Engineering topics

Karns, Tristan

Publications and source records attributed to Karns, Tristan.

15 records

DOE OSTI2024

Overview of SAVY-4000 Lifetime Extension Activities in Fiscal Year 2024

This report provides an overview of activities engaged in during the 2024 fiscal year in support of the SAVY-4000 (hereafter “SAVY”) lifetime extension. As the final full year prior to the submittal of the technical basis, efforts were made to assess the current understanding regarding SAVY degradation in service as well as any knowledge that provided a more substantive view of the challenges that SAVYs face in storage. Close coordination with the stakeholders (i.e. LANL program office) ensured alignment with expectations regarding timelines for the remainder of the activities supporting the technical basis document for the lifetime extension request.

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DOE OSTI2024

Corrosion Analysis of 121103072 (SAVY-4000)

A surveillance feedlist for fiscal year (FY) 2022 was developed with the intent to target containers with contents known to generate corrosive gasses. One SAVY-4000 (hereafter “SAVY”) container with a serial number 121103072 was selected due to the reasonable wattage and known molten salt extraction (MSE) material corrosive behavior. The material was measured at 3.08 W with approximately 200 g of material placed inside of the SAVY for 6.07 years. The inner packaging configuration included a ¼ Qt stainless steel slip top inner container and a sPVC bag-out bag enclosing the inner container. Visual observations of the container during retrieval revealed several concerning features on the exterior of the container, notably on the lid. Fig. 1 shows the container lid along with an inset image further magnifying the features of interest. The corroded tamper indicating device (TID) wire and the corroded radioactive material tag wire indicated that corrosive gas species for steel were produced during storage. Although the TID wire and rad tag wire are not the same composition as the SAVY body and lid, these are often used as an indicator of potential corrosion inside of the SAVY container. The oxide residing inside of the filter holes and significant buildup around one hole provided further evidence supporting the presence of corrosive species inside of the container.

36 MATERIALS SCIENCE↗

DOE OSTI2023

The 65 Elevated Risk Container Status Relative Humidity Measurements RFID RH/T Sensors in Containers [Slides]

In March of 2023, a memo was issued, drafted by the Container Management, Safety, and Engineering Team, identifying 65 elevated risk legacy containers for priority disposition at TA-55. These 65 were identified separately from the “typical” prioritization decision-making method used at TA-55 to disposition legacy items. This new technique gave important feedback and revealed improvement opportunities for the selection process of legacy containers for disposition. The DOE complex and TA-55 have a long history of nuclear operations and therefore the disposition of these legacy materials is vital.

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DOE OSTI2022

Container Evaluation: Analysis of the Swagelok Knuckle with Viewport as an Approved Hermetically Sealed Inner Container

This report outlines the results from the water ingress test, helium leak test and additional atmosphere testing for the Swagelok knuckle with viewport container further referred to as the SKV. This container is constructed from a standard union vacuum fitting, 1.33” conflat to 0.5” male VCR, a 1.33” conflat fused silica lensed viewport fitting, and a 0.5 inch VCR cap. The primary intended use of this container is to store Pu metal samples in the vault for a time interval exceeding 40 years. The samples need to be contained in an air free environment to ensure that the material does not oxidize over time. The container viewport is a critical design feature that will help the operators visually inspect and evaluate the state of the metal samples prior to opening the container. These containers are advertised as leak tight, but experimental tests were performed to test the water resistant criteria and the gas leaking criteria set forth by the TA-55 Criticality Safety Program. The results of the water ingress test show that the container is water-tight, with no signs of water penetrating the container within the required guidelines outlined in TA55-AP-522. The preliminary He leak test performed demonstrate that the conflat window port and VCR cap are able to maintain a hermetic seal. Additionally, all containers will be He leak tested independently by the manufacturer prior to shipping to LANL. A third voluntary test was added to assess the container’s ability to hold atmosphere, with successful results indicating the container is able to hold inert atmosphere to prevent lanthanum metal oxidation. It is the conclusion of the authorsthat there is enough evidence through the test conducted and outlined within this document that the proposed container meets the definition of a water-tight container, and it is able to provide a hermetic seal.

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DOE OSTI2022

Evaluating Corrosion Effects on the Stainless Steel Components of the SAVY-4000/Hagan Nuclear Material Storage Containers: FY2022 Update

This report summarizes the work completed and underway for the Corrosion Working Group (CWG) for FY2022 in support of evaluating a greater than a 15 year design life for the SAVY4000. The CWG meets on an as needed basis to review new work, results or information regarding the corrosion of SAVY-4000 and Hagan nuclear material storage containers. The goal when analyzing corrosion is to develop a design life appropriate for the containers and to identify when a container should be removed from service. There are many parallel efforts associated with identifying and extending the service life of nuclear material storage containers. This report includes information from research and development efforts to address the lifetime. The CWG is closely related to surveillance activities and continues to play a role in identification of issues and paths forward for analysis of surveillance containers. This work summarizes the completed tasks for FY22 of the CWG while keeping in mind that some efforts continue into future years. Brief summaries of identified new avenues of work have been identified for FY23.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Aerosol Engineering Facility 2021-22 summary sheet [Slides]

The Aerosol Engineering Facility solves problems that involve radioactive particulates, including HEPA air filters, storage containers, exhaust stacks, and continuous air monitors. Other work includes silica dust sampling, bioaerosols, and insecticide sprays. Aerosol technology science describes the behavior of microscopic and nano-sized particles, in both molecular and continuum gas flow regimes.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Rules of Use Report Engineering evaluations of nuclear material storage containers against the packaging requirements at TA-55

A set of obligations in the yearly storage container surveillance program, ensures that a retrospective approach is applied with loaded containers in inventory to confirm compliance with all “users” to ensure nuclear material storage container requirements are being followed. Validation that packaged containers are properly used, within a specific set of container types prescribed “bounding conditions of use,” is based on meeting requirements as identified in operating procedures associated with TA55-DOP-091, TA-55 Nuclear Material Packaging, and PA-RD-01022, Nuclear Material Packaging Requirements. The surveillance plan obligation requires the application of local area nuclear material accountability software or (LANMAS) to produce queries. The data queries are used to assess attributes of containers in storage these investigations are conducted on a bi-annual basis. This rules of use (ROU) compliance process ensures proper usage of storage containers as containment systems and therefore provides effective worker protection. It is structured as a supporting effort by implementing aspects of PA-AP-01207, Nuclear Material Container Safety Management at TA-55.

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DOE OSTI2021

Los Alamos National Laboratory SAVY-4000 Field Surveillance Plan (Update for 2021)

The Packaging Surveillance Program section of the Department of Energy (DOE) Manual 441.1- 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.” The Los Alamos National Laboratory (LANL) SAVY-4000 Field Surveillance Plan was first issued in fiscal year (FY) 2013. The surveillance plan is reviewed annually and updated as necessary based on SAVY-4000 surveillance findings, as well as results of the lifetime extension studies. Six surveillance plan updates have been issued, one in 2014, one in 2016, one in 2017, one in 2018 one in 2019 and one in 2020. This 2021 update documents what was actually done in 2020 and what is planned for 2021. Deviations from the 2020 surveillance plan were necessary because some of the planned surveillance containers were not available for examination.

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DOE OSTI2021

2021 Hagan Container Surveillance Plan

Prior to 2021, Hagan containers were examined on an ad hoc basis as part of the SAVY-4000 surveillance plan. Given the size, aging horizon, and unique potential failure mechanisms of the Hagan population, the authors identified the need for Hagan-specific surveillance (Kelly, et al., 2020) and have developed this surveillance plan to meet that need.

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DOE OSTI2021

Evaluation of the Los Alamos Nuclear Material Packaging Risk Ranking Method

Repackaging nuclear material into robust containers to protect workers and the public has been ongoing at LANL and around the DOE complex for nearly two decades. The number of containers at LANL is around 5,000; limited resources for repackaging material has led to extended repackaging campaigns and the need to prioritize repackaging. Various methodologies have been used to prioritize the repackaging efforts and to demonstrate progress in risk reduction over time (e.g., Boerigter, 1997). The 2000-1 DNFSB recommendation recognized the limited DOE resources for repackaging, and acknowledged the need to “prioritize and schedule tasks to be undertaken with available funds according to consideration of risks.” Later, in DNFSB recommendation 2005-1, in addition to recommending that DOE develop a packaging standard, the Board recommended that “Characterization information should also be used to develop a surveillance program prioritized according to expected material and container risk (including, for example, material type, material form, and the age and type of container).” In response to requests and recommendations from the DOE and DNSFB to prioritize according to worker risk, a risk ranking method based on the potential consequence of dropping a container from 3 meters was developed in 2007 (Smith, 2007) and updated in 2014 (Hoffman, 2014). Various LANL implementation plans for repackaging were developed over the years using this methodology (Stone, 2014). Currently, this method is utilized in conjunction with an algorithm to mitigate programmatic risk to prioritize container repackaging and material processing (Prochnow, 2015). The purpose of this study is to document how the current risk ranking method works, how it is used and potential limitations.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2021

A Compilation of Historical Data on Hagan Drop Testing with Results

The Hagan nuclear material storage container was designed in the late 1990’s to provide a robust container for daily use, safe transport within the plutonium facility PF-4, and storage of nuclear material for up to twenty years. There are currently >3000 loaded Hagan containers in use at TA-55. The majority of these are in the TA-55 vault, but they are also used in safes and in floor locations on the main floor of PF-4. The original design criteria are given below

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2021

An Investigation of Critical Pit Size in Savy 4000 Wall

The Department of Energy (DOE) issued DOE M 441.1-1, Nuclear Material Packaging Manual, in March 2008 to protect workers who handle nuclear material from exposure due to loss of containment of stored materials. The Manual specifies a detailed approach to achieve high confidence in containers and includes requirements for container design and performance, design-life determinations, material contents, and surveillance and maintenance to ensure container integrity over time.

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2020

Filter Test System for Nuclear Container Filters

The purpose of this procedure is to measure the collection efficiency of the filters that are integrated into the lids of containers for nuclear material at Los Alamos National Laboratory (LANL). As an application of this procedure, a filter test report certificate can be created to document the measurement process. This procedure is intended to describe the TA-55, PF-4 (room 6A) operation of a Filter Test System (FTS) for Hagan and SAVY storage containers.

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DOE OSTI2020

Proposal for a Hagan Container Surveillance Plan

This white paper proposes a Hagan-specific surveillance plan. Currently, Hagan containers are examined on an ad hoc basis as part of the SAVY-4000 surveillance plan. Given the size, aging horizon, and unique potential failure mechanisms of the Hagan population, the authors believe there is a need to have a Hagan-specific surveillance plan.

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DOE OSTI2020

Comparative Approach for Evaluating the Containment Performance of Legacy NM Storage Containers

Many different types of nuclear material storage containers are used throughout TA-55 and specifically PF-4, in some instances these containers are used outside of engineering control barriers in most cases these barriers are gloveboxes. When a container is used outside of a glovebox or open front hood the container itself is relied upon as the primary engineering control barrier for the user. For this reason a process must be established in order to evaluate Non- Manual Compliant or NMC containers used outside of a glovebox in a comparative approach against Manual compliant containers. Legacy containers are typically understood to be non-standards packaged prior to 1998. For the purposes of this document “legacy” refers to any non-Manual compliant containers.

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