Radioactive effluent discharged from the nuclear power plant (NPP) during normal operation is controlled by the discharge limit in terms of radioactivity concentration (Bq·m−3) and dose constraints in Korea. To ensure compliance with discharge limits of effluents, the licensee operates radioactive effluent monitoring systems in each discharge point to detect radioactivity and control discharge. The predetermined regulatory requirements of analytical sensitivities for sampling devices in the monitoring system are established in various countries to guarantee the performance of the monitoring systems. In Korea, Lower Limits of Detection (LLD) are selected as the regulatory requirements and adopted from the United States Nuclear Regulatory Commission (USNRC) NUREG-1301. The International Atomic Energy Agency stated that the detection limits have to be low enough (e.g., less than 1% of discharge limits) to safely demonstrate compliance with the discharge limits. However, no technical background of LLD has been explained regarding the compliance with discharge limits in Korea. Thus, it is necessary to analyze the compatibility of discharge limits and detection limits. The USNRC Regulatory Guide 1.21 has stated the risk-informed approach for effluent control by identifying the principal radionuclides whose radiological impact is more than 1% of discharge limits. In 2017, Cheong proposed the methodology and derived risk-based detection limits for liquid effluents from Korean NPPs. In 2019, Choi derived risk-based detection limits for liquid and gaseous effluents based on APR 1400 Design Control Document (DCD). The methodology of those studies can derive the detection limit for each principal radionuclide that is comparable to 1% to 10% of discharge limits. However, the previous study based on APR 1400 DCD was for the discharge limits of the US and didn’t consider the multiple discharge points in the reactor. Therefore, this study preliminarily derived the risk-based detection limits consistent with Korean Effluent Concentration Limits for gaseous effluents reflecting the characteristics of each discharge point. Also, this study confirmed the validity of risk-based detection limits and current LLD. This study is expected to be basic research for detection limits of Korean NPPs in line with international safety standards.

The purpose of this study identify that spinal decompression therapy effect on and pain, length Of leg distance(LLD), and muscle power and flexibility in patient with low back pain. The participants is 20 female and male with low back pain, and participant assign to decompression therapy group and control group at random. The decompression therapy apply to 20 minute 3 time for a week during 4 weeks. The Measurement items is pain, LLD, and muscle power, flexibility. The comparison between the before and after was Wilcoxon's U test, and 2 group after spinal decompression therapy application compared Mann-Whithney U test. Spinal decompression therapy reduced statistically significance the pain, LLD, and increased statistically significance the muscle power and flexibility increased the muscle power(p<.05). This study showed that spinal decompression therapy does affect pain, LLD, and muscle power and flexibility in patient with low back pain.