• Nuclear Engineering and Technology
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• 제56권2호
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• pp.389-401
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• 2024

In recent decades, numerous instances of blockages have been reported in coastal nuclear power plants globally, leading to serious safety accidents such as power reduction, manual or automatic power loss, or shutdown of nuclear power units. Loss or shortage of cooling water may compromise the reliability of the cooling water system, thus threatening the operational safety of power plants and resulting in revenue reduction. This study provides a comprehensive review of the current state of cooling water system safety in coastal nuclear power plants worldwide and the common challenges they face, as well as the relevant research on cooling water system safety issues. The research overview and progress in investigation methods, outbreak mechanisms, prevention and control measures, and practical cases of blockages were summarized. Despite existing research, there are still many shortcomings regarding the pertinence, comprehensiveness and prospects of related research, and many problems urgently need to be solved. The most fundamental concern involves understanding the list of potential risks of blockages and their spatially distributed effects in surrounding waters. Furthermore, knowledge of the biological cycles and ecological habits of key organisms is essential for implementing risk prevention and control and for building a scientific and effective monitoring system.

• 방사성폐기물학회지
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• 제17권4호
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• pp.363-373
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• 2019

Waste characterisation associated with nuclear site decommissioning relies on radiochemical analysis of a diverse range of sample types, requiring extensive validation of analytical techniques using matrix-matched materials. The absence of relevant reference materials has hindered robust method development and validation. The paper discusses how method validation in support of nuclear waste characterisation can be achieved without using reference materials. The key stages in an analytical procedure are evaluated and a multi-stage approach is proposed with the ultimate aim of determining an operational envelope for an analytical procedure.

• 한국해안·해양공학회논문집
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• 제28권6호
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• pp.350-360
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• 2016

겨울철 해운대 해역에서 발생하는 파랑 및 흐름에 대한 공간적 변화특성을 살펴보기 위하여, 평면 2차원 파랑변형 모델(SWAN)과 수심평균 2차원 해수유동 모델(Delft3D)을 사용하여 수치실험을 수행하였다. 2014년 2월 중 해운대 여러 정점에서 관측한 현장자료를 사용하여 수치모델을 검증하였다. 두 모델의 보정결과로부터 발견된 파랑 및 흐름의 특징 중 하나는, 해저면에 곳곳에 돌출되어 자리잡고 있는 암반지형의 영향으로 파고 및 파향 뿐만 아니라 유속 및 유향도 만내로 들어올수록 외해역과 다르게 크게 변형되어 나타난다는 것이다. 두 모델의 커플링을 통하여 겨울철 입사파를 고려한 연안 해수유동 모델링 결과, 해안선 인근 천해에서는 겨울철에 발생하는 동쪽(E)계열의 입사파의 영향으로 파고가 높을수록 동에서 서로 흐르는 연안류도 크게 발달하고 조석에 의한 조류의 세기는 상대적으로 약한 것으로 나타났다.

• 한국연안방재학회지
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• 제4권1호
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• pp.7-19
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• 2017

In this study, waves and currents observed by acoustic AWAC, VECTOR and Aquadopp Profiler in Anmok coastal waters were analysed to account for the variability of wave and current and to understand the mechanism of sediment transport generated by wave-induced current in the surf-zone. The monthly variation of wave and residual currents were analysed and processed with long-term observed AWAC data at station W1, located at the water depth of about 18m measured during from February 2015 to September 2016. Wave-induced currents were also analysed with intensive field measurements such as wave, current, suspended sediment, and bathymetry data observed at the surf-zone during in winter and summer. The statistical result of wave data shows that high waves coming from NNE and NE in winter (DEC-FEB) are dominant due to strong winds from NE. But in the other season waves coming from NE and ENE are prevalent due to the seasonal winds from E and SE. The residual currents with southeastern direction parallel to the shoreline are dominant throughout a year except in winter showing in opposite direction. The speed of ebb-dominant southeastern residual currents decreasing from surface to the bottom is strong in summer and fall but weak in winter and spring. By analysing wave-induced current, we found that cross-shore current were generated by swell waves mainly in winter with incoming wave direction about $45^{\circ}$ normal to the shoreline. Depending on the direction of incoming waves, longshore currents in the surf-zone were separated to southeastern and northwestern flows in winter and summer respectively. The variation of observed currents near crescentic bars in the surf-zone shows different direction of longshore and cross-shore currents depending on incoming waves implying to the reason of beach erosion generating the beach cusp and sandbar migration during high waves at Anmok.

• 한국해양학회지:바다
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• 제22권3호
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• pp.103-117
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• 2017

이 노트는 국립해양조사원이 5년(2012~2016년)간에 걸쳐 지역해(동해, 황 동중국해) 수치예측시스템을 구축하여 자동으로 끊임없이 운영하면서 확보한 기술들 중 다음 3가지를 담고 있다. (1) 끊임없이 3일 해양예측 자료를 생산하기 위한 전략, (2) 매일 특정시각에 외부 해양 기상자료(HYCOM, NOAA/NCEP GFS)를 안정적으로 내려 받는 방법과 (3) 해양예측시스템 운영자들이 휴대전화 단문 메시지 서비스(Short Message Service)를 이용하여 해양예측시스템 수행 시 발생하는 시스템 오류를 신속하게 파악할 수 있는 기능에 관하여 기술하였다. 이들 기본 기술과 운영시스템 구성의 기본 개념은 지역해와 연안 해양 수치예측시스템을 자동으로 운영하는 체계를 구축하는 데 있어서 유용하게 사용될 것이다.

• 대한원격탐사학회지
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• 제10권2호
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• pp.83-107
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• 1994

Sea surface temperatures (SSTs) estimated by using the operational SST derivation equations of NOAA/NESDIS were compared with satellite-tracked drifter temperatures. As a result of eliminating cloud-filled or contaminated pixels through several cloud tests, 69 matchup points between the drifter temperatures and the SSTs estimated with NOAA satellite 9, 10. 11 and 12 data from August, 1993 to July, 1994 were collected. Multi-channel sea surface temperature(MCSST) using a split window technique showed an approximately $1.0{\circ}C$ rms error as compared with the drifting buoy temperatures for 69 coincidences. Accuracies for satellete-derived sea surface temperatures were evaluated for only NOAA-11 AVHRR data which had relatively large matchups of 35points as compared with other satellites. For the comparison of the oberved temperatures with the calculated SSTs, linear MCSST and nonlinear cross product sea surface temperature(CPSST) algorithms by the split, the dual and the triple window technique were used respectively. As a result, the split window CPSSTs showed the smallest rms error of $0.72{\circ}C$. Defferences between the split window SSTs and the drifter temperatures appeared th have a linear tendency against the drifter temperatures and also against the differences between AVHRR channel 4 and 5 brighness temperatures. This indicates some possibilities that satelite-derived SSTs operationally calculated from the NOAA/NESDIS equation in the seas around Korea have been underestimated as compared with actural SSTs in case sea water temperature is relatively low or the atmosphere over the sea surface is very dry like in winter, while overstimated in case of high temperature or very moist atmospheric equations based on local sea measurements around Korea instead of global measurements should be derived.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.104-107
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• 2005

COMS(Communication, Ocean, and Meteorological Satellite) is the geostationary satellite for the mission of satellite communication, ocean monitoring, and meteorological service. It is scheduled to be launched at the end of 2008. Ocean payload of COMS named as GOCI(Geostationary Ocean Color Imager) observes ocean color and derives the chlorophyll concentrlition, the concentration of dissolved organic material and so on. In operational oceanography, satellite derived data products are used to provide forecasting and now casting of the ocean and coastal water state. In this work, conceptual design of structural part of GOCI is carried out and two baseline concepts are proposed. The one is dioptric module that uses lens system and the other is TMA(Three Mirror Anastigmat) module that uses mirror system. Trade-off studies between two concepts are investigated by considering optical and mechanical performances. Finally, on-going tasks and future development plan are briefly discussed.

• Ocean and Polar Research
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• 제23권2호
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• pp.189-194
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• 2001

A practical algorithm for prediction of the sea surface temperatures (SST)from the satellite remote sensing data is presented in this paper. The fluctuations of SST consist of deterministic normals and stochastic anomalies. Due to large thermal inertia of sea water, the SST anomalies can be modelled by autoregressive or Markov process, and its near future values can be predicted provided the recent values of SST are available. The actual SST is predicted by superposing the pre-known SST normals and the predicted SST anomalies. We applied this prediction algorithm to the NOAA AVHRR weekly SST data for 18 years (1981-1998) in the seas adjacent to Korea (115-$145^{\circ}E$, 20-$55^{\circ}N$). The algorithm is applicable not only for prediction of SST in near future but also for nowcast of SST in the cloud covered regions.

• 한국수산과학회지
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• 제38권5호
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• pp.323-330
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• 2005

Monthly distributions of fishing boats at night in the East Sea are described, using defense meteorological satellite program (DMSP)/operational linescan system (OLS) images and common squid (Todarodes pacificus) catches data. We also estimated temperature in 50m, which is main catch depth of the squid, by MCSST (multi-channel sea surface temperature). We examined DMSP/OLS, MCSST and other observation data from 1993 to 2000. We assumed that squid were caught in areas where fishing boats were located. Fishing boats at night appeared only near the Korea/Tsushima Strait from January to March. Fishing boats moved to the northward from April to Jun, distribution of fishing boats in spring appeared greater than those in winter. In summer (July-September), center of fishing grounds was formed near the Uleung Island in the south east coast of Korea. The north-south distribution range of fishing boats in October appeared to be greater than that in other months. In particular, we estimated main season of squid catches based on distribution range reflecting the number of fishing boats of north-south and east-west directions from September to December. Relationship between satellite estimate SST and in situ SST showed high correlation (0.91). The correlation between the SST and 50m depth temperature, estimated based on the satellite SST, was relatively high in February, April and October.

• 한국해양학회지:바다
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• 제5권1호
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• pp.10-15
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• 2000

기후변동에 따른 해양생태계의 변화를 예측하기 위한 국제 연구 프로그램인 Global Ocean Ecosystem Dynamics (GLOBEC)은 해양의 탄소순환을 집중적으로 연구한 Joint Global Ocean Flux Study(JGOFS)의 후속조치로서, 이 논문에서는 GLOBEC 프로그램의 목적, 방향, 실천계획, 체제를 정리하였다. 해양과학위원회(SCOR)와 정부간해양위원회(IOC)의 후원을 동시에 받고 있는 대형과학프로그램인 GLOBEC은 기후변화에 따른 생태계의 중위 및 상위포식자의 반응에 대한 연구이며, GLOBEC 과학집행위원회는 연구를 수행하기 위한 실천계획을 1999년에 수립하였다. GLOBEC 프로그램은 국제생지권프로그램(IGBP)의 핵심과제로 지정되어 향후 10년 동안 지속될 것이며, 구체적으로 4개의 연구 초점, 체제구축활동, 지역프로그램, 종합화 등으로 구성되어 있다. 가장 중요한 연구활동인 4개의 연구초점은 다음과 같다: 과거자료분석(Retrospective analyses), 과정 연구(Process studies), 예측과 모델링(Predictive and modelling capability), 되먹임(Feedbacks). 현재, 남극해 GLOBEC(SO-GLOBEC), 소형표층어류와 기후변화(SPACC), 대구와 기후변화(CCC), 기후변화와 환경수용력(CCCC)의 4개 국제적 지역프로그램이 있으며, 이들은 모두 우리나라 해양 및 수산연구와 밀접한 관련이 있다. 미국, 일본 등의 9개국은 국가프로그램을 운영하고 있으며, 이 수효는 점차 증가할 전망이다.