Douglas Kirk Veirs

Assessment of Corrosion-Based Failure in Stainless Steel Containers Used for the Long-Term Storage of Plutonium-Based Salts

Abstract This paper summarizes our efforts to assess corrosion-related failure in stainless steel long-term storage containers bearing plutonium oxides and electrorefining salts. Pitting corrosion of the internal can wall is believed to occur when these salt particles deliquesce forming the electrolyte necessary for corrosion-electrochemistry. Extrapolation of pit depths from coupon studies using generalized extreme value (GEV) statistics found that the probability of a through-wall corrosion pit is finite; the maximum pit depth after 50 years would be on the order of 1.7 mm where the container wall is only 1.6 mm thick. To assess susceptibility to environmental cracking fracture toughness (J1C), experiments were used in conjunction with a J-integral diagram constructed using the GE/EPRI method for linear elastic-plastic materials. As apart of this analysis, the residual stress associated with the weld was measured using the laser contour method. The hoop stress in the weld region was found to be on the o...

Quality quandaries: Statistical detective work to understand the isotopic ratios in Drum 68660 and the radioactive release at WIPP

KEY POINT An incident at the Department of Energys Waste Isolation Pilot Plant (WIPP) in 2014 resulted in the release of radioactive material into the environment. Initially, it was known that at least one drum in WIPP, identified as drum 68660, was involved. However, questions remained. Could the air-monitor isotopic ratios measured in WIPP at the time of the release be explained by materials in drum 68660 or were other drums involved? Could internal conditions in drum 68660 have caused the breach? What were the implications for 68660s sister drum? These questions needed to be answered as quickly as possible. This analysis, which was completed in three weeks, combined combinatorics and uncertainty analysis to provide scientists with the timely evidence they needed to either answer these important questions or to design experiments to answer them.

Surveillance and Monitoring Program Full-Scale Experiments to Evaluate the Potential for Corrosion in 3013 Containers

A set of six long-term, full-scale experiments were initiated to determine the type and extent of corrosion that occurs in 3013 containers packaged with chloride-bearing plutonium oxide materials. The materials were exposed to a high relative humidity environment representative of actual packaging conditions for the materials in storage. The materials were sealed in instrumented, inner 3013 containers with corrosion specimens designed to test the corrosiveness of the environment inside the containers under various conditions. This report focuses on initial loading conditions that are used to establish a baseline to show how the conditions change throughout the storage lifetime of the containers.

Selection of 3013 Containers for Field Surveillance. Fiscal Year 2016 Update

This update is the eighth in a series of reports that document the binning and sample selection of 3013 containers for the Field Surveillance program as part of the Integrated Surveillance Program. This report documents changes made to both the container binning assignments and the sample selection approach. Binning changes documented in this update are a result of changes to the prompt gamma calibration curves and the reassignment of a small number of Hanford items from the Pressure bin to the Pressure and Corrosion (P&C) bin. Field Surveillance sample selection changes are primarily a result of focusing future destructive examinations (DEs) on the potential for stress corrosion cracking in higher moisture containers in the P&C bin. The decision to focus the Field Surveillance program on higher moisture items is based on findings from both the Shelf-life testing program and DEs.

Gap Analysis of Storage Conditions between NNSS and LANL for SAVY 4000 Use

As part of the gap analysis for utilizing the SAVY 4000® at NNSS, the hydrogen gas generation rate and the effect of atmospheric pressure changes on the maximum normal operating pressure (MNOP) of the SAVY container must be evaluated because the nuclear material characteristics and atmospheric conditions will not be the same for NNSS and LANL. This paper documents this analysis and demonstrates that the LANL SAVY Safety Analysis Report (SAR) is bounding with respect to the Nevada facilities.

Assessment of Residual Stresses in 3013 Inner and Outer Containers and Teardrop Samples

This report is an assessment performed by LANL that examines packaging for plutonium-bearing materials and the resilience of its design. This report discusses residual stresses in the 3013 outer, the SRS/Hanford and RFETS/LLNL inner containers, and teardrop samples used in studies to assess the potential for SCC in 3013 containers. Residual tensile stresses in the heat affected zones of the closure welds are of particular concern.

Durability and field condition study of seal of SAVY-4000 storage container

Abstract The conditions of use for rubber O-rings are at least as important as their physical properties in their effect on the quality of a seal. Under normal use conditions, O-rings may be subject to wear and environmental contaminants such as hair and dirt. This study examines how these factors impact the leak tightness of a nuclear material storage container and the likelihood of the inadvertent release of radioactive material. The durability lifetime of an O-ring was explored by opening and closing four SAVY-4000 1 quart containers 100 times and periodically performing helium leak testing, though no significant change in leak rate was observed. This study also explored how the accumulation of dust or hair on the O-ring surface would affect the leak rate of the containers. A single hair crossing the seal, or a sufficient amount of particulate matter would compromise the seal, but after cleaning, the seal was re-established.

SAVY-4000 Surveillance and Life Extension Program Fiscal Year 2013 Annual Report

The Packaging Surveillance Program section of the DOE M441.1-1/sup>1, Nuclear Material Packaging Manual (DOE, 2008) requires DOE contractors to “ensure that a surveillance program is established and implemented to ensure the nuclear material storage package continues to meet its design criteria.” In order to ensure continuing safe storage of nuclear material and the maximization of risk reduction, TA-55 has established a Surveillance Program to ensure storage container integrity for operations within its specified design life. The LANL SAVY-4000 Field Surveillance Plan2 defines the near-term field surveillance plan for SAVY-4000 containers as required by the Manual. A long-term surveillance plan will be established based on the results of the first several years of surveillance and the results of the lifetime extension studies as defined in the Accelerated Aging Plan3. This report details progress in positioning the Surveillance Program for successful implementation in FY14 and status of the Design Life Extension Program in terms of its implementation and data collection for FY13.

Determination of fire resistance of plutonium storage containers

Abstract Seismic upgrades to safety systems at the Plutonium Facility at Los Alamos, NM, USA, are needed based on the latest facility safety analysis. The design basis accident of concern is a large scale seismically induced fire on the processing floor. Such an accident could involve large quantities of plutonium in dispersible forms stored in containers that cannot be counted on to prevent material release. As part of the effort to improve the safety posture of the facility in the near term, we developed a test method to evaluate the capability of storage containers to prevent release of their contents in the event of a seismically induced fire. To provide a defensible basis for testing to the Department of Energy (DOE) and Congressional oversight, we adopted standard test methods from consensus codes and standards. These tests included a time–temperature exposure up to 870°C and a 20 L kerosene open pool fire test. After the thermal tests, containers were dropped from a height of 4 ft onto a steel plate. We measured the amount of a non-toxic plutonium surrogate released following the drop tests to establish a conservative value of expected material release (referred to as damage ratio) in the event of the facility accident. The DOE approved thermal and impact test protocols we developed are used to demonstrate a quantitative value for material release from containers where the assumption of total material release results in unacceptably high accident consequences.

A summary of volatile impurity measurements and gas generation studies on MISSTD-1, a high-purity plutonium oxide produced by low-temperature calcination of plutonium oxalate

Plutonium dioxide of high specific surface area was subjected to long-term tests of gas generation in sealed containers. The material preparation and the storage conditions were outside the bounds of acceptable parameters defined by DOE-STD-3013-2012 in that the material was stabilized to a lower temperature than required and had higher moisture content than allowed. The data provide useful information for better defining the bounding conditions for safe storage. Net increases in internal pressure and transient increases in H{sub 2} and O{sub 2} were observed, but were well within the bounds of gas compositions previously shown to not threaten integrity of 3013 containers.