• Title/Summary/Keyword: biosphere

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INTERNATIONAL COLLABORATION IN ASSESSMENT OF RADIOLOGICAL IMPACTS ARISING FROM RELEASES TO THE BIOSPHERE AFTER DISPOSAL OF RADIOACTIVE WASTE INTO GEOLOGICAL REPOSITORIES

  • Smith, Graham;Kato, Tomoko
    • Nuclear Engineering and Technology
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    • v.42 no.1
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    • pp.1-8
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    • 2010
  • Geological disposal is designed to provide safe containment of radioactive waste for very long times, with the containment provided by a combination of engineered and geological barriers. In the extreme long term, after many thousands of years or longer, residual amounts of long-lived radionulides such as Cl-36, but also radionuclides in the natural decay chains, may be released into the environment normally accessed and used by humans, termed here, the biosphere. It is necessary to ensure that any such releases meet radiation protection objectives through the development of a safety case, which will include assessment of radiation doses to humans. The design of such dose calculations over such long timeframes is not straightforward, because of the range of potentially relevant assumptions which could be made, concerning environmental change and changes in human behavior. These conceptual uncertainties are additional to those that more typically arise, for example, in the assessment of present day situations, but which also have to be addressed. The issue has therefore been subject to international cooperation for many years. This paper summarizes the evolution and results of that collaboration leading up to the present day, taking account of developments in international recommendations on radiation protection objectives and the more recent greater focus on preparation of site specific safety cases.

Method for Evaluating Radionuclide Transport in Biosphere by Calculating Elapsed Transport Time (이동 경과 시간 계산을 이용한 생물권에서의 방사성 핵종 이동 평가 방법)

  • Ko, Nak-Youl;Ji, Sung-Hoon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.2_spc
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    • pp.305-315
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    • 2020
  • For geological disposal of radioactive wastes, a method was proposed to evaluate the radionuclide transport in the biosphere by calculating the elapsed time of nuclide migration. The radionuclides were supposed to be introduced from a natural barrier and reached a large surface water body following a groundwater flow in a shallow subsurface. The biosphere was defined as a shallow subsurface environment that included aquifers on a host rock. Using the proposed method, a calculation algorithm was established, and a computer code that implemented the algorithm was developed. The developed code was verified by comparing the simulation results of the simple cases with the results of the analytical solution and a public program, which has been widely used to evaluate the radiation dose using the radionuclide transport near the surface. A case study was constructed using the previous research for radionuclide transport from the hypothetical geological disposal repository. In the case study, the code calculated the mass discharge rate of radionuclide to a stream in the biosphere. Because the previous research only demonstrated the transport of radionuclides from the hypothetical repository to the host rock, the developed code in the present study could help identify the total transport of radionuclide along the complete pathway.

On the Research and Development for High Level Radioactive Waste Disposal in Korea (고준위 방사성폐기물 처분 기술개발 현황)

  • Lee, Young-Up
    • Economic and Environmental Geology
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    • v.28 no.3
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    • pp.279-286
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    • 1995
  • The amount of the high level radioactive wastes in Korea will be increased up to 14,297 MTU about 2010 year. Most of countries adopt the concept of deep burial repository in high level radioactive waste disposal. Because the high level radioactive wastes are very toxic in biosphere and to human, the data verifing its never return to the biosphere are requisite for the disposal. Presently, the evaluating techniques for the high level radioactive waste disposal are not fully developed. Therefore, in order to dispose the high level radioactive wastes in proper time the R & D of it is urged in our country. The R & D and/or the international joint research programme for the disposal of high level wastes have already been proceeded. In our country no plan for its disposal has been prepared. It is the time that the direction of the R & D is to be discused seriously. The R & D for the disposal of high level radioactive wastes in Korea is believed to be focused on developing the pecular techniques such as in situ characteristics of groundwater flowage, and change of properties of in situ rock mass at thermal effects.

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New earthworm species from NIBR's Jeju-do biosphere compared to historical and new Japanese types (Oligochaeta: Megadrilacea: Megascolecidae)

  • Blakemore, Robert J.
    • Journal of Species Research
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    • v.1 no.2
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    • pp.133-150
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    • 2012
  • Amynthas tralfamadore sp. nov. is described from the Mt Halla, Jeju Island biosphere exhibition housed at NIBR Incheon. This species' taxonomy is problematical since it is similar to Amynthas masatakae (Beddard, 1892) from Japan, itself previously reported from Korea and at one time associated with Amynthas campestris (Goto & Hatai, 1898) and A. parvicystis (Goto & Hatai, 1899), all three variously implicated in prior A. robustus (Perrier, 1872) along with Amynthas aspergillum (Perrier, 1872). Based on reinspection of the London lectotype of A. masatakae-here designated and sketched for the first time-the current solution is for maintenance of all five taxa separately. A closely-related Japanese species-Metaphire ryunome sp. nov.-is comparable to Korean Metaphire reisuiensis (Kobayashi, 1938) comb. nov. Another specimen was identified as Amynthas micronarius (Goto & Hatai, 1898), a new record for Korea. It matches the newly-designated neotype (Tokyo NMST An446) and an annotated synonymy is provided; however, erstwhile synonyms, Amynthas shimaensis (Goto & Hatai, 1899) and A. yamizoyamensis (Ohfuchi, 1935) combs. novae, are briefly redescribed and provisionally restored to the Japanese list. mtDNA COI-5P barcode analyses support species identifications.