• 한국안전학회지
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• 제35권5호
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• pp.22-29
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• 2020

In this study, combustion and smoke release characteristics of a non-class 1E cable for nuclear power plants were investigated according to aging period. The aging was reproduced through an accelerated aging method for interval of 10 years :10, 20, 30 and 40 year, which was applied the Arrhenius equation. The cable was subjected to accelerated aging. In order to understand combustion and smoke release characteristics, the cone calorimeter test was performed according to the standard code of KS F ISO 5660-1. Heat release rate, mass loss rate, average rate of heat emission and smoke production rate were examined through cone calorimeter test. Fire performance index, fire growth index and smoke factor were derived from test results for the comparison of quantitative fire risk. When comparing the fire performance index and the fire growth index, the early fire risk tends to decrease as aging progresses, which might be attributed from the fact that the volatile substances of cables were evaporated. However, when comparing the heat release rate, average rate of heat emission and mass loss rate, which represent the mid and late periods of the fire risk, the values of accelerated aging cables were much higher than those of non-aged cable, which signifies the unstable formation of the char layer resulted in the change in the performance of flame retardants. In addition, the results from the smoke characteristics show that the accelerated aging cables were lager than the non-aged cables in terms of overall fire risk. These results can be used as baseline data when assessing fire risk of cables and establishing fire safety code for nuclear power plants.

• 전기학회논문지
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• 제62권7호
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• pp.987-993
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• 2013

Integrity of the control and instrumental cables in nuclear power plant is important to maintain the stability of the nuclear power plants. In order to diagnose the integrity of the cables, the diagnostic methods based on reflectometry have been studied. The reflectometry is a non-destructive method and it is applicable to diagnose the live cables. We introduce a Gaussian enveloped linear chirp reflectometry to diagnose the cables in the nuclear power plants. In this paper, we estimate the instantaneous frequency of the Gaussian enveloped linear chirp signal by using the weighted robust least squares filtering to localize the impedance discontinuities in the class 1E instrumental cable.

• 한국화재소방학회논문지
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• 제33권6호
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• pp.105-113
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• 2019

본 연구에서는 원자력발전소용 비안전등급케이블 2종(보안상 A사, B사로 지칭키로 함)을 대상으로 가속열화 기간에 따른 독성 특성을 분석하였다. NES 713 시험장비 및 규격에 의거하여 비노화, 20년, 40년으로 가속열화한 케이블에 대해 피복재 및 절연재로 구분하여 시험하였다. 시험결과 20년, 40년 가속열화 케이블의 독성지수가 비노화 케이블의 독성지수보다 높았으며 A, B사 케이블 공통적으로 20년 가속열화 케이블에서의 독성지수가 높게 산출되었다. 이는 급증한 일산화탄소의 방출량과 더불어 염화수소와 브롬화수소의 할로겐계 가스 방출량이 높은 것이 주된 원인으로 파악되었다. 또한, 피복재와 절연재를 구분하여 분석 시 A, B사 케이블 일부 피복재의 독성지수가 높게 나타났다. 또한, 피복재와 절연재의 독성지수를 구체적으로 분석하고자 미국 국방성 규격인 MIL-DTL을 적용하여 독성지수 허용치 초과 여부를 판단하였으며, 이 중 절연재의 경우 상당량 초과하여 방출되는 결과를 보였다.