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Omori, Yasutaka*; Hosoda, Masahiro*; Takahashi, Fumiaki; Sanada, Tetsuya*; Hirao, Shigekazu*; Ono, Koji*; Furukawa, Masahide*
Journal of Radiological Protection, 40(3), p.R99 - R140, 2020/09
Times Cited Count：23 Percentile：75.48(Environmental Sciences)UNSCEAR and the Nuclear Safety Research Association report the annual effective doses from cosmic rays, terrestrial radiation, inhalation and ingestion from natural sources. In this study, radiation doses from natural radiation sources in Japan were reviewed with the latest knowledge and data. Total annual effective dose from cosmic-ray exposure can be evaluated as 0.29 mSv. The annual effective dose from external exposure to terrestrial radiation for Japanese population can be evaluated as 0.33 mSv using the data of nationwide survey by the National Institute of Radiological Sciences. The Japan Chemical Analysis Center (JCAC) performed the nationwide radon survey using a unified method for radon measurements in indoor, outdoor and workplace. The annual effective dose for radon inhalation was estimated using a current dose conversion factor, and the values were estimated to be 0.50 mSv. The annual effective dose from thoron was reported as 0.09 mSv by UNSCEAR and then the annual effective dose from inhalation can be described as 0.59 mSv. According to the report of large scale survey of foodstuff by JCAC, the effective dose from main radionuclides due to dietary intake can be evaluated to be 0.99 mSv. Finally, Japanese population dose from natural radiation can be assessed as 2.2 mSv which is near to the world average value of 2.4 mSv.
Makino, Hitoshi; ; Miyahara, Kaname
JNC TN8400 2000-033, 74 Pages, 2000/11
JNC-TN8400-2000-033.pdf:9.19MB
Natural phenomena is one of the potential factors perturbing the long-term stability of the geological environment, and for natural phenomena, it is necessary to consider uncertainties relevant to time, frequency and effect. Therefore it will be important to have information about the potential impacts of natural phenomena on the safety functions of geological disposal system in the future by assuming that natural phenomena perturbs the safety functions of the geological disposal system. In this report, we have considered 4 natural phenomena, 'uplift, subsidence and denudation', 'climatic and sea-level changes', 'earthquakes and fault movement' and 'volcanism', which had been extracted by investigation in foreign countries and by considering the characteristics of Japan as natural phenomena which may perturb the long-term stability of the geological environment. And we have considered mainly typical effects of naturaI phenomena on geological environment and investigated the typical impacts of those natural phenomena on the safety functions of the geological disposal system. On perturbation scenarios, the maximum of total doses have been less than regulatory guidelines in foreign countries in all situations except the cases assuming that a new fault, which causes significant pathway of groundwater flow and nuclide migration, intersects the waste packages. In the case, the maximum of total doses may reach the same level as regulatory guidelines in foreign countries or natural radiation exposure in Japan depending on fault generation time or grandwater flow rate through the fault. And, on isolation failure scenarios, it has been implied that nuclide mass/flux originated from geological disposal is comparable level with nuclide mass/flux in natural environment. These results could give useful information about the potential impacts of natural phenomena on the safety functions of geological disposal system, and also could show the potential importance of ...
*; *; Nakano, Katsushi
PNC TN7410 98-001, 37 Pages, 1998/02
Power Reactor and Nuclear Fuel Development Corporation (PNC) has been developing groundwater research instruments in order to characterize hydraulic and geochemical environments in the deep underground. As part of this development programme, a support system was developed in 1996 to conduct groundwater investigations efficiently. This system, called the PNC Mobile Investigation System, consists of 5 units: a data acquisition and analysis unit, a maintenance unit, a hoisting unit, a cable drum for hydraulic tests (Type I), and a cable drum for groundwater sampling (Type II). The system is the following features: (1) Groundwater investigation is possible without a drill machine and rig. (2) Long term investigation is possible without housing facilities and utilities. (3) Maintenance of instruments is possible in the field. (4) Control units, such as the computer, are well protected from the external environment. (5) Groundwater analysis is possible in the field. (6)Recovery of instruments stuck in the borehole is possible using the emergency hoisting unit. The first field test of this system was performed in February and March, 1997. Through this test, it was confirmed that the system had met its performance design when combined with a proper hydraulic test instrument. Much useful information for future improvements to the system was also obtained.
Furuya, Kazuo*; *; Kodama, Toshio*
PNC TJ7705 97-001, 154 Pages, 1997/03
no abstracts in English
*; Fuse, Keisuke*; *; Yasuda, Kenya*
PNC TJ7454 97-001, 536 Pages, 1997/03
no abstracts in English
Takano, Toyoji*; Sasaki, Yutaka*; Fuse, Keisuke*; Saito, Akira*; Sato, Yoshikazu*
PNC TJ1454 96-001, 295 Pages, 1996/03
None
Sakamoto, Ryuichi; Nagaoka, Toshi; Saito, Kimiaki; Tsutsumi, Masahiro; Moriuchi, Shigeru
JAERI-M 91-166, 67 Pages, 1991/10
no abstracts in English
