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Evaluation Of The Neutron Dose Received By Personnel At The Llnl
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Book Synopsis Evaluation of the Neutron Dose Received by Personnel at the LLNL. by :
Download or read book Evaluation of the Neutron Dose Received by Personnel at the LLNL. written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report was prepared to document the techniques being used to evaluate the neutron exposures received by personnel at the LLNL. Two types of evaluations are discussed covering the use of the routine personnel dosimeter and of the albedo neutron dosimeter. Included in the report are field survey results which were used to determine the calibration factors being applied to the dosimeter readings. Calibration procedures are discussed and recommendations are made on calibration and evaluation procedures.
Book Synopsis Characterization of the Neutron Fields in the Lawrence Livermore National Laboratory (LLNL) Radiation Calibration Laboratory Low Scatter Calibration Facility by :
Download or read book Characterization of the Neutron Fields in the Lawrence Livermore National Laboratory (LLNL) Radiation Calibration Laboratory Low Scatter Calibration Facility written by and published by . This book was released on 2009 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: In June 2007, the Department of Energy (DOE) revised its rule on Occupational Radiation Protection, Part 10 CFR 835. A significant aspect of the revision was the adoption of the recommendations outlined in International Commission on Radiological Protection (ICRP) Report 60 (ICRP-60), including new radiation weighting factors for neutrons, updated internal dosimetric models, and dose terms consistent with the newer ICRP recommendations. ICRP-60 uses the quantities defined by the International Commission on Radiation Units and Measurements (ICRU) for personnel and area monitoring including the ambient dose equivalent H*(d). A Joint Task Group of ICRU and ICRP has developed various fluence-to-dose conversion coefficients which are published in ICRP-74 for both protection and operational quantities. In February 2008, Lawrence Livermore National Laboratory (LLNL) replaced its old pneumatic transport neutron irradiation system in the Radiation Calibration Laboratory (RCL) Low Scatter Calibration Facility (B255, Room 183A) with a Hopewell Designs irradiator model N40. The exposure tube for the Hopewell system is located close to, but not in exactly the same position as the exposure tube for the pneumatic system. Additionally, the sources for the Hopewell system are stored in Room 183A where, prior to the change, they were stored in a separate room (Room 183C). The new source configuration and revision of the 10 CFR 835 radiation weighting factors necessitate a re-evaluation of the neutron dose rates in B255 Room 183A. This report deals only with the changes in the operational quantities ambient dose equivalent and ambient dose rate equivalent for neutrons as a result of the implementation of the revised 10 CFR 835. In the report, the terms 'neutron dose' and 'neutron dose rate' will be used for convenience for ambient neutron dose equivalent and ambient neutron dose rate equivalent unless otherwise stated.
Book Synopsis Impact of the Revised 10 CFR 835 on the Neutron Dose Rates at LLNL. by :
Download or read book Impact of the Revised 10 CFR 835 on the Neutron Dose Rates at LLNL. written by and published by . This book was released on 2009 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: In June 2007, 10 CFR 835 [1] was revised to include new radiation weighting factors for neutrons, updated dosimetric models, and dose terms consistent with the newer ICRP recommendations. A significant aspect of the revised 10 CFR 835 is the adoption of the recommendations outlined in ICRP-60 [2]. The recommended new quantities demand a review of much of the basic data used in protection against exposure to sources of ionizing radiation. The International Commission on Radiation Units and Measurements has defined a number of quantities for use in personnel and area monitoring [3,4,5] including the ambient dose equivalent H*(d) to be used for area monitoring and instrument calibrations. These quantities are used in ICRP-60 and ICRP-74. This report deals only with the changes in the ambient dose equivalent and ambient dose rate equivalent for neutrons as a result of the implementation of the revised 10 CFR 835. In the report, the terms neutron dose and neutron dose rate will be used for convenience for ambient neutron dose and ambient neutron dose rate unless otherwise stated. This report provides a qualitative and quantitative estimate of how much the neutron dose rates at LLNL will change with the implementation of the revised 10 CFR 835. Neutron spectra and dose rates from selected locations at the LLNL were measured with a high resolution spectroscopic neutron dose rate system (ROSPEC) as well as with a standard neutron rem meter (a.k.a., a remball). The spectra obtained at these locations compare well with the spectra from the Radiation Calibration Laboratory's (RCL) bare californium source that is currently used to calibrate neutron dose rate instruments. The measurements obtained from the high resolution neutron spectrometer and dose meter ROSPEC and the NRD dose meter compare within the range of ±25%. When the new radiation weighting factors are adopted with the implementation of the revised 10 CFR 835, the measured dose rates will increase by up to 22%. The health physicists should consider this increase for any areas that have dose rates near a posting limit, such as near the 100 mrem/hr for a high radiation area, as this increase in measured dose rate may result in some changes to postings and consequent radiological controls.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993-12 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010 by :
Download or read book Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010 written by and published by . This book was released on 2011 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Lawrence Livermore National Laboratory uses neutron activation elements in a Panasonic TLD holder as a personnel nuclear accident dosimeter (PNAD). The LLNL PNAD has periodically been tested using a Cf-252 neutron source, however until 2009, it was more than 25 years since the PNAD has been tested against a source of neutrons that arise from a reactor generated neutron spectrum that simulates a criticality. In October 2009, LLNL participated in an intercomparison of nuclear accident dosimeters at the CEA Valduc Silene reactor (Hickman, et.al. 2010). In September 2010, LLNL participated in a second intercomparison of nuclear accident dosimeters at CEA Valduc. The reactor generated neutron irradiations for the 2010 exercise were performed at the Caliban reactor. The Caliban results are described in this report. The procedure for measuring the nuclear accident dosimeters in the event of an accident has a solid foundation based on many experimental results and comparisons. The entire process, from receiving the activated NADs to collecting and storing them after counting was executed successfully in a field based operation. Under normal conditions at LLNL, detectors are ready and available 24/7 to perform the necessary measurement of nuclear accident components. Likewise LLNL maintains processing laboratories that are separated from the areas where measurements occur, but contained within the same facility for easy movement from processing area to measurement area. In the event of a loss of LLNL permanent facilities, the Caliban and previous Silene exercises have demonstrated that LLNL can establish field operations that will very good nuclear accident dosimetry results. There are still several aspects of LLNL's nuclear accident dosimetry program that have not been tested or confirmed. For instance, LLNL's method for using of biological samples (blood and hair) has not been verified since the method was first developed in the 1980's. Because LLNL and the other DOE participants were limited in what they were allowed to do at the Caliban and Silene exercises and testing of various elements of the nuclear accident dosimetry programs cannot always be performed as guests at other sites, it has become evident that DOE needs its own capability to test nuclear accident dosimeters. Angular dependence determination and correction factors for NADs desperately need testing as well as more evaluation regarding the correct determination of gamma doses. It will be critical to properly design any testing facility so that the necessary experiments can be performed by DOE laboratories as well as guest laboratories. Alternate methods of dose assessment such as using various metals commonly found in pockets and clothing have yet to be evaluated. The DOE is planning to utilize the Godiva or Flattop reactor for testing nuclear accident dosimeters. LLNL has been assigned the primary operational authority for such testing. Proper testing of nuclear accident dosimeters will require highly specific characterization of the pulse fields. Just as important as the characterization of the pulsed fields will be the design of facilities used to process the NADs. Appropriate facilities will be needed to allow for early access to dosimeters to test and develop quick sorting techniques. These facilities will need appropriate laboratory preparation space and an area for measurements. Finally, such a facility will allow greater numbers of LLNL and DOE laboratory personnel to train on the processing and interpretation of nuclear accident dosimeters and results. Until this facility is fully operational for test purposes, DOE laboratories may need to continue periodic testing as guests of other reactor facilities such as Silene and Caliban.
Book Synopsis Personnel Neutron Dose Assessment Upgrade by :
Download or read book Personnel Neutron Dose Assessment Upgrade written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides guidance on the characteristics, use, and calibration criteria for personnel neutron dosimeters. The report is applicable for neutrons with energies ranging from thermal to less than 20 MeV. Background for general neutron dosimetry requirements is provided, as is relevant federal regulations and other standards. The characteristics of personnel neutron dosimeters are discussed, with particular attention paid to passive neutron dosimetry systems. Two of the systems discussed are used at DOE and DOE-contractor facilities (nuclear track emulsion and thermoluminescent-albedo) and another (the combination TLD/TED) was recently developed. Topics discussed in the field applications of these dosimeters include their theory of operation, their processing, readout, and interpretation, and their advantages and disadvantages for field use. The procedures required for occupational neutron dosimetry are discussed, including radiation monitoring and the wearing of dosimeters, their exchange periods, dose equivalent evaluations, and the documenting of neutron exposures. The coverage of dosimeter testing, maintenance, and calibration includes guidance on the selection of calibration sources, the effects of irradiation geometries, lower limits of detectability, fading, frequency of calibration, spectrometry, and quality control. 49 refs., 6 figs., 8 tabs.
Book Synopsis Neutron Exposure for DOD Nuclear Test Personnel by :
Download or read book Neutron Exposure for DOD Nuclear Test Personnel written by and published by . This book was released on 1985 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron doses for Dod units/projects that participated in atmospheric nuclear test programs are assessed using computer codes ATR and ANISN. Units/projects whose personnel are identified as having received a neutron dose of at least 1 mrem are listed by operation and shot. Of the several thousand units/projects screened, 160 are identified as having received a free-field neutron exposure exceeding 1 mrem. Of these, approximately 75 percent are aircrews with the remainder being ground-based units, either scientific projects or military observer/maneuver units. Keywords: Nuclear Test Personnel Review; Neutron Dose; Radiation Transport.
Book Synopsis Personnel Neutron Dosimetry Studies at the Lawrence Livermore National Laboratory by :
Download or read book Personnel Neutron Dosimetry Studies at the Lawrence Livermore National Laboratory written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to determine the effect of phantom size, shape and composition on the response of an albedo neutron dosimeter. The most important feature was the shape. The dose equivalent rate from a californium neutron source was determined. Ten different dose rates were determined which varied from 2.39 to 3.02 rem/h for the CF source used. (ACR).
Book Synopsis Summary and Analysis of Neutron Measurements Conducted During the Oak Ridge Personnel Dosimetry Intercomparison Studies by :
Download or read book Summary and Analysis of Neutron Measurements Conducted During the Oak Ridge Personnel Dosimetry Intercomparison Studies written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1974, neutron personnel dosimetry intercomparison studies (PDIS) have been conducted annually at the Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research Facility. During these studies, neutron dosimeters are mailed to ORNL, exposed to low-level (less than 15 mSv) dose equivalents in a variety of mixed-radiation fields produced using the Health Physics Research Reactor (HPRR), and then returned to the participants for evaluation. Beginning with the Seventh PDIS in 1981, interest and participation in the Oak Ridge intercomparisons increased significantly and consistent and documented techniques for determining reference neutron dose equivalents for the HPRR were introduced. This document presents a summary and analysis of approximately 3400 neutron dose equivalent measurements made using a variety of personnel dosimeters and reported for PDIS 7-12. 16 refs., 3 tabs.
Book Synopsis Retrospective Assessment of Personnel Neutron Dosimetry for Workers at the Hanford Site by :
Download or read book Retrospective Assessment of Personnel Neutron Dosimetry for Workers at the Hanford Site written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report was prepared to examine the specific issue of the potential for unrecorded neutron dose for Hanford workers, particularly in comparison with the recorded whole body (neutron plus photon) dose. During the past several years, historical personnel dosimetry practices at Hanford have been documented in several technical reports. This documentation provides a detailed history of the technology, radiation fields, and administrative practices used to measure and record dose for Hanford workers. Importantly, documentation has been prepared by personnel whose collective experience spans nearly the entire history of Hanford operations beginning in the mid-1940s. Evaluations of selected Hanford radiation dose records have been conducted along with statistical profiles of the recorded dose data. The history of Hanford personnel dosimetry is complex, spanning substantial evolution in radiation protection technology, concepts, and standards. Epidemiologic assessments of Hanford worker mortality and radiation dose data were initiated in the early 1960s. In recent years, Hanford data have been included in combined analyses of worker cohorts from several Department of Energy (DOE) sites and from several countries through the International Agency for Research on Cancer (IARC). Hanford data have also been included in the DOE Comprehensive Epidemiologic Data Resource (CEDR). In the analysis of Hanford, and other site data, the question of comparability of recorded dose through time and across the respective sites has arisen. DOE formed a dosimetry working group composed of dosimetrists and epidemiologists to evaluate data and documentation requirements of CEDR. This working group included in its recommendations the high priority for documentation of site-specific radiation dosimetry practices used to measure and record worker dose by the respective DOE sites.
Book Synopsis Personnel Neutron Dose Assessment Upgrade by : D. E. Hadlock
Download or read book Personnel Neutron Dose Assessment Upgrade written by D. E. Hadlock and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1982 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Neutron Dosimetry in Radiation Protection by : H. Ing
Download or read book Neutron Dosimetry in Radiation Protection written by H. Ing and published by . This book was released on 1985 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1989 with total page 1384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Lawrence Livermore National and Sandia National Laboratories, Continued Operation by :
Download or read book Lawrence Livermore National and Sandia National Laboratories, Continued Operation written by and published by . This book was released on 1992 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book INIS Atomindex written by and published by . This book was released on 1984 with total page 1514 pages. Available in PDF, EPUB and Kindle. Book excerpt:
