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At least 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

CAAS-3S Radiation Testing for Y-12 and UPF with Godiva-IV

The Y-12 National Security Complex and the Uranium Processing Facility (UPF) selected the Mirion CAAS-3S as the Criticality Accident Alarm System for UPF and for Y-12 facilities replacing their legacy CAAS as part of efforts to extend the facility lifespans. As part of this process, the CAAS-3S system was exposed to a high radiation dose and dose rate during reactor testing with the Godiva-IV fast burst reactor. The reactor testing was designed around preliminary analyses that determined Y-12 and UPF requirements, and simulations of the radiation field within the reactor facility were used to determine reactor operating parameters, CAAS equipment locations, and the design of a neutron shield wall. This paper presents the design and results of the testing, and discusses how the test results were interpreted by criticality safety engineers at Y-12 and UPF.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Novel Bremsstrahlung Converter Designs for Ultra High Dose Rate Radiotherapy Systems

Ultra-high dose rates (UHDR) have been shown to improve the therapeutic index in the treatment of cancer using external beam radiotherapy in many preclinical settings by inducing the so-called “FLASH” effect [1]; however, the underlying biological and physical mechanism(s) are still unknown. Recent work has been to expand the energy range of photons used in UHDR studies from keV photons generated in synchrotron to photons less than 8 MeV produced by accelerated electrons undergoing the bremsstrahlung interaction [2]. This work is a part of the FLASH-Experimental X-ray small Animal Conformal Therapy (FLASH-EXACT) project is aimed at producing a preclinical system that induces the FLASH effect with photons >10 MeV.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2023

US Participation in Valahia 2023

In response to invitation to participate in the Valahia, Romania 2023 Full Field Exercise in October, 2023, host country is requesting exercise objectives and resource needs from the US Aerial Measuring System participants. This document is to illustrate to the IAEA 3rd Consultancy Workshop meeting on Marc 6-7, 2023 (virtually) what will be expected from AMS at the exercise.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2023

Consequence Management Monitoring Strategies

This presentation will be used in the pilot NA-81 Consequence Monument course. This presentation discusses monitoring techniques that can be used when responding to a radiological incident.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2023

BRR Cask Use for Pu-238 Isotope Production

US Department of Energy (DOE), in partnership with the National Aeronautics and Space Administration (NASA), needs to produce Pu-238 for space exploration Major activities are focused at Idaho National Laboratory (INL) and Oak Ridge National Laboratory (ORNL) Key part of program is movement of targets between INL and ORNL BEA Research Reactor (BRR) package licensed for transport of unirradiated and irradiated targets

42 ENGINEERING↗
DOE OSTI2023

Recalculating Dissolver Curves for Critical Parameters for Nuclear Criticality Safety

The dissolver paradox is a phenomenon in criticality safety whereby a high density fissile material is being dissolved in a low fissile density solution and is subcritical before and after dissolution. However, as the metal is being dissolved, there may be an intermediate concentration that leads to a critical state. CCG-184 is a Y-12 report written in 1980 that provided critical parameter data for two separate dissolver paradox scenarios: solid metal spheres and hollow metal spheres with internal moderation effects. The sphere and shell are both surrounded by solution, however the shell contains solution of the same concentration within itself. In 1980, there are limitations to the computational methods to determine critical parameters. These are due to the lower number of energy groups utilized (16-group) at the time, smaller number of established cross-sectional data, as well as a larger uncertainty within the resonance region of neutron energies. With these constraints in mind, these critical parameters are recalculated with newer cross-sectional data, a newer Monte Carlo code: SCALE 6.1.3 using KENO V.a, and a larger number of energy bins.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2023

From Count Rates to Quantifying Isotopic Activities – Field Analysis of Radiation Monitoring Data

The Nevada National Security Site (NNSS) provides a comprehensive bicoastal radiological and nuclear emergency response to United States Department of Energy/National Nuclear Security Administration. A major part of the support is to provide systematic radiological search for lost or stolen sources, Radiological search is a core competency of the NNSS with its origin dating back to nuclear weapons test era. Search operations from multiple platforms is the common thread among the various NNSS assets, which include Aerial Measuring System (AMS), Maritime Support Team (MST), National Capitol Response (NCR), National Search Team (NST) and Radiological Assistance Program (RAP). Information collected and analyzed during search operations add to the actionable intelligence for the law enforcement agencies and provide valuable guidance for the tactical resolution of a nuclear or radiological crisis. Search is an intelligence and situational awareness driven operation and most often called upon during a radiological emergency, however it can be brought into play to thwart a potential threat by providing monitoring and surveillance support. The Office of Nuclear Incident Response (NA-84) serves as the technical leader in responding to and resolving nuclear and radiological threats worldwide and integrates its efforts with other NNSA stakeholders (e.g., NNSA office of Defense Nuclear Non-proliferation NA-22). The response includes expertise in the areas of radiological search, render safe, and consequence management. This article will discuss the methodologies, tools, procedures, and techniques to extract maximum radiological characterization information (isotopic composition, activities for individual isotopes, threat assessment etc.) from field monitoring or Search operation data.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2023

CHALLENGES IN THE DEVELOPMENT OF THE ELECTROREFINING PROCESS AT Y-12

In order to ensure future capabilities of the Y-12 site as older buildings retire, a new process was developed, the Metal Purification Process. The purpose of this new process is to provide a simpler and more efficient uranium metal purification that the previous multi-staged, complex chemical processes. The basis for this technology currently exists in the US DOE complex, but it has not been utilized on a large scale for uranium at higher enrichments. The system requires larger-geometry vessels and furnaces in order to meet the through-put requirements. The crux of the process is the electrorefining cell, consisting of several concentric liners and an unfavorable geometry cylindrical crucible. Within the crucible, a molten Li-CL-KCL-UCL3 salt electrolyte is present. ‘Dirty’ metal is placed into a loading basket and loaded into an electrorefining cell. Here, the metal reacts into the molten salt within the cell to form UCL3, while ‘clean’ metal simultaneously plates out from the salt electrolyte in the form of metal dendrites. These dendrites are then collected and removed from the cell. After removal from the cell, the dendrites are taken to a furnace to remove adhered salts. Then, the salt-free dendrites are moved to a separate furnace for consolidation into the final product form. The development of the Criticality Safety Evaluation for this complex system brought with it many NCS Challenges and lessons learned. These challenges include: design decisions for ensuring subcriticalty in the electrorefining cell during abnormal conditions, the interface of the main glovebox system with auxiliary systems such as the purification system and designated storage, implementation of mass tracking, and concerns from production and operation regarding the movement of material within the system.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Criticality Accident Alarm System Modeling for the Uranium Processing Facility

The Criticality Accident Alarm System (CAAS) for the Uranium Processing Facility (UPF) provides coverage for two primary processing facilities. For UPF, detailed documentation and drawings of the design are readily available. While this design information allows for some CAAS modeling features to match the actual design with a high level of accuracy, assumptions and simplifications are necessary as it is unrealistic and unnecessary to replicate many aspects of the design. A set of modeling guidelines and techniques were used to develop consistency between the MCNP6 models. While ensuring conservatism, overly conservative choices must be avoided to demonstrate the minimum accident of concern can be detected. To ensure proper modeling choices were made for the final models, a group of parametric studies were performed to evaluate the impact on the dose rates detected at the individual detectors. Some of these modeling choices and/or associated parametric studies include: - Modeling the grid steel area above the detectors as homogeneous stainless steel and determining the impact on detectability with an increasing density. - Modeling the presence of equipment in close proximity to the CAAS detectors. - Determining an appropriate material density to represent miscellaneous items not specifically modeled. - Evaluating the impact of sprinkler activation. The results of UPF CAAS analyses show that the modeling assumptions made based on the detailed design and parametric studies are appropriate and demonstrate accurate yet conservative models have been developed for detecting minimum accident of concern within the UPF.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2020

Panel Session 117: Panel: Operational Excellence Through a Strong Safety Culture (R9.1)

This panel focused on the what the Department of Energy (DOE) and its contractors are doing to promote safety and excellence. The Integrated Safety Management System (ISMS) is crucial, but additional support provided by the Energy Facility Contractors Group (EFCOG), DOE, and environmental, safety, and health (ES and H) professionals in the field are equally imperative. The panelists discussed the importance of sharing lessons learned as well as are developing performance metrics to track operational and safety successes. This panel focused on current trends in building a strong operational safety culture and will include results from recent national workshops. Safety culture is the foundation of strong operational performance. Panel discussion included best practices from industry, DOE, and US NRC and also review tools being used to measure and evaluate safety culture programs. Panelists with presentations: Strong Safety Culture Promotes Operational Excellence (Kliss McNeel, Patricia Hughes); Safety Culture (Patricia Allen); DOE Safety Culture Improvement (Julie Goeckner); Supporting Safety Culture on the Front Line (Jan Preston); Interdependence of Safety Culture and Organizational Performance (Rizwan Shah)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗