For deep geological repository of the spent nuclear fuel, the fuel assemblies loaded in the storage cask are transferred to the disposal cask and the operation is performed in the fuel handling hot cell at the fuel re-packaging facility. As the fuel handling hot cell shielding is accomplished by the concrete wall and the viewing glass window, the required shielding thickness was evaluated for both materials. The ordinary concrete is applied to hot cell wall and two kinds of glasses, i.e., single layer of lead glass and double layer of lead glass and borosilicate glass, are considered for the viewing glass window. A bare spent PWR fuel assembly exposed to the environment in the hot cell was considered as the neutron and gamma radiation sources. The neutron and gamma transport calculations were performed using the MAVRIC program of the SCALE code system for the dose rate evaluation. The dose limit of 10 μSv/h is applied as the target dose to establish the required shielding thickness. The concrete wall of 94 cm thickness reduces the total dose rate to 6.9 μSv/h, which is the sum of neutron dose and gamma dose. Penetrating the concrete wall, both of the neutron dose and the gamma dose decrease constantly with shield thickness and the gamma dose is always dominant through whole penetrating distance. Single layer lead glass of 74 cm thickness reduces total dose rate to 6.2 μSv/h. Applying double layer shield glass combined of lead glass and borosilicate glass, the total dose rate reduces to 3.6 μSv/h at same shield thickness of 74 cm. Through the shield glass, gamma dose decreases rapidly and neutron dose decreases slowly compared with those for concrete wall. In result, neuron dose becomes dominant on the window glass shielding. The more efficient dose reduction of double layer glass is achieved by the borosilicate glass’s superior neutron shielding power. Thus, the use of double layer glass of lead glass and borosilicate glass is recommended for the viewing glass of the fuel handling hot cell. Finally, it is concluded that about 1 m thick concrete wall and 75 cm thick viewing glass window are sufficient for the radiation shielding of the hot cell at the spent fuel repackaging facility.

In liquid scintillation counting, sample radioactivity is analyzed by measuring photons emitted from counting vials. Quenching effect lowers photon intensity from samples, which leads to lower counting efficiency. So an appropriate quenching correction according to characteristics of samples is important. In this study, the quenching correction for H-3 analysis was conducted according to the characteristics of paper packaging material leached samples. The leached samples are made from H-3 leaching method which is in the process of development for H-3 contamination screening. There are several ways of quenching correction such as internal standard (IS) method, quench correction curve and triple-to-double coincidence ratio (TDCR) method, etc. For quench correction curve, quenched standard set, which has the same matrix as experimental samples, is needed to be prepared. Each leached sample, however, has different matrix and color depending on condition of leaching experiment, which means that it is not capable of preparing standard set having same matrix with the samples. In this study, the counting samples are used for plotting quench correction curve instead of quenched standard set. Spectral quench parameter of the external standard [SQP(E)] is used as quench indicating parameter (QIP). TDCR and counting efficiencies determined by IS method are used as counting efficiencies. The quench curve of TDCR versus SQP(E) has R2 = 0.55 and the curve of efficiency from IS method versus SQP(E) has R2 = 0.99. TDCR is known for approximate counting efficiency, however, TDCR as counting efficiency needs careful use for H-3 analysis of leached samples. The curve used efficiency from IS method is suitable for H-3 analysis of leached samples. In this study, the quench correction curve is prepared for H-3 analysis of leached samples of paper packaging material. SQP(E), TDCR and efficiency from IS method was used as parameters to plot the quench correction curve, and, the efficiency from IS method is suitable for H-3 analysis of the leached samples. The result of this study can be used for H-3 analysis of leached samples of paper packaging material.

Waste containers for packaging, transportation and disposal of NPP (Nuclear Power Plant) decommissioning wastes are being developed. In this study, drop tests were conducted to prove the safety of containers for packaging of the wastes and to verify the reliability of the analysis results by comparing the test and analysis results. The drop height of the waste containers was considered to be 30 mm, which is the maximum lifting speed of a 50 tons crane in the waste treatment facility converted to the drop height. Drop orientation of the containers was considered for bottom-end on drop. The impact acceleration and strain data were obtained to verify the reliability of the analysis results. Before and after the drop tests, measurement of the dose rate and the radiographic testing for concrete wall, and measurement of the wall thickness of steel plate were conducted to evaluate the radiation shielding integrity. Also, measurement of bolt torque, and visual inspection were conducted to evaluate the loss or dispersion of radioactive contents. After the drop tests, the radiation dose rate on the container surface did not increase by more than 20%, and there was no crack in the concrete. In addition, the thickness of the steel plate did not change within the measurement error. Therefore, the radiation shielding integrity of the container was maintained. After the drop tests, the lid bolts were not damaged and there was no loss of pretension in the lid bolts. In addition, there was no loss or dispersion of the contents as a result of visual inspection. In order to prove the reliability of the drop analysis results, safety verifications were performed using the drop test results, and the appropriate conservatism for the analysis results and the validity of the analysis model were confirmed. Therefore, the structural integrity of the waste containers was maintained under the drop test conditions.

In this study, the process of compressing/packaging the spent filters of Kori Unit 1, which was conceptually presented in the previous study, is advanced so that disposal suitability for each step can be secure efficiently. In particular, the differences between the previous study and this study are that the disposable filters are screened using an In-Situ Object Counting System (ISOCS), and the method of collecting representative samples for development of scaling factor is specified. The process of compressing/packaging the spent filters consists of 7 stages as follows. 1) Collecting: The spent filters temporarily stored in the filter room are collected by dose and type remotely using a robot system to minimize the radiation exposure of workers according to a pre-established packaging plan. 2) Screening: The gamma activity concentration of the spent filters received by the robot system is measured by ISOCS. The spent filters below the low-level waste concentration limit and the surface dose are transferred into the compression system, while the others are returned in the filter room again. 3) Sampling: The external perforator drilling/cutting the filter was developed for sampling required for the new scaling factors. Since the sampling is collected remotely, the risk of exposure to workers can be reduced. The newly developed scaling factor will be used to verify the disposal suitability of the packages. 4) Compression: According to the pre-established plan, the spent filter collected by dose and type, is supplied to the compression system considering the dose and radionuclide inventory. Whether to additionally store the compressed filter in the drum is determined by checking the accumulated dose. 5) Immobilization: Immobilization with a safety material is necessary when inhomogeneous wastes, like spent filters, have the total radionuclide concentration with a half-life of more than 20 years is 74,000 Bq/g or more and for filling rate or non-dispersible treatment of particulates. 6) Packaging and Analysis: Waste information is labelled onto the package after the measurements of surface dose rate and surface contamination. Finally, using the drum assay system, the gamma radionuclide concentration is measured to identify at least 95% of the total radioactivity concentration of the package. 7) Temporary Storage and Delivery: The packages are moved to temporary storage in the plant prior to disposal. After establishing the plan for delivery and applying for a takeover request to KORAD, if the acceptance inspection is passed, the packages are transported to the disposal facility.

Currently, Hanul NPP packages glass fiber classified as particulate waste in plastic packaging bags and stores them in 200 L drums. KORAD’s Waste Acceptance Criteria (WAC) presents that very low-level soil can be immobilized by loading it in a soft bag and then packaging it in a 200 L or 320 L steel drum. As currently accepted method of packaging with soft bag applies to only very low-level soils among the wastes with a risk of dispersion, it is necessary to develop a non-dispersible treatment suitable for the characteristics of other particulate waste in the future. Therefore, in order for Hanul packaging pack to be approved as an alternative method for immobilization of dispersible substances, it is necessary to verify the suitability of the packaging bag. In this paper, whether the glass fiber packaging bag used in Hanul NPP satisfies the characteristic of the soft bag presented in the WAC and the possibility of being considered as a non-dispersible measure for particulate are examined. The soft bag must meet the following requirements: material and structure, shape, drop test, and immersion test. The results of the review are as follows. First, since the glass fiber is already packaged in the drum, only the role of the inner layer, made of polyethylene, having a watertight function may be required. Second, when packaging a drum, the packaging bag is compressed into a shaped frame having an inner size of a 200 L drum, so it is packaged with little empty space in the drum. Third, as a result of a drop test of a packaging pack containing 20 kg of contents from a height of 1.2 m, it was confirmed that there was no leakage of contents. Fourth, the packaging bag was immersed in a 1-m depth water tank for 30-minutes, and the performance corresponding to the IPX7 was satisfied. As a result of reviewing the soft bag characteristic of Hanul glass fiber packaging bag, it is considered that the bag can be used as one of the non-dispersible measures because it meets almost the characteristics required by the WAC. In addition, the acceptance criteria of overseas disposal sites present various secure packaging methods in place of immobilization as a non-dispersible measure for waste containing particulate matter. It is necessary to reflect these overseas cases in the establishment of non-dispersible measures for domestic waste acceptance in the future.

본 연구는 비산소 분쇄 및 포장이 해조류 분말의 색도, 항산화활성 및 미생물 수에 미치는 영향을 조사하였다. 대조구로는 산소 조건하에서 분쇄 및 포장을 진행하였다. 색도는 대조구가 저장기간이 지남에 따라 L값과 b값은 감소하고 a값이 증가하여 갈변현상이 일어나는 것을 확인하였다. 또한, 총 페놀함량 (9.8~8.0mg GAE/100g dw), DPPH (12.57~11.00mg BHAE/100g dw), ABTS (13~8.4mg AAE/100g dw) 및 FRAP (11.2~8.0mg Fe(II)/100g dw)활성이 모두 감소하는 것으로 나타났다. 반면에, 진공-질소치환에 의한 비산소 분쇄 및 포장의 경우 유의적으로 차이가 없는 것으로 나타났다. 미생물수는 대장균군, 일반세균수, 효모 및 곰팡이를 분석하였고 대장균군과 곰팡이는 모든 샘플에서 불검출되었다. 대조구는 0~8주차에서 일반세균수와 효모가 각각 1.52~1.96 log CFU/g, 0~1.77 log CFU/g으로 증가하는 것으로 나타났다. 비산소 분쇄 및 포장 조건은 0~8주차에서 일반세균수와 효모가 각각 1.52~1.53 log CFU/g, 0~1.25 log CFU/g으로 각각 나타나 일반세균수는 유의적으로 차이가 없었으나 효모는 약간 증가한 것으로 나타났다. 따라서, 색도유지, 높은 총 페놀함량 및 항산화 활성 유지, 일반세균 및 효모의 성장 억제를 위해서는 진공-질소치환에 의한 비산소 분쇄 및 포장 조건하에서 품질특성과 미생물수를 유지하는데 효과적일 것으로 판단된다.

Currently, in domestic nuclear power plants (NPP), the spent filters (SFs) used for the purpose of reducing and purifying the radiation of the primary cooling water system are temporarily stored in an untreated state. In order to dispose of SFs, radioactive nuclide analysis (RNA) of SFs is required to be conducted. As segmented gamma scanner (SGS) is already being used in Kori NPP, utilizing SGS for RNA of SFs would be practical and economical. In this paper, factors required to be considered to improve accuracy of SGSs for RNA of SFs are studied. The analysis of the nuclide inventory of the packaging drum for radioactive waste should be performed by the indirect drum nuclide analysis method. The material of the SFs is iron (SS304) on the outside, and paper on the inside. In addition, to meet disposal acceptance criteria, radioactive waste drums are packaged in thick grouting or shielding drums. Therefore, it is necessary to derive an appropriate correction method for high inhomogeneity and thick media. Considering these factors, evaluating radionuclides inventory plans to measure gamma rays in SGS mode. Correct the gamma ray measurement by examining the medium attenuation factor and error factors. In this way, the inventory of gamma nuclides is calculated, and the specific radioactivity of beta ray and alpha particle emitting nuclides other than gamma rays is planned to be calculated by applying scaling factors.

큰느타리의 수출시 유통 기한 연장을 목적으로 수확시 품질 등급, 대와 자실체 사이를 잘라낸 손질 처리 유무, 그리고 관행 OPP 봉지에 끈묶음한 포장 방법을 개선시켜 트레이용기에 넣은 후 밀봉처리시 효과를 구명하고자 하였다. 수확시 품질 등급은 수확전 재배사의 온도를 9~11˚C 낮추어 적응시킨 버섯을 특품으로, 관행 13~15˚C로 적응시킨 버섯을 상품으로 설정하였다. 선별한 특품과 상품 버섯을 이용하여 손질 및 포장방법으로 3처리구를 두었다. 첫째는 절단 손질 후 OPP 봉지에 넣어 끈묶음한 포장(Cut & OPP), 둘째는 손질하지 않고 OPP 봉지에 넣어 끈묶음한 포장(Uncut & OPP), 마지막으로 개선포장방 법으로 절단 손질한 후 트레이용기에 넣고 밀봉한 포장 (Cut & Tray)이었다. 포장 완료한 버섯 처리구를 0℃ 저장고에 42일간 보관하면서 포장 내부의 기체 조성, 품질 요인의 변화, 신선 품질에 대한 관능평가를 실시하였다. 특품과 상품의 버섯 모두 Cut & Tray, Cut & OPP, 그리고 Uncut & OPP 처리 순으로 전반적으로 신선도가 높게 유지되었다. 특품 버섯의 유통 수명은 Cut & Tray 처리의 경우 30일, Cut & OPP 처리의 경우 28일, Uncut & OPP 처리의 경우 21일이었고, 상품 버섯의 유통 수명은 Cut & Tray 처리시 22일, Cut & OPP 처리시 17일, 그리고 Uncut & OPP 처리시 14 일이었다. 신선 버섯의 품질에 영향을 미치는 요인은 갓과 대의 갈변과 부패 지수였다. 특히, 버섯 대의 아랫부분의 갈변과 그에 연관된 표피색 a*값과 b*값의 변화가 품질 저하의 주요인이었다.

본 연구는 천적 곤충을 운송하는 동안 제품의 품질을 유지할 수 있는 포장 표준화 방안을 마련하고자 수행되었다. 먼저 4개 업체의 천적 제품 유통 현황을 분석한 결과, 평균 배송 소요시간인 36 ~ 48시간동안 평균 25.6°C(최저온도: 18.1°C, 최고온도: 30.7°C)를 유지하는 것을 확인 하였다. 계절별 최적의 포장방법을 구축하기 위하여 0 ~ 30°C 범위에서 5°C 간격으로 7개의 외부온도조건을 설정하였다. 또한 보냉제의 취급방법별 내부온도 유지성능평가를 실시해 14건의 포장조합을 도출하였다. 도출한 포장조합을 외부온도조건에 맞춰, 포장 후 12시간 이내의 직접 배송 또는 36 ~ 48시간이 소요되는 일반 배송기간 동안 최소한의 에너지로 천적의 생존을 유지할 수 있는 발육영점온도에 근접한 3.0 ~ 9.9°C로 유지할 수 있는 포장조합을 제시하였다.

As of 2018, total yield of lettuce and strawberry amounted to 93,543 tons (representing 1.0 percent) and 183,639 tons (2.0 percent), respectively, among total yields worth 9,185,889 tons in South Korea. Lettuce is affected by a combination of numerous elements such as varieties, cultivation methods and pests during each growth phase (Lee et al., 1999). It is mainly cultivated in spring and fall. Especially due to respiration rate after harvest leading to reduced quality and poor storage, maintaining annual supply is unavailable (Jang et al., 2018). With the distribution of new varieties, forcing culture and indoor insulated facilities for plant cultivation during winter, strawberries are produced every year except for late summer and early fall. Due to active respiration, transpiration, soft flesh and high water content, the fruit is vulnerable to go bad and got rotten compared to other fruits. Furthermore, it is difficult to maintain freshness due to the possibility of softening, discoloration and fungi (Lee et al., 2012). In this regard, developing improved storage and package techniques is needed to ensure maintaining quality and safety even just two to three days after harvest. In order to ensure improved quality and safety of strawberries and lettuce after harvest, the present study applied a modified atmosphere packaging (MAP) technology (Mostofi et. al., 2008). Going forward, it compared the quality and safety of the two products while being stored in a way that put them in an MAP-applied container and a plastic container at room temperature and 4 degree Celsius.

In this study, an appropriate modified atmosphere packaging (MAP) condition to minimize physiological disorders while lowering weight loss was sought. To reduce weight loss during storage, kimchi cabbages packed with 0, 32, 40, 48 perforated low-density polyethylene (LDPE) films, with a diameter of 14 mm, were stored in pallet units for 90 days at 1-2oC, and their loss rate, physiological disorders, total bacteria count, pH, and solid content were analyzed. It was found that as the number of holes increased, the weight loss ratio increased proportionally. However, the difference between the perforations was relatively small compared with the sample without film packaging. On the other hand, it was also observed that the lower the number of holes was, the lower the incidence of physiological disorder was because the cold air penetrated through the perforated hole while inhibiting physiological effects, releasing heat and carbon dioxide generated by respiration. Considering the weight loss rates and physiological disorders such as black speck and soft rot, the kimchi cabbage packed with 48 perforated films (73.9 cm2) exhibited the most satisfactory condition. Using this storage condition, along with 2-3oC temperature and 91-95% relative humidity inside the pallet, a highly suitable condition for kimchi processing was obtained to secure kimchi cabbage.

This study examined the combined effects of high hydrostatic pressure (HHP) and micro-perforated (MP) film packaging on the microbiological and physicochemical qualities of kimchi sauce stored under fluctuating temperature conditions. Before storage, treatment with 600 MPa HHP reduced the total lactic acid bacteria in the sauce samples to below the detection limit (1 log CFU/g). After 68-day storage, ten microbial strains isolated from the non-treated controls were identified as Pediococcus pentosaceus, whereas eight microbial strains isolated from the HHP-treated samples were identified as Bacillus spp., regardless of the packaging type. Additionally, the samples treated with HHP and packaged in a multilayer film bag (ML-HPP), as well as those in the MP-HHP group, exhibited higher pH values and reduced sugar content than the ML-control or MP-control after 68-day storage. No significant differences were observed between the control and treatment groups regarding their electrical conductivity, salinity, and CIE a* values at the end of storage. However, there was no O2 reduction or CO2 accumulation in the MP-HHP group after 68-day storage. These results indicate that the combination of HHP treatment and MP-film packaging can extend the kimchi sauce's shelf life without packaging expansion during long-term storage.