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Nureg/Cr-6673 Ucrl-Id-13852 NUREG/CR-6673 UCRL-ID-13852 Hydrogen Generation in TRU Waste Transporation Packages Lawrence Livermore National Laboratory U.S. Nuclear Regulatory Commission Office of Nuclear Material Safety and Safeguards Washington, DC 20555-0001 AVAILABILITY OF REFERENCE MATERIALS IN NRC PUBLICATIONS NRC Reference Material Non-NRC Reference Material As of November 1999, you may electronically access Documents available from public and special technical NUREG-series publications and other NRC records at libraries include all open literature items, such as NRC's Public Electronic Reading Room at books, journal articles, and transactions, Federal www. nrc.gov/NRC/ADAMSfindex.html. Register notices, Federal and State legislation, and Publicly released records include, to name a few, congressional reports. Such documents as theses, NUREG-series publications; Federal Register notices; dissertations, foreign reports and translations, and applicant, licensee, and vendor documents and non-NRC conference proceedings may be purchased correspondence; NRC correspondence and internal from their sponsoring organization. memoranda; bulletins and information notices; inspection and investigative reports; licensee event Copies of industry codes and standards used in a reports; and Commission papers and their substantive manner in the NRC regulatory process are attachments. maintained at The NRC Technical Library NRC publications in the NUREG series, NRC Two White Flint North regulations, and Title 10, Energy, in the Code of 11545 Rockville Pike FederalRegulations may also be purchased from one Rockville, MD 20852-2738 of these two sources. 1. The Superintendent of Documents These standards are available in the library for U.S. Government Printing Office reference use by the public. Codes and standards are P. 0. Box 37082 usually copyrighted and may be purchased from the Washington, DC 20402-9328 originating organization or, if they are American www. access gpo.gov/su-docs National Standards, from 202-512-1800 American National Standards Institute 2. The National Technical Information Service 11 West 42nd Street Springfield, VA 22161-0002 New York, NY 10036-8002 www.ntis.gov www.ansi.org 1-800-553-6847 or, locally, 703-605-6000 212-642-4900 A single copy of each NRC draft report for comment is available free, to the extent of supply, upon written The NUREG series comprises (1) technical and request as follows: administrative reports and books prepared by the Address: Office of the Chief Information Officer, staff (NUREG-XXXX) or agency contractors Reproduction and Distribution (NUREG/CR-XXXX), (2) proceedings of Services Section conferences •NUREG/CP-XXXX), (3) reports U.S. Nuclear Regulatory Commission resulting from international agreements Washington, DC 20555-0001 (NUREG/IA-.XXX), (4) brochures E-mail: [email protected] (NUREG/BR-XXXX), and (5) compilations of legal Facsimile: 301-415-2289 decisions and orders of the Commission and Atomic and Safety Licensing Boards and of Some publications in the NUREG series that are Directors' decisions under Section 2.206 of NRC's posted at NRC's Web site address regulations (NUREG-0750). www.nrc.govWNRC/NUREGSlindexnum.html are updated regularly and may differ from the last printed version. DISCLAIMER: This report was prepared as an account of work sponsored by an agency of the U.S. Government. Neither the U.S. Government nor any agency thereof, nor any employee, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, apparatus, product, or process disclosed in this publication, or represents that its use .by such third party would not infringe privately owned rights. I I I NUREG/CR-6673 UCRL-ID-13852 Hydrogen Generation in TRU Waste Transportation Packages Manuscript Completed: February 2000 Date Published: May 2000 Prepared by B. L. Anderson, M. K. Sheaffer, L. E. Fischer Lawrence Livermore National Laboratory 7000 East Avenue Livermore, CA 94550 Prepared for Spent Fuel Project Office Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ABSTRACT This document addresses hydrogen generation in TRU waste transportation packages. The potential sources of hydrogen generation are summarized with a special emphasis on radiolysis. After defining various TRU wastes according to groupings of material types, bounding radiolytic G-values are established for each waste type. Analytical methodologies are developed for prediction of hydrogen gas concentrations for various packaging configurations in which hydrogen generation is due to radiolysis. Representative examples are presented to illustrate how analytical procedures can be used to estimate the hydrogen concentration as a function of time. Methodologies and examples are also provided to show how the time to reach a flammable hydrogen concentration in the innermost confinement layer can be estimated. Finally, general guidelines for limiting the hydrogen generation in the payload and hydrogen accumulation in the innermost confinement layer are described. iii CONTENTS ABSTRACT .......................................................................................................................................... EXECUTIVE SUM M ARY ..................................................................................................................... ix SYM OBOLS ............................................................................................................................................. x 1. INTRODUCTION .............................................................................................................................. 1 1.1 Background ................................................................................................................................ 1 1.2 Purpose and Scope ...................................................................................................................... 1 2. MECHANISMS FOR HYDROGEN GENERATION ................................................................... 3 2.1 Chemical Reactions ............................................................................................................ 3 2.2 Thermal Degradation ................................................................................................................ .3 2.3 Biological Activity ............................................................................................................ 4 2.4 Radiolysis ................................................................................................................................... 4 2.4.1 Linear Energy Transfer Effect ...................................................................................... 5 2.4.2 Temperature ............................................................................................................ 5 2.4.3 Pressure ............................................................................................................................. 6 2.4.4 Atmosphere ....................................................................................................................... 6 2.4.5 Total Absorbed Dose .................................................................................................... 6 2.4.6 Dose Rate .......................................................................................................................... 7 2.4.7 Specific M aterial Composition ...................................................................................... 7 2.4.8 Fraction of Energy Absorbed by a M aterial ................................................................... 8 2.4.9 Energy Transfer ............................................................................................................ 9 3. HYDROGEN GENERATION RATES IN TRANSURANIC WASTE .......................................... 11 3.1 Radiolysis of Water and Other Materials Commonly in TRU Waste .................................... 11 3.2 Classification of Transuranic W aste Types .......................................................................... 11 3.2.1 Solidified Aqueous Inorganic W aste .......................................................................... 11 3.2.2 Solid Inorganic Waste........................................... 13 3.2.3 Solid Organic W aste .................................................................................................. 13 3.3 Effective Radiolytic G Values for Various W aste Types ....................................................... 15 3.3.1 Effective G-Value for a General Mixture of M aterials ................................................ 15 3.3.2 Effective G Values for Solidified Aqueous Inorganic Waste ....................................... 17 3.3.3 Effective G Values for Solid Inorganic W aste ............................................................ 22 3.3.4 Effective G Values for Solid Organic W aste .............................................................. 23 3.3.5 Summary of the Effective G Values for Various Waste Types When the Radionuclides are Primarily Alpha-Emitters ...................................................................................... 24 4 CALCULATION OF HYDROGEN CONCENTRATION FOR VARIOUS PACKAGING CONFIGURATIONS ...................................................................................................................... 27 4.1 Modeling Hydrogen Concentration in TRU Waste Transportation Containers
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