The air dilution olfactory method to measure complex odors needs to store and carry odor samples from the field sampling until the analysis in laboratories. Until the analysis of sample in the laboratory, odor dilution factor (odor sensitivity) in the sample bag may decrease over time depending on the characteristics of each odor substances. This is one of the limitation for the air dilution olfactory method. Thus, the air dilution device enable to measure without loss in complex odors of samples. Recently, many studies on the performance test of on-site air dilution devices, i.e., field olfactometer, has been conducted to figure out the feasibility of the field olfactometers. In this study, seven odor samples were collected from five odor emission source sites. And comparative analysis with the air dilution olfactory method was carried out to assess the field applicability of the olfactometer. As results, the performance of the field olfactometer used in this study is regared as the affordable method. The dilution factors from between two methods showed the similar values, indicating low values of standard deviations. In order to ensure the accuracy and precision of measurement data using the field olfactometer, methodology minimized variables (that may affect measurement) needs to establish.

Graphite Isotope Ratio Method (GIRM) can be used to estimate plutonium production in a graphite-moderated reactor. This study presents verification results for the GIRM combined with a 3-D polynomial regression function to estimate cumulative plutonium production in a graphite-moderated reactor. Using the 3-D Monte-Carlo method, verification was done by comparing the cumulative plutonium production with the GIRM. The GIRM can estimate plutonium production for specific sampling points using a function that is based on an isotope ratio of impurity elements. In this study, the 10B/11B isotope ratio was chosen and calculated for sampling points. Then, 3-D polynomial regression was used to derive a function that represents a whole core cumulative plutonium production map. To verify the accuracy of the GIRM with polynomial regression, the reference value of plutonium production was calculated using a Monte-Carlo code, MCS, up to 4250 days of depletion. Moreover, the amount of plutonium produced in certain axial layers and fuel pins at 1250, 2250, and 3250 days of depletion was obtained and used for additional verification. As a result, the difference in the total cumulative plutonium production based on the MCS and GIRM results was found below 3.1% with regard to the root mean square (RMS) error.

Recently, there has been growing interest in harmful substances released from household items such as volatile organic compounds (VOCs) and this has increased people’s environmental awareness. In this study, adhesives and manicures were used as samples of indoor household goods and formaldehyde emission and tested over time under temperature conditions of 15oC, 25oC, 35oC, and 45oC. The small chamber method as the indoor air quality process test method was employed and used to evaluate the concentration of formaldehyde emissions. As a result, formaldehyde emissions gradually decreased over time in both tests using adhesives and manicures. The cumulative emission showed a logarithmic function over time, and the formaldehyde can be released for longer periods of time at lower temperature conditions. The logarithmic value and response time showed linear relationships, and it can be inferred that the formaldehyde was released from the sample through the first order reaction. Furthermore, the relationship between temperature and velocity constants which was determined using the Arenius linear equation showed that the reaction rate of formaldehyde can be estimated by a temperature change.

Environmental fundamental facilities have different odor emission characteristics depending on the type of treatment facilities. To overcome the limitations of the olfactometry method, research needs to be conducted on how to calculate the dilution factor from the individual odor concentrations. The aim of this study was to determine the air dilution factor estimated from manually measured concentration data of individual odor substances (22 specified odor species) in three environmental treatment facilities. In order to calculate the optimum algorism for each environmental fundamental facility, three types of facilities were selected, the concentration of odor substances in the exhaust gas was measured, and the contribution of the overall dilution factor was evaluated. To estimate the dilution factor, four to six algorism were induced and evaluated by correlation analysis between substance concentration and complex odor data. Dilution factors from O municipal water treatment (MWT) and Y livestock wastewater treatment (LWT) facilities showed high level of dilution factors, because concentration levels of hydrogen sulfide and methylmercaptan, which had low odor threshold concentrations, were high. In S food waste treatment (FWT) facility, the aldehyde group strongly influenced dilution the factor (dominant substance: acetaldehyde, i-valeraldhyde and methylmercaptan). In the evaluation of four to six algorism to estimate the dilution factor, the vector algorism (described in the text) was optimum for O MWT and Y LWT, while the algorism using the sum of the top-three dominant substances showed the best outcome for S FWT. In further studies, estimation of the dilution factor from simultaneously monitored data by odor sensors will be developed and integrated with the results in this study.

흑연 동위원소 비율법(GIRM)은 비핵화 검증 도구로써 흑연감속로의 플루토늄 생산량을 예측하는데 사용된다. 원자로가 가동되면 238U의 중성자 포획 반응에 의해 플루토늄이 생성되어 축적되고 동시에 흑연 내 불순물도 핵반응을 통해 다른 핵종 으로 바뀌기 때문에 플루토늄의 생성량과 불순물의 농도는 일정한 상관 관계를 갖는다. 이러한 상관관계에도 불구하고 어느 특정 시점에서의 불순물의 농도는 불순물의 초기 농도에 의존하기 때문에 불순물의 초기 농도가 알려지지 않으면 불순물의 절대 농도만으로 플루토늄 생산량을 예측하는 것은 불가능하다. 그러나 불순물의 초기 동위원소 비율은 초기 불순물 농 도에 상관없이 알려져 있기 때문에 불순물의 동위원소 비율과 플루토늄 생산량의 관계는 흑연감속로에서 플루토늄 생성량을 예측하는 유용한 도구가 될 수 있다. 흑연동위원소 비율법의 지표 원소로 Boron, Lithium, Chlorine, Titanium, Uranium 등이 이용되는 것으로 알려져 있다. 위 지표원소의 동위원소 비와 플루토늄 생성량 사이의 상관 관계가 초기 불순물 농도에 의존하지 않는지를 네 가지 다른 흑연 불순물 조성을 이용하여 평가하였다. 10B/11B, 36Cl/35Cl, 48Ti/49Ti, 235U/238U은 흑연의 초기 불순물 농도에 상관없이 누적 플루토늄 생성량과 일관된 상관 관계를 갖는다. 이러한 원소들은 다른 원소의 핵반응에 의해 해당 원소의 동위원소가 생성되지 않기 때문이다. 반면 6Li/7Li과 플루토늄 생성량의 상관관계는 흑연 내 불순물의 초기 농도에 의존한다. 7Li은 6Li의 중성자 포획 반응에 의해서 생성되기도 하지만 10B의 (n, α)반응으로도 생성되는 것이 더 지배 적이기 때문에 10B의 초기 농도가 7Li의 생성량에 영향을 미치는 것이다. 따라서 Lithium은 흑연 동위원소 비율법을 위한 지표 원소로 적절하지 않음을 알 수 있다.

We used three gas sensors to monitor hydrogen sulfide, ammonia, and volatile organic compounds (VOCs), which were frequently emitted from environmental facilities, such as municipal wastewater treatment, livestock manure treatment, and food waste composting facilities. Two electrochemical (EC) sensors for detecting hydrogen sulfide and ammonia, and a photoionization detector (PID) sensor for detecting VOCs were characterized in this study. The performance of their linearity by concentration levels, lower detection limit (LDL), repeatability, reproducibility, precision, and response time were tested under the laboratory condition. The linearity according to concentration levels were favorable for all three sensors with high correlation coefficients (R2 > 0.98). The ammonia sensor showed the highest LDL (18.6 ppb) and the hydrogen sulfide and VOC sensors showed 22.3 ppb and 26.7 ppb of LDL, respectively. The reproducibility and precision were favorable for all three sensors, indicating a lower relative standard deviation (RSD) than 0.9% in the reproducibility test and 7.2% in the precision test. The response times to reach target concentration were varied from 1 to 12 minutes. The ammonia sensor needed 12 minutes of response time at 1 ppm target the NH3 concentration and the hydrogen sulfide and VOC sensors needed less than 2 minutes of response time.