Search NASA⌕ Search

SEARCH · Search NASA

Results for “CURIUM 244”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Mark-18A Ion Exchange Raffinate Management Strategy & Processing Recommendations

It is desired to recover Cm-244 through Cm-248 from dissolved Mark-18A targets following anion exchange processing to remove the Pu. The Cm will be sent to Oak Ridge National Laboratory (ORNL) for additional R&D. Approximately 5-8 L per quarter of a Mark-18A target will have undergone anion exchange treatment and will contain Cm. A significant portion of this volume of anion exchange raffinate solution is dissolved fission products not desired to be recovered which could be sent to waste. To reduce the amount of material being sent to ORNL, a waste and volume minimization strategy was developed and is described in this report.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Criticality detection method based on FP gamma radiation measurement

A method is proposed to evaluate the extent of subcriticality of an accident-damaged nuclear reactor. In this method the radiation ratio of two FP rare gas nuclides, {sup 88}Kr and {sup 133}Xe, is measured. From the measured value, the value in the core is estimated by correcting for the time required by the gases to diffuse from the core to the measuring point. A simple expression for neutron multiplication factor has been derived, which uses the corrected {sup 88}Kr-to-{sup 133}Xe radiation ratio and the {sup 88}Kr-to-{sup 133}Xe fission yield ratios from {sup 244}Cm and {sup 235}U but no information on the amount or distribution of fissile materials, making the proposed method very simple. The method has the advantage that FP rare gases can easily leak from the reactor core through many openings and gaps, reaching germanium counters without reacting with other materials. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

Autonomous Sampling Platform Development: Radiological Contamination Mapping at SRS

From 1961 to 1964, radioactive elements were released from the Savannah River Site into local bodies of water via cooling water charges from the reactors on site. In 1983, the extent of the radioactive contamination was first studied, and elements such as 137 Cs, 90 Sr, 238 Pu, 241 Am, 244 Cm, and tritium were found to have seeped from local bodies of water into sediment and the surrounding flora and fauna. The current method of tracking and monitoring radioactive contamination at the SRS is to gather samples and conduct measurements in a laboratory. A cheaper, and safer, method to conduct such measurements would be to automate the process by using an autonomous boat that can travel to locations, conduct measurements, and return home all without human intervention. To introduce this idea, the construction of an autonomous boat prototype was completed to demonstrate the practicality and feasibility of such an idea. The prototype travels to a set of waypoints, stops at each waypoint, and returns when all waypoints have been reached. It does this by employing a simple battery-powered boat with an Arduino controller that steers the boat using a steering algorithm incorporated into a Proportional Integral Derivative (PID) function. A total of three tests were conducted at two different bodies of water; and after working out some hardware problems, the boat drone was able to successfully steer and reach all programmed waypoints. With the prototype complete, the next steps to realizing the final product of the boat drone will include adopting a processing unit with higher-bit architecture, using a bigger boat with a more powerful trolling motor, and incorporating a solar panel for continuous power and round-the-clock performance.

42 ENGINEERING↗
DOE OSTI2018

Spectroscopic Measurements of L X-rays with a TES Microcalorimeter for a Non-destructive Assay of Transuranium Elements

Spectroscopic measurement of the L X-rays emitted from transuranium elements is one of the most useful techniques for the non-destructive assays of nuclear materials. In this study, we fabricated a transition-edge-sensor (TES) microcalorimeter using a 5-μm-thick Au absorber and tested its ability to measure the L X-rays emitted from two transuranium elements, Np-237 and Cm-244 sources. The microcalorimeter was found to successfully measure the L X-rays with an energy resolution (full width at half maximum) below 70 eV. These results confirm that L X-rays can be identified using the proposed TES microcalorimeter to enable non-destructive assays of transuranium elements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Radionuclide inventories for the F- and H-area seepage basin groundwater plumes

Within the General Separations Areas (GSA) at the Savannah River Site (SRS), significant inventories of radionuclides exist within two major groundwater contamination plumes that are emanating from the F- and H-Area seepage basins. These radionuclides are moving slowly with groundwater migration, albeit more slowly due to interaction with the soil and aquifer matrix material. The purpose of this investigation is to quantify the activity of radionuclides associated with the pore water component of the groundwater plumes. The scope of this effort included evaluation of all groundwater sample analyses obtained from the wells that have been established by the Environmental Compliance & Area Completion Projects (EC&ACP) Department at SRS to monitor groundwater contamination emanating from the F- and H-Area Seepage Basins. Using this data, generalized groundwater plume maps for the radionuclides that occur in elevated concentrations (Am-241, Cm-243/244, Cs-137, I-129, Ni-63, Ra-226/228, Sr-90, Tc-99, U-233/234, U-235 and U-238) were generated and utilized to calculate both the volume of contaminated groundwater and the representative concentration of each radionuclide associated with different plume concentration zones.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Disposition Options for Mk-42 Materials - 17072

In the late 1980s, the DOE Defense Programs identified a need to recover special isotopes of americium, curium, and plutonium (Am/Cm/Pu) from Mark-42 (Mk-42) targets that had been irradiated at the SRS. Eighty Mk-42 target segments were transferred from SRS to ORNL for recovery of these special isotopes. Approximately 65% of the target materials has been processed and converted to solids. The remaining Mk-42 materials are either targets stored in their irradiated forms or target material stored from various stages of processing. The Pu, Am-243 and Cm-244 in these targets are valuable materials; for example, the Am/Cm materials are potential feedstocks for production of heavy actinides (Cf-252, Bk-249, etc.). Although the isotopes in the Mk-42 materials have value, there is continual pressure to look at de-inventorying material in storage to only retain the most valuable materials needed to meet mission needs and to allow other materials to be added to the inventory as they become available. Evaluations are underway for potential disposition options for the Mk-42 materials. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

The Off-Site Source Recovery Program Capabilities in Recovering Transuranic Sealed Sources - 17599

Over the past 16 years, the mission of the Off-Site Source Recovery Program (OSRP) has been recovering disused radioactive sealed sources in the interest of national security, public health and safety. This program, which is sponsored by the National Nuclear Security Administration's Office of Global Material Security's Office of Radiological Security, is managed at Los Alamos National Laboratory and Idaho National Laboratory and has recovered sources worldwide. To date, OSRP has recovered more than 38,000 sources from over 1,300 locations worldwide. Since its inception, OSRP has grown from recovering only sealed sources containing one transuranic (TRU) isotope, Pu-239, in the early days of the program, to recovering sealed sources containing several other TRU and non-TRU isotopes. Primarily, OSRP's mission includes Pu-238, Pu-239, Am-241, Cf-252, Cm-244, Sr-90, Cs-137, Co-60, Ir-192 and Ra-226 sources that are US-origin, defense related and not commercially disposable. Over the lifetime of this program the types of recoveries performed have expanded from a single site to multi-site round-up recoveries. An additional approach, referred to as self-ship recoveries, is also used in cases where only a few sources may be present at a licensee's site. In these situations, the licensee ships their source(s) to an OSRP staging facility for ultimate consolidation and disposal. OSRP recovers sources from many types of licensees, with the majority of sources being removed from industry, universities and hospitals. These include sealed sources used in industrial radiological devices like moisture-density gauges and thickness gauges, medical devices such as blood irradiators and radiotherapy devices and sealed sources from nuclear power plants, among others. The recovery and management of sealed sources is a complex process covering multidisciplinary areas, including source construction, characteristics of the radioactive material, source packaging and transportation per DOT regulations, safe and secure storage, and final disposition per waste acceptance criteria of repository sites. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2016

Recovering New Type of Sources by Off-Site Source Recovery Project for WIPP Disposal - 16604

OSRP uses two types of eligible packaging configurations for Cm-244 and Cf-252 disposal to WIPP: an S-100 drum and a 12'' Pipe Overpack (POC) drum. Both types of packaging are WIPP accepted configurations for Contact Handled (CH) waste, which offer different advantages and disadvantages when used in the case of the two isotopes. The S-100 is a poly-shielded type A, 55 gallon drum, containing a 6'' diameter POC. The 12'' POC drum is a type A, 55 gallon drum without the internal poly-shield and with a pipe component of 12'' diameter. The S-100 drum presents the advantage of poly-shielding which is very important for neutron sources, such as the Cf-252, or Cm-244Be, at the expense of reduced internal volume. The 12'' POC drum presents a larger pipe component accommodating many more sources, like Cm-244 alpha emitters or shielded Cf-252, for which the CH dose rate is not an issue. All the sources prepared for disposal to WIPP are required to be special form, as defined in 49 CFR 173.403. When OSRP recovers normal form sources, these can be packaged in a field closable DOT certified Special Form Capsule (SFC) model II or model III, thus becoming special form. These capsules are then packaged in the type-A containers. The difference between the two types of packaging is that the 12'' POC can hold more sources, or a mix of sources and capsules at the expense of less shielding. This becomes important when the TRU content criteria of 100 nCi/g of TRU waste has to be met for the drums that are packaged for WIPP disposal. Measured neutron dose rates for Cm-244 packaged in S-100 agree reasonably well with calculated dose rates based on the models developed with MCNP. Future work will include validating the model for Cm-244 packaged in 12'' POC. A 1:1 ratio of neutron to gamma is expected for Cm-244Be dose rates packaged in S-100 drums. For Cf-252 packaged in S-100 and 12'' POC, the contribution of Cf-250 to the total emission neutron rate had to be taken into account due to the increasing role of Cf-250 as sources age. The uncertainty in the measurement of Cf-252 neutron dose rate for S-100 drum was quite high due to a high neutron background. A larger Cf- 252 source needs to be used for measurements in the future, in order to fully validate the model developed. A better agreement for measured versus calculated rate was obtained for a Cf-252 packaged in 12'' POC. For the WIPP disposal of these sources, OSRP will use the best packaging configuration for these isotopes in order to minimize the dose rate and maximize the TRU content. The S-100 packaging will be used for Cf-252 and Cm-244Be sources, when neutron dose reduction by the poly-shielding is important. Neutron dose rates will be estimated using the new MCNP correlations.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2018

Evaluation of Options for Disposition of Mk-42 Materials - 18034

In the late 1980's, the DOE defense programs identified a need to recover special isotopes of americium, curium, and plutonium from Mark-42 (Mk-42) targets that had been irradiated at the SRS. Eighty Mk-42 target segments were transferred from SRS to ORNL for recovery of these special isotopes. Approximately 65% of the target material has been processed, and the recovered material converted to solids. The remaining Mk-42 materials are stored either as targets in their irradiated forms or as target material from various stages of processing. The Pu, Am-243 and Cm-244 in these targets are valuable materials; for example, the Am/Cm materials are potential feedstocks for production of heavy actinides (Cf-252, Bk-249, etc.). In addition, rare long-lived fission product (LLFP) isotopes present in the targets in much smaller quantities, such as Zr-93, also have value to the research community. Although the isotopes in the Mk-42 materials have value, there is continual pressure to de-inventory the material in storage and only retain the most valuable materials needed to meet mission needs and provide inventory space for other materials to be added as they become available. Evaluations are underway for potential disposition options for the Mk-42 materials. Previous studies have included identification and evaluation of disposition options for the various Mk-42 materials in storage at ORNL [1]. Evaluations have included options for recovering the major isotopes and evaluating the waste that would be sent to disposal facilities. This paper summarizes the next steps in the evaluation process to develop an optimum path forward for the disposition of the Mk-42 materials. It includes an evaluation of the future programmatic need for the materials, the impact of storage on facility operations, and additional evaluations of options for dispositioning the materials. In addition to recovery of the major isotopes previously evaluated, it also looks at the potential to recover rare LLFP isotopes present in the targets in small quantities. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Sensitivity Studies and Experimental Evaluation for Optimizing Transcurium Isotope Production

This work applies to recent initiatives at the Radiochemical Engineering Development Center at Oak Ridge National Laboratory to optimize the production of transcurium isotopes in the High Flux Isotope Reactor in such a way as to prolong the use of high quality heavy curium feedstock. By studying the sensitivity of fission and transmutation reaction rates to the neutron flux spectrum a means of increasing the fraction of (n,γ) reactions per neutron absorption is explored. Filter materials which preferentially absorb neutrons at energies considered detrimental to optimal transcurium production are identified and transmutation rates are examined with high energy resolution. Experimental capsules are irradiated employing filter materials and the resulting fission and activation products studied to validate the filtering methodology. Improvement is seen in the production efficiency of heavier curium isotopes in 244 Cm and 245 Cm targets, and potentially in production of 252 Cf from mixed californium targets. Finally, further analysis is recommended to evaluate longer duration irradiations more representative of typical transcurium production.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2023

Packaging Plan for Mark-18A Plutonium Oxide

Mark-18A (Mk-18A) targets were irradiated at the Savannah River Site and have been in wet storage at the site since the 1970s. The Mk-18A Target Material Recovery Program has been established to recover the 244 Pu and heavy curium (≥50% 246 Cm and 248 Cm) in the targets at the Savannah River National Laboratory (SRNL) and ship the materials to Oak Ridge National Laboratory’s (ORNL’s) Radiochemical Engineering Development Center for programmatic use. Two products will be recovered from the Mk- 18A targets for shipment from SRNL to ORNL: a plutonium oxide stream and an oxide material that will contain the americium, curium, and lanthanides. This document presents the plan for packaging of the plutonium oxide material for shipment and storage at ORNL.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2019

Dissolution of Light Curium Oxide with a Catalyzed Electrolytic Process

The ability to produce transcurium elements and isotopes, such as 249 Bk and 252 Cf, requires the appropriate feed material and a high thermal neutron flux. Currently, at Oak Ridge National Laboratory (ORNL), the High Flux Isotope Reactor (HFIR) provides one of the world’s highest steady state thermal neutron fluxes. The feed material consists of recycled curium from the decades of production of 249 Bk, 252 Cf, 253 Es, and 255/257 Fm at the Radiochemical Engineering Development Center (REDC). Over time, the feed material has been depleted and needs to be replenished. The current feed material is called “heavy recycled curium” and consists of over 50 wt% of 246/248 Cm isotopes. In order to replenish this stock material, additional curium is needed. The only curium material that is currently available consists predominantly (greater than 80 wt%) of 244 Cm. This material also contains 240 Pu from the radioactive decay of the 244 Cm. Because of the amount of 244 Cm is greater than 50% of the total Cm, this material is termed “light curium.” Today, 249 Bk and 252 Cf are produced in only two places in the world: the United States and Russia. In the United States, the US Department of Energy and its predecessors have made these isotopes and others available to research agencies and commercial users since the late 1960s as part of the Department of Energy heavy-element production program located at ORNL. Currently these materials are provided through the DOE Office of Science Nuclear Physics-Isotope Development and Production for Research and Applications and the Basic Energy Science-Heavy Element Chemistry. Feedstock for the production of 252 Cf and other transcurium element by-product isotopes was originally prepared by means of irradiation of multi-kilograms of 239 Pu in the large production reactors at the Savannah River Site. Products of the Savannah River Site irradiation were predominantly 242 Pu, 243 Am, and 244 Cm. These materials were shipped to ORNL for production of multi-milligram amounts per year of 252 Cf and other transcurium element isotopes by means of irradiation in the HFIR, followed by separation and purification processing in the Radiochemical Engineering Development Center (REDC). The transcurium element isotopes produced were distributed to other US and collaborating foreign laboratories for research studies to determine the nuclear and chemical properties of these rare materials. The Cm feed material plays a key role in the efficient production of 252 Cf. The early targets irradiated in HFIR contained only the 242 Pu, 243 Am, and 244 Cm produced at Savannah River Site, and the rate of production of 252 Cf was less than 1 mg per 8 g of target material as shown in Figure 1. Also, shown in Figure 1 is the significant difference in 252 Cf production between the light and heavy curium; it differs by approximately 2 orders of magnitude.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Extraction of americium, curium, and californium with LN resin from HCl and HNO 3

The uptake of 241 Am, 244 Cm and 249 Cf with LN resin was studied in HCl and HNO3 solutions with concentrations ranging from 0.02 to 2.5 M. There is high uptake at concentrations < 0.1 M in both acids for all three isotopes with decreasing uptake at higher concentrations and negligible extraction at ≥ 0.6 M. Californium has a higher extraction than americium and curium, which are extremely similar. Kinetics studies showed rapid uptake of all three isotopes. Here, column studies were performed to demonstrate the separation of 241 Am and 249 Cf, and a bulk separation including nine stable lanthanides along with 241 Am, 249 Cf, and 88 Y.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2016

Preliminary Mark-18A (Mk-18A) Target Material Recovery Program Product Acceptance Criteria

The Mk-18A Target Material Recovery Program (MTMRP) was established in 2015 to preserve the unique materials, e.g. 244 Pu, in 65 previously irradiated Mk-18A targets for future use. This program utilizes existing capabilities at SRS and Savannah River National Laboratory (SRNL) to process targets, recover materials from them, and to package the recovered materials for shipping to ORNL. It also utilizes existing capabilities at ORNL to receive and store the recovered materials, and to provide any additional processing of the recovered materials or residuals required to prepare them for future beneficial use. The MTMRP is presently preparing for the processing of these valuable targets which is expected to begin in ~2019. As part of the preparations for operations, this report documents the preliminary acceptance criteria for the plutonium and heavy curium materials to be recovered from the Mk-18A targets at SRNL for transport and storage at ORNL. These acceptance criteria were developed based on preliminary concepts developed for processing, transporting, and storing the recovered Mk-18A materials. They will need to be refined as these concepts are developed in more detail.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Analysis of a Bulk 237 Np Oxide Sample for Trace Actinides

A neptunium oxide sample was dissolved and trace actinide constituents were measured by isotope dilution ICP-MS (for 239–244 Pu, 233–238 U, 237 Np, 241–243 Am) and alpha spectrometry ( 238 Pu, 242 Cm, 244 Cm). This material contained significant quantities of transuranic elements, notably americium and curium. The isotopic composition of the material will continue to evolve over time due to radioactive decay; the measurements reported here include all isotopes decay corrected to a reference date of 1/1/2022. These factors may be considerations in criticality studies of the related 237 Np sphere.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2017

Processing and Disposition of Special Actinide Target Materials - 17071

The DOE manages an inventory of materials that contain a range of long-lived radioisotopes that were produced from the 1960's through the 1980's by irradiating targets in high-flux reactors at the SRS to produce special heavy isotopes for DOE programmatic use, scientific research, and industrial and medical applications. Among the products were Cf-249, -250, -251, and -252; heavy curium (=50% Cm-246); and Pu-242 and -244. The irradiation of the Mark-18A (Mk-18A) targets at extremely high fluxes produced the world's supply of heavy curium and Pu-244. Approximately one fourth of the Mk-18A targets were processed in the 1970's to recover and enrich the material that has been used as the global source of Pu-244 and heavy curium by industry and researchers. These isotopes are still in demand, and the available supply of purified material is dwindling. A program has been initiated to recover heavy curium and Pu-244 from the remaining stored unprocessed Mk-18A targets. Improved flowsheets to process the materials to recover Pu-244 and heavy curium are being developed. Evaluations are also underway to determine whether additional materials present in the targets in much smaller quantities, such as long-lived fission product (LLFP) isotopes, can be recovered for research and development applications. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Formation of Superheavy Elements: Study Based on Dynamical Approach

Using multi-dimensional Langevin equations for the probability distribution of the distance between the surfaces of two approaching nuclei, we have studied the formation of superheavy elements via calculation of evaporation and fission cross sections of these elements. Evaporation residue cross sections have been calculated for the 1n, 2n, 3n, 4n, and 5n evaporation channels using one and four dimensional Langevin equations for the {sup 48}Ca+{sup 226}Ra, {sup 232}Th, {sup 238}U, {sup 237}Np, {sup 239,240,242,244}Pu, {sup 243}Am, {sup 245,248}Cm, {sup 249}Bk, and {sup 249}Cf reactions. Our results show that with increasing dimension of Langevin equations the evaporation residue cross section is increased. Also, obtained results based on fourdimensional Langevin are in better agreement with experimental data in comparison with one-dimensional model.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Scaling Trivalent Actinide and Lanthanide Recovery by Diglycolamide Resin from Savannah River Site’s Mark-18A Targets

The Savannah River National Laboratory is implementing a separation flowsheet to recover rare isotopes and transplutonium elements from irradiated 242 Pu targets known as Mark-18A targets. The Mark-18A targets contain the United States’ supply of nonseparated 244 Pu, which has a wide range of applications from nuclear forensics to production of superheavy elements such as flerovium. The targets also contain hundreds of grams of heavy curium ( 246–248 Cm), which is used as a target material for 252 Cf production. This work investigates the use of diglycolomide resin (DGA Resin) to recover valuable trivalent actinides from the Mark-18A targets. Batch contact experiments were performed on a representative simulant to determine mass loadings. Furthermore, the resin showed an overall capacity of 11 mg/mL for a mixed metal matrix (Zr and La–Gd). Column experiments showed chromatographic separation with transition-metal breakthroughs occurring first followed by the lanthanide series La–Gd. The experiments showed that lanthanide breakthrough occurred after 11 mg/mL mass loading was reached on the column with the mixed metal matrix. A radiological column experiment with an in-line UV/vis cell was able to detect Nd breakthrough just prior to 241 Am breakthrough. Implementing an in-line UV/vis cell into full-scale Mark-18A target processing will be used to limit breakthrough of trivalent actinides recovered from the targets.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗