著者

山田 裕司 小泉 彰 宮本 勝宏 稲葉 次郎

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.29, no.3, pp.283-289, 1994 (Released:2010-02-25)

参考文献数

11

被引用文献数

1 1

---

Decontamination Factors (DFs) of HEPA filter were measured against 239Pu oxide aerosols. Collection performance of HEPA filter media was investigated using monodisperse NaCl aerosols at various air flow face velocities. From the penetration curves the most penetrating particle size, MPPS, and the maximum penetration, Pmax, were obtained in each face velocity. The MPPSs at 0.8-11cm s-1 flow were not found in 0.3μm size range but in 0.1-0.15μm size range. The reciprocal of Pmax, which means the minimum of decontamination factor, DFmin, linearly increased with decreasing face velocity in a logarithmic paper. Experimental DFs against Pu aerosols in the MPPS range were nearly equal to the DFmin, and the others were always larger than the DFmin. This means that there are no differences between Pu and NaCl aerosols in terms of filtration. The DFmin estimated from the nonradioactive test aerosols is important for evaluating the performance of HEPA filters in the radiation protection field.

著者

小泉 彰 花辺 充広 細野 洋平 メチアニ ヤーヤ・ムバラク 尾辻 泰一 佐野 栄一

出版者

一般社団法人電子情報通信学会

雑誌

電子情報通信学会総合大会講演論文集

巻号頁・発行日

vol.2007, no.2, 2007-03-07

著者

小西 恵美子 小野 道実 小泉 彰 河内 典子 吉沢 康雄

出版者

Japan Health Physics Society

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.4, no.4, pp.594-602, 1969 (Released:2010-03-15)

参考文献数

5

---

In spite of the increasing use of electron microscopes, very few considerations have been given to the emission of radiation from the equipment. This is mainly due to the fact that the radiation is emmitted as “an unwanted by-product”of the equipment. Radiation surveys were carried out on twelve epuipments of Japanese manufacture. Informations obtained from the surveys were;1) Radiation leakage was observed from eight equipments.2) Electron gun, viewing window and photo-chamber were main locations where radiation leakage was observed.3) Structural defects in the equipment were important causes of radiation leakage.Following opinions were offered from a health physics standpoint;1) The equipment is required to be constructed and installed so as to provide adequate protection.2) A legalistic radiation safety standard is neededfor theequipment manufacturer.3) In a radiation safety program, it is important to obviate any radiation leakage rather than to assess the doses liable to be incurred.

著者

山田 裕司 宮本 勝宏 森 貞次 小泉 彰

出版者

Japan Health Physics Society

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.17, no.4, pp.461-467, 1982 (Released:2010-02-25)

参考文献数

11

---

Collection performance of a HEPA filter and a new type filter which was recently developed for removing fine particles below 0.3μm was verified by using a laser aerosol particle counter in the particle size range from 0.12 to 0.42μm diameter in which the filter performance was not sufficiently clarified. Tested filter sheets were 14.5cm by 14.5cm in dimensions.DOP particles ranging from 0.12 to 0.17μm exhibited higher penetration of HEPA filter than DOP particles from 0.27 to 0.42μm by a factor of 20 at the standard face velocity of 2.4cm/sec. The penetration of HEPA filter was 6.6×10-4 for 0.12 to 0.17μm DOP particles, and that of the new type filter was 3.1×10-6.It was confirmed that overall system penetration of two HEPA filters in series could be described as the product of each stage penetration.

著者

小泉 彰 福田 俊

出版者

Japan Health Physics Society

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.33, no.3, pp.286-293, 1998 (Released:2010-02-25)

参考文献数

9

著者

山田 裕司 宮本 勝宏 小泉 彰

出版者

Japan Health Physics Society

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.21, no.4, pp.237-244, 1986

被引用文献数

3 1

---

It is very important in a nuclear air cleaning system that HEPA (High Efficiency Particulate Air) filter is for reduction of releasing amounts of airborne radioactive particles. HEPA filter, by definition, has a minimum collection efficiency of 99.97% for 0.3μm particles. However, <i>DF</i> (Decontamination Factor), which is necessary for safety management, can not be directly derived from the efficiency. And the current standard defined for 0.3μm particles has no scientific justification, because it has been found that the most penetrating particle size through HEPA filter is not always 0.3μm.<br>In the present paper, a numerical experiment was made in order to estimate a relationship between <i>DF</i> and the efficiency. And new standard, in which the minimum <i>DF</i> is able to be easily obtained, was proposed. In the multistage filtration system, it was found that lower values of <i>DF</i> was possible to be experimentally indicated in the second and the third stages, even if the collection performance of the each filter is the same.

著者

山田 裕司 小泉 彰 宮本 勝宏

出版者

日本エアロゾル学会

雑誌

エアロゾル研究 = Journal of aerosol research (ISSN:09122834)

巻号頁・発行日

vol.11, no.1, pp.35-43, 1996-03-20

被引用文献数

7

---

Aerosol penetrations through fibrous filters with pinholes were studied theoretically and experimentally. An equivalent thin filter layer (ETFL) model assuming a virtual filter layer was proposed to account for penetration through filters with pinholes. From one to thirty pinholes per filter were made on HEPA filter media using columnar pins of 0.195, 0.150 or 0.130 mm in diameter. Aerosol penetration through these filters was measured using monodisperse NaCl aerosols ranging from 0.05 to 0.3 μm in diameter at air flow face velocities of 0.00775, 0.0233 and 0.0698 m/s. Net penetration through the pinholes increased in proportion to the pinhole number and size. But there was no change in pressure drops across the filters. As a result of analysis based on the ETFL model, the layer thickness was estimated to range from 1/5 to 1/12 of the normal filter thickness. The predicted penetration curves were confirmed to agree well with the measured curves.

著者

小泉 彰 福田 俊

出版者

Japan Health Physics Society

雑誌

保健物理 : hoken buturi (ISSN:03676110)

巻号頁・発行日

vol.33, no.3, pp.286-293, 1998-09

著者

山田 裕司 宮本 勝宏 小泉 彰

出版者

Japan Health Physics Society

雑誌

保健物理 : hoken buturi (ISSN:03676110)

巻号頁・発行日

vol.33, no.3, pp.294-297, 1998-09