For safeguarding dry storage facilities, a tomography system based on fast and thermal neutron detection was studied in Korea Institute of Nuclear Nonproliferation and Control. The study was conducted laboratory-scale experiments based on a custom built 1/10th scale model cask, He-4 gas scintillation detector array, and multiple 252Cf sources. A filtered back projection (FBP) was utilized to obtain the cask image via MATLAB. The Ram-Lak filter (ramp filter) was employed in FBP for improved the reconstructed image quality. The Ram-Lak filter is the increasing amplitude filter due to the increasing spatial frequency of the image. In spatial frequency, the frequency of brightness change in the low-frequency region is relatively low, and the frequency of brightness change in the highfrequency region is large. Thus, the high-frequency region in the neutron tomographic image is near the neutron sources and the cask, and the low-frequency region is outside of the cask and/or between the source and cask in the study. In order to apply the ramp filter, a Fourier transform is initially performed on projection data, and image reconstruction is performed with the corrected projection data. In this case, the filter is linearly changed. Therefore, a small filter value is applied at lower spatial frequencies to reduce the projection data, and a large filter value is applied at high spatial frequencies to reduce the projection data. The filter scale is a fraction of frequency amplitude, and the filter value applied to the projection data is determined according to the filter scale. This study was conducted for discussion of the image quality due to the effect of the filter scale used for image reconstruction of a neutron tomography system. The results show that in the experiment with one source, the source location was founded when we used the frequency scale of 0.5 and over. In the double or triple source experiment, the source locations and relative activities were found when we used a filter scale of 0.4 to 0.6. When the filter frequency scale of 0.7 to over, the relative activities are hard to know. It can be found that if the filter value is too large or too small, distortion may occur in the reconstruction results. Therefore, it seems reasonable to set a value between 0.4 and 0.6 as the scaling factor for the neutron tomography system. In the future, additional comparative studies will perform validation of the frequency scaling methods.

For spent nuclear fuel transferred to dry storage facilities, it is difficult to apply safeguards approaches and long-term integrity verification due to the structural characteristics of the facility. There is a need to check the integrity of the nuclear fuel assembly before transferring it to a dry storage facility and are need to provide information on whether there are any defects. At the Korea Institute of Nuclear Nonproliferation and Control, as a non-destructive testing technology for ensuring Continuity of Knowledge (CoK) of the dry storage facilities, a methodology for reconstructing images by neutron tomographic technique from spent nuclear fuel using a He-4 gas scintillation detector was presented. It is thought that the He-4 gas scintillation detector-based technology can be used to verify the defect of the nuclear fuel assembly. This methodology must be accompanied by accurate neutron measurements. The place where the technique was conducted is surrounded by a concrete wall. Concrete contains water molecules, which can affect neutron measurements. In this study, reconstruction images based on neutron measurements and MCNP simulations are compared to verify the effects of the concrete. Neutron measurements were performed by measuring Cf-252 neutron sources in a 1/10 lab-scale TN- 32 cask with six He-4 gas scintillation detectors as an array. Neutron sources are fixed at each point in the cask, and the He-4 detector array is rotated from 0° to 360° at 10° intervals to reconstruct the image using the filtered back-projection (FBP) method. Also, in MCNP reconstructed images, there are two versions depending on whether concrete wall. The source image and ring shape were found in the measurement-based thermal neutron reconstruction image, which was similar to the simulation image that considering the concrete effects. On the other hand, in the simulation reconstruction image without the concrete, only the shape of the source was found. Thus, the effect of concrete should be considered when performing the neutron tomographic techniques using He-4 gas scintillation detectors.

The Republic of Korea is expected to participate in the denuclearization verification activities by the International Atomic Energy Agency (IAEA) in case any neighboring countries declared denuclearization. In this study, samples for the verification of nuclear activities in undeclared areas were selected for the denuclearization of neighboring countries, and the appropriateness of the procedures was considered. If a country with nuclear weapons declares denuclearization, it must be accompanied by the IAEA’s verification regarding nuclear materials and weapons in the declared and undeclared areas. The analysis of the process samples or on-site environmental samples and the verification of undeclared nuclear facilities and materials aid in uncovering any evidence of concealment of nuclear activity in undeclared areas. Therefore, a methodology was established for effective sampling and analysis in accordance with proper procedures. Preparations for sampling in undeclared areas were undertaken for various potential scenarios, such as, the establishment of zones according to radiation dose, methods of supplying electricity, wireless communication networks, targets of sampling according to characteristics of nuclides, manned sampling method, and unmanned sampling method. Through this, procedures were established for pre- and post-site settings in preparation for hazards and limiting factors at nuclear inspection sites.

A new Asiatic lily cultivar “Fantasia” was derived from a cross between “Gran-paradiso” and line “No. 96-13” made in 1997. The cultivar was selected mainly for cut flower. “Gran-paradiso” is a orange red cultivar, while “No. 96-13” is a red-purple colored hybrid line. The selection and the survey for the flower characteristics were conducted from 1998 to 2005 in vinyl tunnels and greenhouses of National Institute of Highland Agriculture. The flowering date of “Fantasia” is July 22. The flower has no fragrance and its medium sized flower is 13.4 cm in width. The orange (O28A) colored petals have no spots. The bulb weight of “Fantasia” is about 68 g and its bulb size is about 18.6 cm in circumference.

A new Asiatic lily cultivar “Dajeong” was derived from a cross between “Prato” and “Positano” made in 1997. The cultivar was selected mainly for cut flower. Both “Prato” and “Positano” are well known for their flower color of orange red and yellow, respectively. The selection and the survey for the flower characteristics were conducted from 1998 to 2005 in vinyl tunnels and greenhouses of National Institute of Highland Agriculture. The flowering date of “Dajeong” is July 23. The flower has no fragrance and its medium sized flower is 12.0 cm in width. The medium orange and yellow (ON25 + YO23B) colored petals have no spot. The bulb weight of “Dajeong” is about 55.4 g and its bulb size is about 16.4 cm in circumference.

“Miso”, A new Asiatic lily cultivar was derived from a cross between “Kinks” and a line “A61” made in 1997. Both “Kinks” and “A61” are yellow flower cultivars, while “A61” is a hybrid line. The cultivar was selected mainly for cut flower. The selection and the survey for the flower characteristics were conducted from 1998 to 2005 in vinyl tunnels and greenhouses of National Institute of Highland Agriculture. The flowering date of “Miso” is July 26. The flower has no fragrance and its medium sized flower is 13.7 cm in width. The yellow (Y9A) petal have no spot. The bulb weight of “Miso” is about 42 g and its bulb size is about 15 cm in circumference.