초록 ▼

⦁ 기상청의 대용량 수치예보자료 자동 송ㆍ수신 프로토콜을 개발하고 수치예보자료 수신서버를 구축하여 대용량의 수치예보자료를 안정적으로 수신하고, 자료저장/검색 모듈 및 자료 색인화/동기화 DB 모듈을 개발함.

⦁ 국제 표준방법의 단계적 생태계 방사능영향평가 코드 (K-BIOTA) 아시아 최초 개발, 세계 최고수준 대비 90% 이상 기술력 확보

⦁ IAEA 국제공동연구에 참가를 통한 코드의 성능검증 및 국제공동연구 논문 생산, 코드의 국제화 추진 및 국제전문가 네트워크 구축

⦁ 국내 원전의 부지적합

⦁ 기상청의 대용량 수치예보자료 자동 송ㆍ수신 프로토콜을 개발하고 수치예보자료 수신서버를 구축하여 대용량의 수치예보자료를 안정적으로 수신하고, 자료저장/검색 모듈 및 자료 색인화/동기화 DB 모듈을 개발함.

⦁ 국제 표준방법의 단계적 생태계 방사능영향평가 코드 (K-BIOTA) 아시아 최초 개발, 세계 최고수준 대비 90% 이상 기술력 확보

⦁ IAEA 국제공동연구에 참가를 통한 코드의 성능검증 및 국제공동연구 논문 생산, 코드의 국제화 추진 및 국제전문가 네트워크 구축

⦁ 국내 원전의 부지적합성평가 기술기준에 기반하여 사고시 경·중수로 통합 사고결말평가 코드 ACCESS를 개발

⦁ 확산이 잘 이루어지지 않은 기상조건(풍속이 낮고 대기가 안정)에서 추적자 SF6와 공기 샘플러 약 150대를 사용하여 야외확산 실증실험을 수행

⦁ 사고 대응 현장 연속 소형 검출시스템 설계, 제작 및 성능평가

⦁ 방사선 사고 및 테러 대비 방사선량 회구 평가 기술 확보 및 방사성핵종 섭취 신모델 해석 및 적용체계 개발

⦁ 방사선방호/방재/보안용 측정기 성능시험 체계구축

(출처 : 요약서 3p)

Abstract ▼

IV. Results
1. In this study, a server was setup to receive the numerical forecast data without any data loss from KMA and preprocess/DB modules have been developed to treat and manage big data in connection with atmospheric and marine dispersion models. Especially, a data server has been operate

IV. Results
1. In this study, a server was setup to receive the numerical forecast data without any data loss from KMA and preprocess/DB modules have been developed to treat and manage big data in connection with atmospheric and marine dispersion models. Especially, a data server has been operated to receive UM data to send in real time on the basis of MOU between KAERI and KMA in 2012. The operation of the atmospheric dispersion model has been simplified by development of the shell program to control the calculation date and time for automatic connection with the model.

Three dimensional atmospheric dispersion model named LADAS-Global has been developed to evaluate the effects to have an influence in Korea by the radionuclides released into the air after the Fukushima accident. Developed LADAS-Global was applied to simulate the dispersion patterns of Xe-133, I-131 and Cs-137 released into the air after the accident, and it was validated through comparing with the measurements at some points in the world and Korea. In the Fukushima accident 2011, the regional atmospheric dispersion model named LADAS-Regional in Korea was only operated for the Northeast Asian region and the radiological effects was evaluated to the human and environment due to the radioactive materials released into the air. Therefore, it is necessary to develop LADAS-Global of the global scale to evaluate the radiological assessment to have an influence on the human and environment in Korea by the radionuclides released into the air from the radiological accidents in the world. Radiological assessments including internal and external dose were performed in connection with the air concentrations, and the deposited concentrations on the surface were calculated.

Three dimensional marine dispersion model named LORAS-Global has been also developed to estimate the dispersion characteristics of the radionuclides released into the sea.

LORAS-Global could simulate the concentrations of the radionuclide in the seawater, suspended matter and sediment. Also, it was constructed in parallel mode for fast simulation. The dispersion pattern of Cs-137 released into the sea after the Fukushima accident was simulated and predicted that the patch of radioactive materials could be reached near the south sea in Korea. The oceanic compartment model was also developed to understand the dose and cancer risks to have an influence on human from ingestion of the contaminated seafood by the radionuclides released into the sea. The comparative results showed a good agreement between the calculations of the model and measurements.

Hydraulic scale instrument based on the distortion and similarity theory was designed and manufactured to validate the regional marine dispersion model. It has included the detection instruments to measure velocity and height of solitary wave like tsunami. Wolsung nuclear site in hydraulic scale model was selected to investigate the phenomena of sedimentation, erosion, sinking of sea floor and inundation from tsunami. Hydraulic scale model was mainly composed of wave generator, rotating coastal structure, water tank, detective instruments of velocity and soil pressure.

2-1. Development of wildlife dose assessment code.
The Korean wildlife dose assessment code K-BIOTA has been upgraded through the extension to 78 radionuclides which allow the code to apply a wide variety of conceivable exposure situations including those arising from routine discharges, potential releases from repository for the radioactive waste, and a nuclear accident. The upgraded K-BIOTA considers 11 groups of organisms that have similar habitats in three ecosystems (terrestrial, marine, and freshwater), and use the graded approach of three steps (level 1 to level 3).

Level 1 assessment calculates the risk quotients using the measured media concentration and the environmental media concentration limit (EMCL) that have been derived from a bench-mark screening dose. Level 2 assessment calculates dose rates but allows the user to examine and edit some major parameters used in the calculation including concentrations ratios and distribution coefficients. Level 3 assessment is a detailed assessment stage using the site specific data. A module for the uncertainty analysis of dose rate on major model parameters (concentration ratio, Kd, and environmental medium concentration) was also developed. The module can use four probability density functions of normal, log-normal, uniform and exponential distribution for a data with the Latine Hypercube Sampling method.

The upgraded K-BIOTA was applied to analyze the radiation risk of marine biota in the port of the FDNPS contaminated by the Fukushima nuclear accident. The analysis results showed that the accumulated dose for 3 months after the accident was about 4 to 4.5 Gy, indicating the possibility of occurrence of an acute radiation effect in the early phase after the Fukushima accident; however, the total dose rate for most organisms studied was usually below the UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation)’s bench mark level for chronic exposure except for the initial phase of the accident, suggesting a very limited radiological effect on the marine biota at the population level.

Three different types of dynamic compartment model were developed to assess the activity concentration and radiation dose for wildlife in marine, lake, and forest, respectively, as consequences of a nuclear accident. The performance of the models was tested through the analysis of the radiological impact of wildlife due to the Fukushima and Chernobyl nuclear accidents. The dynamic model (K-BIOTA-DYN-F) for a lake was applied to assess the 137Cs concentration of water and fish in seven lakes of Europe contaminated owing to the Chernobyl nuclear accident. A good agreement was found between the predicted and observed 137Cs activity concentration of water and fish which had been measured from lakes after the Chernobyl accident. The calculated temporal radiation dose rate showed that the maximum radiation dose rate would be about 1.5E2 μGy/d for predator fish in Ovre Heimdalsvatn, Norway, which was much lower than the UNSCEAR’benchmark level of 1.E7 μGy/d for aquatic biota. The results indicate that the population of biota in all lakes studied will maintain its integrity without any radiological effect despite a Chernobyl type disaster.

The predictive capability of the dynamic model for a forest (K-BIOTA-DYN-T) was tested through a comparison with the measured radioactive cesium inventory of trees and the activity concentration of animals from the Fukushima forest after the Fukushima accident.

The predicted radioactive cesium inventories for trees agreed well with those for evergreens and deciduous trees measured in the Fukushima forest area after the Fukushima nuclear accident. The predicted temporal activity concentrations for animals were within the range of the measured activity concentration of deer, wild boar, and black bear, which exhibited a very scattered trend through the sampling from a wide area. The radiation dose rates for wild animals were estimated to be much smaller than the lower limit (0.1 mGy/d) of the derived consideration reference level (DCRL) of ICRP for terrestrial plants and animals, indicating that the radiation effect of the Fukushima accident on the wildlife in the Fukushima forest would be insignificant.

2-2 Development of comprehensive database for radionuclide transfer characteristic of domestic ecosystems.
A total of 8000 transfer factor (TF) values were measured for about 170 wildlife species and 26 different elements through the collections of wildlife (plants and animals) and media (water and soil) samples in different types of ecosystems (marine, freshwater, estuary, water bottom and terrestrial). The field works were carried around the Wolseong and Younggwang NPPs for the first four years and around Daedeok facilities for the last year. Wildlife samples were collected by means of trapping, netting, fishing, diving, shooting and hand-catching by employed divers and hunters, and self-catching using with or without instruments according to the characteristics of the organisms. Water samples were collected using a van Dorn sampler or collected directly into sample bottles. Soil was sampled using a cylindrical sampler of a height of 10 cm.

In the study of marine and freshwater ecosystems, about 1700 TF values were obtained for about 50 wildlife species (fish, mollusca, crustacean, seaweed, vascular plant) and 22 nuclides (K, Ca, Na, Mg, Al, Fe, Ti, Sr, Mn, Cr, Cu, Zn, Li, Ni, Co, V, Rb, Cs, Ba, Pb, Th, U). In the study of estuaries and adjacent seas, more than 60 wildlife species were sampled near four estuaries located around the NPP sites, and a total of 2300 TF values were produced for 26 nuclides including K, Na, Sr, Mn, Zn, Co, Cs, U. In the study of the water-bottom ecosystem, a total of 2800 TF values were acquired as the result of analyzing about 90 wildlife species. The TF values for aquatic organisms were mostly higher than 1, reflecting the phenomenon of biological concentration.

In the study of terrestrial ecosystems, a total of 1200 TF values were measured for about 40 wildlife species including mammals, reptiles, amphibians, birds, insects, trees, shrubs, composites and grasses, and 24 nuclides (Ca, K, Mg, Na, P, S, Al, Sr, Fe, Mn, Li, Ba, Cr, Co, Zn, Th, U et al.). For terrestrial ecosystems, where soil acts as the medium for radionuclide transfer to wildlife, almost all of the measured TF values were lower than 1 except for Ca, Mg, P and S.

The measured TF values for the domestic ecosystems showed different values from the corresponding IAEA generic values by factors of several tens to several hundreds.

Therefore, it is recommended to use domestic site-specific data for enhancing the reliability of the assessment.

2-3. Development of phyto-technology to remedy the contaminated environment.
The state of art of the phytoremediation was investigated, and a number of criteria was developed to select an appropriate plant, which can be used to remove radionuclide from the environment contaminated with radionuclides. Based on the criteria, a few aquatic and terrestrial plants that are able to absorb radioactive cesium highly were selected as the candidate plants for the experimental investigation.

The 137Cs uptake by water parsley, raupo, and wild rice was studied while cultivating the plants in a hydroponic medium. The result of the present study showed that more than 70% of the initial Cs in solution was removed by the candidate plants in 60 hours, indicating the potential possibility to remove 137Cs successfully from a contaminated solution. Of all the studied aquatic candidate plants, the highest uptake of Cs was obtained from the water parsley. The water parsley absorbed more than 98% of 137Cs in solution for 120 hours, which can be considered as one of strong candidates of aquatic plant to remove of 137Cs in solution.

Radiocesium uptake for the candidate terrestrial plants appeared to be higher in the order of tomato, sweet potato, kenaf, sorghum, rapeseed, corn tomato, buckwheat, pachysadra and liliaceae. When fertilizer was applied, it was found that the radioactive cesium absorption of corn, sorghum and tomato was better than when it was not applied. The absorption power of radioactive cesium in cotton was very weak. In the case of pachysadra and liliaceae, the absorption of radioactive cesium did not occur any longer after a certain period of time.

This was because the biomass of the two plants was not greatly increased according to the growth, and consequently the absorption of radioactive cesium was limited. The buckwheat was observed to absorb more radioactive cesium from the soil with high concentrations than from the soil with low concentration. However, in order to understand its absorption characteristics better, additional experiments are needed.

2-4. Investigation of the biological characteristics on radiation of domestic wildlife.
By some criteria including a small size, an inhabitation over wide areas, a moving within a limited range, a living on local grains, and enough number of population and taxonomy on the basis of external and skull forms, Apodemus agrarius coreae (A. a. coreae), which is a species of wild mouse was selected as a reference model animal for the study. They were captured from fields, and were bred in a laboratory to secure enough population for the experiment. A chromosomal aberration method was developed to evaluate the biological effects caused by radiation using commercial mouse strain of C57BL/6, and the same method was subsequently applied to F1 of A. a. coreae.

The wild dark-striped field mice captured were irradiated with doses(0, 0.25, 0.5, 0.75, 1, 3, 5 Gy, n=3-5 mice/dose), and the following dose-responses were derived.

Gap and break based chromosome aberrations:
(YGap/break frequency=0.058(±0.0103)+0.0485(±0.0296)*D+0.0046(±0.013)*D2, R2=0.96),

Dicentric and ring based chromosome aberrations:
(YDic/ring frequency=0.0042(±0.0028)+0.0075(±0.0060)*D+0.0013(±0.0024)*D2, R2=0.99), and

Micronucleus frequency:
(YMicronucleus frequency=0006(±0.0004)+0.003(±0.0014)×D+0.0005(±0.0005)×D2, R2=0.99)

It was proved that the radiation dose less than 1 Gy can be evaluated by combining each dose-effect relationship of the gap chromosomal aberration, the frequency of micronucleus in polychromatic erythrocytes, and apoplectic splenocytes.

3. The ACCESS (Accident Consequence Assessment Code for Evaluating Site Suitability) code, integrating the PWR and CANDU, was developed for hypothetical accidental analysis based on the requirement of the evaluation of site suitability. This code is written by the Visual Basic language under the GUI (Graphic User Interface) environment. The field trace experiments in the unfavorable condition with low wind speed and stable atmosphere were performed by using SF6 and 150 air samplers to validate the atmospheric diffusion model.
The experiments have been performed 2 and 4 times in the flat and complex terrains, respectively. The calculation results are verified to be conservative compared to those from experiments. The regulatory guide for ACCESS was developed, and the optimal assessments are proposed reflecting the domestic characteristics.

The PRESS (Program for Radiological Dose Evaluation from Steady-State Radioactive Releases) code was developed for dose assessment of gaseous effluents in normal operation based on the new recommendations of the ICRP. It is constitute of JFD (Joint Frequency Distribution), atmospheric diffusion and deposition, dose assessment under the GUI environment. The optimized parameters were chosen reflecting the NRC-based improved ENDOS model of KAERI and the representative person of the ICRP. The results of this code was validated with those by hand calculation.

4. Development of continuous detection system in high radiation areas
A continuous gamma radiation detection system based on the CZT sensor was designed and developed for the emergency environmental monitoring in high radiation areas from high level radioactive materials as well as nuclear disaster. As assembling and improving the electric circuits for signal processing and system control by domestic technology except for the detector sensor, the energy spectrum with high resolution was achieved. An IRIS collimator was developed to make the quick and efficient measurement in high radiation area, This made the areal classification according to the radiation level practical. It was possible to remotely interface and control the system of hand-held CZT detector with Bluetooth communication. The sustainable measurement in the loss of the outer electric power was enhanced with internal battery of a detector. The dose rate spectroscopy, which is a new concept for the simultaneous measurement of the individual dose rate and radioactivity for detected gamma nuclides, was first developed and experimentally verified. In addition, a program for the calculation of the calibration factor in the in-situ measurement was developed to convert the measured cps from the detector into the radioactivity.
Development of rapid analysis methods for certain released radionuclides

The sample preparation and radiochemical separation methods on food stuffs was developed for the rapid analysis of certain released radionuclides. In terms of the pre-treatment time, the current developed methods was tremendously improved than the typical dry-digestion (10 days → < 12 hrs). An automated sequential separation system for the radionuclides (radio strontium and plutonium) was designed and fabricated. The developed system can process 8 samples at a time for certain radionuclide. In addition, it can handle four samples at a time for more than two radionuclides. The performance of the system was evaluated using simulated samples. All process is operated in a fully computer controlled mode with a user-friendly software. We developed the rapid determination method of 89/90Sr activity for mixed samples with 89/90Sr. The determination of Plutonium in environment was developed using LSC (Liquid Scintillation Counter) and alpha spectrometry for emergency responses.

Identification technique for radioactive materials released into the sea The sequential separation method of 89/90Sr, Pu, 99Tc and 129I in seawater was developed with anion-exchange resin and co-precipitation. We tested the performance of the recommended procedure with 1 ∼ 10 L seawater. The automated pre-treatment system for large volume of samples was developed. It can process 8 samples at a time. It can handle 20 L of seawater for the concentration of 89/90Sr from sample. All process is operated in computer controlled mode. We developed the determination of 129I in environmental samples.

129I is very useful indicator to reconstrut the contamination map caused by 131I at nuclear accident. We suggested the determination of 129I using RNAA, ICP-MS and LSC.

5-1. Establishment of retrospective dosimetry technology for radiation accident dosimetry
1) Development of retrospective dosimetry technology using personal electronic devices(smart phones)
• Dose dependence of OSL from resistors, inductors, and IC chips
- Linear in the tested dose range (8.7 mGy - 8909 mGy) on the whole

• Fading test of OSL from the samples
- Inductors: about 50 % in 36 hours after the irradiation
- Resistors: about 80 % in 36 hours after the irradiation

• Estimation of minimum detectable dose for resistors and inductors
- Inductors: 2.4 mGy; Resistors: 6.6 mGy

• Development of a protocol for retrospective dosimetry using electronic devices
- Procedures from sample preparation and dose estimation

• Field test of the developed procedures for retrospective dosimetry
- It was possible to estimated the irradiated dose respectively in deviation from 5 % to 40 % (depends on dose range)

• Dose re-evaluation technique
- Re-evaluation ratio for the first given dose : 80~97%(Inductor), 78~111%(Resistor)
- Fading ratio after 36 hours : 7%(Inductor), 35%(Resistor)

• Participate in EURADOS intercomparison (using a glass in mobile phone)

• Optimization of TL measurement using emission spectrums of resistor and inductors
- Emission spectrums of resistor and inductors : high flux emission spectrum with 700 nm peak
- Measurement residual TL without filter : 85 times increase(Inductor), 16 times increase(Resistor)

• Development of RestroAnal

2) Development of retrospective accident dosimetry technique using building materials
• Selection of building materials for retrospective accident dosimetry
- Fired bricks, tiles, roof tiles, toilet porcelain

• Sample extraction of quartz inclusion and core-disc method for TL/OSL/POSL measurement

• Reliability test of equivalent dose obtained from building materials
- Verification of SAR-OSL method using quartz grains(90-250 ㎛)
- Verification of SAAD-POSL method using core-disc sample(Ø8 mm)

• Development of accidental dosimetry as fast assessment using SAAD-POSL method
- Regeneration test of equivalent dose up to 7 Gy
- Minimum detectable dose of 10 mGy in SAAD-POSL method
- Measurement time as short as about 2 hours in SAAD-POSL method

3) Designing and assembling of OSL spectrum measurement equipment and development of required software for OSL/TL analysis
• Photon measurement devices: CCD and PMT

• Spectrum wavelength band: 325 nm - 800 nm

• Stimulation light sources: Green and Red LED, Green Laser

• Measurement of OSL spectrum from Al2O3:C and LiAlO2 materials

• Development of an algorithm for analysis of OSL, TL based on trap interaction model

4) Development of radioluminescence material for real time-remote dosimetry
• Crystal growing system based on Czochralski and Automatic diameter control program

• Emisson spectrum and dose response of RL materials based on LiAlO2

5-2. Interpretation of new models for intake of radionuclides and it’s application to internal dosimetry system
1) Analysis and application of NCRP 156 wound model
• Analysis of the wound model
- Analysis of wound model developed in NCRP 156 publication
- Analysis of wound compartment model and initial compartment
- Establishment of database for default transfer rates between compartments of wound model

• Application of wound model
- Development and validation of wound model analysis module
- Calculation of intake retention and excretion functions for radionuclides in ICRP part 2, 3
- Establishment of database for wound contamination intake route

2) Development of internal dose assessment computational code based on the newest international recommendations
• Establishment of internal dosimetry methodology using the newest international recommendations
- Establishment of methodology for application of measurement data having log-normal distribution
- Establishment of methodology for intake estimation using maximum likelihood estimate

• Development of internal dose assessment computational code based on the newest international recommendations
- Application of database based on the newest international recommendations
- Realization of internal dose assessment algorithm based on the newest international recommendations
- Realization of statistics algorithm based on the newest international recommendations
- Modification of the GUI of computational code for application of the newest international recommendations
- Verification of the developed computational code

5-3. Establishment of radiological performance testing scheme of radiation detection systems used for radiation protection, radiological emergency and security

1) Production of the reference X-ray fields (ISO LK qualities) and gamma ray field for test and calibration of personal electronic dosimeters and workplace monitors.
• Production of the reference X-ray fields (ISO LK qualities)
- ISO LK beam series : LK35, LK55, LK70, LK100, LK125, LK170, LK210, LK240.
- Quantification of the produced LK X-ray beams using the measurement method of half value layer (HVL).
- Homogeneity of LK X-ray beams were satisfied within 5% according to ISO4037.
- Air-kerma rates of eight LK X-ray beams were measured using ionization chamber calibrated at KRISS (Korea Research Institute Standard and Science) and JAEA (Japan Atomic Energy Agency).
- Air-kerma rates of KAERI’s LK X-ray (0.1－0.24 mGy·h-1·mA-1) were satisfied with ISO criterion (< 0.3 mGy·h-1·mA-1)

• Production of the low air-kerma rate gamma ray fields using a radiation source of 241Am
- Air-kerma rates of radiation fields of 241Am were 0.43 mGy·h-1 @5 cm, 0.11 mGy·h-1 @10 cm.

2) Establishment of field performance testing systems used for radiation protection, radiological emergency and security at workplace.
• Evaluation and preparation of performance test manuals and protocols of radiation detection portal monitors and hand-held radionuclide identifiers.

• Establishment of the radionuclide check source set for evaluation and performance test of portal and hand-held monitors.
- Gamma sources: 57Co, 133Ba, 137Cs, and 60Co, and radioactivities are 3.5, 0.7, 0.56, 0.12 MBq, respectively.
- Neutron source: 252Cf, neutron emission rate is 1.4×104 n/s.

• Production of a check source transfer equipment: moving speed and a height of source position can be adjusted and the function of automatic round-trip was provided.

3) Manufacture of field calibration kits for gamma and neutron area monitors.
• Establishment of instant performance testing systems for gamma-ray area monitor by using the portable gamma-ray irradiator.
- Using the attenuation filtration(Sn, Cu, Al), derivation of the relation for dose rate-distance using the attenuation filters, correlation coefficient factors for various attenuation filters.
- Evaluation of the effects of the scattered radiation: up to 7% dose rate increase due to build-up effects.

• Establishment of instant performance testing systems for neutron area monitor by using the movable neutron irradiator.
- Manufacture of the movable neutron irradiator using HDPE (High Density Polyethylene): 50 cm (L) × 50 cm (W) × 46 cm (H)
- Derivation of dosimetric quantities at 100 cm from the source: fluence-average energy, dose equivalent-average energy
- Dosimetric quantities of neutron field constructed by movable irradiator at various position: 80, 100, 120, 140, 160, 180, 200 cm
- Correction coefficient, and Reference and measured ambient equivalent dose rate of neutron field constructed by movable irradiator at various position: 0.94 @ 100 cm (252Cf)

(출처 : SUMMARY 29p)

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 보고서 요약서 ... 3
• 요약문 ... 4
• SUMMARY ... 23
• CONTENTS ... 44
• 목차 ... 45
• 제 1 장 연구개발과제의 개요 ... 46
• 제 2 장 국내외 기술개발 현황 ... 51
• 제 3 장 연구개발 수행 내용 및 결과 ... 62
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 84
• 제 1 절 연구개발 목표 달성도 ... 84
• 제 2 절 관련 분야 기여도 ... 98
• 제 5 장 연구개발결과의 활용계획 ... 102
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 107
• 끝페이지 ... 110