Uncertainty Analysis of Nondestructive Assay Measurements of Nuclear Waste

Uncertainty Analysis of Nondestructive Assay Measurements of Nuclear Waste
Author:
Publisher:
Total Pages:
Release: 1998
Genre:
ISBN:

Regulatory agencies governing the disposal of nuclear waste require that the waste be appropriately characterized prior to disposition. The most important aspect of the characterization process, establishing radionuclide content, is often achieved by nondestructive assay (NDA). For NDA systems to be approved for use in these applications, measurement uncertainty must be established. Standard propagation of errors methods provide a good starting point for considering the uncertainty analysis of NDA systems for nuclear waste. However, as compared with other applications (e.g., nuclear material accountability), using NDA systems for nuclear waste measurements presents some unique challenges. These challenges, stemming primarily from the diverse nature of the waste materials encountered, carry over into the uncertainty analysis as well. This paper reviews performance measures appropriate for the assessment of NDA uncertainty, describes characteristics of nuclear waste measurements that contribute to difficulties in assessing uncertainty, and outlines some statistics based methods for incorporating variability in waste characteristics in an uncertainty analysis.

SWEPP PAN Assay System Uncertainty Analysis

SWEPP PAN Assay System Uncertainty Analysis
Author:
Publisher:
Total Pages: 80
Release: 1997
Genre:
ISBN:

The Idaho National Engineering and Environmental Laboratory is being used as a temporary storage facility for transuranic waste generated by the U.S. Nuclear Weapons program at the Rocky Flats Plant (RFP) in Golden, Colorado. Currently, there is a large effort in progress to prepare to ship this waste to the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. In order to meet the TRU Waste Characterization Quality Assurance Program Plan nondestructive assay compliance requirements and quality assurance objectives, it is necessary to determine the total uncertainty of the radioassay results produced by the Stored Waste Examination Pilot Plant (SWEPP) Passive Active Neutron (PAN) radioassay system. To this end a modified statistical sampling and verification approach has been developed to determine the total uncertainty of a PAN measurement. In this approach the total performance of the PAN nondestructive assay system is simulated using computer models of the assay system and the resultant output is compared with the known input to assess the total uncertainty. This paper is one of a series of reports quantifying the results of the uncertainty analysis of the PAN system measurements for specific waste types and measurement modes. In particular this report covers passive mode measurements of weapons grade plutonium-contaminated graphite molds contained in 208 liter drums (waste code 300). The validity of the simulation approach is verified by comparing simulated output against results from measurements using known plutonium sources and a surrogate graphite waste form drum. For actual graphite waste form conditions, a set of 50 cases covering a statistical sampling of the conditions exhibited in graphite wastes was compiled using a Latin hypercube statistical sampling approach.

Strategy and Methodology for Radioactive Waste Characterization

Strategy and Methodology for Radioactive Waste Characterization
Author: International Atomic Energy Agency
Publisher: IAEA
Total Pages: 188
Release: 2007
Genre: Business & Economics
ISBN:

Over the past decade significant progress has been achieved in the development of waste characterization and control procedures and equipment as a direct response to ever-increasing requirements for quality and reliability of information on waste characteristics. Failure in control procedures at any step can have important, adverse consequences and may result in producing waste packages which are not compliant with the waste acceptance criteria for disposal, thereby adversely impacting the repository. The information and guidance included in this publication corresponds to recent achievements and reflects the optimum approaches, thereby reducing the potential for error and enhancing the quality of the end product. -- Publisher's description.

SWEPP PAN Assay System Uncertainty Analysis

SWEPP PAN Assay System Uncertainty Analysis
Author:
Publisher:
Total Pages: 35
Release: 1997
Genre:
ISBN:

The Idaho National Engineering and Environmental Laboratory is being used as a temporary storage facility for transuranic waste generated by the US Nuclear Weapons program at the Rocky Flats Plant (RFP) in Golden, Colorado. Currently, there is a large effort in progress to prepare to ship this waste to the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. In order to meet the TRU Waste Characterization Quality Assurance Program Plan nondestructive assay compliance requirements and quality assurance objectives, it is necessary to determine the total uncertainty of the radioassay results produced by the Stored Waste Examination Pilot Plant (SWEPP) Passive Active Neutron (PAN) radioassay system. This paper is one of a series of reports quantifying the results of the uncertainty analysis of the PAN system measurements for specific waste types and measurement modes. In particular this report covers active mode measurements of weapons grade plutonium-contaminated aqueous sludge waste contained in 208 liter drums (item description codes 1, 2, 7, 800, 803, and 807). Results of the uncertainty analysis for PAN active mode measurements of aqueous sludge indicate that a bias correction multiplier of 1.55 should be applied to the PAN aqueous sludge measurements. With the bias correction, the uncertainty bounds on the expected bias are 0 " 27%. These bounds meet the Quality Assurance Program Plan requirements for radioassay systems.

Challenges of Non-Destructive Assay Waste Measurement

Challenges of Non-Destructive Assay Waste Measurement
Author: A. H. Shull
Publisher:
Total Pages: 5
Release: 2003
Genre:
ISBN:

Historically, the Savannah River Site (SRS) routinely produced special nuclear material (SNM), which provided stable measurement conditions for the non-destructive assay (NDA) methods. However, the main mission of SRS has changed from the production of SNM to the processing of waste and material stabilization. Currently, the purpose of processing is to recover the SNM from the waste and stabilization materials, much of which is from other DOE facilities. These missions are usually of a short duration, but require non-destructive assay (NDA) accountability measurements on materials of varying composition and geometric configuration. These missions usually have cost and time constraints, which sometimes require re-application of existing NDA methods to waste measurements. Usually, each new material or re-application of the NDA method to a different SNM campaign requires new standards and timely re-calibration of the method. These constraints provide numerous challenges for the NDA methods, particularly in the area of measurement uncertainty. This paper will discuss the challenges of these situations, mainly from a measurement and statistical point of view and provide some possible solutions to the problems encountered. Specific examples will be discussed for the segmented gamma scanner (SGS), neutron multiplicity counter (NMC) and passive neutron coincidence counter (PNCC), which are some of the most common NDA instruments at SRS.

Nondestructive Assay of Nuclear Materials for Safeguards and Security

Nondestructive Assay of Nuclear Materials for Safeguards and Security
Author: William H. Geist
Publisher: Springer
Total Pages: 0
Release: 2024-08-07
Genre: Science
ISBN: 9783031582769

This open access book describes the nondestructive assay techniques that are used for the measurement of nuclear material (primarily uranium and plutonium) for nuclear material accountancy purposes. It is a substantial revision to the so-called PANDA manual that has been a standard reference since its publication in 1991. The book covers the origin and interactions of gamma rays and neutrons as they affect nuclear measurements and also describes the theory and practice of calorimetry. The book gives a description of many instruments based on these techniques that are applied in the field. Although the basic physics has not changed since PANDA was first published, the last thirty years have seen many advances in analysis methods, instrumentation, and applications. The basic descriptions of the origin and interactions of radiation have been updated and include newer references. There have been extensive revisions of the description of gamma detection methods, attenuation correction procedures, and analysis methods, including for the measurement of uranium enrichment and the determination of plutonium isotopic composition. Extensive revisions and additions have also been made to the description of neutron detectors and to the explanation of neutron coincidence techniques. The chapter on neutron multiplicity techniques is a new addition to this edition. The applications of gamma and neutron techniques have been completely overhauled to remove obsolete systems and to include many current applications. The values of, and references to, nuclear data have been updated. This updated edition is an essential reference for academic researchers and practitioners in the field. This is an open access book.