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Volume 40 (2005)
- Issue 4 Pages 306-
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Volume 40, Issue 1
Displaying 1-11 of 11 articles from this issue
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2005 Volume 40 Issue 1 Pages 2
Published: 2005
Released on J-STAGE: August 05, 2010
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Tadayoshi YOSHIDA, Norio TSUJIMURA2005 Volume 40 Issue 1 Pages 37-42
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSCorrection for the influence of room-scattered neutrons in irradiation rooms is essential in the case of calibrating neutron dosemeters. The ISO8529-2 recommends some correction method such as the shadow-cone method and the generalized-fit method for the calibration of neutron ambient dose equivalent (rate) meters. However, the ISO standard does not describe the correction methods for personal neutron dosemeters in detail. The authors investigated the variation of responses of neutron detectors mounted on phantom as a function of source-to-phantom distance, and discussed the applicability of the shadow-cone method and generalized-fit method for calibrating personal neutron dosemeters. The measurements were carried out using 3He and hydrogen-filled proportional counters as surrogates of albedo and recoil-proton type dosemeters, respectively, at different distances ranging from 30cm to 400cm. As a result, it was clarified that both correction methods are applicable for recoil-proton type detectors over any distance. Contrarily, for albedo-type detectors, the variation of response does not follow the curve predicted from the generalized fit method at distances smaller than 70cm. This result strongly suggests that the correction for source-to-phantom geometry effect should be made for calibrating albedo-type detectors at smaller distances.View full abstractDownload PDF (4665K) -
Masahiro YOSHIDA2005 Volume 40 Issue 1 Pages 43-48
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSIn skyshine dose evaluation for gamma-rays, simple calculation methods are still used in many radiation facilities since various computer codes for the skyshine calculation require considerable experience and expertise to obtain reliable results. The effect of scattered radiations in ceilings needs to be considered in order to obtain reasonable results using simple calculation methods. Therefore, dose distributions on the ceiling were calculated using MCNP-4C in the geometry of the KSU experiment. The results showed that gamma-rays of 0.3MeV or less scattered inside the facility made a contribution to the dose at the ceiling position, and the dose distribution on the concrete ceiling was strongly affected by the oblique incidence on the ceiling in the case of a point source. Additional calculations confirmed that the effect of the oblique incidence depended on the thickness of the ceiling as a function of mean-free-path. It was found that the effect was expressed as a simple formula considering gamma-ray attenuation and build-up, which would be useful in the simple skyshine calculation.View full abstractDownload PDF (3625K) -
Questionnaire for Medical Radiation TechnologistsChie TSUBONE, Nobuhiko BAN, Michiaki KAI2005 Volume 40 Issue 1 Pages 49-55
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThere has been great concern regarding the radiation protection for women of reproductive age when exposed to diagnostic radiation. The 10-day-rule proposed by the ICRP has not been recommended since 1983 because the risk to embryo and fetus within four weeks after menstruation may be small. However, some experts see that incomplete abandon of the 10-day-rule might cause confusion among the medical doctors and patients, and consequently unwarranted abortion happens. This paper surveyed the views of radiation technologists in hospitals and discussed how radiation exposure of women of reproductive age in medicine should be controlled. We found that the views to the 10-day-rule were spilt 50:50 and that radiation technologists do not necessarily think the 10-day-rule should be abandoned. Even the radiation technologists who are supposed to be able to explain to the patients the health risk following diagnostic exposure do not fully understand the risk involved. In conclusion, although a low-dose risk of diagnostic exposure should be sufficiently educated in order to obtain an exact understanding, the 10-day-rule may be useful in order to actually avoid any trouble in diagnostic radiology.View full abstractDownload PDF (12300K) -
Centralized Radioactivity Measurement System for Radiation Control in Tokai Research Establishment of JAERI / Dose Constraints: Past, Present and FhtureKatsuya KAWASAKI, Shinichiro MIYAZAKI2005 Volume 40 Issue 1 Pages 56-66
Published: 2005
Released on J-STAGE: August 05, 2010
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Toshiso KOSAKO, Nobuyuki SUGIURA, Hidenori YONEHARA, Minoru OKOSHI, Ku ...2005 Volume 40 Issue 1 Pages 67-78
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSSome of technologically enhanced naturally occurring radioactive material (TENORM), such as radon and monazite sand, gradually became a target for radiological protection. In order to regulate TENORM safely and economically, it is essential to consider the characteristics of TENORM such as ubiquity, huge volume, and very low activity levels. In this paper, radiation protection principles and standards for NORM/TENORM are summarized based on the reports published by the international organizations (e. g. ICRP and IAEA) to assist the development of national regulatory framework. The survey results on the present Japanese situations on industries related to NORM/TENORM are provided, and the categorization for NORM/TENORM, which is established by the Radiation Council of Japan, is explained how to control NORM/TENORM based on their exposure doses instead of their activity levels. Finally, basic processes to solve the problems related to NORM/TENORM are discussed.View full abstractDownload PDF (7754K) -
Lubi DIMITROVSKI2005 Volume 40 Issue 1 Pages 79-86
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSAustralia is a major producer and exporter of ores and minerals (coal, oil, gas, iron ore, bauxite, phosphate rock and mineral sands) which unfortunately can contain NORM. In some industries the management of possible NORM/TENORM exposures is already being. In the oil and gas industry for example radiation protection measures are implemented for staff undertaking maintenance on non-contaminated equipment. However there is still widespread non-regulation in other industries that adequately address the potential occupational and public health concerns relating to NORM/TENORM. The application of radiological protection regulations is currently not uniform throughout Australia. There are nine separate jurisdictions (State, Territory and Commonwealth) having responsibility for radiation safety legislation associated with artificial and naturally occurring radioactive material (NORM). The lack of uniformity in areas such as licensing, exemption limits and the fact that some parts of regulations in individual jurisdictions do not meet current international best practice, creates problems across jurisdictions.View full abstractDownload PDF (5207K) -
Hasmadi HASSAN2005 Volume 40 Issue 1 Pages 87-91
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSIn Malaysia, waste associated with TENORM are generated mostly in the tin mining and smelting, processing of minerals, and oil and gas industry. As one of a major tin producer in the world and the country current activities in oil production, the amount of waste generated in this kind of activities is quite substantial. Currently the government of Malaysia did not provide any provision in the law specifically for the exclusion of TENORM waste, however, the government did imposed the criteria for exclusion of this waste by adopting the guideline limit established by the IAEA safety series 26, which is very vital for the regulatory body i. e. Atomic Energy Licensing Board (AELB) to overcome the problems in managing some of waste related to TENORM industries. As one example, this guideline has been applied to one of the mineral processing industries in the country on decommissioning and disposing of their waste. Furthermore, due to economic reason and price of tin and its by-product is not viable and profitable so much, making this industry not significant in business and trade industries, several practices have been exempted from the regulatory control under the Atomic Energy Licensing Act, 1984.View full abstractDownload PDF (1080K) -
Ba Tien NGUYEN2005 Volume 40 Issue 1 Pages 92-94
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSAs an implementation of work planned by the FNCA task group on TENORM, a discussion/survey meeting on TENORM was held in Vietnam during August 25-29, 2003. The meeting consisted of the technical discussion on several TENORM topics including technical visit on TENORM sites. This report summarized those activities. The remarkable source of TENORM in Vietnam is scales and sludge from petroleum industry and waste from sand beach processing. Estimated TENORM waste volume generated and stored at Institute for Technology of Radioactive Rare Elements (ITRRE) is about 19-29t·y-1, which contained 0.02-1%U, not include TENORM waste produced from other mineral industries that did not keep their records. Currently, there is about 130t of untreated TENORM waste stored at Phung Interim Storage. Typical dose rate in work place ranges from 0.15-90μSv·hr-1. Annual dose of worker was estimated 6mSv·y-1 based on the assumption of 2, 000 work-hr in a year. There are three regulations concerned to TENORM in Vietnam: Ordinance on Radiation Safety and Control (ORSC) (June 25, 1996), Decree on the Detail Directions for implementing of ORSC (July 16, 1998), and National Standard on Radioactive Waste Management—Classification of RW (TCVN-6868. 2001).View full abstractDownload PDF (571K) -
Jintao ZHANG, Qinghong SUN2005 Volume 40 Issue 1 Pages 95-98
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSChina has long history in exploiting, processing and using of NORM/TENORM materials and has also paid attention to control and use properly of these materials. Although radiation level in these industry fields has been investigated and primary regulatory principles have been established, some problems still exist such as having not practicable criteria on exemption and clearance of residues and wastes. Considering the fact that NORM/TENORM is involved in a variety of industrial fields in China as well as its specific characteristics of large waste volume, low radioactivity concentration and long lived radionuclides contained in wastes. Regulatory polices should be considered carefully so that the contradiction between cost and benefit can be in balance.View full abstractDownload PDF (878K) -
Kanitha SRISUKSAWAD, Sutat THIANGTRONGJIT, Nanthavan CHANTARAPRACHOOM2005 Volume 40 Issue 1 Pages 99-103
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThis report summarized activities of the TENORM task group of the FNCA held in Thailand during August 23-27, 2004. TENORM inventory, regulations and laws, and the country specific problems are also included in this report. Groups of industries lead to enhanced occupational and public exposure to TENORM in Thailand included oil and gas exploration and production, metal production i. e. tantalum, niobium, tin, and rare earths, cement production, steel refinery, water treatment, coal and coal power production, chemical fertilizer, and residues from past activities with various range of capacity. Waste volume generated and TENORM activity concentrations in waste were estimated based on information from various reports and data. TENORM waste volume generated was estimated 150, 000t·y-1 with activity concentration ranges from 0.14-1.3Bq·g-1 of 226Ra. Thailand has no regulation directly control of NORM and TENORM. However, article 2 of the Thai Ministerial Regulation No. 5 B. E. 2516 (1973) clarified: any materials that contained uranium oxide (U3O8) or thorium oxide (ThO2)/or uranium oxide and thorium oxide at concentrated level more than 15% of the original ore element will be accounted as radioactive source materials. Practical guidance based on BSS No. 115 must be applied on all activities dealing with those materials. The specific problems of the country for controlling TENORM are the lack of: understanding on TENORM sources, information on location and extent of existing TENORM sites, safely and economically guidance on controlling exposure to TENORM, information distribution and cooperation network, and a suitable and correct method on sampling and measurement of TENORM.View full abstractDownload PDF (1836K)
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