[en] The national waste treatment centre at the Nuclear Energy Unit (N.E.U.) at Bangi was formed to manage all the radioactive wastes being produced in Malaysia. The aim of this study was to determine the condition of radioactive wastes being produced by radioisotope users and other relevant services that can be offered by N.E.U. to outside related agencies. Questionaires were sent to various government and private agencies which are expected to handle radioactive materials. The results show that most of the private agencies use radioactive sealed source while the government agencies use radioactive liquid and radioactive sealed source. The sealed source and liquid radioactive are mostly used for non-destructive testing and tracer studies, respectively. Radioactive gases are used mostly in electronic industries. An approximate value rate of volume and weight of liquid and solid wastes, respectively, produced per month was determined. Some important proposals were concluded in this study to improve the management of radioactive wastes in Malaysia. (author)

[en] Due to the growing amounts of low-level radioactive waste being produced from the nuclear industry and research establishments, there is considerable interest in the study of migration of radionuclides from the shallow-land burial sites. A brief description is presented about some aspect of effectiveness of soil in retarding the migration of radionuclides with special emphasis given to those environmentally critical fission and activation products, elements. (author)

[en] Low level liquid waste treatment plant at the Nuclear Energy Unit was completely built in May, 1984. The function of the plant is to treat aqueous low lewel radioactive effluent by using coagulation-flocculation processes. Chemicals used to treat the effluent are sodium carbonate (Na₂CO₃), Aluminium Sulphate (Al₂(SO₄)₃13 1/2H₂O) and a polyelectrolyte commercial name Preastol as a coagulant aid. The first efficiency test was done on 22 October, 1984. Effluent radioactivity in the Third Collection Tank was spiked with 1.2 x 10⁹ Bq(32 mCi) of Cu-6.4. Four effluent samples each with 1000 ml was treated in a laboratory scale test. Results obtained were then used for a bigger scale treatment at the plant. The second and the third efficiency test was done on 29 November, 1984 and 1 February, 1985 respectively. From the three efficiency tests, different parameters such as decontamination factor, effluent activity, pH, conductivity and dissolved solid were observed to fulfill some of the characteristics of water quality that were set up by different International Bodies sup(1-3). This shows that the plant is capable of treating low level liquid waste to be released to the environment without giving any harm. (author)

[en] Active measures are a necessity but also recognizes that long-term safety does not solely rely on active measures and the duration of such active measures should be optimized. At different time period, nature of active and passive measures preventing human intrusion were linked to the radiological hazard of the waste content in the disposal facility. (Author)

No abstract available

[en] Laboratory batch experiments were conducted to determine the adsorption of 90 Sr by a soil sediment, mineralogically pure clay phases (vermiculites, smectites and illites) and feldspar minerals (adesine, albite, microcline and oligoclase) as a function of ionic composition. The clay minerals were present at different proportion in the soil sediment. The important adsorbing phases and the adsorption mechanism(s) can be determined from the studies. Twenty two stock solutions were prepared with concentrations of the major cations Ca, Mg and Na and were varied from 0.0 to 0.00312 M, 0.0 to 0.00165 M, and 0.0 to 0.00312 M, respectively. The experiments yielded adsorption coefficient values K sub d that could be described by equations. Theoretical slope value -1 for pure ion-exchange mechanism of strontium adsorption onto Ca-saturated clay was described. The slopes obtained in the experiments represented an average of adsorption on several different mineral surfaces having different relative affinities for strontium, calcium and magnesium. Experiment results showed that strontium was adsorbed to ion-exchange sites and that calcium and magnesium cations were effective competitors for these sites. Pure clay minerals yielded adsorption coefficients that could be described by equations slopes -1.0 similar to the theoretical value. The feldspar minerals yielded slope ranges from -072 to -1.13, and the sediments slope value of -0.81. These suggest that ion-exchange was the dominant adsorption mechanism for strontium

[en] The aim of this study is to investigate the efficiency treatment in removing Zn-65, Mo-99 and I-1 25 from an aqueous radioactive effluent. The wastes are currently being produced from hospitals, research institutes, clinics and universities. Effluent was spiked separately with each type of the radioisotope and was treated by the coagulation-flocculation process. By varying the chemical dosages (i.e., alum, soda ash, ferric chloride and coagulant aid) in the treatment, different decontamination factor values were obtained. Optimum dosages and types of chemical used to remove a particular radioisotope was determined. Results indicated that optimum pH value for removing Zn-65 in an effluent was pH 8. The highest decontamination factor value was 61. In removal of 1-125 radioisotope, ferric chloride was suitable as a coagulant that gives the highest decontamination factor value of 5.0. Treatment to remove Mo-99 radioisotopes was conducted in the laboratory and treatment plant scale. For Mo-99 radioisotope treatment by laboratory and Plant scale, the highest decontamination factor obtained was between pH values of 4.0 to 4.5. By extrapolation of both scales, the plant scale treatment does not vary significantly from laboratory scale. This indicated treatment dosages of chemicals for the Low Level Treatment Plant scale be deduced from the laboratory scale

[en] Radiological Impact Assessment (RIA) can be conducted in Malaysia by using the RESRAD computer code developed by Argonne National Laboratory, U.S.A. The code can do analysis to derive site specific guidelines for allowable residual concentrations of radionuclides in soil. Concepts of the RIA in the context of waste management concern in Malaysia, some regulatory information and assess status of data collection are shown. Appropriate use scenarios and site specific parameters are used as much as possible so as to be realistic so that will reasonably ensure that individual dose limits and or constraints will be achieved. Case study have been conducted to fulfil Atomic Energy Licensing Board (AELB) requirements where for disposal purpose the operator must be required to carry out. a radiological impact assessment to all proposed disposals. This is to demonstrate that no member of public will be exposed to more than 1 mSv/year from all activities. Results obtained from analyses show the RESRAD computer code is able to calculate doses, risks, and guideline values. Sensitivity analysis by the computer code shows that the parameters used as input are justified so as to improve confidence to the public and the AELB the results of the analysis. The computer code can also be used as an initial assessment to conduct screening assessment in order to determine a proper disposal site. (Author)

[en] Iodine-125 that are produced by hospitals and other agencies, are attracted from aqueous solutions by several naturally occurring minerals such as kaolinite, ferrous oxide and hydrous aluminum oxides. At a moderate pH value of 4.5, the minerals exhibited modest positive charges which are able to attract the anions of 125 I. Coagulation-flocculation, batch and column experiments were conducted and compared to determine which method can effectively and conveniently treat the effluent. The results indicated for activities of effluent similar or higher than effluent activities received from producers, both treatment by coagulation-flocculation and column (mixture of kaolin and clay soil) experiments were suitable. However, column method treatment was more convenient, easy to handle, low capital cost and less maintenance cost. The results indicate that the wastes can be treated by the soil column method

[en] Radiological Impact Assessments (RIAs) on proposed disposal sites for NORM wastes were performed in Malaysia. Analysis results were used to derive site specific guidelines for allowable residual concentrations of radionuclides in soil, calculation of doses and risks. Appropriate use scenarios and site specific parameters were used as much as possible so as to be realistic so that will reasonably ensure that individual dose limits and or constraints will be achieved. Disposals were performed to fulfil Atomic Energy Licensing Board of Malaysia (AELB) requirements for which the operator must carry out a radiological impact assessment. This is to demonstrate that no member of public will be exposed to more than 1 mSv/year from all activities. Fatal cancer risk factor is 5x10^-2 per man.Sv. Radionuclides of main concern are radium-226 and radium-228 which are considered as toxic. Sensitivity and uncertainty analyses were performed to show that the parameters used as input into the computer model were justified so as to improve confidence of the public and the AELB in respect of the results of the analysis. Case study to determine a proposed near surface disposal site for treated oil sludge was described. (author)