• Nuclear Engineering and Technology
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• 제41권10호
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• pp.1307-1314
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• 2009

The isotope ratio of $^{134}Cs/^{137}Cs$ in a spent PWR fuel sample was obtained with a newly developed gamma/neutron combined measuring system at KAERI. Burnup and Pu/U ratio of the spent fuel sample were determined by using the measured isotope ratio and the burnup-isotope ratio correlation equations calculated from the ORIGEN-ARP computer code. The results were compared and evaluated with the chemically determined burnup and Pu/U ratio. As a result of the comparative evaluation, the nondestructively determined burnup and Pu/U ratio values showed a good agreement with the chemically obtained results to within a 4.5% and 0.8% difference, respectively.

• Mass Spectrometry Letters
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• 제2권4호
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• pp.80-83
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• 2011

Isotope ratio analysis of nuclear materials in individual particles is of great importance for nuclear safeguards. Although secondary ion mass spectrometry (SIMS) and thermal ionization mass spectrometry (TIMS) are utilized for the analysis of individual uranium particles, few studies were conducted for the analysis of individual uranium-plutonium mixed oxide particles. In this study, we applied SIMS and inductively coupled plasma mass spectrometry (ICP-MS) to the isotope ratio analysis of individual U-Pu mixed oxide particles. In the analysis of individual U-Pu particles prepared from mixed solution of uranium and plutonium standard reference materials, accurate $^{235}U/^{238}U$, $^{240}Pu/^{239}Pu$ and $^{242}Pu/^{239}Pu$ isotope ratios were obtained with both methods. However, accurate analysis of $^{241}Pu/^{239}Pu$ isotope ratio was impossible, due to the interference of the $^{241}Am$ peak to the $^{241}Pu$ peak. In addition, it was indicated that the interference of the $^{238}UH$ peak to the $^{239}Pu$ peak has a possibility to prevent accurate analysis of plutonium isotope ratios. These problems would be avoided by a combination of ICP-MS and chemical separation of uranium, plutonium and americium in individual U-Pu particles.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.245-256
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• 2004

The extraction of three kinds of amido podands, N,N,N'N'-tetrabutyl-3-oxa-pentanedi- amide (TBDGA), N,N,N'N'-tetra-isobutyl-3-oxa-pentanediamide(TiBDGA) and N,N,N'N'-tetra- butyl-3,6-dioxa-oct-anediam- ide(TBDOODA) on U(VI),Pu(IV), Am(III), Eu(III) and other metal ions is studied in nitric acid solutions. 40%octanol-kerosene is chosen as diluents to eliminate third phase and emulsion. TBDGA and TiBDGA show extraction selectivity to An(III) and Ln(III) much higher than to U(VI) and Pu(IV). Fe, Ru and Mo is poorly extracted by the three kinds of amid podands in 2~3mol/L $HNO_3$ solutions. Aiming to eliminate interface crude when using simulated HLLW solution in the system of 0.2mol/L TBDGA/Octanol＋kerosene, acetohydroxyamic acid was adapted. Distribution ratio of zirconium was decreased when adding acetohydroxyamic acid in aqueous solution, and interface crude disappeared as mixing extractant with HLLW. The counter-current extraction test is carried out in a set of miniature mixer-settler, with 0.2mol/L TBDGA/ 40% octanol-kerosene as extractant to separate U(VI), Pu(IV), Am(III) and Eu(III) from simulated high level liquid waste(HLLW) solution. In battery A, lanthanides and actinides are coextracted into organic phase with the recovery of 99.98% for U(Ⅵ), >99.99% for Pu(IV), and >99.99% for Am(III) and Eu(III) respectively. In battery R1, 99.99% U, 86.2% Pu and a part of Am or Eu are stripped into aqueous phase by 0.2mol/L acetohydroxyamic acid (AHA) in 0.01mol/L $HNO_3$ solution. In battery $R_2$, Am, Eu and remained Pu are completely back-extracted by 0.2mol/L AHA. This separation process contains no salt reagent, and it is not necessary to dilute HLLW feed.

• Applied Biological Chemistry
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• 제5권
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• pp.7-21
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• 1964

가잠(家蠶)(Bombyx mori)의 잠체(蠶體), 용체 및 견사선(絹絲腺)(후부(後部))에서 phenol법(法)으로 RNA를 추출(抽出)하여 RNA의 nucleotide 조성(組成)(mole ratio)을 살피는 한편, 견사선(絹絲腺)(후부(後部))에서 초원심법(超遠沈法)으로 r-RNA, s-RNA를 분리(分離)하여 이에 대(對)한 nucleotide조성(組成)을 조사(調査)하고 또 가잠견사선(家蠶絹絲腺)과 비교(比較)할 목적(目的)으로 거미 방적선(紡績腺)의 t-RNA를 분리(分離)하여 nucleotide성분(成分)을 측정(測定)하여 다음과 같은 결과(結果)를 얻었다. 1) 잠란(蠶卵)에 있어서 이것을 마수(磨粹), 탈지(脫脂) 후(後) lysozyme을 작용(作用)시키고 10% NaCl용액(溶液)으로 가열(加熱) 추출(抽出)하는 새방법(方法)을 고찰(考察)하여 RNA의 추출(抽出)이 극난(極難)한 잠란(蠶卵)에서 RNA를 분리(分離)하는데 성공(成功)하였다. 2) 가잠란(家蠶卵), 잠체(蠶體), 용체 및 견사선(絹絲腺)(후부(後部))의 t-RNA nucleotide 조성(組成)은 다음과 같다. 시료(試料) $\frac{G+C}{A+U}$ $\frac{G+U}{A+C}$ $\frac{Pu}{Py}$ 가잠란(家蠶卵)의 RNA 1.14 1.24 0.99 가잠체(家蠶體)의 RNA 1.40 1.36 0.80 용체의 RNA 1.40 1.33 1.35 후부견사선(後部絹絲腺)의 RNA 1.05 1.32 1.15 이로서 잠체(蠶體). 용체 및 견사선(絹絲腺)의 Pu/Py는 각각(各各) 차이(差異)가 있으나 G+U/A+C는 3자간(者間)에 1.3의 거이 동일(同一)한 수치(數値)를 보여주고 있다. G+C/A+U는 잠체(蠶體)와 용체에 있어서 동일(同一)하나 견사선(絹絲腺)의 그것과는 차이(差異)가 있다. 한편 잠란(蠶卵)에 있어서는 Pu/Py, G+C/A+U, G+U/A+C가 각각(各各) 잠체(蠶體), 용체 및 견사선(絹絲腺)에 있어서와 현저(顯著)한 차이(差異)를 보여주고 있다. G+C/A+U가 1.3이나 되는 RNA의 base ratio를 가진 생물(生物)에 관(關)해서는 아직 보고(報告)된 바 없고 다만 본논문(本論文)의 가잠(家蠶)에 관(關)한 RNA와 속편(續編)인 각종(各種) 패류(貝類) RNA의 nucleotide 조성(組成)에서 모두 1.3에 가까운 수치(數値)를 보여주고 있다. 3) 견사선(絹絲腺)(후부(後部)) t-RNA와 거미 방적선(紡績腺)의 t-RNA의 nucleotide molar ratio 및 견사선(絹絲腺)의 r-RNA, s-RNA nucleotide 조성(組成)은 다음과 같다. 재료(材料) $\frac{G+C}{A+U}$ $\frac{G+U}{A+C}$ $\frac{Pu}{Py}$ 가잠견사선(家蠶絹絲腺)(후부(後部)의 t-RNA 1.05 1.32 1.15의 r-RNA 1.12 1.30 1.20의 s-RNA 1.55 1.33 0.65 지주방적선(蜘蛛紡績腺)의 t-RNA 1.35 1.24 1.16 즉(卽) 가잠견사선(家蠶絹絲腺)(후부(後部))과 거미방적선(紡績腺)의 t-RNA nucleotide 조성(組成)은 Pu/Py가 1.15와 1.16으로서 거이 동일(同一)하지만 G+C/A+U, G+U/A+C에 차이(差異)가 있음을 보았다. 한편 가잠견사선(家蠶絹絲腺)(후부(後部)) r-RNA와 s-RNA의 Pu/Py와 G+C/A+U는 현저(顯著)한 차이(差異)가 있고, G+U/A+C에 있어서는 1.3으로서 거이 동일(同一)한 수치(數値)를 보여주고 있다. 4. 이상(以上)과 같이 잠체(蠶體)에 관(關)한 RNA의 nucleotide 조성(組成)은 소위(所謂) GC-type로서, 현재(現在)까지 문헌(文獻)에 보고(報告)된 각종(各種) 생물(生物)의 RNA의 base ratio에 관(關)하여 비교(比較) 검토(檢討)하였으며, RNA의 nucleotide ratio의 차이(差異)의 의의(意義)에 대(對)하여 고찰(考察)하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.124-129
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• 1998

A sensitivity study has been done to determine the composition of DUPIC fuel from the viewpoint of neutronics fuel design. The spent PWR fuel compositions were generated and fissile contents adjusted by blending fresh uranium after mixing two spent PWR fuel assemblies. The $^{239}$ Pu and $^{235}$ U enrichments of DUPIC fuel were adjusted by controlling the amount of fresh uranium feed and the ratio of slightly enriched and depleted uranium in the fled uranium. Based on the material balance calculation, it is recommended that DUPIC fuel composition be such that spent PWR fuel utilization is more than 90%.. A sensitivity study on the temperature reactivity coefficient of DUPIC fuel has shown that it is desirable to increase the $^{239}$ Pu and $^{235}$ U contents to reduce both the fuel and coolant temperature coefficients. On the other hand, refueling simulations of the DUPIC core have shown that the channel power peaking factor, which is a measure of the reactor trip margin, increases with the total fissile content. Considering these neutronic characteristics of the DUPIC fuel, il is recommended to have enrichments of 0.45 and 1.00 wt% for $^{239}$ Pu and $^{235}$ U, respectively.

• Nuclear Engineering and Technology
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• 제42권1호
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• pp.79-88
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• 2010

Spent $UO_2$ nuclear fuel discharged from a nuclear power plant (NPP) contains fission products, U, Pu, and other actinides. Due to neutron capture by $^{238}U$ in the rim region and a temperature gradient between the center and the rim of a fuel pellet, a considerable increase in the concentration of fission products, Pu, and other actinides are expected in the pellet periphery of high burnup fuel. The characterization of the radial profiles of the various isotopic concentrations is our main concern. For an analysis, spent nuclear fuels originating from the Yeonggwang-2 pressurized water reactor (PWR) were chosen as the test specimens. In this work, the distributions of some actinide isotopes were measured from center to rim of the spent fuel specimens by a radiation shielded laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system. Sampling was performed along the diameter of the specimen by reducing the sampling intervals from 500 ${\mu}m$ in the center to 100 ${\mu}m$ in the pellet periphery region. It was observed that the isotopic concentration ratios for minor actinides in the center of the specimen remain almost constant and increase near the pellet periphery due to the rim effect apart from the $^{236}U$ to $^{235}U$ ratio, which remains approximately constant. In addition, the distributions of local burnup were derived from the measured isotope ratios by applying the relationship between burnup and isotopic ratio for plutonium and minor actinides calculated by the ORIGEN2 code.

• Applied Biological Chemistry
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• 제5권
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• pp.23-31
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• 1964

해산(海産) 패류(貝類) 6종(種)(대합, 모시조개, 피조개, 굴(토화(土花)), 소라, 전복)의 중간선(中腸腺)(간(肝))에 대(對)하여 RNA와 DNA의 함량(含量)을 측정(測定)하고 또한 phenol법(法)으로 RNA를 추출(抽出) 분리(分離)하여 그 nucleotide 조성(組成)을 분석(分析)하여 다음과 같은 결과(結果)를 얻었다. 1) 각시료(各試料)(모시 조개 제외(除外)) 중장선(中腸腺)의 탈지분말(脫脂粉末) 100mg 중(中) RNA의 함량(含量)은 굴이 8.74mg으로서 가장 많고 순차(順次)로 전복 7.92mg, 대합 6.82mg, 피조개 4.62mg이며, 소라는 2.16mg로서 가장 그 함량(含量)이 낮다. 이와 같이 RNA 함량치(含量値)는 굴, 전복, 대합에 있어서 rat간(肝)의 RNA 함량(含量)(4.0mg)보다 높은 값을 나타 내고 있다. 2) 상기(上記) 시료중(試料中) DNA 함량(含量)은 굴이 1.03mg로서 가장 많고, 대합 0.89mg, 피조개 0.70mg, 소라 0.60mg이며 전복은 0.22mg로서 그 함량(含量)이 가장 낮다. 전복을 제외(除外)하고는 모두 rat간(肝)의 함량(含量)(0.34mg) 보다 $2{\sim}3$배(倍)의 DNA 함량(含量)을 보여주고 특(特)히 굴은 RNA 및 DNA의 함량(含量)이 모두 가장 높다. 한편 소라와 전복에 있어서 RNA/DNA 함량비(含量比)가 3.6과 36.0으로서 큰 차이(差異)를 나타내고 있다. 3) 이들 패류(貝類)의 중장선(中腸腺)(간(肝))의 RNA nucleotide 조성(組成)(mole ratio)은 다음 표(表)와 같다. 즉(卽) 해산(海産) 패류(貝類) 6종(種)에 있어서 중장선(中腸線) RNA의 Pu/Py는 $1.02{\sim}1.31$로서 그 폭(幅)이 넓고 G+C/A+U는 $0.97{\sim}1.51$로서 그 차이(差異)가 심(甚)하다. 그러나 G+U/A+C는 $1.26{\sim}1.46$으로서 1.3에 가까우며 패류(貝類)에 있어서는 G+U/A+C가 종(種)의 특이성(特異性)이 있는 것으로 사료(思料)되는 바이다. 한편 패류(貝類)의 RNA nucleotide 조성(組成)은 고등식물(高等植物), 세균(細菌), 조류(藻類) 및 고등동물(高等動物)의 그것과 경향(傾向)이 다르다.

• 방사성폐기물학회지
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• 제20권1호
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• pp.23-32
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• 2022

Pyroprocessing is a promising technology for managing spent nuclear fuel. The nuclear material accounting of feed material is a challenging issue in safeguarding pyroprocessing facilities. The input material in pyroprocessing is in a solid-state, unlike the solution state in an input accountability tank used in conventional wet-type reprocessing. To reduce the uncertainty of the input material accounting, a double-stage homogenization process is proposed in considering the process throughput, remote controllability, and remote maintenance of an engineering-scale pyroprocessing facility. This study tests two types of mixing equipment in the proposed double-stage homogenization process using surrogate materials. The expected heterogeneity and accounting uncertainty of Pu are calculated based on the surrogate test results. The heterogeneity of Pu was 0.584% obtained from Pressurized Water Reactor (PWR) spent fuel of 59 WGd/tU when the relative standard deviation of the mass ratio, tested from the surrogate powder, is 1%. The uncertainty of the Pu accounting can be lower than 1% when the uncertainty of the spent fuel mass charged into the first mixers is 2%, and the uncertainty of the first sampling mass is 5%.

• Journal of Radiation Protection and Research
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• 제40권4호
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• pp.223-230
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• 2015

공공수역 내 방사성물질 분포특성 파악을 위하여 춘천시 의암호 퇴적물 내 인공방사성핵종인 $^{134}Cs$, $^{137}Cs$, $^{239+240}Pu$과 자연방사성동위원소인 $^{210}Pb$을 분석하였고, 퇴적물 내 유기물의 특성을 파악하기 위하여 총 유기탄소(total organic carbon, TOC)를 분석하였다. 의암호 퇴적물 내 $^{134}Cs$ 농도는 4지점 모두 minimum detectable activity(MDA) 미만으로 나타났으며, $^{137}Cs$ 농도는 $MDA{\sim}8.79Bq{\cdot}kg^{-1}-dry$으로 나타났다. 표층 내 $^{137}Cs$의 농도는 $2.4{\sim}4.2Bq{\cdot}kg^{-1}-dry$의 범위를 나타냈고, St. 4에서 최소값, St. 3에서 최대값을 보였다. 의암호 퇴적물 내 $^{239+240}Pu$ 농도는 $0.049{\sim}0.47Bq{\cdot}kg^{-1}-dry$의 농도를 보였고, St. 2에서 최소값이, St. 3에서 최대값이 나타났다. $^{239+240}Pu$과 $^{137}Cs$ 농도의 상관관계 (r)는 0.54~0.97로 이들 두 핵종의 퇴적물 내 거동과 기원이 유사한 것으로 사료된다. $^{134}Cs$의 농도가 MDA 미만으로 검출된 점과 $^{239+240}Pu/^{137}Cs$의 평균값 0.041이 과거 대기 핵실험기원의 농도 비와 비슷한 값이 나타나는 점으로 의암호 퇴적물 내 인공방사성동위원소 ($^{134}Cs$, $^{137}Cs$, $^{239+240}Pu$)의 기원은 후쿠시마 사고가 아닌 과거 핵실험에 인한 낙진의 영향으로 사료된다. 의암호 퇴적물 내 $^{210}Pb$의 결과를 이용하여 퇴적물의 퇴적률을 산출한 결과, St. 2에서 $0.31{\pm}0.06cm{\cdot}y^{-1}$의 퇴적률을 나타냈으며, 이는 $^{137}Cs$의 퇴적물 내 peak를 1963년으로 가정하였을 때 측정된 퇴적률, $0.41{\pm}0.05cm{\cdot}y^{-1}$와 불확도($2{\sigma}$)의 범위에서 유사한 값으로 나타내었다. 의암호 퇴적물 내 TOC는 0.20~13.01%의 값이 나타났으며, 퇴적물 내 TOC와 $^{137}Cs$의 상관관계는 St. 1에서 다른 지점에 비해 높게 나타났다.

• Wind and Structures
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• 제12권4호
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• pp.299-312
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• 2009

It has long been studied about the flow around bluff bodies, but the effect of aspect ratio on the sharp-edged bodies in thick turbulent boundary layers is still argued. The author investigates the flow characteristics around a series of rectangular bodies ($40^d{\times}80^w{\times}80^h$, $80^d{\times}80^w{\times}80^h$ and $160^d{\times}80^w{\times}80^h$ in mm) placed in a deep turbulent boundary layer. The study is aiming to identify the extant Reynolds number independence of the rectangular bodies and furthermore understand the surface pressure distribution around the bodies such as the suction pressure in the leading edge, when the shape of bodies is changed, responsible for producing extreme suction pressures around the bluff bodies. The experiments are carried out at three different Reynolds numbers, based on the velocity U at the body height h, of 24,000, 46,000 and 67,000, and large enough that the mean boundary layer flow is effectively Reynolds number independent. The experiment includes wind tunnel work with the velocity and surface pressure measurements. The results show that the generation of the deep turbulent boundary layer in the wind tunnel and the surface pressure around the bodies were all independent of Reynolds number and the longitudinal length, but highly dependent of the transverse width.