Engineering topics

Mozin, Vladimir

Publications and source records attributed to Mozin, Vladimir.

8 records

DOE OSTI2024

Uranium measurements in the field using high-resolution cadmium zinc telluride detectors

A new generation of cadmium zinc telluride (CZT) detectors has become available and is being evaluated by the International Atomic Energy Agency (IAEA) for safeguards verifications in the field. The new CZT detector, model M400, is a room temperature spectrometer manufactured by H3D, Inc. The M400 demonstrates superior energy resolution, effective isotope identification capabilities, and convenient usability features when tested in a controlled laboratory environment. These characteristics define the M400 as a potential platform for IAEA field detection applications, which could become suitable for nuclear material characterization (e.g., enrichment verification) and nuclear safeguards missions. The capabilities of gamma spectrometry codes including Fixed energy, Response function Analysis with Multiple efficiencies (FRAM) from Los Alamos National Laboratory, CZT for Uranium (CZTU) from Lawrence Livermore National Laboratory, and Gamma Detector Response and Analysis Software (GADRAS) from Sandia National Laboratories were adapted for M400 spectra, and the performance of the codes has been validated. This was reported in a prior work. To further validate the performance of the high-energy resolution CZT detector and the isotopic analysis codes, a field measurement campaign consisting of uranium hexafluoride (UF 6 ) cylinder measurements was conducted at a fuel fabrication facility. A total of 34 Type 30B cylinders containing UF6 were measured using three different M400 CZT detectors. Each detector was outfitted with a custom rectangular collimator and shield made out T-Flex®, a tungsten-impregnated polymer. Measurements were performed at three different locations of the cylinder, ensuring that the measurement geometry satisfied the infinite thickness criterion. The spectra from the M400 CZT were analyzed using the code General Enrichment Meter (GEM). For analyzing the gamma-ray spectra from UF 6 cylinder, the GEM code is the appropriate tool since it relies only on the gamma-ray emissions from 235 U and not from other isotopes. Results from the spectral analysis were compared with the known abundance of 235 U in the cylinders, as well as with the International Target Values 2020 (ITV2020). The suitability of the different underlying techniques used by the various codes for UF 6 analysis is discussed. The challenges of measuring UF 6 contained in cylinders and mitigation strategies are highlighted.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2024

Measuring the surface abundance of iron and nickel on the asteroid (16) Psyche in the presence of large solar particle events

Not Available

(16) Psyche↗

DOE OSTI2023

Gamma Spectrometry Code Rodeo for Uranium Enrichment—FY 2022 Report

In the first two quarters of FY22, data acquisition continued at ORNL and LLNL using uranium sources of known enrichments. This was an FY21 task which could not be completed in FY21 because of problems encountered with the ORNL M400 CZT in Q4 of FY21, and the subsequent repairs. The detector was received back from H3D in the first of September 2021 , and the measurements resumed . Measurements using the repaired detector were completed in Q1 of FY22. The spectra were distributed by ORNL to the analyzing labs. Analysis results were received in Q2 of FY2022. The results from the various codes were intercompared and an ANOVA analysis was performed. Random and systematic uncertainties were established for each code. The ANOVA results and discussions were included in a revised version of FY21Annual Report issued in March 2022. A paper was presented at the INMM 2022Annual Conference, with the analysis results from the various isotopic codes, and the ANOVA table with random and systematic uncertainties. The Project Work Plan (PWP) for FY22 included a task to perform field testing of the M400 CZT and the analysis codes using UF 6 cylinder measurements at the Framatome Fuel Fabrication Facility in Richland, WA. PNNL was the lead for the field testing task. PNNL drafted a Field Test Plan, and refined it based on comments received from the team. PNNL coordinated with Framatome facility, the logistics of carrying out the field testing . A collimator and shield made out of TFlex (tungsten impregnated polymer) was designed and professionally manufactured. The collimators were used in the field test measurements. The measurements at Framatome were completed on April 21, 2022. A total of 34 Type 30B cylinders were measured using three M400 detectors (PNNL, LLNL, and ORNL detectors). Measurements using M400 were taken at two locations on the side of each cylinder and from the end-on bottom location. Additionally, HPGe measurements were taken at the end-on location to establish ground truth. Cylinder wall thickness measurements were also made at all three locations. To gain a better understanding of the effect of background from surrounding cylinders, the same five cylinders measured individually in low background locations were measured again in the cylinder storage yards. Due to inclement weather, manufacturer delays, shipping delays, and equipment failure, the measurement campaign spanned twice as long compared to the original timeline. Gamma-ray spectra from M400 and HPGe detectors, along with the cylinder data and photographs were organized and shared with the collaborators for further analysis. Spectra were analyzed by the participating laboratories. FY22 PWP also consists of tasks related to plutonium source measurements, adapting the codes to analyze plutonium spectra, and inter-comparison of the results from various codes. Plutonium spectra are being acquired at LANL, ORNL, and LLNL. LANL, SNL and LLNL are in the process of modifying FRAM, GADRAS, and CZTU, respectively. The plutonium related tasks will be completed in Q2 of FY23.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2022

Gamma Spectrometry Code Rodeo for Uranium Enrichment—FY 2021 Report

In FY22, the participating Department of Energy (DOE) laboratories continued the work on the project “Gamma Spectrometry Code Rodeo for Uranium Enrichment”. Oak Ridge National Laboratory (ORNL) and Lawrence Livermore National Laboratory (LLNL) continued their efforts to acquire spectra using uranium sources. A collimator (with side and back shields) was custom designed and constructed at ORNL. Spectra were acquired at ORNL using the uranium enrichment standards supplied by New Brunswick Laboratory (NBL) and the collimated M400 detector. Spectra were also acquired using steel absorbers of different thickness placed between the source and the collimated M400 detector. The plan was to ship the collimator to LLNL so that spectra could be acquired using the LLNL detector in collimated geometries. This activity was suspended since problems were noticed with the performance of the LLNL M400 detector. Also, it was brought to light to the project team that some of the aspects of the M400 detector had been updated by the vendor H3D in response to requests by the IAEA. In February 2021, the ORNL and LLNL M400 detectors were returned to the H3D factory in order to resolve the problems with the LLNL detector and to update ORNL and LLNL detectors to the same configuration as the M400 supplied to the IAEA. H3D repaired the LLNL M400 and performed the IAEA updates on both the ORNL and LLNL detectors. ORNL and LLNL received the detectors in April 2021. Data acquisition was continued using the upgraded detectors. ORNL re-collected the spectra using point sources and the NBL standards in uncollimated and collimated geometries. The collimator was shipped from ORNL to LLNL. Spectra were acquired at LLNL through Q4 of FY22. When the ORNL spectra were examined closely, it became apparent that there were spurious artifacts present in some of the spectra. This rendered suspect the ORNL spectra collected in June/July 2021 time frame. ORNL contacted H3D and per H3D’s advice, the M400 detector was returned to H3D for repairs in mid-August 2021. H3D diagnosed the problem and established that the root cause was the extra tight packaging that created a strain on the CZT crystals, causing one of them to break down. The repaired M400 was returned to ORNL in early September 2021. ORNL re-started data acquisition for the third time. Data was continued to be acquired at ORNL and LLNL through September 2021. The ORNL and LLNL data will be shared with the principal investigators from the analyzing laboratories. The GADRAS code and FRAM have been developed to have the capability to analyze the M400 spectra. Good quality spectra from FY21 have been analyzed using modified versions of GADRAS and FRAM. The spectra have also been analyzed using the GEM code. The analysis results from GADRAS, FRAM and GEM codes are presented and discussed in this report. Some preliminary results from FRAM and GEM analysis were presented in February 2021 at the U-Pu Isotopics Workshop sponsored by the IAEA. CZTU code is being modified to analyze M400 spectra. Data collection, code development and analysis will be continued in FY22 as per the FY22 Project Work Plan (PWP).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2019

Delayed Gamma-ray Assay for Nuclear Materials Safeguards. Comprehensive Technology Readiness Assessment

Spectroscopic analysis of beta-delayed gamma-rays emitted from fission products following active interrogation was investigated as a non-destructive assay technique for detection and characterization of nuclear materials in shielded and complex configurations. This measurement technique is expected to be applicable to a variety of applications within the nuclear material safeguards, arms control, and emergency response areas, where active neutron interrogation is acceptable. Potential applications of the delayed gamma-ray assay in the nuclear material safeguards area include characterization of U and Pu isotopic content in spent and unirradiated nuclear fuel, enrichment measurements, verification of bulk material in containers, and the characterization of nuclear wastes. In the arms control area, this method can be used as a part of warhead dismantlement measurements to confirm separation of components, and may be applicable in warhead confirmation. In the context of emergency response, it can be used for detailed diagnostics of an unknown item. At present, the delayed gamma-ray assay technology reliably qualifies for the Technical Readiness Level 3 (TRL 3). The R&D work completed under this project has successfully demonstrated the empirical proof-of-concept for this active interrogation technology for a variety of measurement configurations, neutron sources, and nuclear material samples. A robust first-principles analytical signature modeling methodology was developed, experimentally validated, and can be easily extrapolated to a range of realistic measurement scenarios. Several response analysis methodologies have been implemented and deemed reliable for a variety of active interrogation applications in the areas of nuclear material safeguards, arms control, and emergency response. The initial readiness level before the start of this project was assessed at TRL 0, since only fragmentary records of the signature observations and speculative statements of the relevant non-destructive assay applications existed at that time. The delayed gamma-ray technology readiness can be easily advanced to TRL 4 in a short period, if a certain measurement application is specified and set for a demonstration in a laboratory environment. The critical hardware components of the delayed gamma-ray measurement technology (neutron generators, gamma-ray spectrometers) are readily available as COTS and can be configured for a specific deployment configuration. The primary risk of the delayed gamma-ray assay methodology is defined by the applicationspecific uncertainties. Evaluation of the system performance can be effectively completed once the expected measurement purpose, nuclear material characteristics, dimensions, and radiation exposure constraints are specified. A minor risk can be associated with the delayed gamma-ray response analysis techniques. Several approaches were proposed and demonstrated primarily using the modeled signatures. The observed performance may not be easily transferrable to the conditions of a real measurement setup, and some additional R&D may be required. Overall, the delayed gamma-ray assay technology can be recommended for follow-up demonstrations addressing relevant measurement applications in the areas of nuclear material safeguards, arms control, and emergency response.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2019

Delayed Gamma-ray Assay for Nuclear Materials Safeguards: Additional Tasks

This report documents the activities and findings completed under the extended task scope in FY17-18. This work was performed as a follow-up to the original effort that investigated the delayed gamma-ray signatures of nuclear materials and was a collaborative effort between Lawrence Livermore, Lawrence Berkeley, Los Alamos National Laboratories and the Idaho Accelerator Center. The original project was focused on the delayed gamma-ray (DG) assay application for spent nuclear fuel safeguards, as a methodology to directly quantify the content and composition of U and Pu isotopes in irradiated assemblies in storage or before transfer to a difficult-to-access repository.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2018

Stilbene Scintillator Detector Array and Data-Acquisition System for Active Interrogation

A large area Stilbene crystal detector array has been assembled and calibrated for use in active interrogation measurements. The array consists of 10 high-efficiency 4”x2” stilbene cells. The cells were grown by Inrad Optics using LLNL developed technology. The array can be used to detect multiple signatures of SNM items, both actively and passively. Prompt and delayed gamma rays as well as prompt and delay neutrons can be detected and counted separately. The array is coupled to the Mesytec MDPP-16 VME-based digitizer module for data acquisition. This module performs on-board pulse-shape discrimination of signals from the Stilbene crystal detectors. This data-acquisition module allows separation of neutron and gamma-ray events with a low demand on data transfer rates. In addition, the high-resolution timing (<100 ps) is suitable for correlated gamma-ray and neutron multiplicity counting. This report describes the construction and calibration of the system. We also discuss applications of the system as well as how the system is currently being utilized by end users.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2017

RASE OSS

The Replicative Assessment of Spectroscopic Equipment (RASE) methodology is a semi-empirical approach to generating synthetic gamma-ray spectra for injection into a radionuclide identification algorithm of a vendor-provided detection system. RASE facilitates studies of the spectroscopic device performance and a quantitative assessment of its capabilities to correctly distinguish and identify isotopes of interest in realistic scenarios.

Sangiorgio, Samuele↗