Radiation has been increasingly used for various purposes in diverse fields, and the risk of radiation exposure varies depending on the nature of the work. Therefore, I analyzed the radiological work environment in each field through literature research and confirmed that the risk involved in nondestructive testing (NDT) is the highest. In this field, there is a high probability of exposure accidents resulting from radiation protection carelessness during field work and night work. The risk of radiation exposure is related to the field of work; however, currently, risk assessment is conducted solely based on the exposure dose.
Therefore, herein, I have developed a model for risk assessment in NDT that considers the following factors based on existing research data, expert advice, and questionnaire responses: 1) exposure dose, 2) radiation sources used, 3) workplace management, 4) number of workers receiving high radiation doses, and 5) periodic inspection practices. Additionally, I suggested classification criteria for grading the model. However, the model presented the following problems: 1) the assessor must manually input the company’s information and manually grade the model, 2) the risk assessment file of each NDT company needs to be made continuously for annual assessments. In order to overcome these limitations, I developed the following macros for the risk assessment model by writing a VBA code in Microsoft Excel: 1) a macro for reviewing the risk assessment data (exposure dose data, ordering company’s report data, and so on), 2) a macro for automatically entering the company’s information, 3) a macro for automatically classifying the grade for each company, and 4) a macro for automatically presenting the risk assessment model for each company.
Subsequently, I obtained NDT data for 2016 and 2017 for radiation risk assessment from the relevant regulatory body. I then confirmed the unusual factors for the 55 companies represented in these data. Here, an unusual factor implies that the company''s parameter for the main factor exceeds the average value of the main factor. The following are the results of the analysis: 1) Most of the companies use Ir-192, 2) two to three factors related to the exposure dose were simultaneously classified as unusual factors, 3) factors related to workplace management were essential for confirming the work characteristic. I expect that my risk assessment model for NDT can be employed for the following tasks. 1) After the radiation safety manager determines the shortcomings of the NDT company, the company can proactively prevent accidents by autonomously monitoring the workplace. 2) After the assessor determines the weaknesses of each NDT company, the appropriate regulatory body can use the supplementary data for periodic (or frequent) inspection.