Plutonium Facility Research Articles

Chelation Model Validation: Modeling of a Plutonium-238 Inhalation Incident Treated with DTPA at Los Alamos National Laboratory.

Accidental inhalation of plutonium at the workplace is a non-negligible risk, even when rigorous safety standards are in place. The intake and retention of plutonium in the human body may be a source of concern. Thus, if there is a suspicion of a significant intake of plutonium, medical countermeasures such as chelation treatment may be administered to the worker. The present work aimed to interpret the bioassay data of a worker involved in an inhalation incident due to a glovebox breach at Los Alamos National Laboratory's plutonium facility. The worker was treated with intravenous injections of calcium salts of diethylenetriaminepentaacetic acid (DTPA) in an attempt to reduce the amount of plutonium from the body and therefore reduce the internal radiation dose. It is well known in the internal dosimetry field that the administration of chelation treatment poses additional challenges to the dose assessment. Hence, a recently developed chelation model was used for the modeling of the bioassay data. The objectives of this work are to describe the incident, model the chelation-affected and non-affected bioassay data, estimate the plutonium intake, and assess the internal radiation dose.

Luminescence dosimetry for evaluation of the external exposure in Metlino, upper Techa River valley, Southern Urals, Russia: Analysis of new results

Luminescence dosimetry was applied in the former settlement of Metlino, Southern Urals, Russia as part of a full-scale study to validate the Techa River Dosimetry System (TRDS) 2016 for the upper Techa River region. The village, which was evacuated in 1956, was located 7 km downstream of the release point of liquid radioactive waste by the Mayak plutonium facility. Several brick samples were taken from north-eastern and south-eastern walls of the granary, facing the former Techa river shoreline and floodplain. Samples were all taken at the same height and measured at different depths into the brick. For the majority of brick samples, good Optically Stimulated Luminescence properties of the quartz grains were observed. In some cases, however, strong levels of sensitization and/or signal recuperation were encountered which necessitated adjustment in the measurement protocols. Anthropogenic doses in bricks varied from 1.5 to 6.6 Gy and the horizontal profiles along both walls showed significant variation, which is explained on a qualitative basis. A dose depth profile is observed for selected samples, which is different from the dose depth profile measured and simulated for samples from the north-western wall of the granary in previous studies. This is qualitatively explained by the differences in source configuration.

Dose Assessment Following a 238 Pu Inhalation Incident at Los Alamos National Laboratory.

A glovebox breach at the plutonium facility at Los Alamos National Laboratory potentially exposed 15 individuals to 238 Pu aerosols. One of the individuals (P0) received two 1-g intravenous DTPA treatments, one on the day of the intake and another the following day. Several urine samples were collected from the individuals involved in the incident. Particle size analysis on the PPE and solubility analysis of the particles on a filter sample were conducted in vitro. The applicability of the results from the in vitro studies for dose assessment was questionable because of the effect of the cloth mask the workers were wearing for COVID-related protection. Based on several considerations, including the effect of cloth masks on the "effective" particle size inhaled and the analysis of fecal-to-urine ratio, the default Type M 1 μm AMAD model was used to estimate intakes and doses. Using the urinary excretion data collected after 100 d post last chelation treatment, the committed effective dose, E(50), for P0 was calculated to be 5.2 mSv. For all others, the bioassay data were consistent with no intakes or very small intakes [corresponding to E(50) less than 0.1 mSv].

A Nuclear Generator of Clouds: Accidents and Radioactive Contamination Identified on Declassified Satellite Photographs in the Mayak Chemical Combine, Southern Urals

The Mayak Chemical Combine was one of the most secretive places in the Soviet Union. It was built in the southern Urals, close to Kyshtym. The facility produced weapons-grade plutonium and other radioactive isotopes for the Soviet nuclear military programme. Fugitives from behind the Iron Curtain mentioned the site, usually due to accidents and peculiar, unexplained observations. Such reports were often treated in the West as exaggerated or fictional, as they spoke of large-scale disasters, deportations and vast landscape transformations. This paper aims to present the research potential of declassified Cold War intelligence records for archaeological landscape studies of off-limits military sites. To outline a somewhat broader perspective, I will combine those sources with contemporary historical knowledge and modern remote sensing data. The analysis will be focused on the Central Intelligence Agency [CIA] satellite imagery (CORONA and GAMBIT) from the 1960s to the beginning of the 1970s. The discussed sources recorded outcomes of nuclear disasters, hundreds of square kilometres of uninhabited wasteland, abandoned villages, disappearing lakes, dying forests, diverted rivers, and other features related to this clandestine plutonium facility.

Enhancements in the Techa River Dosimetry System: TRDS-2016D Code for Reconstruction of Deterministic Estimates of Dose From Environmental Exposures.

Waterborne releases to the Techa River from the Mayak plutonium facility in Russia during 1949-1956 resulted in significant doses to persons living downstream. The dosimetry system Techa River Dosimetry System-2016D has been developed, which provides individual doses of external and internal exposure for the members of the Techa River cohort and other persons who were exposed to releases of radioactive material to the Southern Urals. The results of computation of individual doses absorbed in red bone marrow and extraskeletal tissues for the Techa River cohort members (29,647 persons) are presented, which are based on residence histories on the contaminated Techa River and the East Urals Radioactive Trace, which was formed in 1957 as a result of the Kyshtym Accident. Available Sr body-burden measurements and available information on individual household locations have been used for refinement of individual dose estimates. Techa River Dosimetry System-2016D-based dose estimates will be used for verification of risk of low-dose-rate effects of ionizing radiation in the Techa River cohort.

Contamination control monitoring at the Los Alamos National Laboratory’s Plutonium Facility

Plutonium airborne contamination creates a particular hazard because of the possibility of intake by inhalation. To preclude excursions of radioactive materials into the operator’s breathing zone, controls are used to prevent contamination. Measures to control radioactive contamination include eliminating or minimizing the spread of contamination and preventing cross-contamination. Contamination control philosophy at the plutonium facility is conveyed in one simple statement: Detect the contamination closest to the source as possible! Speed and distance when self-monitoring is critical to detecting plutonium contamination. Responding correctly to an alarm or monitor not working properly minimizes the consequences of plutonium contamination. Performing a full body frisking correctly and using the Peer-checking tool also minimize the consequences of plutonium contamination.

Investigation of a “Sharps” incident

Special nuclear material research, process development, technology demonstration, and manufacturing capabilities are provided at the Los Alamos National Laboratory Plutonium Facility. Engineered barriers provide the most effective protection from radioactive and hazardous materials. The Worker Safety Security Team augments these passive safety feature by investigating incidents to identify appropriate prevention and mitigation measures. “Learning Teams” facilitate employee feedback loop and integration toward process improvement. This article reports an investigation of a “Sharps” incident and reviews a case study of a technician that cuts his left thumb while making a gasket. Causal analysis of the sharps incident uncovered contributing factors that created the environment in which the incident occurred. Latent organizational conditions that created error-likely situations or weakened defenses were identified and controlled. Effective improvements that reduce the probability or consequence of similar sharps incidents were implemented.

Investigation of injury/illness data at a nuclear facility: Part II

At Los Alamos National Laboratory (LANL), there are several nuclear facilities, accelerator facilities, radiological facilities, explosives sites, moderate- and high-hazard non-nuclear facilities, biosciences laboratory, etc. The Plutonium Science and Manufacturing Directorate (ADPSM) provides special nuclear material research, process development, technology demonstration, and manufacturing capabilities. ADPSM manages the LANL Plutonium Facility. Within the Radiological Control Area at TA-55 (PF-4), chemical and metallurgical operations with plutonium and other hazardous materials are performed. LANL Health and Safety Programs investigate injury and illness data. In this study, statistically significant trends have been identified and compared for LANL, ADPSM, and PF-4 injury/illness cases. A previously described output metric is used to measures LANL management progress towards meeting its operational safety objectives and goals. Timelines are used to determine trends in Injury/Illness types. Pareto Charts are used to prioritize causal factors. Data generated from analysis of Injury/Illness data have helped identify and reduce the number of corresponding causal factors.

Investigation of criticality safety control infraction data at a nuclear facility

Chemical and metallurgical operations involving plutonium and other nuclear materials account for most activities performed at the Los Alamos National Laboratory's Plutonium Facility (PF-4). The presence of large quantities of fissile materials in numerous forms at PF-4 makes it necessary to maintain an active criticality safety program. The LANL Nuclear Criticality Safety (NCS) Program provides guidance to enable efficient operations while ensuring prevention of criticality accidents in the handling, storing, processing and transportation of fissionable material at PF-4. In order to achieve and sustain lower criticality safety control infraction (CSCI) rates, PF-4 operations are continuously improved, through the use of Lean Manufacturing and Six Sigma (LSS) business practices. Employing LSS, statistically significant variations (trends) can be identified in PF-4 CSCI reports. In this study, trends have been identified in the NCS Program using the NCS Database. An output metric has been developed that measures ADPSM Management progress toward meeting its NCS objectives and goals. Using a Pareto Chart, the primary CSCI attributes have been determined in order of those requiring the most management support. Data generated from analysis of CSCI data help identify and reduce number of corresponding attributes. In-field monitoring of CSCI's contribute to an organization's scientific and technological excellence by providing information that can be used to improve criticality safety operation safety. This increases technical knowledge and augments operational safety.

Pu(V) transport through Savannah River Site soils - an evaluation of a conceptual model of surface- mediated reduction to Pu (IV)

Over the last fifteen years the Savannah River Site (SRS) in South Carolina, USA, was selected as the site of three new plutonium facilities: the Mixed Oxide Fuel Fabrication Facility, Pit Disassembly and Conversion Facility, and the Pu Immobilization Plant. In order to assess the potential human and environmental risk associated with these recent initiatives, improved understanding of the fate and transport of Pu in the SRS subsurface environment is necessary. The hypothesis of this study was that the more mobile forms of Pu, Pu(V) and Pu(VI), would be reduced to the less mobile Pu(III/IV) oxidation states under ambient SRS subsurface conditions. Laboratory-scale dynamic flow experiments (i.e., column studies) indicated that Pu(V) was very mobile in SRS sediments. At higher pH values the mobility of Pu decreased and the fraction of Pu that became irreversibly sorbed to the sediment increased, albeit, only slightly. Conversely, these column experiments showed that Pu(IV) was essentially immobile and was largely irreversibly sorbed to the sediment. More than 100 batch sorption experiments were also conducted with four end-member sediments, i.e., sediments that include the chemical, textural, and mineralogical properties likely to exist in the SRS. These tests were conducted as a function of initial Pu oxidation state, pH, and contact time and consistently demonstrated that although Pu(V) sorbed initially quite weakly to sediments, it slowly, over the course of <33 days, sorbed very strongly to sediments, to approximately the same degree as Pu(IV). This is consistent with our hypothesis that Pu(V) is reduced to the more strongly sorbing form of Pu, Pu(IV). These studies provide important experimental support for a conceptual geochemical model for dissolved Pu in a highly weathered subsurface environment. That is that, irrespective of the initial oxidation state of the dissolved Pu introduced into a SRS sediment system, Pu(IV) controls the environmental transport within a couple weeks and Pu strongly binds to the sediment, limiting its mobility.

Investigation of radiation protection observation data at a nuclear facility

Programmatic operations at the Los Alamos National Laboratory Plutonium Facility (TA-55) involve working with various amounts of plutonium and other highly toxic, alpha-emitting materials. The spread of radiological contamination on surfaces, airborne contamination, and excursions of contaminants into the operator's breathing zone are controlled through the Radiological Protection Program (RPP). A key element of the program is in-field monitoring of radiological conditions, observations, and incidents reports. The Los Alamos National Laboratory Radiation Protection Observation System (RPO), supported by the Health Physics Operations Group, captures, documents, and records radiological conditions, observations, or incidents that are considered off-normal. The RPO database has been mined for glovebox glove event detection data. Lean Manufacturing and Six Sigma (LSS) business practices have been employed to identify statistically significant variations (trends) in RPO reports. An input metric has been developed that measure glovebox glove event detection opportunities. This information has been incorporated into a visual format that management can use to make decisions. The results presented in this paper are pivotal to the ultimate focus of the TA-55 RPP, which is to maintain radiation exposures well below regulatory limits, minimize the number of contamination events, and prevent uncontrolled releases.

Causal analysis of a glovebox glove breach

Programmatic operations at the Los Alamos National Laboratory Plutonium Facility (TA-55) involve working with plutonium and other highly toxic, alpha-emitting materials in gloveboxes. Evaluating the glovebox configuration, the glovebox gloves are the weakest part of this engineering control. Recognizing this vulnerability, the TA-55 Glovebox Glove Integrity Program (GGIP) was developed to minimize loss of confinement of the glovebox through an opening in the glove, i.e., a breach or failure. A key element of this program is to perform causal analyses of breaches and failures. In the following report, the causal analysis methodology is defined below, and one case study is presented. The contributing factors that caused a marble size hole in glovebox glove during the repair of an auger are analyzed. Underlying conditions, decisions, actions, and inactions that contribute to the event are identified. This includes weaknesses that may warrant improvements that tolerate error. Measures that reduce consequences or likelihood of recurrence are discussed.

Soils radiological characterization under a nuclear facility

Nowadays, nuclear industry is facing a crucial need in establishing radiological characterization for the appraisal and the monitoring of any remediation work.Regarding its experience in this domain, the French Alternative Energies and Atomic Energy Commission (CEA) of Fontenay-aux-Roses, established an important feedback and developed over the last 10 years a sound methodology for radiological characterization. This approach is based on several steps:- historical investigations,- assumption and confirmation of the contamination,- surface characterization,- in-depth characterization,- rehabilitation objectives,- remediation process.The amount of measures, samples and analyses is optimized for data processing through geostatistics.This approach is now used to characterize soils under facilities. The paper presents the radiological characterization of soils under a facility basement. This facility has been built after the first generation of nuclear facilities, replacing a plutonium facility which has been dismantled in 1960.The paper details the different steps of radiological characterization from historical investigations to optimization of excavation depths, impact studies and contaminated volumes.

Microscopic analysis of glovebox glove failures and breaches: Part II

At the Los Alamos National Laboratory Plutonium Facility, gloveboxes are used to confine plutonium to prevent uncontrolled releases of the element. From a structural design standpoint, glovebox gloves are the weakest part of the glovebox system. As a continuation of a previous paper, data generated from microscopic analysis are used to identify the causes of glove failures. This paper illustrates three cases in which microscopic analyses have helped determine the causes of three glove breaches. Photographs illustrate examples of cuts and tears. Sectioning a breach caused by grinding show the rough surface of the breach. Another glove failure is caused by exposure to strong acid.

Glovebox issues: Controlling fire hazards after an earthquake

Seismic considerations for gloveboxes installed in nuclear facilities are of extreme importance. One of the most challenging accident scenarios is the post-seismic fire event. A sustained fire in a glovebox can be a large safety risk because of its potential to affect the glovebox's containment integrity. The Los Alamos National Laboratory Plutonium Facility is testing self-contained fire extinguisher tubes, as a reliable minimally invasive and seismically robust fire suppression system in gloveboxes. Issues with extinguishing of Class A listed fires and pressure surge need to be addressed before they can be authorized in a nuclear facility. This study demonstrated self-contained fire extinguisher tubes are capable of extinguishing Class A, B, and C fires in gloveboxes up to 250 cubic feet under negative pressure with airflow equivalent to one air change per minute. Pressure surge issues were addressed. Fire testing results permit the installation of self-contained fire extinguisher tubes in gloveboxes and fume hoods with Class A, B, and C combustibles. The result presented in this report increases technical knowledge and augments operational safety.

Determination of fire resistance of plutonium storage containers

AbstractSeismic 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...

Risk reduction benefits of cryogen-free refrigeration

High Purity Germanium (HPGe) gamma-ray detectors are used at Los Alamos National Laboratory's Plutonium Facility (TA-55) for nondestructive assay. Liquid nitrogen (LN2), a cryogen, is commonly used to cool these detectors. Cryogen use is associated with several health risks and operational problems. This has prompted the development of cryogen-free refrigeration. Although the efficacy of the coolers has been proven for use with HPGe detectors, the health and safety aspect implications have not been studied. Both LN2 and mechanical coolers were examined and their application effectiveness on health and safety aspects in HPGe gamma-ray detector use at TA-55 was compared. Overall, cryogen-free refrigeration is an engineering equivalent to LN2 systems used in gamma spectroscopy and eliminates the health and physical hazards associated with LN2 systems without adding hazards.

Microscopic analysis of glovebox glove failures and breaches

Programmatic operations at the Los Alamos National Laboratory Plutonium Facility (TA-55) involve working with plutonium and other highly toxic, alpha-emitting materials. The spread of radiological contamination on surfaces, airborne contamination, and excursions of contaminants into the operator's breathing zone are prevented using gloveboxes. The TA-55 Glovebox Safety Program augments this passive safety feature. A key element of this program is to perform microscopic analyses of glovebox glove failures and breaches when their causes are unknown. Initial examinations provide little information about the causes of failures and breaches. This has prompted the development of an instrument that permits cross-sections of glove perforations to be studied. This paper discusses the methodology used to perform microscopic analysis of failures and breaches. It presents three case studies in which microscopic analyses have helped to determine the causes of the glove openings.

Preliminary FISH-Based Assessment of External Dose for Residents Exposed on the Techa River

This paper presents the results of a feasibility cytogenetic study using the fluorescence in situ hybridization (FISH) translocation assay for residents of villages located on the Techa River (Southern Urals, Russia) contaminated with liquid radioactive wastes from the Mayak plutonium facility in 1949-1956. The study was conducted with two groups of donors that differed in their main pathways of exposure. The first group comprised 18 residents of the middle Techa region who were exposed predominantly from ingestion of radionuclides (mostly (89,90)Sr) via the river water and local foodstuffs. The second group included 20 residents of Metlino, the closest village to the site of releases, who were exposed to external γ radiation from the contaminated river bank and exposed internally from dietary intake of radionuclides. A significant linear dependence between the radiation-induced translocation frequency and individual red bone marrow dose from incorporated (89,90)Sr, calculated with the Techa River Dosimetry System (TRDS), was found in the first group of donors. This allowed us to take the contribution of (89,90)Sr to the total radiation-induced translocation frequency into account for the second group of donors and to analyze translocations resulting from external γ-ray exposure. Individual doses from external exposure derived from the corrected translocation frequency for the second group of donors (Metlino residents), using a linear dose-response coefficient of 0.015 translocation/cell/Gy recommended by Edwards et al. in 2005, were shown to vary up to 2.1 Gy, with an average value of 0.48 Gy, which was in agreement with TRDS-based external dose estimates for Metlino residents.

Cortical bone resorption rate in elderly persons: Estimates from long-term in vivo measurements of 90Sr in the skeleton

The rate of cortical bone resorption was assessed from long-term in vivo measurements of 90Sr content in the skeleton for men aged 50–80 years and for women 0–30 years after menopause. Measurements of 90Sr were conducted with a whole body counter (WBC) for residents of the Techa Riverside communities (Southern Urals, Russia), who ingested large amounts of 90Sr as a result of releases of liquid radioactive wastes into the river from the Mayak plutonium facility in early 1950s. The results of this study showed an increase in the rate of cortical bone resorption in both men and women, as based on the use of accidentally ingested 90Sr as a tracer for bone metabolism. In men there was a continuous gradual increase in the rate of cortical bone resorption after 55 years from 2.8 to 4.5%/year by the age of 75 years. In women, there was a doubled increase in the rate of cortical bone resorption after menopause of up to 6%/year; then the rate remained unchanged for 10–12 years with a subsequent gradual decline down to 5–5.5%/year. Comparison of the rate of cortical bone resorption in men and women older than 55 years showed that women expressed significantly higher levels of cortical bone resorption.