• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.279-287
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• 2020

Recently, interest in radiation protection is increasing because of the occurrence of accidents related to exposure dose. So, the nuclear safety act provides to install the shields to avoid exceeding the dose limit. In particular, when the worker conducts the non-destructive testing (NDT) without the fixed shielding structure, we should monitor the access to the workplace based on a constant dose rate. However, when we apply for permits for NDT work in these work environments, the consideration factors to the estimation of the distance and exposure dose are not legally specified. Therefore, we developed the excel model that automatically calculates the distance, exposure dose, and cost if we input the factors. We applied the assumption data to this model. As a result of the application, the distance change rate was low when the thickness of the lead blanket and collimator is above 25 mm, 21.5 mm, respectively. However, we didn't consider the scattering and build-up factor. And, we assumed the shape of the lead blanket and collimator. Therefore, if we make up for these limitations and use the actual data, we expect that we can build a database on the distance and exposure dose.

• Nuclear Engineering and Technology
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• v.26 no.2
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• pp.324-336
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• 1994

경수로형 원전에서 발생되는 작업종사자에 대한 피폭선량의 약90%는 1차계통내 재질성분으로부터 방사화되는 코발트 핵종에 기인한다. 원전 선진국에서는 이러한 코발트 생성원을 근원적으로 제거하여 1차계통내 방사선량을 획기적으로 감소시킬 목적으로 Co reduction program을 중점적으로 추진하여 왔으며, 이중 계통내 코발트 주생성원인 각종 밸브재질을 저 Co 또는 Co-free 합금으로 대체시키는 기술이 이미 상당한 수준에 이르렀다. 국내의 건설예정 원전에 있어서도 이러한 기술개발의 적용에 대한 검토가 요구되고 있는 점을 미루어 볼 때, 머지 않은 장래에 국내 원전에 대한 이 기술의 적용이 불가피할 것으로 보여진다. 본 기고문에서는 원전 1차계통내 밸브의 코발트 합금재질 대체기술과 관련된 내용을 중점적으로 소개, 검토하고자 한다.

• Radioisotope journal
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• v.12 no.3
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• pp.92-100
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• 1997

• Radioisotope journal
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• v.16 no.3
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• pp.83-88
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• 2001

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.4
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• pp.381-390
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• 2017

In Korea, commercial nuclear power plants and research reactors have on-site storage systems for the spent nuclear fuel, but it is difficult to expand the facilities used for the storage systems. If decommissioning of nuclear power plants starts, an amount of high level radioactive waste will be generated. In this study, a radiological impact assessment of the railroad transport of high level radioactive waste was carried out considering radiation workers and the public, using the developed transport container as the transport package. The dose rates for workers and the public during the transport period were estimated, considering anticipated transport scenarios, and the results compared with the regulatory limit. A sensitivity analysis was also carried out by considering the different release ratios of the radioactive materials in the high level radioactive waste, and different distances between the transport container and workers during loading and unloading phases and while attaching another freight car. For all the anticipated transport scenarios, the radiological impacts for workers and the public met the regulatory limits.

• Journal of the Korean Society of Radiology
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• v.6 no.4
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• pp.281-290
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• 2012

The difference of radiation dose of MDCT due to different protocols between hospitals was analyzed by CTDI, DLP, the number of Slice and the number of DLP/Slice in 30 cases of the head, the abdomen and the chest that have 10 cases each from MDCT examination of the department of diagnostic imaging of three general hospitals in Gyeongsangbuk-do. The difference of image quality, CTDI, DLP, radiation dose in the eye and radiation dose in thyroid was analyzed after both helical scan and normal scan for head CT were performed because a protocol of head CT is relatively simple and head CT is the most frequent case. Head CT was significantly higher in two-thirds of hospitals compared to A hospital that does not exceed a CTDI diagnostic reference level (IAEA 50mGy, Korea 60mGy) (p<0.001). DLP was higher in one-third of hospitals than a diagnostic reference level of IAEA 1,050mGy.cm and Korea 1,000mGy.cm and two-thirds exceeded the recommendation of Korea and those were significantly higher than A hospital that does not exceed a diagnostic reference level (p<0.001). Abdomen CT showed 119mGy that was higher than a diagnostic reference level of IAEA 25mGy and Korea 20mGy in one-third. DLP in all hospitals was higher that Korea recommendation of 700mGy.cm. Among target hospitals, C hospital showed high radiation dose in all tests because MPR and 3D were of great importance due to low pitch and high Tube Curren. To analyze the difference of radiation dose by scan methods, normal scan and helical scan for head CT of the same patient were performed. In the result, CTDI and DLP of helical CT were higher 63.4% and 93.7% than normal scan (p<0.05, p<0.01). However, normal scan of radiation dose in thyroid was higher 87.26% (p<0.01). Beam of helical CT looked like a bell in the deep part and the marginal part so thyroid was exposed with low radiation dose deviated from central beam. In addition, helical scan used Gantry angle perpendicularly and normal scan used it parallel to the orbitomeatal line. Therefore, radiation dose in thyroid decreased in helical scan. However, a protocol in this study showed higher radiation dose than diagnostic reference level of KFDA. To obey the recommendation of KFDA, low Tube Curren and high pitch were demanded. In this study, the difference of image quality between normal scan and helical scan was not significant. Therefore, a standardized protocol of normal scan was generally used and protective gear for thyroid was needed except a special case. We studied a part of CT cases in the local area. Therefore, the result could not represent the entire cases. However, we confirmed that patient's radiation dose in some cases exceeded the recommendation and the deviation between hospitals was observed. To improve this issue, doctors of diagnostic imaging or technologists of radiology should perform CT by the optimized protocol to decrease a level of CT radiation and also reveal radiation dose for the right to know of patients. However, they had little understanding of the situation. Therefore, the effort of relevant agencies with education program for CT radiation dose, release of radiation dose from CT examination and addition of radiation dose control and open CT contents into evaluation for hospital services and certification, and also the effort of health professionals with the best protocol to realize optimized CT examination.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.191-192
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• 2011

X선 촬영을 통한 집단 건강검진은 경제성, 신속성, 대량처리 능력을 충족시키고 있으며 찾아가는 이동 의료서비스에서 중요한 부분을 차지하고 있다. 이와 함께 X선 촬영을 통한 집단 건강검진 시스템도 발전하여 간접촬영방식에서 Digital Radiography를 이용한 직접촬영방식으로 기술력이 향상되었고 이로써 검진차량에서 검진을 받는 환자나 종사자들에 대한 피폭선량의 증가하고 있으나 차량 외부의 누설방사선량에 대한 조사는 아직도 미미하다 할 수 있다[1]. 이에 본 연구에서 실험을 통한 결과는 다음과 같이 나타났다. 누설방사설량이 가장 많이 발생하는 곳은 출입문과 후면(검출기)에서는 우측, 양측면에서는 중앙이 가장 많은 누설방사선량이 나타났고, 측정위치별로는 검출기가 인접한 후면에서 누설방사선량이 가장 높았다. 기준치에 크게 벗어나지는 않았지만 누설방사선량은 다양하게 나타났다. 특히 후면에서의 누설방사선량은 기준치를 크게 웃돌아 방사선 차폐시설이 잘 갖추어지지 않은 것을 알 수 있으며 향후 이동검진차량의 방사선 차폐시설을 갖추는데 있어 각별한 관심이 필요하리라 사료된다.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.88-89
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• 2009

• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.207-213
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• 2003

Carbon-14 is one of the major radionuclides released by CANDU Nuclear Power Plants(NPPs). It is almost always emitted as gas through the stack. From CANDU NPPs about 95% of all carbon-14 is released as carbon dioxide. Carbon-14 is a low energy beta emitter which, therefore, gives only a small skin dose from external radiation. As carbon dioxide Is physiologically rather inert gases for man's metabolism, the inhalation dose is probably less than 1 % of the ingestion dose. But this source of carbon-14, formed in a closed, nor-oxidative environment, was subsequently released into the workplace as an insoluble particulate when these systems were opened lip for re-tubing at CANDU NPPs. As a part of the improvement of dosimetry program at Wolsong Nuclear Power Plants, the carbon-14 metabolism based on references was investigated and studied to setup the internal dosimetry program due to inhalation of carbon-14.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.250-251
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• 2004

하나로(HANARO) 수조고온층 정화 계통은 수조고온층에 유입되는 원자로 수조수의 방사성 이온을 거르는 장치이다. 주기적인 수조고온층 계통의 이온교환수지 교체 및 폐기물 처리 작업은 원자로실에서 행하는 작업 중 방사선 피폭이 큰 작업 중의 하나이다. 지금까지 교환되어 일정기간 붕괴된 수조고온층 이온교환수지의 시료를 채취하고 HPGe MCA를 이용하여 수지에 흡착된 방사성 핵종의 종류 및 농도를 측정하고 이를 토대로 붕괴 추세선을 작성하였다.(중략)