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Abstract  

Tritium and 14C concentration in hot spring water in Korea were determined. Tritium in the most hot spring samples could not detected and concentration range was <0.5–1.31 TU. And 14C contents were ranged 1.7–78.6 pMC. From the 3H and 14C analysis, we found some hot springs are mixed with recent groundwater and hot spring water ages were estimated from 1,940 to 32,800 years. And also, 226Ra and 228Ra were determined simultaneously in hot spring water, and some other radionuclides were also analyzed. Content distribution of 222Rn was 50–3,760 pCi/L, 226Ra was <0.003–0.15 Bq/L and 228Ra was below the detection limit.

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Abstract  

The nucleus23Na has been investigated by studying the primary γ-rays emitted from 53 keV neutron capture in it using a high resolution and high efficiency (100%) HPGe detector and NaI(T1) detector for anti-Compton. 24 primary γ-rays were placed in the24Na, in which 3 primary γ-rays were new ones from a (n, γ) reaction, and reported for the first time. In order to obtain an exact energy calibration within 7 MeV,56Fe(n,γ)57Fe reaction was used at thermal neutron energy. Intensity calibration was obtained from the27Al(p,γ)28Si reaction atE p=2046 keV. The neutron binding energy of24Na was determined to be 6959.75 keV.

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Abstract  

The manganese sulphate bath method is widely used for measurements of neutron source strength. In this study, the analytical chemistry method based on the Inductively Coupled Plasma (ICP) spectrometry was used for examining the impurity contents of MnSO4·H2O, to induce55Mn(n,γ)56Mn reactions. From the analytical results, mainly K, Co, and Zn as well as trace amounts of Cd, Li, etc., have turned out to be the relevant impurities absorbing the neutrons and the fraction of neutron absorbed by the total impurities was determined to be 1.37%.

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Abstract  

A new two-step process was investigated to treat LiCl molten salt waste containing volatile radionuclides generated from an electro-metallurgical processing (pyro-processing) of spent oxide fuels. First, the chemical form of the soluble LiCl waste was transformed into a chloride-free and less soluble hydroxide compound by an electrochemical method, where an electrolytic de-chlorination was performed without adding any chemical salt. Then, a gelation process of the chemical form-changed Li compound, named gel-route stabilization/solidification (GRSS) system aimed to reduce the volatility of the radionuclides greatly, was introduced to stabilize/solidify the hydroxide salt wastes. The application of the electrochemical dechlorination/transformation process and the subsequent gel-route stabilization process to treat the soluble LiCl salt wastes was found to be effective.

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Abstract  

Collisional processes involving a negative muon in the deuterium and tritium system were studied using the classical binary encounter theory. The time needed for slowing down of a 10 keV muon was found to be of the order of 10–8s to 10–12s, depending on the density of the system. The Sticking Probabilities for the d-t and d-d fusions were obtained to be 0.48% and 10.2%, respectively. The usefulness of the classical model for understanding fundamental processes in muon catalyzed fusion is suggested.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Kwang-Pill Lee
,
Sun-Tae Hwang
,
Y. Yamada
,
K. Furukawa
, and
Shin-Ichi Ohno

Abstract  

Impact of energetic heavy particles on europium compound surfaces gives rise to radiative optical emission from reflected and sputtered particles and from the excited states of the solid compounds. In the present paper we discuss the optical spectrum and the sputtered secondary ion mass spectrum observed when solid europium oxide (Eu2O3) and europium chloride (EuCl3) are bombarded with 90 keV Ar+ ions from an ion accelerator. We observe the reduction reaction in solid europium chloride (EuCl3) by bombardment with a 20 A/cm2 beam of 90 keV Ar+ ions.

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Reaction Kinetics, Mechanisms and Catalysis
Authors:
Bo-Hyun Kim
,
Tae-Hee Lim
,
Jin-Woong Roh
,
Sang-Geun Lee
,
Chang Ju
,
Seong Park
,
Seong Hong
, and
Gun Lee

Abstract  

Undoped and Cr-doped Bi12TiO20 (BTO) were prepared and used as photocatalysts for the degradation of formic acid both under visible light and UV irradiation. The effects of the Cr doping on the visible light response and the photocatalytic activity of BTO were investigated. The prepared catalysts were characterized by using XRD, XPS, UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The doping of Bi12TiO20 with low concentration of Cr leads to noticeable increase in visible light absorption and decrease in the recombination rate of photo-generated electrons and holes. As a result, the Cr-doped BTO showed a higher photocatalytic activity for the degradation of formic acid both under visible light and UV irradiation, as compared with undoped BTO.

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Abstract  

We measured the isomeric yield ratios for the photonuclear reactions of 93Nb(γ,4n)89m,gNb and natMo(γ,xnp)95m,gNb by using the activation method. The high-purity 93Nb and natMo metallic foils in disc shape were irradiated with uncollimated bremsstrahlung beams of 50-, 60-, and 70-MeV generated from an electron linear accelerator in Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometry with a calibrated high-purity Germanium (HPGe) detector coupled to a PC-based 4 K multichannel analyzer. The reaction 93Nb(γ,4n)89m,gNb was studied for the first time which has no comparable literature data. The result of 95m,gNb isomeric pair was measured based on (γ,p), (γ,np), and (γ,2np) reactions which is the first measurement at the intermediate energy region of 50–70-MeV with a natMo target.

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Abstract

Ta2O5 powder was heat treated in flowing NH3 at varying temperature for 2 h. When heat treated at 680–720 °C, nitrogen was doped to Ta2O5, but showed only a slight improvement of photocatalysis of rhodamine B dye in solution under visible light irradiation. From the heat treatment temperature of 740 °C, seeds of TaON and Ta3N5 formed newly and grew with the temperature. The optical absorption edge at 410–510 nm by TaON and absorption shoulder at 535 nm by Ta3N5 were observed. These specimens with N-doped Ta2O5, TaON, and Ta3N5 demonstrated notably improved photocatalytic performance, and the photocatalysis was facilitated by surface photosensitization.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Md. Rahman
,
Kyung-Sook Kim
,
Manwoo Lee
,
Guinyun Kim
,
Youngdo Oh
,
Hee-Seock Lee
,
Moo-Hyun Cho
,
In Ko
,
Won Namkung
,
Van Nguyen
,
Duc Pham
,
Tien Kim
, and
Tae-Ik Ro

Abstract  

We measured isomeric-yield ratios for the 197Au(γ,n)196m,gAu reactions with bremsstrahlung energies of 50-, 60-, 70- MeV, and 2.5-GeV at the two different electron linac of the Pohang accelerator laboratory by using the activation method. The photons were produced when a pulsed electron beam hit a thin tungsten target. The well-known photoactivation method was used and hence the induced activities in the irradiated foils were measured with the high-resolution γ-ray spectrometric system consisting of lithium drifted high-purity Germanium detector and a multichannel analyzer. The measured isomeric-yield ratios for the 197Au(γ,n)196m,gAu reactions were (4.95 ± 0.51) × 10−4, (5.72 ± 0.72) × 10−4, (6.03 ± 0.50) × 10−4, and (9.27 ± 0.83) × 10−4 for 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies, respectively. The present results measured with the bremsstrahlung energy higher than 60-MeV are the first measurement.

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