture led to a significant loss of fiberboard strength, the subsequent compression of the bottom layers, and the growth of mold observed on both the upper and lower fiberboard assemblies. In its current state, the fiberboard from this package retains a density (related to the criticality control function) within the range measured in other packages. The amount of excess moisture present is modest throughout most of the fiberboard, and its effect on thermal conductivity should be small. The thermal conductivity should increase significantly only near the bottom of the lower fiberboard assembly where the majority of excess moisture was found. The impact absorption capability is affected, and the ability of the fiberboard to perform this function in the current state must be evaluated. The longer such a condition persists, the greater the impact on fiberboard mechanical properties.
Date: April 14, 2009
Creator: Daugherty, W
Partner: UNT Libraries Government Documents Department

EXAMINATION OF SHIPPING PACKAGES 9975-01818, 9975-01903 AND 9975-02287

Description: Three 9975 shipping packages were examined to investigate the non-conforming condition of an axial air gap greater than 1 inch. This condition typically indicates the presence of excess moisture in the fiberboard overpack, and may be accompanied by degradation in the fiberboard properties. The package with the largest axial air gap (9975-01818, with an air gap of 1.437 inches) was found to contain significant excess moisture, and the lower fiberboard assembly was covered with mold and was significantly degraded in strength. This condition is very similar to that observed previously in package 9975-01819. Both packages (-1818 and -1819) appear to contain a similar amount of excess moisture, which was previously estimated for 9975-01819 as {approx}2.5 liters. The condition of 9975-01818 was also evidenced by several rust spots along the bottom chime of the drum, although no significant rust was noted on the closure bolts. Packages 9975-01903 and 9975-02287 were also examined. The axial air gap in these two packages was less than in 9975-01818, but still exceeded 1 inch. These two packages contained elevated moisture levels, although not significantly higher than seen in other 'typical' packages. The fiberboard in these two packages was of sound integrity, and appeared generally consistent with undegraded material. A few small patches of mold on and near the bottom of the fiberboard in 9975-01903 appeared dormant. No mold was observed on package 9975-02287. The SPA will provide recommendations on possible follow-up activities with these three packages. This might include a demonstration in SRNL of whether removal of the caplugs from similar packages would facilitate removal of excess moisture. Future efforts should also include an assessment of using the 1 inch axial gap criterion as a valid indicator of fiberboard degradation.
Date: November 18, 2009
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

EXAMINATION OF SHIPPING PACKAGES 9975-01968, 9975-04353 AND 9975-06870

Description: Three 9975 shipping packages were examined to investigate the non-conforming condition of an axial air gap greater than 1 inch. This condition typically indicates the presence of excess moisture in the fiberboard overpack, and may be accompanied by degradation in the fiberboard properties. In the case of these three packages, no excess moisture was present, and the fiberboard was not visibly degraded. However, the lower fiberboard assembly from 9975-06870 was separated into two pieces. The lead shield from 9975-04353 was heavily corroded, while the shield from 9975-01968 had very little corrosion. In the case of 9975-06870, the shield was covered by a stainless steel sleeve, and the condition of the lead was not observed. No other conditions of concern were observed in these three packages.
Date: April 26, 2010
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

EXAMINATION OF SHIPPING PACKAGES 9975-02274 AND 9975-04769

Description: Shipping packages 9975-02274 and 9975-04769 were examined in K-Area following the identification of a non-conforming condition; the axial gap between the drum flange and upper fiberboard assembly exceeded the maximum allowed value of 1 inch. The fiberboard in package 9975-02274 had slightly elevated moisture content, up to 19% wood moisture equivalent (WME). Other compliant packages have displayed similar moisture levels locally, but not as consistently throughout the entire fiberboard assembly. Evidence of mold was observed on the lower assembly, although it appeared relatively dormant. Relatively little compaction or physical degradation was observed in this package. Due to the mold, it is recommended that the fiberboard in this package not be re-used. The fiberboard in package 9975-04769 was relatively dry (7-10% WME) and showed no sign of compaction or physical degradation. Variations in the axial gap that have been measured on this package result from variations in the height of the upper and lower fiberboard assemblies, and their relative orientation to each other. The fiberboard in this package is physically sound and considered fit for continued use.
Date: December 20, 2011
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

MODEL 9975 LIFE EXTENSION PACKAGE 1 - FINAL REPORT

Description: Life extension package LE1 (9975-03382) was instrumented and subjected to a temperature/humidity environment that bounds KAMS package storage conditions for 92 weeks. During this time, the maximum fiberboard temperature was {approx}180 F, and was established by a combination of internal heat (12 watts) and external heat ({approx}142 F). The relative humidity external to the package was maintained at 80 %RH. This package was removed from test in November 2010 after several degraded conditions were observed during a periodic examination. These conditions included degraded fiberboard (easily broken, bottom layer stuck to the drum), corrosion of the drum, and separation of the air shield from the upper fiberboard assembly. Several tests and parameters were used to characterize the package components. Results from these tests generally indicate agreement between this full-scale shipping package and small-scale laboratory tests on fiberboard and O-ring samples. These areas of agreement include the rate of fiberboard weight loss, change in fiberboard thermal conductivity, fiberboard compression strength, and O-ring compression set. In addition, this package provides an example of the extent to which moisture within the fiberboard can redistribute in the presence of a temperature gradient such as might be created by a 12 watt internal heat load. Much of the moisture near the fiberboard ID surface migrated towards the OD surface, but there was not a significant axial moisture gradient during most of the test duration. Only during the last inspection period (i.e. after 92 weeks exposure during the second phase) did enough moisture migrate to the bottom fiberboard layers to cause saturation. A side effect of moisture migration is the leaching of soluble compounds from the fiberboard. In particular, the corrosion observed on the drum appears related primarily to the leaching and concentration of chlorides. In most locations, this attack appears to be general corrosion, with shallow ...
Date: March 4, 2011
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

MODEL 9975 LIFE EXTENSION PACKAGE 2 FINAL REPORT

Description: Life extension package LE2 (9975-04162) was instrumented and subjected to an extreme temperature environment for 81 weeks. During this time, the maximum fiberboard temperature was {approx}240 - 250 degrees F, and was established by a combination of internal heat (19 watts) and external heat. This temperature matches the fiberboard continuous service rating, although such extremes are not expected for normal operation in KAMS. Several tests and parameters were used to characterize the package components. Results from these tests generally indicate agreement between this full-scale shipping package and small-scale laboratory tests on fiberboard and O-ring samples. These areas of agreement include the rate of fiberboard weight loss, change in fiberboard thermal conductivity, fiberboard compression strength, and O-ring compression set. In addition, this package provides an example of the extent to which moisture within the fiberboard can redistribute in the presence of a temperature gradient such as might be created by a 19 watt internal heat load. Moisture re distribution in this package was further exaggerated by a majority of the fiberboard being heated to above the boiling point of water. The majority of water within the fiberboard migrated to the bottom layers of fiberboard, where it contributed to accelerated degradation beyond that expected based solely on the temperature.
Date: April 27, 2010
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

MODEL 9975 SHIPPING PACKAGE: IMPACT OF CAPLUG REMOVAL ON FIBERBOARD MOISTURE LEVEL

Description: 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 ...
Date: June 23, 2011
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

FIRST STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

Description: 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 fiberboard 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], ...
Date: January 8, 2010
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

FOURTH STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

Description: Samples have been prepared from a 9975 lower fiberboard subassembly fabricated from softwood fiberboard. 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, with a few differences. Some softwood fiberboard properties tend to degrade faster in elevated humidity environments, while some cane fiberboard properties degrade faster in the hotter dry environments. As a result, it is premature to assume both materials will age at the same rates, and the preliminary aging models developed for cane fiberboard might not apply to softwood fiberboard. However, it is expected that both cane and softwood fiberboard assemblies will perform satisfactorily in conforming packages stored in a typical KAMS environment for up to 15 years. Aging and testing of softwood fiberboard will continue and additional data will be collected. Post-conditioning data have been measured on samples from a single softwood fiberboard 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 some portions of the data trends are skewed toward the lower end of that range. Further understanding of the variability of softwood fiberboard properties will require testing of additional material.
Date: March 5, 2013
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

REVIEW OF CLEANING SOLUTIONS FOR USE ON COMPONENTS OF THE 9975 SHIPPING PACKAGE

Description: Several candidate cleaning products have been reviewed for use as a disinfectant on 9975 shipping package components which contain or have contacted mold. Following review of the compatibility of these products with each component, ammonia (ammonium hydroxide diluted to 1.5 wt% concentration) appears compatible with all package components that it might contact. Each of the other candidate products is incompatible with one or more package components. Accordingly, ammonia is recommended for this purpose. It is further recommended that all components which are disinfected be subsequently rinsed with di-ionized or distilled water.
Date: September 30, 2013
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

SIXTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

Description: A series of experiments to monitor the aging performance of Viton{reg_sign} GLT O-rings used in the Model 9975 package has been ongoing for seven years at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues for 33 GLT O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 F and higher temperatures, and in 7 fixtures aging at 300 F. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 41-60 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 F will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging within the past year at an intermediate temperature of 270 F, with hopes that they may leak before the 200 F fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 F. No failures have yet been observed in GLT-S O-ring fixtures aging at 200-300 F for up to 26 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the Orings displayed a compression set ranging from 51-96%. This is greater than seen to date for packages inspected ...
Date: August 31, 2011
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

SEVENTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

Description: A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 54-72 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 30 - 36 months. For O-ring fixtures that ...
Date: August 30, 2012
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

ANALYSIS OF THE AXIAL GAP VS FIBERBOARD MOISTURE CONTENT IN A 9975 SHIPPING PACKAGE

Description: The fiberboard assembly within a 9975 shipping package contains a modest amount of moisture, which can migrate to the cooler regions of the package when an internal heat load is present. Typically, this leads to increased moisture levels in the bottom fiberboard layers, along with elevated chloride levels which can leach from the fiberboard. Concerns have been raised that this condition could lead to corrosion of the stainless steel drum. It has been postulated that checking the axial gap at the top of the package against the current 1 inch maximum criterion provides a sufficient indication regarding the integrity of the fiberboard and drum. This report estimates the increase in axial gap that might be expected for a given moisture increase in the bottom fiberboard layers, and the likelihood that the increase will create a nonconforming condition that will lead to identification of the moisture increase. Using data relating the fiberboard moisture content with the degree of compaction under load, the present analysis indicates that the axial gap will increase by 0.282 inch as the bottom fiberboard layers approach the saturation point. This increase will cause approximately 58% of packages with otherwise nominal package component dimensions to fail the axial gap criterion, based on a survey of axial gap values recorded in K-Area surveillance activities. As the moisture content increases above saturation, the predicted increase in axial gap jumps to 0.405 inch, which would result in 92% or more of all packages failing the axial gap criterion. The data and analysis described in this report are specific to cane fiberboard. While it is expected that softwood fiberboard will behave similarly, such behavior has not yet been demonstrated.
Date: September 30, 2013
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

EIGHTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

Description: A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 61 - 85 months, which is still bounding to O-ring temperatures during storage in KArea Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leaktight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 41 - 45 months. Aging and ...
Date: September 3, 2013
Creator: Daugherty, W. L.
Partner: UNT Libraries Government Documents Department

SECOND STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

Description: 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, with a few differences. On the positive side, the softwood fiberboard data to date shows less sample-to-sample variation in physical properties than cane fiberboard, and the thermal conductivity decreases at a slower rate at 250F for softwood fiberboard than for cane fiberboard. On the other hand, the softwood fiberboard physical property samples generally show degradation rates greater than cane fiberboard samples in the 185F 30%RH environment. Testing following additional conditioning will continue and the addition of samples in other elevated humidity environment(s) will be pursued to identify the extent of these trends. Post-conditioning data have been measured on samples from a single softwood fiberboard 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 some portions of the data trends are skewed toward the lower end of that range. Further understanding of the variability of softwood fiberboard properties will require testing of additional material.
Date: December 27, 2010
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

THIRD STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

Description: Samples have been prepared from a 9975 lower fiberboard subassembly fabricated from softwood fiberboard. 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, with a few differences. There is no clear trend thus far to indicate one material ages in a manner significantly different from the other material. Some softwood fiberboard properties degrade faster in some environments, while cane fiberboard degrades faster with regards to other properties and environments. Given the limited aging time accumulated to date in the elevated humidity environments, it is recommended that aging and testing of softwood fiberboard continue for another year. Post-conditioning data have been measured on samples from a single softwood fiberboard 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 some portions of the data trends are skewed toward the lower end of that range. Further understanding of the variability of softwood fiberboard properties will require testing of additional material.
Date: December 13, 2011
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department