scholarly journals Pressurization Analysis for Heating of a Screw Top Utility Can Loaded With Plutonium Oxide Powder by a 1273 K Fire

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
James E. Laurinat ◽  
Matthew R. Kesterson ◽  
Steve J. Hensel

Abstract The documented safety analysis for the Savannah River National Laboratory (SRNL) evaluates the consequences of a postulated 1273 K fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage containers. The oxide storage configuration selected for analysis is can/bag/can, comprised of oxide powder inside an 8.38 × 10−6 m3 stainless steel B vial inside 0.006 kg of polyethylene bagging inside a one-quart screw top utility can of the type commonly used to package solvents or rubber cements. To enable evaluation of the dose consequences, temperature and pressure transients have been calculated for exposure of a typical set of storage containers to the fire. The pressurization analysis credits venting to and from the B vial but does not credit venting or leakage from the can. Due to the low rate of venting from the B vial into the can gas space, the can pressure is nearly independent of the B vial pressure. Calculated maximum pressures are compared to the utility can burst pressure. In lieu of a structural analysis of the utility cans, burst pressures and leakage rates were measured using compressed nitrogen gas. The measured gauge burst pressure was 0.250 ± 0.043 MPa. The measured burst pressures are lower than the calculated maximum pressure due to fire exposure, indicating that the utility cans could burst during exposure to a 1273 K fire.

Author(s):  
James E. Laurinat ◽  
Matthew R. Kesterson ◽  
Steve J. Hensel

The documented safety analysis for the Savannah River Site (SRS) evaluates the consequences of a postulated 1000 °C (1273 K) fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage containers. To enable evaluation of the dose consequences, temperature and pressure transients have been calculated for exposure of a typical set of storage containers to the fire. The oxide storage configuration selected for analysis is can/bag/can, comprised of oxide powder inside an 8.38E−6 m3 stainless steel B vial inside 0.006 kg of polyethylene bagging inside a one-quart screw top utility can of the type commonly used to package solvents or rubber cements. The analysis accounts for pressurization from gases generated by pyrolysis of the polyethylene bagging and evaporation of moisture adsorbed onto the oxide powder. Results were obtained for different can orientations and different surface fire exposures, with and without initial pressurization of the B vial by hydrogen from the radiolysis of moisture. Based on the results of hydrogen back pressure tests for plutonium oxide powders loaded with moisture, the initial gauge pressure from radiolytic hydrogen was set at a bounding value of 82 psig (5.65E5 Pa). The pressurization analysis credits venting to and from the B vial but does not credit venting or leakage from the can. Calculated maximum gauge pressures inside the utility can range from 1.98E5 Pa for an upright can exposed to fire on only one side, to 7.78E5 Pa for an upright can engulfed by fire. Maximum gauge pressures inside the B vial vary from 1.36E5 to 1.43E6 Pa. Due to the low rate of venting from the B vial into the can gas space, the can pressure is nearly independent of the B vial pressure. Calculated maximum pressures are compared to the utility can burst pressure. In lieu of an analytic structural analysis of the utility cans, burst pressures and leakage rates were measured using compressed nitrogen gas. Leakage of gas through the can lid thread and seams prevented the test apparatus from reaching the burst pressure. To achieve the burst pressure, it was necessary to seal the can lid threads and seams by brazing. The measured gauge burst pressure was 2.50E5 +/− 0.43E5 Pa. The measured burst pressures are lower than the calculated maximum pressure due to fire exposure, indicating that the utility cans could burst during exposure to a 1000 °C (1273 K) fire. Leakage rates were measured for cans initially pressurized to a gauge pressure of 1.24E5 Pa. The measured leakage rates were found to be proportional to the gauge pressure inside the can, with a time constant for leakage of 0.424 +/− 0.010 reciprocal seconds. The leakage time constants follow a threshold Weibull distribution.


Author(s):  
Donald J. Trapp

Pacific Northwest National Laboratory (PNNL) is replacing its 6M nuclear shipping fleet with 9977 shipping packages, which were designed by Savannah River National Laboratory (SRNL). The new packages require PNNL to perform a preshipment leak test on the lid seals of the containment vessel before the package is shipped on public roads. Savannah River National Laboratory (SRNL) developed a preshipment leak test using a TM Electronics Solution leak tester for PNNL. The Solution is an automatic vacuum leak tester that uses the Gas Pressure Rise leak test method to check the O-ring lid seals and the test port plug seal. The two tests take three minutes each to perform. Because the Solution is fully automatic, the leak test can be done by operators after a few hours of training. This paper describes the test equipment and the testing sequence.


Author(s):  
James E. Laurinat ◽  
Matthew R. Kesterson ◽  
Jeffery L. England ◽  
Edward T. Ketusky ◽  
Charles A. McKeel ◽  
...  

The thermal aspects of a safety analysis for shipment of the West Valley melter are presented. The West Valley melter was used from 1996 to 2002 to vitrify regionally sourced high level radioactive waste. The U.S. Department of Energy (DOE) set up the West Valley Demonstration Project to encase this melter and grout it in low density cellular concrete, for disposal. DOE-West Valley requested the Savannah River National Laboratory to prepare a Safety Analysis Report. The thermal portion of the safety analysis covers Normal Conditions of Transport (NCT) and Hypothetical Accidents Conditions (HAC), as defined in the Code of Federal Regulations. For NCT, it is assumed that the encased melter is stored in either shade or direct sunlight at an ambient temperature of 311 K (100 °F). The defining HAC is exposure to a 1075 K (1475 °F) fire for 30 minutes. Finite element computer models were used to compute temperature profiles for NCT and HAC, given the thermal properties of the melter and its contents and tabulated radiolytic heating source concentrations. The resulting temperature conditions were used to estimate the pressurization due to evaporation of water from the concrete. The maximum calculated gauge pressures were determined to be 81 kPa (12 psig) for NCT and 580 kPa (84 psig) for HAC.


Author(s):  
Si Y. Lee

Primary objective of the work is to model resin particles within the column during the particle fluidization and sedimentation processes and to understand hydraulic behavior for particles within column during the resin fluidization and sedimentation processes. The modeling results will assist in interpreting experimental results, providing guidance on specific details of testing design, and establishing a basic understanding of resin particle’s hydraulic behavior within the column. The model was benchmarked against the literature data and the test data conducted by Savannah River National Laboratory at Savannah River Site (SRS). A scoping analysis effort has been undertaken to address the feasibility of simulating the basic fluidization and sedimentation aspects pertinent to the resin addition/removal process considered here. The existing computational fluid dynamics (CFD) code Fluent was chosen for this effort. Both fluidization and sedimentation of granular particles (i.e., of varying sizes) were based on an Eulerian model for granular flow. A two-dimensional axial symmetrical cylindrical geometry was chosen to perform the solid-fluid simulations. The column consisted of a fluid region of 48” in diameter by 94” in height where at both the top and bottom boundaries liquid fluid could pass through, but resin particle could not (i.e., assuming screens at both ends).


Author(s):  
James E. Laurinat ◽  
Matthew R. Kesterson ◽  
Steve J. Hensel

The documented safety analysis for the Savannah River Site evaluates the consequences of a postulated 1000 °C fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage vial. To enable evaluation of the dose consequences, pressure transients and venting flow rates have been calculated for exposure of the storage vial to the fire. A standard B vial with a capacity of approximately 8 cm3 was selected for analysis. The analysis compares the pressurization rate from heating and evaporation of moisture adsorbed onto the plutonium oxide contents of the vial with the pressure loss due to venting of gas through the threaded connection between the vial cap and body. Tabulated results from the analysis include maximum pressures, maximum venting velocities, and cumulative vial volumes vented during the first 10 minutes of the fire transient. Results are obtained for various amounts of oxide in the vial, various amounts of adsorbed moisture, different vial orientations, and different surface fire exposures.


Author(s):  
N. M. Askew ◽  
J. E. Laurinat ◽  
S. J. Hensel

As part of a surveillance program intended to ensure the safe storage of plutonium bearing nuclear materials in the Savannah River Site (SRS) K-Area Materials Storage, samples of these materials are shipped to Savannah River National Laboratory (SRNL) for analysis. These samples are in the form of solids or powders which will have absorbed moisture. Potentially flammable hydrogen gas is generated due to radiolysis of the moisture. The samples are shipped for processing after chemical analysis. To preclude the possibility of a hydrogen deflagration or detonation inside the shipping containers, the shipping times are limited to ensure that hydrogen concentration in the vapor space of every layer of confinement is below the lower flammability limit of 4 volume percent (vol%) [1]. This study presents an analysis of the rate of hydrogen accumulation due to radiolysis and calculation of allowable shipping times for typical K-Area materials.


2015 ◽  
Author(s):  
◽  
Isaac D. Simmonds

The events on September 11th 2001 and subsequent attacks in America and around the world have brought a renewed interest in the nation's security including the concern over the use of a nuclear or a radiological dispersal device (RDD). Research has been done in two separate projects in order to help address some of these concerns. A research assistantship from Savannah River National Laboratory was granted in order to identify the unique characteristics of radioactive 192Ir materials (chapters 2-4). A method for the dissolving of the iridium with electrochemistry was developed and used for sample preparation for analysis. Mass spectrometry (ICP-MS) analysis was then used to identify and quantify impurities and isotope ratios in iridium from various locations across the country. The second research project has developed a series of nanoparticles for use as tagging and tracking explosives (chapters 5-7). The composition of the nanoparticles were created with lanthanides with varying composition to provide a unique signature that can be rapidly and precisely measured in the field via neutron activation analysis. The nanoparticles could be used as a real-time in the field method for tracking and identifying materials such as explosives in a post detonation scenario.


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