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Title: WASTE CRATE ASSAY SYSTEM (WCAS): ASSAY SOLUTIONS FOR VERY LARGE REMOTE HANDLED CRATES

Abstract

No abstract prepared.

Authors:
; ;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
788235
Report Number(s):
LA-UR-01-5681
TRN: US0302047
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Oct 2001
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; RADIOACTIVE WASTES; REMOTE HANDLING; CONTAINERS; RADIOISOTOPE SCANNERS; DESIGN

Citation Formats

H. O. MENLOVE, P. M. RINARD, and ET AL. WASTE CRATE ASSAY SYSTEM (WCAS): ASSAY SOLUTIONS FOR VERY LARGE REMOTE HANDLED CRATES. United States: N. p., 2001. Web.
H. O. MENLOVE, P. M. RINARD, & ET AL. WASTE CRATE ASSAY SYSTEM (WCAS): ASSAY SOLUTIONS FOR VERY LARGE REMOTE HANDLED CRATES. United States.
H. O. MENLOVE, P. M. RINARD, and ET AL. 2001. "WASTE CRATE ASSAY SYSTEM (WCAS): ASSAY SOLUTIONS FOR VERY LARGE REMOTE HANDLED CRATES". United States. doi:. https://www.osti.gov/servlets/purl/788235.
@article{osti_788235,
title = {WASTE CRATE ASSAY SYSTEM (WCAS): ASSAY SOLUTIONS FOR VERY LARGE REMOTE HANDLED CRATES},
author = {H. O. MENLOVE and P. M. RINARD and ET AL},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2001,
month =
}

Conference:
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  • An advanced passive neutron counter has been designed and fabricated to measure the plutonium content in large remote handled (RH) waste crates. The waste crate assay system (WCAS) was developed under an agreement between Los Alamos National Laboratory, Japan Nuclear Fuel Limited (JNFL), and BNFL Instruments Inc. (BII) to measure the plutonium content in the waste generated in the Rokkasho reprocessing facility. The primary goal of the design was to produce an assay system for large waste containers. The system also includes 200-L drum pallet assay capability. The measurements are based on neutron-time correlation counting of the passive neutron emissionsmore » from the 240Pu, and the plutonium isotopic ratios are used to calculate the total plutonium. The system is designed for both RH waste and low-activity plutonium waste. The system permits the measurement of the singles, doubles, and triples rates and the multiplicity mode analysis is used together with the 'add-a-source' method to correct for the matrix materials in the crates. In the multiplicity analysis, the efficiency for counting the neutrons emitted from the crate is directly calculated from the three measured rates. For improved detectability limits, advanced methods have been incorporated in the WCAS-A to reduce the cosmic-ray neutron backgrounds. These methods include statistical filters and truncation of high-multiplicity events. The paper describes the WCAS-A design, performance, and calibration.« less
  • BIL Solutions Ltd Decommissioning In-Situ Plutonium Inventory Monitor (DISPIM{sup R}) is a versatile neutron and gamma assay system designed to be deployable in a wide range of decommissioning and waste management situations. The system utilizes Totals and Coincidence neutron counting to determine both total Pu mass values and the 3D Pu mass distribution inside the target object. DISPIM{sup R}'s modular, mobile design allows the system to be used in the assay of a range of objects of varying size and shape in locations where alternative monitoring equipment would not normally be available. The DISPIM{sup R} system has recently been successfullymore » used for the in-situ measurement of crated and drummed Plutonium Contaminated Material (PCM) waste items to provide Pu mass values in preparation for their treatment as part of a decommissioning program. A description of the operation of the DISPIM{sup R} system is given, including calibration of the system prior to the on-site survey, the measurement and quality control methodology employed during assay of waste items and discussion of the data analysis techniques. The results of 'imaging' measurements (i.e. Pu mass distribution results) recorded from the PCM crate measurements are likely to be of particular benefit when planning any future operations on these waste items. The results of this DISPIM{sup R} survey represent a complete solution for the customer with minimal requirement for use of their own resources. Technically substantiated Pu mass assay results have been provided which can now be easily adopted for use in criticality safety cases for the future treatment of these waste items. In summary, the DISPIM{sup R} system has successfully delivered a safe, fast and cost effective measurement solution to this challenging assay task and demonstrated its flexibility as a PCM monitoring system. (authors)« less
  • The purpose of this investigation is to examine the use of an electron linear accelerator (LINAC) in the performance of nondestructive assay (NDA) and nondestructive examination (NDE) measurements of remote-handled transuranic wastes. The system will be used to perform waste characterization and certification activities at the Oak Ridge National Laboratory's proposed Waste Handling and Packaging Plant. The NDA and NDE technologies which were developed for contact-handled wastes are inadequate to perform such measurements on high gamma and neutron dose-rate wastes. A single LINAC will provide the interrogating fluxes required for both NDA and NDE measurements of the wastes. 11 refs.,more » 6 figs.« less
  • Recent studies indicate LaBr3(Ce) scintillation detectors have desirable attributes, such as room temperature operability, which may make them viable alternatives as primary detectors (PD) in a Compton suppression spectrometer (CSS) used for remote-handled transuranic (RH-TRU) waste assay. A CSS with a LaBr3(Ce) PD has been designed and its expected performance evaluated using Monte Carlo analysis. The unique design of this unit minimizes the amount of "dead" material between the PD and the secondary guard detector. The analysis results indicate that this detector will have a relatively high Compton-suppression capability, with greater suppression ability for large angle-scattered photons in the PD.more » J. K. Hartwell1, M. E. McIlwain1, R. P. Gardner2, J. Kulisek3 1) Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2114 USA 2) North Carolina State University, Dept of Nuclear Eng., PO Box 7909, Raleigh, NC 27695 USA 3) Ohio State University, Columbus, Ohio 43210 The US Department of Energy’s transuranic (TRU) waste inventory includes about 4,500 m3 of remote-handled TRU (RH-TRU) wastes. The RH-TRU waste stream is composed of a variety of containerized waste forms having a contact surface dose rate that exceeds 2 mSv/hr (200 mrem/hr) containing waste materials with a total TRU concentration greater than 3700 Bq/g (100 nCi/g). As part of a research project to investigate the use of active Compton-suppressed room-temperature gamma-ray detectors for direct non-destructive quantification of the TRU content of these RH-TRU wastes, we have designed and purchased a unique detector system using a LaBr3(Ce) primary detector and a NaI(Tl) suppression mantle. The expected detector performance has been modeled using MCNP-X [1] and CEARCPG [2], and incorporates certain design features modeled as important to active Compton suppression systems in previously-published work [3]. The unique detector system is sketched in Fig. 1. The ~25 mm diameter by 75 mm long LaBr3(Ce) primary detector is inserted in the 25.4 mm diameter well of a 175 mm by 175 mm NaI(Tl) secondary (suppression) detector and is viewed by a 38 mm diameter PMT. An important feature of this arrangement is the lack of any "can" between the primary and secondary detectors. These primary and secondary detectors are optically isolated by a thin layer of aluminized Mylar, but the hermetic seal and thus the aluminum can surrounds the outer bound of the detector system envelope. The hermetic seal at the primary detector PMT is at the PMT wall. This arrangement virtually eliminates the "dead" material between the primary and secondary detectors, a feature that modeling indicates will substantially improve the Compton suppression capability of this device. This detector arrangement has been carefully modeled using the MCNP-X and the CEARCPG Monte Carlo codes. The results of these design calculations are compared with each other and with preliminary laboratory measurements performed on a detector system procured to these specifications. References [1]John S. Hendricks, MCNPX version 2.5c, Report LA_UR_03-2202, 2003. [2]Xiogang Han, Robin P. Gardner, and W. A. Metwally, CEARCPG: A Monte Carlo Simulation Code for Normal and Coincidence Prompt Gamma-ray Neutron Activation Analysis (PGNAA), in press Nuclear Science and Engineering, American Nuclear Society. [3]Wade Scates, John K. Hartwell, Rahmat Aryaeinejad, and Michael E. McIlwain, Optimization studies« less
  • The Advanced Nuclear Technology Group of the Los Alamos National Laboratory recently designed and built a combined passive- and active-neutron assay system on which group members performed initial characterization measurements. The system is intended to provide sensitive assays at the 100-nCi/g level of both spontaneous fission and fissile transuranic isotopes in large crates of bulk waste. Such crates can be accommodated in the system's assay chamber whose internal dimensions are 64 by 64 by 96 in. Moderated /sup 3/He proportional counters provide a measured total 4..pi.. neutron detection efficiency of 13.5 + or - 1% for bare and moderated-fission spectrummore » sources placed anywhere within the volume of a standard empty crate. Initial passive neutron coincidence measurements indicate a /sup 240/Pu detection sensitivity of about 10 mg. Enhancement of the fissile-isotope assay sensitivity results from lining the assay chamber walls with a thick layer of graphite and placing specially designed prompt-fission neutron detectors within the walls. Initial pulsed-neutron measurements indicate a fissile assay sensitivity of about 30 mg of /sup 239/Pu. After completion of checkout and initial calibration measurements at Los Alamos, the assay system will be installed at a DOE facility for a 1-year test-and-evaluation program beginning in July 1983. During the period, actual transuranic waste crates averaging nearly 1000 kg each will be assayed on a routine basis.« less