• 한국유체기계학회 논문집
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• 제17권6호
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• pp.104-108
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• 2014

The recent Fukushima nuclear power plant accidents shows that the core make up at high RCS pressure condition is very important to prevent core melting. The core make up flow at high pressure condition should be driven by gravity force or passive forces because the AC-powered safety features are not available during a Station Black Out (SBO) accident. The reactor Coolant System (RCS) mass inventory is continuously decreased by releasing steam through the pressurizer safety valves after reactor trip during a SBO accident. The core will be melted down within 2~3 hours without core make up action by active or passive mode. In the new design concept of a Hybrid Safety Injection Tank (Hybrid SIT) both for low and high RCS pressure conditions, the low pressure nitrogen gas serves as a charging pressure for a LBLOCA injection mode, while the PZR high pressure steam provides an equalizing pressure for a high pressure injection mode such as a SBO accident. After the pressure equalizing process by battery driven initiation valve at a high pressure SBO condition, the Hybrid SIT injection water will be passively injected into the reactor downcomer by gravity head. The SBO simulation by MARS code show that the core makeup injection flow through the Hybrid SIT continued up to the SIT empty condition, and the core heatup is delayed as much.

• 한국유체기계학회 논문집
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• 제10권5호
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• pp.20-26
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• 2007

Some gate valves are susceptible to pressure locking and thermal binding which prevent the safety function. The safety related gate valves susceptible to pressure locking and thermal binding shall be identified and taken preventive actions to ensure the safety function. The identification of the gate valves susceptible to pressure locking and thermal binding needs the evaluation of system design, valve and piping arrangement, test requirements, and operating conditions. Application of preventive methods should consider the system safety function, applicability, effectiveness, interface with system design, and cost. The selection procedure of valves susceptible to pressure locking and thermal binding can be effectively used in industry including nuclear power plants. In order to prevent the pressure locking, the hole can be drilled through the one disc of upstream side or down stream and the external equalizing line can be installed from bonnet to downstream or upstream. The double disc parallel seat valve type can be used instead of flexible wedge gate valve to prevent the thermal binding. The identification of gate valves susceptible to pressure locking and thermal binding, and preventive actions will meet the regulatory requirements and enhance the availability and safety of plants.

• 한국식품과학회지
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• 제20권6호
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• pp.845-849
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• 1988

저장실, 저장상자, 공기분배장치 등을 포함한 실험실 규모의 저장실을 설계, 제작하였다. 과실류를 수용할 수 있는 저장상자(1.7 l)는 투명아크릴을 재질로 일정 공기가 계속해서 순환되도록 하고 저장실은 $0{\sim}30^{\circ}C$ 범위내에서 ${\pm}0.5^{\circ}C$의 정확도로 온도제어가 가능하였다. 저장상자로 유입되는 공기는 공기분배 장치를 통하여 예냉과 공기압의 균일화가 이루어지도록 하였고 Solenoid valve를 사용한 저장상자 선택장치를 제작하였다. 이와 같은 저장시설의 환경제어와 계측을 전담할 수 있는 마이크로프로셰서 시스템을 8 bit 마이크로프로쎄서와 기억장치, 그리고 입출력장치 등의 IC chip을 이용하여 설계 제작하였다. 동 시스템을 활용하기 위하여 저장환경의 제어를 위한 소프트웨어를 개발하고 운영프로그램을 ROM화 할 수 있었다. 제작된 저장 자동제어장치 시스템을 이용 밀감류 저장에 적용하여 저장시설의 운영 및 온도의 자료수집을 성공적으로 수행할 수 있었다.