로봇청소기를 활용한 바닥의 방사성 표면오염 제거 가능성 평가

초록

Radioisotopes are used in various fields, and handling mistakes can cause radioactive liquidcontamination on laboratory floors. Such contamination requires rapid decontamination; however, conventionalmanual decontamination is labor-intensive and poses a radiation exposure risk to workers. Therefore, this studyaims to evaluate the feasibility of decontaminating radioactive surface contamination using a robot vacuum cleaner. Surface contamination levels in the contaminated area were confirmed using a portable survey meter with an externaldetector, and decontamination was performed in the mopping mode of a pad-replacement robot vacuum cleaner; aftermapping the contaminated area, the designated zones were cleaned repeatedly. After each cycle, the used cleaningpad was collected and measured for 10 min with a gamma counter, and decontamination was repeated until no furtherdecrease in pad radioactivity was observed. The contaminating radionuclides were identified as 177Lu and 131I. Afterrepeated decontamination, radioactivity decreased from 1,472 to 21 Bq in Zone A after 20 cycles (98.57%), from51,485 to 38 Bq in Zone B after 100 cycles (99.93%), and from 10,826 to 66 Bq in Zone C after 150 cycles. In allthree zones, the decontamination effect was pronounced during the early cycles, and the magnitude of reductiongradually became more modest in later cycles. Although the contamination level could not be reduced to below theregulatory limit for allowable surface contamination, an average decontamination rate of 98.5% was achieved afterapproximately 20 cycles, confirming a measurable contamination-reduction effect. Therefore, a robot vacuum cleanercould be considered a practical option for repeated decontamination of radioactive contamination on laboratoryfloors, potentially substituting for manual decontamination.

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