As part of strengthening pyro safety measures, the Korea Atomic Energy Research Institute is developing LIBS (Laser-Induced Breakdown Spectroscopy) application technology to analyze molten salt components in electrolytic recovery device in real time. LIBS performs qualitative and quantitative analysis by analyzing the spectrum of energy emitted by atomizing and ionizing elements on the surface of a salt sample with a high-focused laser. Since salt easily corrodes metal, it must be managed in an environment with a dew point of -40°C or lower. In this study, we designed and manufactured a device that places a rod-type sampling stick on a mounting base, automatically moves it to the optimal measurement position for LIBS, and retrieves the sample. Its characteristics are as follows. First, LIBS is stationary and does not move. Second, the sample stick is placed on a mounting base and can rotate 360 degrees. Third, according to the command, the sample stick automatically moves to the optimal measurement position of LIBS with three degrees of freedom (X, Y, Z). Fourth, the salt attached to the sampling stick is recovered for chemical analysis by driving the gripper mounted at the bottom of the Z axis, Z axis, and rotation axis (R). The X, Y, and Z movement distances of this device are each 100 mm, rotation is 360 degrees, grip stroke is 50 mm, and position accuracy is ±20 m. Once the performance test of the automated salt sample analysis device is completed, it will be installed in a dry room with a dew point of - 40°C or lower. Samples will be collected remotely in connection with the electrolytic recovery device and gantry robot built in the dry room. We plan to conduct experiments to seat the sample stick. Ultimately, we plan to conduct comprehensive experiments in conjunction with LIBS.

The nuclear facilities at Korea Atomic Energy Research Institute (KAERI) have generated a variety of liquid radioactive waste and most of them have low-level radioactive or lower levels. Some of the liquid radioactive waste generated in KAERI is transported to Radioactive Waste Treatment Facility (RWTF) in 20 L container. Liquid radioactive waste transported in a 20 L container is stored in a Sewer Tank after passing through a solid-liquid separation filter. It is then transferred to a very low-level liquid radioactive waste Tank after removing impurities such as sludge through a pre-treatment device. The previous pre-treatment process involved an underwater pump and a cartridge filter device passively, but this presented challenges such as the inconvenience of having to install the underwater pump each time, radiation exposure for workers due to frequent replacement of the cartridge filter, and the generation of large amounts of radioactive waste from the filter. To address these challenges and improve efficiency and safety in radiation work, an automated liquid radioactive waste pre-treatment device was developed. The automated liquid radioactive waste pre-treatment device is a pressure filtration system that utilizes multiple overlapping filter plates and pump pressure to effectively remove impurities such as sludge from liquid radioactive waste. With just the push of a button, the device automatically supplies and processes the waste, reducing radiation hazards and ensuring worker safety. Its modular and mobile design allows for flexible utilization in various locations, enabling efficient pre-treatment of liquid radioactive waste. To evaluate the performance of the newly constructed automated liquid radioactive waste treatment device, samples were taken before and after treatment for 1 hour cycling and analyzed for turbidity. The results showed that the turbidity after treatment was more than about four times lower than before treatment, confirming the excellent performance of the device. Also, it is expected that the treatment efficiency will improve further as the treatment time and number of cycles increase.

본 실험은 토마토(Solanum lycopersicum L. ‘Hoyong’ ‘Super Doterang’) 암면재배에서 배지 전체의 정전용량을 측정할 수 있는 장치(Substrate capacitance measurement device, SCMD)를 기반으로 한 적정 급액 방법을 구명하기 위하여 누적일사량 제어구(Integrated solar radiation automated irrigation, ISR)와 물관수액흐름 제어구(sap flow automated irrigation, SF)를 대조구로 비교하면서 봄부터 여름철과 겨울철에 재배를 실시하였다. SCMD 제어구는 급액 개시 후 배지 한 개당 설정된 배액 목표량이 처음 발생하는 시점까지 10분간격으로 급액하였고 첫 배액이 배출되면 그 때의 배지의 정전용량(Capacitance)을 100%로 간주하고 그 기준치의 급액제어 점(Capacitance threshold, CT)에 도달하면 급액 되었고 그 뒤 목표 배액량이 발생하면 급액이 멈추는 방식으로 제어되었다. 봄부터 여름재배에서 실험 처리를 위해 SCMD제어구의 일회 급액량 (Irrigation volume per event)을 50, 75, 또는 100mL로 설정하였고 겨울철 재배에서는 CT가 0.65, 0.75, 또는 0.90가 되면 급액 되도록 설정하였다. 봄부터 여름철 재배에서 일회 급액량을 50, 75, 100mL로 설정하였을 때 급액 횟수는 각각 39, 29, 19회 였고 배액율은 각각 3.04, 9.25, 20.18%였다. 겨울철 재 배에서 CT를 0.65, 0.75, 0.90로 설정하였을 때 급액횟수는 각각 5.67, 6.50, 14.67회였고 배액율은 9.91, 10.78, 35.3%였다. 봄부터 여름철 재배에서 일회 급액량 처리에 따른 물관수액흐름속도(SF) 변화는 1회 급액량과 배액량을 각각 50과 75mL로 제한한 경우 100mL로 제 한한 경우와 비교하여SF 신호가 외부 광량 신호 (SI) 보다 늦어지는 경향(time lag)을 보였고 겨울철 재배에서 CT를 0.65로 설정한 경우는 물관수액흐름 속도나 함수율이 매우 낮아졌고 CT를 0.90로 설정한 경우는 함수율과 물관수액흐름 속도는 매우 높았으나 많은 배액이 배출되었다. 따라서 토마토 봄부터 여름철 재배에서 SCMD를 활용하여 CT를 0.9로, 배지 한 개당 배액 목 표량을 100mL로 설정하였을 때 일회 급액량은 75~100mL 범위가 적합하고 겨울철 재배에서는 1회 급 액량을 75mL로, 배액 목표량을 70mL로 설정하였을 때 CT는 0.75이상 0.9이하 범위가 적합할 것으로 판단되었다. 앞으로 정전용량 값과 배지 용적수분함량의 관계성을 구명하고 보정계수를 구하는 연구가 필요할 것으로 판단된다.