16 Matching Results

Search Results

Advanced search parameters have been applied.

REVIEW OF AGING DATA ON EPDM O-RINGS IN THE H1616 SHIPPING PACKAGE

Description: Currently, all H1616 shipping package containers undergo annual re-verification testing, including containment vessel leak testing to verify leak-tightness (<1 x 10{sup -7} ref cc/sec air) as per ANSI N14.5. The purpose of this literature review is to supplement aging studies currently being performed by SRNL on the EPDM O-rings to provide the technical basis for extending annual re-verification testing for the H1616 shipping package and to predict the life of the seals at bounding service conditions. The available data suggest that the EPDM O-rings can retain significant mechanical properties and sealing force at or below bounding service temperatures (169 F or 76 C) beyond the 1 year maintenance period. Interpretation of available data suggests that a service life of at least 2 years and potentially 4-6 years may be possible at bounding temperatures. Seal lifetimes at lower, more realistic temperatures will likely be longer. Being a hydrocarbon elastomer, EPDM O-rings may exhibit an inhibition period due to the presence of antioxidants. Once antioxidants are consumed, mechanical properties and seal performance could decline at a faster rate. Testing is being performed to validate the assumptions outlined in this report and to assess the long-term performance of O-ring seals under actual service conditions.
Date: March 27, 2012
Creator: Skidmore, E.
Partner: UNT Libraries Government Documents Department

THE USE OF POLYMERS IN RADIOACTIVE WASTE PROCESSING SYSTEMS

Description: The Savannah River Site (SRS), one of the largest U.S. Department of Energy (DOE) sites, has operated since the early 1950s. The early mission of the site was to produce critical nuclear materials for national defense. Many facilities have been constructed at the SRS over the years to process, stabilize and/or store radioactive waste and related materials. The primary materials of construction used in such facilities are inorganic (metals, concrete), but polymeric materials are inevitably used in various applications. The effects of aging, radiation, chemicals, heat and other environmental variables must therefore be understood to maximize service life of polymeric components. In particular, the potential for dose rate effects and synergistic effects on polymeric materials in multivariable environments can complicate compatibility reviews and life predictions. The selection and performance of polymeric materials in radioactive waste processing systems at the SRS are discussed.
Date: April 15, 2013
Creator: Skidmore, E. & Fondeur, F.
Partner: UNT Libraries Government Documents Department

LIFETIME PREDICTION FOR MODEL 9975 O-RINGS IN KAMS

Description: The Savannah River Site (SRS) is currently storing plutonium materials in the K-Area Materials Storage (KAMS) facility. The materials are packaged per the DOE 3013 Standard and transported and stored in KAMS in Model 9975 shipping packages, which include double containment vessels sealed with dual O-rings made of Parker Seals compound V0835-75 (based on Viton{reg_sign} GLT). The outer O-ring of each containment vessel is credited for leaktight containment per ANSI N14.5. O-ring service life depends on many factors, including the failure criterion, environmental conditions, overall design, fabrication quality and assembly practices. A preliminary life prediction model has been developed for the V0835-75 O-rings in KAMS. The conservative model is based primarily on long-term compression stress relaxation (CSR) experiments and Arrhenius accelerated-aging methodology. For model development purposes, seal lifetime is defined as a 90% loss of measurable sealing force. Thus far, CSR experiments have only reached this target level of degradation at temperatures {ge} 300 F. At lower temperatures, relaxation values are more tolerable. Using time-temperature superposition principles, the conservative model predicts a service life of approximately 20-25 years at a constant seal temperature of 175 F. This represents a maximum payload package at a constant ambient temperature of 104 F, the highest recorded in KAMS to date. This is considered a highly conservative value as such ambient temperatures are only reached on occasion and for short durations. The presence of fiberboard in the package minimizes the impact of such temperature swings, with many hours to several days required for seal temperatures to respond proportionately. At 85 F ambient, a more realistic but still conservative value, bounding seal temperatures are reduced to {approx}158 F, with an estimated seal lifetime of {approx}35-45 years. The actual service life for O-rings in a maximum wattage package likely lies higher than the estimates due to ...
Date: November 24, 2009
Creator: Hoffman, E. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE

Description: The Department of Energy Savannah River Site vitrifies nuclear waste incident to defense programs through its Defense Waste Processing Facility (DWPF). The piping in the DWPF seal pot jumper configuration must withstand the stresses during an unlikely but potential deflagration event, and maintain its safety function for a 20-year service life. Carbon fiber-reinforced epoxy composites (CFR) were proposed for protection and reinforcement of piping during such an event. The proposed CFR materials have been ASME-approved (Section XI, Code Case N-589-1) for post-construction maintenance and is DOT-compliant per 49CFR 192 and 195. The proposed carbon fiber/epoxy composite reinforcement system was originally developed for pipeline rehabilitation and post-construction maintenance in petrochemical, refineries, DOT applications and other industries. The effects of ionizing radiation on polymers and organic materials have been studied for many years. The majority of available data are based on traditional exposures to gamma irradiation at high dose rates ({approx}10,000 Gy/hr) allowing high total dose within reasonable test periods and general comparison of different materials exposed at such conditions. However, studies in recent years have shown that degradation of many polymers are sensitive to dose rate, with more severe degradation often observed at similar or even lower total doses when exposed to lower dose rates. This behavior has been primarily attributed to diffusion-limited oxidation which is minimized during very high dose rate exposures. Most test standards for accelerated aging and nuclear qualification of components acknowledge these limitations. The results of testing to determine the radiation resistance and microstructural effects of gamma irradiation exposure on a bisphenol-A based epoxy matrix composite reinforced with carbon fibers are presented. This work provides a foundation for a more extensive evaluation of dose rate effects on advanced epoxy reinforced composites.
Date: December 12, 2008
Creator: Hoffman, E & Eric Skidmore, E
Partner: UNT Libraries Government Documents Department

MATERIAL COMPATIBILITY EVALUATION FOR DWPF NITRIC-GLYCOLIC ACID - LITERATURE REVIEW

Description: Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reported corrosion rates and degradation characteristics have shown the following for the materials of construction.  For C276 alloy, the primary material of construction for the CPC vessels, corrosion rates of either 2 or 20 mpy were reported up to a temperature of 93 C.  For the austenitic stainless steels, 304L and 316L, variable rates were reported over a range of temperatures, varying from 2 mpy up to 200 mpy (at 100 C).  For 690, G30, Allcorr, Ultimet and Stellite alloys no data were available.  For relevant polymers where data are available, the data suggests that exposure to glycolic acid is not detrimental. The literature data had limited application to the DWPF process since only the storage and feed vessels, pumps and piping used to handle the glycolic acid are directly covered by the available data. These components are either 304L or 316L alloys for which the literature data is inconsistent (See Bullet 2 above). Corrosion rates in pure glycolic acid solutions also are not representative of the DWPF process streams. This stream is complex and contains aggressive species, i.e. chlorides, sulfates, mercury, as well as antifoaming agents which cumulatively have an unknown effect on the corrosion rates ...
Date: June 5, 2013
Creator: Mickalonis, J. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

STATUS REPORT FOR AGING STUDIES OF EPDM O-RING MATERIAL FOR THE H1616 SHIPPING PACKAGE

Description: This is an interim status report for tasks carried out per Task Technical Plan SRNL-STI-2011-00506. A series of tasks/experiments are being performed at the Savannah River National Laboratory to monitor the aging performance of ethylene propylene diene monomer (EPDM) Orings used in the H1616 shipping package. The data will support the technical basis to extend the annual maintenance of the EPDM O-rings in the H1616 shipping package and to predict the life of the seals at bounding service conditions. Current expectations are that the O-rings will maintain a seal at bounding normal temperatures in service (152 F) for at least 12 months. The baseline aging data review suggests that the EPDM O-rings are likely to retain significant mechanical properties and sealing force at bounding service temperatures to provide a service life of at least 2 years. At lower, more realistic temperatures, longer service life is likely. Parallel compression stress relaxation and vessel leak test efforts are in progress to further validate this assessment and quantify a more realistic service life prediction. The H1616 shipping package O-rings were evaluated for baseline property data as part of this test program. This was done to provide a basis for comparison of changes in material properties and performance parameters as a function of aging. This initial characterization was limited to physical and mechanical properties, namely hardness, thickness and tensile strength. These properties appear to be consistent with O-ring specifications. Three H1616-1 Containment Vessels were placed in test conditions and are aging at temperatures ranging from 160 to 300 F. The vessels were Helium leak-tested initially and have been tested at periodic intervals after cooling to room temperature to determine if they meet the criterion of leaktightness defined in ANSI standard N14.5-97 (< 1E-07 std cc air/sec at room temperature). To date, no leak test ...
Date: August 31, 2012
Creator: Stefek, T.; Daugherty, W. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

Application of wind energy to Great Plains irrigation pumping. Final report

Description: Wind energy systems without energy storage for irrigation in the Great Plains are studied. Major uses of irrigation energy were identified as pumping for surface distribution systems, which could be supplied by variable flow, and pumping for sprinkler systems using constant flow. A computer program was developed to simulate operation of wind-powered irrigation wells. Pumping by wind turbine systems was simulated for 2 variable and 2 constant flow operational modes in which auxiliary motors were used in 3 of the modes. Using the simulation program, the well yields and maximum pumping rates among the 4 modes as a function of drawdown in a typical well are compared.
Date: October 1, 1979
Creator: Hagen, L.J.; Lyles, L. & Skidmore, E.L.
Partner: UNT Libraries Government Documents Department

LEVERAGING AGING MATERIALS DATA TO SUPPORT EXTENSION OF TRANSPORTATION SHIPPING PACKAGES SERVICE LIFE

Description: Nuclear material inventories are increasingly being transferred to interim storage locations where they may reside for extended periods of time. Use of a shipping package to store nuclear materials after the transfer has become more common for a variety of reasons. Shipping packages are robust and have a qualified pedigree for performance in normal operation and accident conditions but are only certified over an approved transportation window. The continued use of shipping packages to contain nuclear material during interim storage will result in reduced overall costs and reduced exposure to workers. However, the shipping package materials of construction must maintain integrity as specified by the safety basis of the storage facility throughout the storage period, which is typically well beyond the certified transportation window. In many ways, the certification processes required for interim storage of nuclear materials in shipping packages is similar to life extension programs required for dry cask storage systems for commercial nuclear fuels. The storage of spent nuclear fuel in dry cask storage systems is federally-regulated, and over 1500 individual dry casks have been in successful service up to 20 years in the US. The uncertainty in final disposition will likely require extended storage of this fuel well beyond initial license periods and perhaps multiple re-licenses may be needed. Thus, both the shipping packages and the dry cask storage systems require materials integrity assessments and assurance of continued satisfactory materials performance over times not considered in the original evaluation processes. Test programs for the shipping packages have been established to obtain aging data on materials of construction to demonstrate continued system integrity. The collective data may be coupled with similar data for the dry cask storage systems and used to support extending the service life of shipping packages in both transportation and storage.
Date: August 18, 2013
Creator: Dunn, K.; Bellamy, S.; Daugherty, W.; Sindelar, R. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

LONG TERM AGING AND SURVEILLANCE OF 9975 PACKAGE COMPONENTS

Description: The mission of the 9975 package, originally designed only for transportation of radioactive materials, has been broadened to include storage at the Savannah River Site. Two components of this package, namely the containment vessel O-rings and fiberboard overpack, require continued integrity assessment under the storage conditions. The performance of the components over time is being evaluated using accelerated-aging studies. Compression stress relaxation (CSR) and leak testing are being used to measure the performance of O-rings. The performance of the fiberboard is being evaluated using compression strength, thermal conductivity, specific heat capacity and other physical properties. Models developed from the data collected provide an initial prediction of service life for the two components, and support the conclusion that normal service conditions will not degrade the performance of the package beyond specified functional requirements for the first assessment interval. Increased confidence in this conclusion is derived from field surveillance data and destructive evaluation of packages removed from storage.
Date: November 10, 2009
Creator: Hoffman, E.; Skidmore, E.; Daugherty, W. & Dunn, K.
Partner: UNT Libraries Government Documents Department

9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY

Description: Results from the 9975 shipping package Storage and Surveillance Program at the Savannah River Site (SRS) are summarized for justification to extend the life of the 9975 packages currently stored in the K-Area Complex (KAC). This justification is established with the stipulation that surveillance activities will continue throughout the extended time to ensure the continued integrity of the 9975 materials of construction and to further understand the currently identified degradation mechanisms. The 10 year storage life justification was developed prior to storage. A subsequent report was later used to validate the qualification of the 9975 shipping packages for 10 years in storage. However the qualification for the storage period was provided by the monitoring requirements of the 9975 Storage and Surveillance Program. This report summarizes efforts to determine a new safe storage limit for the 9975 shipping package based on the surveillance data collected since 2005 when the 9975 Storage and Surveillance Program began. The Program has demonstrated that the 9975 package has a robust design that can perform under a variety of conditions. The primary emphasis of the on-going 9975 Storage and Surveillance Program is an aging study of the 9975 Viton{reg_sign} containment vessel O-rings and the Celotex{reg_sign} fiberboard thermal insulation at bounding conditions of radiation, elevated temperatures and/or elevated humidity.
Date: May 27, 2011
Creator: Dunn, K.; Daugherty, W.; Hackney, B.; Hoffman, E. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY

Description: Results from the 9975 Surveillance Program at the Savannah River Site (SRS) are summarized for justification to extend the life of the 9975 packages currently stored in the K-Area Materials Storage (KAMS) facility from 10 years to 15 years. This justification is established with the stipulation that surveillance activities will continue throughout this extended time to ensure the continued integrity of the 9975 materials of construction and to further understand the currently identified degradation mechanisms. The current 10 year storage life was developed prior to storage. A subsequent report was later used to extend the qualification of the 9975 shipping packages for 2 years for shipping plus 10 years for storage. However the qualification for the storage period was provided by the monitoring requirements of the Storage and Surveillance Program. This report summarizes efforts to determine a new safe storage limit for the 9975 shipping package based on the surveillance data collected since 2005 when the surveillance program began. KAMS is a zero-release facility that depends upon containment by the 9975 to meet design basis storage requirements. Therefore, to confirm the continued integrity of the 9975 packages while stored in KAMS, a 9975 Storage and Surveillance Program was implemented alongside the DOE required Integrated Surveillance Program (ISP) for 3013 plutonium-bearing containers. The 9975 Storage and Surveillance Program performs field surveillance as well as accelerated aging tests to ensure any degradation due to aging, to the extent that could affect packaging performance, is detected in advance of such degradation occurring in the field. The Program has demonstrated that the 9975 package has a robust design that can perform under a variety of conditions. As such the primary emphasis of the on-going 9975 Surveillance Program is an aging study of the 9975 Viton(reg.sign) GLT containment vessel O-rings and the Celotex(reg.sign) fiberboard thermal ...
Date: January 6, 2011
Creator: Daugherty, W.; Dunn, K.; Hackney, B.; Hoffman, E. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

AGING AND SURVEILLANCE OF VITON GLT O-RINGS IN MODEL 9975 SHIPPING PACKAGES

Description: Radioactive material packages (DOT Type B) such as the Model 9975 are used to transport Pu-bearing materials. The 9975 package provides double payload containment via nested stainless steel primary (PCV) and secondary (SCV) containment vessels. The containment vessels are closed by a conical plug sealed with dual O-rings (Figure 1) made of Parker Seals compound V0835-75, based on Viton{reg_sign} GLT fluoroelastomer. The outer O-ring is credited as being leaktight per ANSI N14.5 with a leak rate of <1E-07 ref cc/sec. The 9975 package is being used for interim storage in the K-Area Material Storage (KAMS) facility at the Savannah River Site. The aging performance of the O-rings is being studied to provide the storage facility a technical basis for service life prediction and safety analysis.
Date: June 26, 2009
Creator: Hoffman, E; Skidmore,E; Daugherty, W; Dunn, A & Dunn, K
Partner: UNT Libraries Government Documents Department

AGING BEHAVIOR OF VITON O-RING SEALS IN THE 9975 SHIPPING PACKAGE

Description: The Savannah River Site (SRS) is storing plutonium (Pu) materials in the K-Area Materials Storage (KAMS) facility. The Pu materials were packaged according to the DOE-STD-3013 standard and shipped to the SRS in Type B 9975 packages. The robust 9975 shipping package was not designed for long-term product storage, but it is a specified part of the storage configuration and the KAMS facility safety basis credits the 9975 design with containment. Within the 9975 package, nested stainless steel containment vessels are closed with dual O-ring seals based on Viton{reg_sign} GLT or GLT-S fluoroelastomer. The aging behavior of the O-ring compounds is being studied to provide the facility with advanced notice of nonconformance and to develop life prediction models. A combination of field surveillance, leak testing of surrogate fixtures aged at bounding service temperatures, and accelerated-aging methodologies based on compression stress-relaxation and oxygen consumption analysis is being used to evaluate seal performance. A summary of the surveillance program relative to seal aging behavior is presented.
Date: January 13, 2012
Creator: Skidmore, E.; Daugherty, W.; Hoffman, E.; Dunn, K. & Bellamy, S.
Partner: UNT Libraries Government Documents Department

AGING PERFORMANCE OF MODEL 9975 PACKAGE FLUOROELASTOMER O-RINGS

Description: The influence of temperature and radiation on Viton{reg_sign} GLT and GLT-S fluoroelastomer O-rings is an ongoing research focus at the Savannah River National Laboratory. The O-rings are credited for leaktight containment in the Model 9975 shipping package used for transportation of plutonium-bearing materials. At the Savannah River Site, the Model 9975 packages are being used for interim storage. Primary research efforts have focused on surveillance of O-rings from actual packages, leak testing of seals at bounding aging conditions and the effect of aging temperature on compression stress relaxation behavior, with the goal of service life prediction for long-term storage conditions. Recently, an additional effort to evaluate the effect of aging temperature on the oxidation of the materials has begun. Degradation in the mechanical properties of elastomers is directly related to the oxidation of the polymer. Sensitive measurements of the oxidation rate can be performed in a more timely manner than waiting for a measurable change in mechanical properties, especially at service temperatures. Measuring the oxidation rate therefore provides a means to validate the assumption that the degradation mechanisms(s) do not change from the elevated temperatures used for accelerated aging and the lower service temperatures. Monitoring the amount of oxygen uptake by the material over time at various temperatures can provide increased confidence in lifetime predictions. Preliminary oxygen consumption analysis of a Viton GLT-based fluoroelastomer compound (Parker V0835-75) using an Oxzilla II differential oxygen analyzer in the temperature range of 40-120 C was performed. Early data suggests oxygen consumption rates may level off within the first 100,000 hours (10-12 years) at 40 C and that sharp changes in the degradation mechanism (stress-relaxation) are not expected over the temperature range examined. This is consistent with the known long-term heat aging resistance of fluoroelastomers relative to hydrocarbon-based elastomers, and in absence of antioxidants ...
Date: May 31, 2011
Creator: Hoffman, E.; Daugherty, W.; Skidmore, E.; Dunn, K. & Fisher, D.
Partner: UNT Libraries Government Documents Department

Leveraging Available Data to Support Extension of Transportation Packages Service Life

Description: Data obtained from testing shipping package materials have been leveraged to support extending the service life of select shipping packages while in nuclear materials transportation. Increasingly, nuclear material inventories are being transferred to an interim storage location where they will reside for extended periods of time. Use of a shipping package to store nuclear materials in an interim storage location has become more attractive for a variety of reasons. Shipping packages are robust and have a qualified pedigree for their performance in normal operation and accident conditions within the approved shipment period and storing nuclear material within a shipping package results in reduced operations for the storage facility. However, the shipping package materials of construction must maintain a level of integrity as specified by the safety basis of the storage facility through the duration of the storage period, which is typically well beyond the one year transportation window. Test programs have been established to obtain aging data on materials of construction that are the most sensitive/susceptible to aging in certain shipping package designs. The collective data are being used to support extending the service life of shipping packages in both transportation and storage.
Date: June 12, 2012
Creator: Dunn, K.; Abramczyk, G.; Bellamy, S.; Daugherty, W.; Hackney, B.; Hoffman, E. et al.
Partner: UNT Libraries Government Documents Department

AGING PERFORMANCE OF VITON GLT O-RINGS IN RADIOACTIVE MATERIAL PACKAGES

Description: Radioactive material packages used for transportation of plutonium-bearing materials often contain multiple O-ring seals for containment. Packages such as the Model 9975 are also being used for interim storage of Pu-bearing materials at the Savannah River Site (SRS). One of the seal materials used in such packages is Viton{reg_sign} GLT fluoroelastomer. The aging behavior of containment vessel O-rings based on Viton{reg_sign} GLT at long-term containment term storage conditions is being characterized to assess its performance in such applications. This paper summarizes the program and test results to date.
Date: May 7, 2007
Creator: Skidmore, E; Kerry Dunn, K; Elizabeth Hoffman, E; Elise Fox, E & Kathryn Counts, K
Partner: UNT Libraries Government Documents Department