• 제목/요약/키워드: Radioactive dose

검색결과 459건 처리시간 0.031초

Radiological Safety Assessment of Transporting Radioactive Wastes to the Gyeongju Disposal Facility in Korea

  • Jeong, Jongtae;Baik, Min Hoon;Kang, Mun Ja;Ahn, Hong-Joo;Hwang, Doo-Seong;Hong, Dae Seok;Jeong, Yong-Hwan;Kim, Kyungsu
    • Nuclear Engineering and Technology
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    • 제48권6호
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    • pp.1368-1375
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    • 2016
  • A radiological safety assessment study was performed for the transportation of low level radioactive wastes which are temporarily stored in Korea Atomic Energy Research Institute (KAERI), Daejeon, Korea. We considered two kinds of wastes: (1) operation wastes generated from the routine operation of facilities; and (2) decommissioning wastes generated from the decommissioning of a research reactor in KAERI. The important part of the radiological safety assessment is related to the exposure dose assessment for the incidentfree (normal) transportation of wastes, i.e., the radiation exposure of transport personnel, radiation workers for loading and unloading of radioactive waste drums, and the general public. The effective doses were estimated based on the detailed information on the transportation plan and on the radiological characteristics of waste packages. We also estimated radiological risks and the effective doses for the general public resulting from accidents such as an impact and a fire caused by the impact during the transportation. According to the results, the effective doses for transport personnel, radiation workers, and the general public are far below the regulatory limits. Therefore, we can secure safety from the viewpoint of radiological safety for all situations during the transportation of radioactive wastes which have been stored temporarily in KAERI.

Acceptable Decontamination Factor for Near-Surface Disposal of PEACER Wastes

  • Kim, Sung-Il;Lee, Kun-Jai
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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    • pp.280-289
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    • 2005
  • A pyrochemical process has been introduced and utilized so that the transmutation of spent PWR fuel in PEACER can produce mainly low and intermediate level waste for near surface disposal. Major radioactive nuclides from PEACER pyroprocessing are composed of TRU and LLFP. In this study, the requirement for the final waste from PEACER is evaluated based on the methodology for establishment of waste acceptance criteria. Also, sensitivity analysis for several input parameters is conducted in order to determine acceptable decontamination factor (DF) and LLFP removal efficiency and to find out input parameter that extremely have an effect on DE As a result of the study, LLFP removal efficiency, especially Sr-90 and Tc-99, is proved to be a major nuclide which contributes to annual dose by human intrusion scenario rather than TRU DF. More than $98.5\%$ of LLFP have to be removed to meet below dose constraint within the DF more than 5.0E+03. Besides, because of the relative short half-life of Sr-90, the increasing of the institutional control period is recommended for most important input parameter to determine DF.

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Assessing the Feasibility of Diver Access During Dismantling of Reactor Vessel Internals

  • Kukhyun Son;Chang-Lak Kim
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • 제22권1호
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    • pp.37-44
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    • 2024
  • In 2017, a decision was made to permanently shut down Kori Unit 1, and preparations began to be made for its decontamination and decommissioning. The dismantling of the biological shields concrete, reactor vessel (RV), and reactor vessel internals (RVI) is crucial to the nuclear decommissioning process. These components were radiologically activated by the neutron activation reaction occurring in the reactor during its operational period. Because of the radioactivity of the RV and RVI of Kori Unit 1, remotely controlled systems were developed for cutting within the cavity to reduce radiation exposure. Specialized equipment was developed for underwater cutting operations. This paper focuses on modeling related to RVI operations using the MAVRIC code and the dose calculation for a diver entering the cavity. The upper and lower parts of the RVI are classified as low-level radioactive waste, while the sides that came into contact with the fuel are classified as intermediate-level radioactive waste. Therefore, the modeling presented in this paper only considers the RVI sides because the upper and lower parts have a minimal impact on the radiation exposure. These research findings are anticipated to contribute to enhancing the efficiency and safety of nuclear reactor decommissioning operations.

Air Density Correction of Ionization Chamber using $^{90}Sr$ Radioactive Check Device ($^{90}Sr$ 방사성 동위원소를 이용한 전리함의 대기 보정계수 측정)

  • Park, Sung-Y.;Kim, Woo-C.;Shin, Dong-O.;Ji, Young-H.;Kwon, Soo-I.;Lee, Kil-D.;Cho, Young-K.;Loh, John-J.
    • Journal of Radiation Protection and Research
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    • 제23권4호
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    • pp.267-271
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    • 1998
  • It is required to measure air density correction factor at the time of absorbed dose calibration or measurement. In general, thermometer and barometer are widely used for air density correction. However, this can be done using the radioactive check device with better accuracy. The measurements of air density correction were performed by using the radioactive check device, Unidos electrometer, and 0.6 cc Farmer-type ion chamber of PTW under the different environmental conditions. Above experiments were repeated with thermometer and barometer. By comparing the two methods, they were within the difference of 0.2 %. The overall uncertainty for the dose found in thermometer and barometer was 1.2 - 1.6 %, depending upon either one step or two, whereas the overall uncertainty for the radioactive check device was 1.02 %. This method may reduce the possible error which could occur when thermometer and barometer are not calibrated at regular basis.

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Calculation of Absorbed Dose for Immersion in Semi-Infinite Radioactive Cloud...(1) (반무한(半無限) 방사성운(放射性雲)에서의 흡수선량계산(吸收線量計算) - 1. 단일(單一)에너지 감마 방출체(放出體)에 대한 산난광자(散亂光子)스펙트럼의 계산(計算) -)

  • Lee, Soo-Yong
    • Journal of Radiation Protection and Research
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    • 제10권2호
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    • pp.155-159
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    • 1985
  • In general, dose rates for a monoenergetic gamma emitter uniformly distributed in an infinite cloud have been calulated by using the monoenergetic point-isotorpic source kernel technique. The most serious limitation on use of the kernel technique is subjected to the fact that it estimates the dose only at the surface of body. As a result, an alternative method is presented in which estimates of dose rate for immersion in a radioactive cloud are resulted from the scattered photon spectra incident on the surface of body. The results are in excellent agreement with other's. Work is currently in progress to apply these results to immersion dose problems associated with absorbed dose distribution in the MIRD phatom.

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Assessment of Maternal Organs and Fetal Doses in Pregnant Female Nuclear Medicine Practitioners Using the Monte Carlo Method (몬테카를로 방법을 이용한 임신한 여성 핵의학 종사자의 모체 장기 및 태아선량 평가)

  • Cho, Yong-In
    • Journal of radiological science and technology
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    • 제45권4호
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    • pp.331-339
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    • 2022
  • The purpose of this study was to evaluate maternal organ and fetal doses by week of pregnancy for pregnant women nuclear medicine practitioners in the nuclear medicine field. In addition, we intend to present basic data for the management of exposure doses of female nuclear medicine practitioners. In this study, phantoms of childbearing women, 3, 6, 9 months pregnant women were simulated using MCNPX(Monte Carlo N-Particle Extended) among the Monte Carlo methods. First, volume source was constructed based on 10 cm of the anterior part of the lower abdomen of the phantom, and the organ and fetal doses were evaluated for each week of the pregnant woman according to the type of radioactive isotope. Second, the organ and fetal dose of pregnant women were evaluated by increasing the distance between the source and the abdominal surface by 50 and 100 cm. As a result, 18F sources showed high organ and fetal doses in pregnant women 0 to 3 months, and the dose distribution gradually decreased in 6 to 9 months pregnant women. The distribution of organ and fetal doses for 99mTc and 123I sources showed the same tendency as that of 18F, and the overall absorbed dose distribution was relatively lower than that of 18F. Through this study, it is considered that workers in the early stages of pregnancy within 3 months will need appropriate management to minimize occupational exposure dose.

Medical Preparedness in Radiation Accidents (방사선 사고시의 의료대책)

  • Kim, Eun-Sil;Kim, Jong-Soon
    • Journal of Radiation Protection and Research
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    • 제21권3호
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    • pp.201-215
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    • 1996
  • Radiation and radioactive materials serve man in many beneficial ways. Diagnostic X-ray, radiation therapy, and other nuclear medicine uses of radioactivity save thousands of lives each year. Industrial application of radiation, such as radiography, make many manufactured products more reliable and less expensive. Nuclear power plants are producing more electrical power each year and reducing our dependence on imported oil. However, radiation can and dose produce harmful effects particularly as the reault of a radiation accident in which a victim receives as the result of a radiation accident in which a victim receives a large dose. Fortunately such accidents are very rare and recently we need more electric power produced by nuclear power plants. Considering increase of use of radiation or radioactive materials, we have to establish the radiological emergency response system prepared for radiation accidents.

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Controversies about Radioactive Iodine-131 Remnant Ablation in Low Risk Thyroid Cancers: Are We Near A Consensus?

  • Zaman, Maseeh Uz;Fatima, Nosheen;Padhy, Ajit Kumar;Zaman, Unaiza
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권11호
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    • pp.6209-6213
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    • 2013
  • Well differentiated thyroid cancers (WDTC), including papillary (80%) and follicular (10%) types, are the most common endocrine cancers globally. Over the last few decades most the diagnosed cases have fallen into low risk categories. Radioactive iodine-131 (RAI) has an established role in reducing recurrence and improving the survival in high risk patients. In patients with primary tumor size <1 cm, RAI is not recommended by many thyroid societies. However, low risk WDTC has been an arena of major controversies, most importantly the role and dose of adjuvant RAI for remnant ablation to minimize chances of recurrence and improving survival. This review is an attempt to update readers about the previous and existing practice based on results of non-randomized trials and evolving trends fueled by recently published randomized studies.

Treatment of Differentiated Thyroid Cancer (분화된 갑상선암의 치료)

  • Shong, Young-Kee
    • 대한핵의학회:학술대회논문집
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    • 대한핵의학회 2002년도 제23차 연수교육
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    • pp.77-95
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    • 2002
  • During the last several decades, prognosis of differentiated thvroid cancers improved markedly, mainly due to refinement of surgical techniques and routine use of radioactive iodine. Total or neat-total thyroidectomy is to be performed as the first line of treatment. Routine remnant ablation just after surgery decreases recurrence and increases survival. After then patients are maintained on suppressive dose of thyroid hormone to keep endogenous TSH below normal. Regular follow-up of the patients with serum thyroglobulin measurement and iodine whole body scan after thyroid hormone withdrawal or under recombinant human thyrotropin stimulation select high risk patients with recurrence or metastatic disease and treatment with therapeutic dose of radioactive iodine prolongs survival and sometimes leads cure. Currently recommended diagnostic and therapeutic strategies, present controversies and future directions are discussed.

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Application of Dose to Curie Conversion Method using MCNP-4C code for the evaluation of Radionuclide Inventory in a Radioactive Waste Container

  • Sang-hee, Kang;Hwang, Ki-ha;Lee, Sang-chul;Lee, Kun-jai;Kim, Tae-wook;Kim, Kyoung-deok;Herr, Young-hoi;Song, Myung-jae
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 한국방사성폐기물학회 2004년도 학술논문집
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    • pp.174-174
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    • 2004
  • It is necessary to perform the radionuclide inventory assessment for the disposal of low and intermediate radioactive waste containers. The $\gamma$ nuclide analyzer can be used for the assessment of containers. However, if the radioactivity in the containers is extremely low or high, radionuclide inventory of the containers can not be evaluated properly. Also, gamma scanning method is time consuming and has economical burden to the utilities.(omitted)

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