Table I Radioisotopes Used in Y.G.H.
Maung Maung Tin
Atomic Energy Department
Manma
Scientific & Technological Research Department
Ministry of Science &
Technology
No 6, Kabaraye Pagoda Road, Yankin P.O, Yangon, Myanmar
Telephone: 095-01-663025
Fax: 095-01-665292
ABSTRACT
Although Myanmar is a non-nuclear country, uses of ionizing radiation, radioisotopes and radioactive sources to some extent for health, social and economic benefits have been started since late 1950's in Myanmar. The main sources of radioactive wastes are mainly from hospitals that use short-lived radioisotopes for nuclear medicine purposes. Spent seal sources are generated from the application of radioactive sources in medical diagnosis, treatment and agricultural research. Management of radioactive wastes in Myanmar including collection, treatment, conditioning, packaging and storage are presented. Status of IAEA model project entitled " INT / 9 / 143- Upgrading Radiation Protection and Waste Management Infrastructure", in Myanmar are also described. Systematic handling of radioactive waste in Myanmar, leads discharge of radioactive waste to the environment to be kept as low as reasonably achievable ( ALARA ).
INTRODUCTION
The use of ionizing radiation and radiation sources in various fields of science and technology has existed in Myanmar for the past forty years. Now, in various area such as radiotherapy, radio diagnosis, nuclear medicine, medical research, agricultural services, livestock breeding, environmental radiation monitoring,training and research etc., ionizing radiation and radioisotopes have been widely applied in the country.
When considering the use of radio nuclides for a given purpose, there must be detailed planning, not only for the use itself and the associated safety precautions, but also for the safe handling of the resulting radioactive waste. When using short-lived radio nuclides, waste management may involve simply collection and storage of the waste for decay until they can be exempted from further regulatory control. If radionuclides with long half-lives are used, waste management may have to include not only collection and storage, but also more complicated activities such as conditioning and disposal.
It is important carefully evaluated in the context of the national waste management program, before radionuclides are produced, imported or purchased. Information on waste management shall be submitted already when applying for a license to produce, import, purchase or use radionuclides.
With the uses of ionizing radiation and radioactive sources in the country are expanded it becomes imperative to establish and overall radiation protection infrastructure. Hence, the Myanma Atomic Energy Committee ( MAEC) formed on 7 August, 1992 has prepared fourth draft of Myanmar Atomic Energy Law and has been submitted to the cabinet. The MAEC had prepared radiation protection regulations for the establishment of a legal basis for a radiation protection regime in the country. In 1993, the IAEA provided assistance under the project MYA / 9 / 003 with the objectives: to establish a radiation protection infrastructure in the country and introduce internationally agreed basic safety standards.
NATIONAL POLICY ON RADIOACTIVE WASTE
The Atomic Energy Department, Myanma Scientific and Technological Research Department is responsible for carrying out research and development in radioactive waste management.
The basic policy of radioactive waste management in Myanmar should be as follows:
Management of radioactive waste shall be in accordance with waste management policy established by the Myanma Atomic Energy Committee and such policy shall be aimed to protect human health environmental without imposing and undue burden on the future generations.
The propose waste management policy has three components, namely:
Under this policy the waste shell not be disposed into the environment save those with a very short half-life. The policy also requires the Myanma Atomic Energy Committee to established a National Waste Center.
RADIOACTIVE WASTE PRODUCERS
Followings are the main sectors which produce radioactive waste in Myanmar:
Industries
In order to assess the quality and quantity of raw material, intermediate and finished products, Myanma Airways International, Myanma Heavy Industry and Myanma Railways Transportation etc. have been using various radiation sources as analytical tolls. The fixed sealed sources are being used for measurement of physical parameters such as density, volume, thickness, level, etc. The radioactive sources are being used by Myanma Oil Corporation in the exploration of natural resources. The sources of higher activities ( 25-100 Ci ) are being used for industrial radiography. Natural Thorium is used for manufacturing gas mantles.
The fixed sealed sources used in industries are replaced after completion of their life. The sources in solid form require little processing before disposal as radioactive waste. The users deposit their sources at their own temporary storage where these are stored in accordance with the IAEA and MAEC guidelines. For cases requiring return of spent sources to the supplier for replacement with new one, the No Objection Certificate ( NOC ) for shipment to the country of origin is issue by MAEC. The shipment is regulated through MAEC guidelines on transportation of radioactive material.
The source of liquid waste in industry is through gas mantle manufacturing. the production of gas mantle involves absorption Thorium on the fibre of mantles from aqueous solution of Thorium Nitrate. The residual solution is liquid radwaste and is stored in polythene container. The manufacturers maintain a record of the liquid radwaste generated for subsequent disposal at MAEC waste management facility.
Medicine
Co-60 tele therapy machines have been used for radiotherapy in three big cities hospital. Radiophermacy techniques for preparation of generator-produced radiophermaceuticals, radiobiochemistry in medical application of radioisotopes, radioimmunoassay procedures for thyroid related hormones, cortisone and sex hormones using bulk regents have been performed in department of nuclear medicine YGH. DMR have undertaken application of nuclear techniques in the identification of pharmacological active groups/ compounds present in the medical plant extracts, immunoradiometric assays (IRMA) using monoclonal antibodies for the detection of circulatory or urinary antigents in patients with filariasis or malaria and IRMA methods for assessment of malaria transmission.
Recently, a number of private hospitals have entered the field of nuclear medicine. In addition to these, there are hospitals and clinics used diagnostic X-ray machines which are not more than 400.
The radioisotopes commonly used in nuclear medicine are shown in Table I. The Radium-226 had been used as brachytherapy source for treatment of cancer. MAEC have made concerted efforts to withdraw Radium from hospitals and replace with Cs-137 due to their hazards associated with its use. Efforts are in progress for the withdrawal of all most of all of Radium-226 sources and their safe disposal at MAEC waste management facility after proper conditioning process. (Fig. 1)
Table I Radioisotopes Used in Y.G.H.
Fig. 1. Conditioning process for
spent radium-226 needles
The typical radioisotopes used and radioactive waste at YGH is given in Table I. The low level solid waste along with the use technician generators are disposed at MAEC waste management facility. The liquid wastes are collected and stored in double stage delay tanks and discharged into main sewerage system when their activities approach background level. Sample of liquid wastes are collected and analyzed carefully before is its release to normal sewerage. In small laboratories dealing with RIA facility the liquid wastes are collected in polythene bottles for disposal at their own temporary storage for subsequent disposal at a suitable MAEC waste management facility.
Agricultural Services
Radiation induced mutation breeding for evolution of better varieties of crops, improvement soil fertility and the environment by introduction of nitrogen fixing ; application of isotope and nuclear techniques in pesticide residue agriculture implemented in Myanma Agriculture Services.
In the Seed Division of Myanmar Agriculture Service, the two Gamma Chamber facilities including:
Although the Gamma Chamber 900 source was being thought to be treated as a waste, we are in the opinion that the source can be used at the Atomic Energy Department for irradiation dosimeters, dosimetry calibration and also some other applications. It was transferred to a safe storage room and kept under careful control.
RESEARCH CENTERS AND OTHER INSTITUTIONS
In these days there has been a considerable application of radioisotopes in research and development activities in field of physical, medical and biological sciences. Beside Department of Medical Research (DMR), Agricultural Research Institute (ARI), Universities Research Center (URC), a number of national organization and teaching institutes are using various types of radioisotopes and Radium sources.
Fast neutron activation analysis (FNAA) has been carried out in the department of physics, Yangon university by using neutron generator an Pu-Be neutron source for post-graduate research and applications. Wavelength disperse X-ray fluorescence analysis for elemental analysis of various samples and X-ray diffraction technique for determination of structure of geological samples have been performed in the University Research Center. Nuclear Chemistry Research Laboratory, Yangon university has been under taken radiochemical studies of various chemical process. Energy dispersive X-ray fluorescence analysis and high resolution gamma ray spectrometry have been performed in department of physics, Yangon University (YU) and Atomic Energy Department, MSTRD.
Radiochemical Waste Treatment in (NCRL)
Radioisotopes such as 131I , 60Co , 137Cs etc. are used for research work on Radiometric Flow Injection Analysis ( RFIA ) in the Nuclear Chemistry Research Laboratory (NCRL) of Department of Chemistry of University of Yangon. Since amounts of reagents involved in RFIA type of work is very low, the activities are of the order of micro curie quantity. Isotopes are used both as sample solution and carrier stream. RFIA studies involves two types.
In the type (a) work radioisotopes were reclaimed by simple reconcentration such as evaporation. In that case reclaimed isotopes can be further used for other RFIA studies. In the type (b) work a chemical compound is formed ( e.g. cobalt dithizone complex ). In that case chemical procedure will be necessary for reclaiming the isotope. Such a study is in progress in NCRL for the radioactive wastes from type (b) work.
The isotopes and waste were sealed stored and kept away from counting room according to normal procedures for handling and use of radioisotopes. The above reclaiming work is not only cost effective for continuation of radiochemical work in the NCRL but also reduces the problem of radioactive wastes.
CONCLUSION
At present we do not have nuclear power plant, research reactors or fuel cycle facilities and as such we do not have problems related to high level waste but appropriate measures are to be taken for disposal of these sources if any.
However, the current situation of our country demands safe and systematic handling and storage of radioactive waste until their disposal. The small amount of activity and expected volume of radwaste is handled conveniently at MAEC waste disposal facility but site for ultimate waste disposal facility (repository ) is yet to be finalized.
All the departments using ionizing radiation sources have followed the IAEA Safety Rules and Standard ( 1982 )with care and caution, no radiation hazard or accident or incident has ever occurred at all.
Fig. 2. Organization Chart of Myanmar
Atomic Energy Committee
REFERENCES