Radiation Safety Information Safe Handling of Tritium Sources in Radioluminescent Devices
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TECHNICAL REPORT CECOM TR 94-1 1 (REVISION 2) RADIATION SAFETY INFORMATION SAFE HANDLING OF TRITIUM SOURCES IN RADIOLUMINESCENT DEVICES Radiological Engineering Division CECOM Directorate for Safety September 2001 DISTRIBUTION STATEMENT: Distribution authorized to U.S. Government Agencies only, administrative or operational use, September 2001. Other requests for this document shall be referred to U.S. Army CECOM, Directorate for Safety, ATTN: AMSEL-SF-RE, Fort Monmouth, NJ 07703-5024 CECOM U.S. ARMY COMMUNICATIONS-ELECTRONICS COMMAND DIRECTORATE FOR SAFETY, ATTN: AMSEL-SF-RE FORT MONMOLITH, NEW JERSEY 07703-5024 NOTICES Disclaimers The policies and procedures in this document are not to be construed as official Department of the Army position, unless so designated by other authorized documents. The citation of trade names and names of manufacturers in this report is not to be construed as official Government endorsement or approval of commercial products or services referenced herein. Prepared By: CECOM Directorate for Safety Radiological Engineering Division CONTENTS Page 1. PURPOSE AND SCOPE ......................................................................................................1 2 . DEFINITIONS ......................................................................................................................1 3 . TRITIUM SAFETY ..............................................................................................................2 3.1 Tritium Hazards .....................................................................................................2 3.2 Working Safely With Tritium ................................................................................3 3.3 First Rule of Tritium Safety ...................................................................................4 3.4 Performing Authorized Maintenance .....................................................................4 3.5 Identification and Handling of a Damaged Tritium Source .......................................................................................................5 3.6 Tritium Bioassay General Procedure .....................................................................6 3.7 Lessons Learned .....................................................................................................7 3.8 Identification and Location of Gaseous Tritium Sources on Military Equipment .............................................................................8 3.9 Summary ................................................................................................................9 4 . AUTHOR'S NOTES ..........................................................................................................10 A . Commodities Containing Tritium ................................................................................11-36 B . Major End Items Containing Tritium Sources .............................................................37-39 C . Incident Response Plan ................................................................................................40-46 D . Item Managers and Safety Support for Radioactive Commodities Containing Tritium ...............................................................................................................................47 1. PURPOSE AND SCOPE This document was developed to inform Radiation Safety Officers (RSOs), users and maintenance personnel of the hazards that may be associated with the possession and handling of tritium radioluminescent (RL) devices. The information provided can also be used as a reference in developing or augmenting local procedures for response to radiation accidents. This document identifies commodities containing tritium for illumination in low light conditions. The location of the tritium source on the device, the activity of the source and a listing of the most common end items utilizing tritium commodities are included. The biological hazards associated with a tritium exposure, recommended work practices and actions that will reduce the spread of contamination or exposure to personnel when a tritium source is damaged are discussed. A suggested response plan for the mitigation of tritium source incidents, investigation, and reporting practices is included to assist RSOs in development of local procedures. ***NOTE*** Most items discussed in this report are sealed to prevent leakage of radioactive material. Do not attempt disassembly of the radioactive items. These items present no radiation hazard to personnel unless the sealed source is broken or the radioactive material is otherwise exposed. This information and special instructions contained in the technical manual (TM) and/or technical bulletin (TB) for the device and/or the end item equipment shall be followed to ensure safe handling of tritium commodities and the safety of personnel. All personnel engaged in the operation and maintenance of tritium commodities should be aware of the information contained both in this report and the TMITB for the commodity. 2. DEFINITIONS Activity. Rate of nuclear disintegration or decay of radioactive material. The units of activity are the Curie (Ci) or the Becquerel (Bq). 1 Curie = 3.7x101° disintegrations per second (dps), and 1 Ci = 3.7x101° Bq. ALARA. Acronym for "As low as is reasonably achievable." Refers to the operating philosophy in which occupational radiation exposures are reduced as far below specified limits as is reasonably achievable. Bioassay. The determination of radioactivity in a biological specimen and estimation of the internal exposure to the individual from that radioactivity. Electron volt (eV). The energy of an electron under a potential difference of one volt. Equal to 1.6x10-l9 joule. The electron volt is used with all multiple and submultiple prefixes now in common use. The most common are the MeV (million electron volts) and the keV (thousand electron volts). Ionizing radiation. Electromagnetic or particulate radiation capable of causing ionization in its passage through matter. Alpha, beta and neutron particles, gamma and x-rays, are examples of ionizing radiation. Licensed material. Radioactive material that is received, possessed, used, or transferred under a general or specific license issued by the U.S. Nuclear Regulatory Commission (NRC) or NRC Agreement State. RADIOLOGICAL ENGlNEERlNG DIVISION CECOM DIRECTORATE FOR SAFETY Radioactive commodity. An item of government property composed in whole or in part of radioactive materials and to which a National Stock Number (NSN) or part number has been assigned. m. Special unit of radiation dose equivalent. In SI (System International) units, 1 rem = 0.01 Sieverts (Sv); 1 millirem = 0.00 1 rem or 0.0000 1 Sv. Radiation Safety Officer (RSO). The individual responsible for the administration and oversight of the Radiation Safety Program. Radiation Safety Program. A set of controls initiated to insure that personnel are not exposed to potentially hazardous levels of radiation during use or maintenance of licensed material. These controls include documented procedures. Radiation Safety Staff Officer (RSSO). The responsible Radiation Safety Officer at the major army command (MACOM). Radioluminescence (RL). The process of providing illumination from the activation of a phosphor by energy from radioactive decay. Radioluminescent device. An illuminating device consisting of a phosphor and a radiation source. Phosphor and gaseous radiation sources are usually contained in a glass vial or ampoule. The phosphor and radiation source may be solid and deposited on the surface of a dial or scale. Tritium commodity. Equipment or component of equipment containing one or more tritium sources. Tritium. A radioactive isotope of hydrogen containing one proton and two neutrons. Tritium, often designated H-3, decays to helium by the emission of a beta particle with a maximum energy of 18.6 keV and an average energy of 5.7 keV. The radiological half-life is 12.28 years. 10 CFR 20. Designation for Part 20 - Standards For Protection Against Radiation, Title 10 - Energy, Code of Federal Regulations. 3. TRITIUM SAFETY Tritium sources have been damaged through improper handling, unauthorized maintenance, or the use of improper tools. In addition to the loss of equipment, tritium incidents have resulted in unnecessary radiation exposure to personnel and contamination of personnel and work areas. 3.1 Tritium Hazards. (1) Biological Effects. Tritium contamination and airborne radioactivity are biological hazards. If you breathe tritium oxide (tritiated water vapors) or if it contacts your skin, the tritium will be absorbed by your body. Studies have shown that a person exposed to an atmosphere containing tritiated water vapor will absorb about one-third to one-half as much tritium through the skin as via inhalation (i.e., one-third through the skin and two-thirds via inhalation). Therefore, release of tritium into a closed space may constitute an internal hazard. Tritium distributes equally among all body fluids because these fluids contain water. A whole body radiation dose results since soft tissues make up about 90 percent of the body. (2) Tritium Elinzination. The average adult takes in about three liters of water a day. The average adult also excretes about three liters of water per day. About one-half of this water is in urine, the rest is eliminated via exhalation, diffusion through the skin and sweat. After an exposure to an atmosphere RADlOLOGICAL ENGINEERING DlVlSlON CECOM DIRECTORATE FOR SAFETY