tailieunhanh - TRITIUM IN THE ENVIRONMENT

Tritium, the heaviest and only radioactive isotope of hydrogen, is increasing in importance in energy and environmental considerations. This nuclide is widely distributed throughout man's environment because of its ubiquitous form as tritiated water and its persistence in the environment. This report considers and evaluates the available information on tritium in terms of its physical properties, production sources, physical transport, biological behavior, projected future production, waste management, and the long-term dose implications of tritium in the environment | NCRP REPORT No. 62 TRITIUM IN THE ENVIRONMENT Recommendations of the NATIONAL COUNCIL ON RADIATION PROTECTION AND MEASUREMENTS Issued March 9 1979 Second Reprinting May 15 1989 National Council on Radiation Protection and Measurements 7910 WOODMONT AVENUE WASHINGTON . 20014 Copyright National Council on Radiation Protection and Measurements 1979 All rights reserved. This publication is protected by copyright. No part of this publication may be reproduced in any form or by any means including photocopying or utilized by any information storage and retrieval system without written permission from the copyright owner except for brief quotation in critical articles or reviews. Library of Congress Catalog Card Number 79-63514 International Standard Book Number 0-913392-46-4 Preface Tritium the heaviest and only radioactive isotope of hydrogen is increasing in importance in energy and environmental considerations. This nuclide is widely distributed throughout man s environment because of its ubiquitous form as tritiated water and its persistence in the environment. This report considers and evaluates the available information on tritium in terms of its physical properties production sources physical transport biological behavior projected future production waste management and the long-term dose implications of tritium in the environment. The naturally occurring levels of this isotope of hydrogen 3H are the result of cosmic ray interactions in the atmosphere. Additional sources are from fallout from weapons testing and by-product waste of nuclear power reactors. Large quantities of tritium will be accumulated with concomitant fractional releases of significant quantities to the environment. The possible use of tritium as the fuel for fusion reactors in the next century may result in an additional source of tritium. Emission of tritium from the nuclear fuel cycle will increasingly become the dominant source of this nuclide and can become more important than the residue