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Harada, Hideo; Takayama, Naoki; Komeda, Masao
Journal of Physics Communications (Internet), 4(8), p.085004_1 - 085004_17, 2020/08
A new convention of epithermal neutron spectrum is formulated for improving accuracy of resonance integrals. The new type function is proposed as an approximating function of epithermal neutron spectrum based on calculations by the state-of-art Monte Carlo code MVP-3. Bias effects on determination of resonance integrals due to utilizing approximating functions of the traditional types and the new type are compared. The other bias effect is also investigated, which is caused by neglecting position dependence of a neutron spectrum inside an irradiation capsule. For demonstrating the bias effects due to these assumptions on neutron spectrum quantitatively in a practical case, the thermal neutron-capture cross section and resonance integral of Cs measured at a research reactor JRR-3 are re-evaluated. A superior property of the proposed new convention is discussed. The experimental method is proposed to determine the new shape factor
introduced in the convention by a combinational use of triple flux monitors (
Au,
Co and
Zr), and its analytical methodology is formulated.
Hales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
Asai, Shiho*; Ohata, Masaki*; Hanzawa, Yukiko; Yomogida, Takumi; Horita, Takuma; Kitatsuji, Yoshihiro
no journal, ,
A large amount of Cs adsorbents left over after decontamination of waste water has continued to accumulate in the Fukushima Daiichi Nuclear Power Plant. For safe disposal of such Cs adsorbents, estimation of the radioactivity is crucial. A long-lived beta emitting nuclide Cs which is captured in the Cs adsorbents along with a major radiation contributor
Cs. Different from
Cs which can be measured in gamma spectrometry, the activity of
Cs is generally measured in liquid form, requiring elution of Cs
. However, high radiation from the Cs adsorbents hampers the operations. In this study, we applied LA-ICP-MS which allows direct measurement of Cs adsorbent. With
Cs /
Cs given by LA-ICP-MS,
Cs can be calculated by combining a measured
Cs radioactivity. A radiocesium-containing sample was used to verify the proposed method. The results agreed well with those obtained through the measurement of Cs-separated solution.