Skyshine dose evaluation of trench disposal facilities for waste generated from research, industrial and medical facilities

Nakamura, Mizuki; Izumo, Sari; Ogawa, Rina; Nakata, Hisakazu; Amazawa, Hiroya; Sakai, Akihiro

JAEA-Technology 2022-025, 73 Pages, 2022/12

JAEA-Technology-2022-025.pdf:1.64MB

Japan Atomic Energy Agency (JAEA) has been establishing as the implementing body of the near surface disposal of low-level radioactive waste (LLW) generated from research facilities and other facilities in order to actualize the near surface disposal. It is necessary to evaluate the effective doses by direct and skyshine -rays from disposal facilities and reduce the doses below the target dose (50 Sv/y) at the site boundary for the safety assessment during operation. It was shown at the results of conceptual design that the distance from the trench disposal facilities to site boundary needed to be kept more than 120m in order to satisfy the target dose. However, the design of trench disposal facilities was changed because of increasing amount of waste subject to the trench disposal. Therefore, the dose by skyshine -rays from trench disposal facilities was recalculated by use of two-dimensional discrete ordinates Sn code DOT 3.5. As a result, it was evaluated that the dose by skyshine -rays from each trench facility at the site boundary whose distance was 120m from a trench facility was lower than 50 Sv/y, respectively, and the dose added up the doses from trench facilities was also lower than 50 Sv/y. In addition, it was suggested to reduce the target skyshine dose by thickening the covered soil on the top layer.

D-T neutron skyshine experiments at JAERI/FNS

Nishitani, Takeo; Ochiai, Kentaro; Yoshida, Shigeo*; Tanaka, Ryohei*; Wakisaka, Masashi*; Nakao, Makoto*; Sato, Satoshi; Yamauchi, Michinori*; Hori, Junichi; Takahashi, Akito*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 79(3), p.282 - 289, 2003/03

http://ci.nii.ac.jp/naid/110003825346

no abstracts in English

Demonstration study on shielding safety analysis code (VII)

Sawamura, Sadashi*

JNC TJ8400 2000-053, 41 Pages, 2000/02

JNC-TJ8400-2000-053.pdf:1.6MB

Dose evaluation for direct radiation and skyshine from nuclear fuel facilities is one of the environment evaluation items. This evaluation is carried out by using some shielding calculation codes. Because of extremely few benchmark data of skyshine, the calculation has to be performed very conservatively. Therefore, the benchmark data of skyshine and the well-investigated code for skyshine would be necessary to carry out the rational evaluation of nuclear facilities. The purpose of this study is to obtain the benchmark data of skyshine and to investigate the calculation code for skyshine. In this fiscal year, the followings are investigated; (1)To improve the detection sensitivity of pulsed neutron measurement, two neutron detectors and some electronic circuits are added to the system constructed last year. (2)To estimate the neutron dose at the distant point from the facility instead of the commercialized rem-counter, a He detector with paraffin moderator is equipped to the system. (3)Using the new detection system, the skyshine of neutrons from 45Mev LINAC facility was measured in the distance up to 300m. The results show that the time structure of pulsed neutrons almost disappears at the further points than 150m. (4)In the distance from 90m to 300m ordinal total counting method without gate pulse are applied to detect the neutrons. (5)The experimental results of space dependency up to 300m is fitted fairly well by the Gui's response function.

Demonstration study on shielding safety analysis code (IV)

Sawamura, Sadashi*

PNC TJ1600 97-001, 77 Pages, 1997/03

PNC-TJ1600-97-001.pdf:2.17MB

no abstracts in English

Evaluation of the environmental gamma-ray dose rate by skyshine analysis during the maintenance of an activated TFC in ITER

Sato, Satoshi; Takatsu, Hideyuki; *; *; Mori, Seiji*; Iida, Hiromasa; R.Santoro*

Journal of Fusion Energy, 16(3), p.211 - 218, 1997/00

https://doi.org/10.1023/A:1021891203613

no abstracts in English

Demonstration study on shielding safety analysis code (III)

Sawamura, Sadashi*

PNC TJ1600 96-003, 77 Pages, 1996/03

PNC-TJ1600-96-003.pdf:5.15MB

no abstracts in English

Demonstration study on shielding safety analysis code

Sawamura, Sadashi*

PNC TJ1600 94-002, 61 Pages, 1994/02

PNC-TJ1600-94-002.pdf:1.81MB

None

DUCT-II and SHINE-II: Simple design code for duct-streaming and skyshine

*; *; Shin, Kazuo*; Masukawa, Fumihiro; Naito, Yoshitaka

JAERI-M 91-013, 54 Pages, 1991/02

JAERI-M-91-013.pdf:1.39MB

no abstracts in English

applied example MCNP5 on skyshine of nuclear facility

Zaima, Naoki; Naganuma, Masaki; Sakao, Ryota; Tokizawa, Takayuki

no journal, , 

In the field of safety analysis on nuclear fuel facility, conventional calculation code (QAD/G33 etc.) had been used. However some confines of codes had lead overestimation. At the chance of trial for shielding or skyshine calculation, Monte Carlo transport calculation code MCNP5 was applied. The comparison between both, error estimations, model designs, several artifices will be introduced.