著者

松村 宏 斎藤 究 石岡 純 上蓑 義朋

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.10, no.3, pp.152-162, 2011 (Released:2011-07-29)

参考文献数

3

被引用文献数

18 18

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In Fukushima and neighboring prefectures, the distributions of dose rate and γ-ray count rate of radionuclides from the Fukushima Daiichi Nuclear Power Station were measured on expressways on March 15, 16, 17, and April 8, 2011, using an NaI(Tl) detector and a LaBr3 detector. A radioactive plume that contained 133Xe, 132Te, 132I, 131I, 134Cs, and 136Cs was observed at Koriyama on the afternoon of March 15. The plume arrived in the Nakadori region of Fukushima prefecture, which is surrounded by two mountain ranges, and most of the radioactivity there was deposited by rainfall. Although the distributions of 132Te, 132I, 134Cs, 136Cs, and 137Cs were similar, the distribution of 131I was different from the others. The effective nuclides for the dose rate measurement were 132Te and 132I on March 15-17 and 134Cs and 137Cs on April 8. The initial distribution profile of the dose rate on March 15-17 was retained on April 8 because the deposited radioactive material was not moved from the initial location and there was no additional effective deposition of radioactivity.

著者

平山 英夫 松村 宏 波戸 芳仁 佐波 俊哉

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.14, no.1, pp.1-11, 2015 (Released:2015-02-15)

参考文献数

13

被引用文献数

2 9

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Time histories of the I-131 concentration in air at monitoring posts in Fukushima prefecture in March 2011 were estimated using the pulse height distribution of a NaI(Tl) detector, which was opened to the public. Several corrections to the pulse height distribution were necessary owing to high count rates. The contribution to the count rates from I-131 accumulated around the monitoring post was estimated on the basis of the time history of the peak count rate by the method proposed by the authors. The concentrations of I-131 in air were converted from the peak count rates using the calculated response of the NaI(Tl) detector with egs5 for a model of a plume containing I-131 uniformly. The obtained time histories of the I-131 concentration in air at a fixed point in March 2011 were the first ones for Fukushima prefecture. The results at 3 monitoring posts, Naraha Town Shoukan, Hirono Town Futatunuma and Fukushima City Momijiyama, which can be analyzed during almost all of March, show that a plume including I-131 arrived after March 15. The results at other monitoring posts near Fukushima Daiichi Nuclear Power Station are used to characterize plume diffusion at the early period of the accident before March 15. The I-131 time-integrated concentrations in air at several monitoring posts were compared with those given in UNSCEAR 2013 ANNEX A, which were obtained using estimated time-dependent rates of release to the atmosphere. The agreement between the two results varies depending on the places compared, owing to the large uncertainties in the estimated release rate used in UNSCEAR. The results obtained in this study can be used to increase the accuracy of the time-dependent release rate estimation.

著者

平山 英夫 近藤 健次郎 海野 泰裕 松村 宏 岩瀬 広 柚木 彰 佐々木 慎一

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.J14.048, (Released:2015-06-30)

参考文献数

16

被引用文献数

1

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A rapid and simple method to measure the concentration of 90Sr in water by measuring β-rays from 90Y was presented. Under the situation that 90Sr/90Y, 134Cs and 137Cs are the main radionuclides included in the water sample, only β-rays from 90Y can transmit through 1.5-mm-thick polyethylene. From this fact, it is possible to measure β-rays from 90Y using a β-ray detector, such as the GM-counter, set beneath the 1.5-mm-thick bottom of the water bottle containing the sample with 90Sr/90Y. The acrylic resin collimator having 0 cm, 1.00 cm, 1.50 cm or 3.00 cm diameter was made to detect β-rays at the fixed region of the GM-counter used. Contributions from bremsstrahlung produced by β-rays and γ-rays from radionuclides such as 134Cs and 137Cs/137mBa are removed by subtracting the count rate measured with a 1.00 cm acrylic resin collimator without a hole as the background count rate. The developed method was studied using the bottle routinely used at the Fukushima Daiichi Nuclear Power Station. It was confirmed that the developed method can be applied to measure the 90Sr concentration in water to the order of several Bq/cm3 if 134Cs and 137Cs concentrations are less than or equal to the 90Sr/90Y concentration.

著者

平山 英夫 松村 宏 波戸 芳仁 佐波 俊哉

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.16, no.1, pp.1-14, 2017 (Released:2017-02-15)

参考文献数

11

被引用文献数

3 5

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The Xe-135, I-131, I-132, I-133 and Te-132 concentrations in plumes at the monitoring posts in Fukushima prefecture in March 2011 were estimated using the pulse height distribution obtained from a NaI(Tl) detector, which were available to the public. Several corrections to the pulse height distribution were necessary owing to high count rates. The contribution to the count rates from each radionuclide except Xe-135 accumulated around each monitoring post was estimated using a method based on the time history of the peak count rate proposed by the authors. The concentration of each radionuclide in the plume was converted from the peak count rate using the response of the NaI(Tl) detector calculated with the egs5 code for a model of a plume containing a uniform distribution of radionuclides. The obtained time histories of Xe-135, I-131, I-132, I-133 and Te-132 concentrations in air at a fixed point in March 2011 were the first ones for Fukushima prefecture. The results at five monitoring posts near Fukushima Daiichi Nuclear Power Station were used to characterize radionuclides in the plume before March 15, soon after the accident. The results at three monitoring posts, Naraha-town Shoukan, Hirono-town Futatsunuma and Fukushima-city Momijiyama, which were analyzed during almost all of March, were used to characterize radionuclides in the plume in the period after March 14. It was fourd that Xe-135 was dominant on March 12 and Te-132 increased from March 13. For the radionuclides of iodine, I-131, I-132 and I-133 were detected with almost the same concentration for the first few days after the reactor shutdown.

著者

近藤 健次郎 平山 英夫 平 雅文 松村 宏 岩瀬 広 佐々木 慎一

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.J14.034, (Released:2015-06-30)

参考文献数

16

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Strontium-90/Y-90 are major radionuclides observed in the water samples tested recently at the site of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company. A simple method of evaluating Sr-90 concentration in these water samples by measuring β rays from Y-90 with a GM-detector setup was developed. By applying the precipitation method, Sr-90 and Y-90 were separated and quantitatively collected with a filter. β rays from Y-90 in the filter were measured two times at appropriate intervals by inserting a polyethylene plate of 2 mm thickness as a β-ray absorber. The contribution of γ rays from Cs-134 and Cs-137 to the Y-90 count rates was quantitatively evaluated using a 10-mm-thick acrylic resin plate. From the parent-daughter relationship between Sr-90 and Y-90, the Sr-90 concentration was evaluated using the conversion coefficient of Y-90 count rate (cps) to Sr-90 concentration (Bq/cm3). It was verified that Sr-90 concentration of below 0.01 Bq/cm3 in water samples can be correctly measured by this simple method.

著者

平山 英夫 松村 宏 波戸 芳仁 佐波 俊哉

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.J14.027, (Released:2015-01-28)

参考文献数

13

被引用文献数

9 9

---

Time histories of the I-131 concentration in air at monitoring posts in Fukushima prefecture in March 2011 were estimated using the pulse height distribution of a NaI(Tl) detector, which was opened to the public. Several corrections to the pulse height distribution were necessary owing to high count rates. The contribution to the count rates from I-131 accumulated around the monitoring post was estimated on the basis of the time history of the peak count rate by the method proposed by the authors. The concentrations of I-131 in air were converted from the peak count rates using the calculated response of the NaI(Tl) detector with egs5 for a model of a plume containing I-131 uniformly. The obtained time histories of the I-131 concentration in air at a fixed point in March 2011 were the first ones for Fukushima prefecture. The results at 3 monitoring posts, Naraha Town Shoukan, Hirono Town Futatunuma and Fukushima City Momijiyama, which can be analyzed during almost all of March, show that a plume including I-131 arrived after March 15. The results at other monitoring posts near Fukushima Daiichi Nuclear Power Station are used to characterize plume diffusion at the early period of the accident before March 15. The I-131 time-integrated concentrations in air at several monitoring posts were compared with those given in UNSCEAR 2013 ANNEX A, which were obtained using estimated time-dependent rates of release to the atmosphere. The agreement between the two results varies depending on the places compared, owing to the large uncertainties in the estimated release rate used in UNSCEAR. The results obtained in this study can be used to increase the accuracy of the time-dependent release rate estimation.

著者

平山 英夫 松村 宏 波戸 芳仁 佐波 俊哉

雑誌

2016年秋の大会

巻号頁・発行日

2016-07-22

著者

松村 宏 桝本 和義 吉田 剛 豊田 晃弘 中村 一 三浦 太一

出版者

日本加速器学会

雑誌

加速器 (ISSN:13493833)

巻号頁・発行日

vol.18, no.2, pp.63-71, 2021-07-31 (Released:2021-08-04)

参考文献数

16

---

Measurement of activated materials and evaluation of activated areas of several types of accelerator facilities were studied for decommissioning planning from FY2017 to FY2020 under the contract of the Nuclear Regulation Authority. The research results were summarized in “Manual of Measurement and Evaluation of Activation for Decommissioning of Accelerator Facilities.” This manual consists of the classification of the activation area of accelerator facilities and the measurement and evaluation of the activation of concrete structures and metallic accelerator components in the decommissioning of accelerator facilities. This manual will be used for the decommissioning of accelerator facilities in Japan.

著者

平山 英夫 松村 宏 波戸 芳仁 佐波 俊哉

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.12, no.4, pp.304-310, 2013 (Released:2013-11-15)

参考文献数

4

被引用文献数

1 3

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A method was presented to estimate radionuclide concentration in plume using the pulse height distribution measured by a LaBr3 scintillation detector and its calculated response to radionuclides in plume with egs5. Radionuclide concentration was estimated from the ratio between the peak count rates corresponding to each radionuclide in the measured pulse height distribution on an expressway on March 15 and in the calculated one from each radionuclide in plume using the egs5 Monte Carlo code. The pulse height distribution reconstructed based on the estimated concentrations agrees well with the measured one at the time that the contribution from radionuclides deposited on a ground surface is negligible.

著者

平山 英夫 近藤 健次郎 海野 泰裕 松村 宏 岩瀬 広 柚木 彰 佐々木 慎一

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.14, no.3, pp.141-150, 2015 (Released:2015-08-15)

参考文献数

16

被引用文献数

1

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A rapid and simple method to measure the concentration of 90Sr in water by measuring β-rays from 90Y was presented. Under the situation that 90Sr/90Y, 134Cs and 137Cs are the main radionuclides included in the water sample, only β-rays from 90Y can transmit through 1.5-mm-thick polyethylene. From this fact, it is possible to measure β-rays from 90Y using a β-ray detector, such as the GM-counter, set beneath the 1.5-mm-thick bottom of the water bottle containing the sample with 90Sr/90Y. The acrylic resin collimator having 0 cm, 1.00 cm, 1.50 cm or 3.00 cm diameter was made to detect β-rays at the fixed region of the GM-counter used. Contributions from bremsstrahlung produced by β-rays and γ-rays from radionuclides such as 134Cs and 137Cs/137mBa are removed by subtracting the count rate measured with a 1.00 cm acrylic resin collimator without a hole as the background count rate. The developed method was studied using the bottle routinely used at the Fukushima Daiichi Nuclear Power Station. It was confirmed that the developed method can be applied to measure the 90Sr concentration in water to the order of several Bq/cm3 if 134Cs and 137Cs concentrations are less than or equal to the 90Sr/90Y concentration.

著者

平山 英夫 川崎 将亜 松村 宏 大倉 毅史 波戸 芳仁 佐波 俊哉 滝 光成 大石 哲也 吉澤 道夫

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.13, no.3, pp.119-126, 2014 (Released:2014-08-15)

参考文献数

4

被引用文献数

3 6

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A method of deducing the I-131 concentration in a radioactive plume from the time history of peak count rates determined from pulse height spectra obtained from an NaI(Tl) scintillation detector employed as a detector of a monitoring post was presented. The contribution to the count rates from I-131 accumulated around the monitoring post was subtracted in accordance with the time history, taking into consideration the cumulative attachment and its decay. The concentrations of I-131 in the plumes were estimated from the count rates using the calculated response of the NaI(Tl) detector with egs5 for a model of a plume uniformly containing I-131. This method was applied to the data from the monitoring posts at Nuclear Science Research Institutes of Japan Atomic Energy Agency (JAEA). The estimated time history variation of I-131 concentrations in plumes was in fair agreement with those measured directly by an air sampling method. The difference was less than a factor of 4 for plumes that arrived on March 15 and March 21, indicating relatively high I-131 concentrations among the plumes studied in this work.

著者

伊藤 正 枝松 圭一 村松 宏 松村 宏

出版者

大阪大学

雑誌

基盤研究(B)

巻号頁・発行日

1999

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近接場光学顕微鏡(SNOM)のナノスケール分光と高機能化を研究した。1.ポリスチレン微小球配列結晶の近接場効果(1)結晶のフォトニックバンドに共鳴する波長をはさんで、SNOM透過光像が反転した。長波長側は球の周辺部、短波長側は球の中心部が明るい。共鳴付近では全体に広がった。この様子は計算でも再現できる。(2)照射モードと集光モードにおけるSNOM像は一致した。計算との比較によると、SNOMプローブは2次元面内に平行な偏光成分を主に検知している。(3)微小球の直径、プローブの開口径、光波長の3つの要素により、SNOM像は大きく変化するので、プローブの解像度を知る方法として有効である。(4)反応性イオンエッチングによって配列位置は変えずに微小球の大きさを削ると、フォトニックバンド幅が減少した。微小球に固有なWGモードの球間重なり積分の変化が原因であり、結晶中の電子のバンド構造形成と類似ている。2.高機能化(1)プローブの縦方向の位置制御用に水晶振動子を用い、非光化プローブを作製した。(2)クライオスタット内にSNOM装置を設置し、試料を熱伝導で約100Kまで冷やした。(3)ストレートタイプのプローブを用いて、偏光度測定の感度を向上させ、サブミクロンサイズのペリレン微結晶の方位を決定した。(4)石英ファイバープローブを用いた紫外光近接場測定や、バネ定数の小さなプローブにより基板に密着力の弱い微結晶試料の測定を可能とした。3.ナノスケール光加工(1)ペリレン微結晶表面への近接場光照射により直径100nm以下、深さ数10nmの穴を光加工できた。光生成された表面励起子が表面分子の蒸発又は光分解を引き起こすものと解釈される。(2)加工後の微結晶表面形状に経時変化が見られる。AFM観察により室温における表面分子の平均拡散速度は2-3nm/minと求まった。