• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1830-1837
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• 2023

The thermal cutting of contaminated or activated metals during decommissioning nuclear power plants inevitably results in the release of radioactive aerosol. Since radioactive aerosols are pernicious particles that contribute to the internal dose of workers, air conditioning units with a HEPA filter are used to remove radioactive aerosols. However, a HEPA filter cannot be used permanently. This study evaluates the efficiency and lifetime of filters in actual metal cutting condition using a plasma arc cutter and a high-resolution aerosol detector. The number concentration and size distribution of aerosols from 6 nm to 10 ㎛ were measured on both the upstream and downstream sides of the filter. The total aerosol removal efficiency of HEPA filter satisfies the standard of removing at least 99.97% of 0.3 ㎛ airborne particles, even if the pressure drop increases due to dust feeding load. The pressure drop and particle size removal efficiency at 0.3 ㎛ of the HEPA filter were found to increase with repeated cutting experiments. By contrast, the efficiency of used HEPA filter reduced in removing nano-sized aerosols by up to 79.26%. Altogether, these results can be used to determine the performance guidance and replacement frequency of HEPA filters used in nuclear power plants.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.149-157
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• 2003

원자력산업 분야의 공기정화장치에 사용되고 있는 HEPA 필터폐기물은 무게 약 20kg, 크기 $610{\times}610{\times}292mm$의 직육면체로써 무게에 비해 부피가 상대적으로 크다. 따라서 이는 방사성 폐기물의 임시저장 및 영구처분 시에 필요 이상의 많은 저장 공간을 차지하게 되고 관리에 따른 비용도 많이 소요된다. 각 국에서는 이런 HEPA 필터폐기물의 부피를 최소화하기 위해서 일반적으로 압축처리를 하고 있는데, 본고에서는 한국원자력연구소(KAERI)에서 개발한 HEPA 필터폐기물 압축처리장치의 특성을 소개하고 일본 및 미국의 압축처리장치와 비교 검토하였다.

• 환경위생공학
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• 제24권3호
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• pp.16-27
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• 2009

In this paper, I examined the level of fine dust in medical institutions, educational institutions and multi-purposed facilities to grasp the exact state of the present, and decided the level of air-borne particulate(KSM ISO Standard and ISO Standard 14644-1). We compared new proposed cleaner equipped with HEPA Filter with general cleaner and analyzed the rate of removal according to height, air volume and the equipment with the compulsive air intake. Through this comparison, I reached the conclusion as follows: 1. According to the examination, the fine dust of medical institutions, educational institutions and multi-purposed facilities in Kwang Ju is class 9. 2. The filter used in general cleaner on the market is that of HEPA-type, and its removal efficiency for fine particles($0.3{\sim}0.5{\mu}m$) is very low. 3. In the removal efficiency of new proposed cleaner equipped with HEPA Filter, the higher it is, the better, especially more than 180cm in height. 4. In case it is operated for 5 minutes under the condition of the space of $9.4m^{3}$ and the maximum air volume equipped with two induction pipes, we can keep the air cleanness level of 5 ~ 6. 5. To maintain the air cleanness for a long time, if we first operate for 5 minutes at maximum air volume and then operate at medium maximum air volume, we can keep the air cleanness with low energy.

• 한국기계연구소 소보
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• 통권18호
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• pp.49-54
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• 1988

• 토지주택연구
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• 제11권4호
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• pp.93-98
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• 2020

This study examined the particulate removal performance of three different types of air filters inside a heat exchanger. Of interest was the ability of each filter type in reducing the transmission of outdoor particulate matter of PM10 from entering an apartment while the heat exchanger was in operation. The study tested one commonly used medium filter (E11 grade) and two HEPA filters (H13 grade) of different thicknesses. Two different concentrations of particulate matter were used in the experiment to address different ambient air quality conditions in Korea, 32.75 ㎍/㎥ and 67.26 ㎍/㎥. Study results indicated that under the particulate matter concentration of 32.75 ㎍/㎥, all three filters were capable of removing more than 95% of the fine dust. However at a particulate matter concentration of 67.26 ㎍/㎥, the medium E11 grade filter was only able to remove about 90% of the particulates whereas the HEPA H13 grade filters were able to remove 95% or more of the particulates. The thicker HEPA filter (40T) was also more effective in removing particulates than the thinner HEPA filter (20T) by about 1.6 to 3 percentage points. Based on the findings of this study, it is recommended that HEPA filters of 20T thickness or greater be used during the high air pollution seasons of winter and spring in Korea while medium filters can be used during the other seasons to reduce outdoor air pollution transmission indoors.

• 대한설비공학회지:설비저널
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• 제15권2호
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• pp.123-143
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• 1986

• 공업화학
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• 제24권4호
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• pp.357-362
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• 2013

High efficiency particulate air (HEPA) 필터를 시험하기 위하여 단분산 polystyrene latex spheres (PLS) 및 PS-MPS/실리카복합 나노구체가 이용되었다. 사용된 모든 나노구체들은 필터시험 전에 평균입경과 변동계수 값을 측정하여 시험용 인조먼지로서 적정함을 평가하였다. PLS 및 복합 나노구체의 입경은 유화중합 중 반응온도와 안정제의 양을 조절하여 100~300 nm 범위에서 잘 조절되었으며, 변동계수의 경우도 단분산 입자분포로 판단되는 15%보다 낮은 3~7% 범위이었다. 한편 HEPA 필터시험 결과는 사용된 모든 나노구체들이 공기필터의 시험을 위한 시험용 인조먼지로서 아주 적절함을 보여주었다.

• 한국산학기술학회논문지
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• 제20권6호
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• pp.587-591
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• 2019

미세먼지는 대기를 타고 호흡기를 거쳐 폐 혹은 혈관에 침투 한다. 최근 미세먼지 문제 때문에 국내에 공기청정기 수요도 급증하고 있다. 이끼는 가장 오래된 지상식물로 중금속과 미세먼지를 흡착하여 분해하는 성질을 가지고 있는 것으로 알려졌고 본 연구진은 이를 활용하여 화학적 필터를 대체 할 수 있는 시스템에 대해 연구하였다. 이끼와 기존 화학적 필터(Hepa)의 미세먼지 감소 효과를 비교하기 위하여 $1m^3$의 큐브를 제작하고 통제된 환경하에서 미세먼지의 감소량을 비교하였다. 미세먼지 상황 하에서 이끼, 헤파, 무필터를 탑재한 공기정화 시스템을 각 30회씩 총 90회 가동 하였고 각각의 미세먼지 감소량 및 감소율을 비교한 결과 감소량은 미세먼지 이끼필터를 사용한 평균이 138.93으로 헤파필터를 사용한 평균 76.57과 무필터 상태의 평균인 0.10보다 유의하게 높았으며 감소율의 평균 역시 이끼필터를 사용한 경우 0.2379로 헤파필터를 사용한 경우의 0.1298이나 무필터인 0.0063보다 유의하게 높았다. 이 결과를 통해 이끼의 미세먼지 감소효과를 확인하였고 향후 개선을 통해 기존 공기정화기의 화학필터를 대체하거나 보조할 것으로 기대된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 춘계학술발표회요약집
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• pp.318-318
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• 1999

• 설비공학논문집
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• 제6권4호
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• pp.417-426
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• 1994

Filter media performance was evaluated using monodisperse NaCl particles with Differential Mobility Analyzer and Ultrafine Condensation Particle Counter. Low or medium performance filters show that the most penetrating particles size(MPPS) is around $0.3{\mu}m$ in diameter and is shifted to smaller sizes as the filter face velocity increases. However, HEPA and ULPA filters show MPPS is around $0.15{\mu}m$ in diameter and is also shifted to $0.1{\mu}m$ in diameter as the face velocity increases. In case of electret filter, the MPPS is found around $0.04{\mu}m$ region for Boltzmann charge equilibrium particles. There is a tendency of strong collection efficiency decrease for large particles as the face velocity increases on the contrary to the other filters. One of the medium performance filter efficiency was compared with filtration theory and the good agreetment was found in the experimental range.