초록 ▼

파이로 공정폐기물 처분시스템(A-KRS)의 성능 향상과 KURT 기반 확충, MWCF의 특성 평가, 그리고 이를 기반으로 하는 개념 설정 단계의 Safety Case 보고서를 발간하는 것을 주요 목표로 하여 4개 기술분야 별로 세부과제를 구성하여 연구를 수행하였고 주요 연구결과는 다음과 같음.

○ 공학적방벽시스템 성능 20% 향상 및 이를 기반으로 하는 처분시스템 개선
- 열 효율이 향상된 고성능 공학적방벽을 개발하여 이를 기반으로 파이로 공정 물질수지를 반영한 처분시스템을 개발하고, 처분소요면적 관점에서 효율성을

파이로 공정폐기물 처분시스템(A-KRS)의 성능 향상과 KURT 기반 확충, MWCF의 특성 평가, 그리고 이를 기반으로 하는 개념 설정 단계의 Safety Case 보고서를 발간하는 것을 주요 목표로 하여 4개 기술분야 별로 세부과제를 구성하여 연구를 수행하였고 주요 연구결과는 다음과 같음.

○ 공학적방벽시스템 성능 20% 향상 및 이를 기반으로 하는 처분시스템 개선
- 열 효율이 향상된 고성능 공학적방벽을 개발하여 이를 기반으로 파이로 공정 물질수지를 반영한 처분시스템을 개발하고, 처분소요면적 관점에서 효율성을 향상

○ 처분안전성평가 신뢰도 향상 기술개발 및 Safety Case 보고서 발간
- 복합피폭 시나리오 및 보조안전지표 평가모델 개발, 공학적방벽 경계에서 핵종 복합거동 해석, KURT 지하수 및 암반에서의 우라늄 장기거동을 해석하고, 국내 최초로 Safety Case (AKRS-16) 보고서를 발간

○ KURT 시설 주변의 MWCF 지질구조·수리·지화학특성 평가
- MWCF 구조의 지하수 및 단열충전광물 변화모델을 제시하고, MWCF 이동경로 특성을 규명함. MWCF에 대한 장기 수리간섭시험을 통해 부지특성모델을 검증하고, 심부환경 영향과 적정 처분 위치 선정 기법을 제안

○ KURT 시설을 성공적으로 확장하여 처분시스템 현장검증 기반 확보
- 향후 10년 간의 장기현장시험계획을 수립, 각 현장시험 요구조건을 설계에 반영한 확장공사를 완공하여 총길이 551m, 최고심도 120m, 독립적인 6개의 연구모듈을 확보

○ KURT 공학규모 공학적방벽 열-수리-역학 복합거동 현장시험장치(In-DEBS) 구축
- KURT 내 공학규모 공학적방벽 복합거동 현장시험장치(In-DEBS)를 설치, 운영함으로써 현장 실험데이터를 반영한 처분시스템 장기 성능평가 기반을 마련

(출처 : 요약서 5p)

Abstract ▼

Ⅳ. Result of Project
1. Development of Engineered Barrier System Performance

Seventeen RFPs have been carried out to meet the goal of the research, that is, to enhance the performance of engineered barrier system(EBS) and to develop a geological disposal system based on the high-efficiency

Ⅳ. Result of Project
1. Development of Engineered Barrier System Performance

Seventeen RFPs have been carried out to meet the goal of the research, that is, to enhance the performance of engineered barrier system(EBS) and to develop a geological disposal system based on the high-efficiency EBS, for five years. By adding 3wt% graphite, the thermal conductivity was increased from 0.8 W/mK to 1.0 w/mK, which was more than 20%, maintaining the performance of bentonite buffer. We proposed a 'pellet' type buffer to increase the earthquake-resistance. A disposal canister at the 1/3 scale was manufactured using the scaled-up cold spray coating facility, and the performance test was carried out. The very long-term corrosion experiment has been carried out using KURT groundwater. A computer program-KAERI SIMULATOR-to analyze the THM coupled processes was developed by the authors and verified through the international joint study. A Lab-scale TH experiment was carried out at the elevated temperature to understand the TH coupled process in the buffer. To predict lifetime of disposal canister exactly, an English-version report was published regarding the long-term corrosion experiment carried out in KURT, and the numerical models for canister corrosion were developed. The evaluations of thermal performance for the disposal systems were carried out through the thermal analysis for the characteristics of the radioactive waste.

Based on these results, the disposal efficiency such as disposal area comparison with the direct disposal system of spent fuel were analyzed.

2. Development of confidence improvement technologies for disposal safety

We developed the integrated assessment methodology for the complex scenario assessment which consists of characterization of external events, characterization of impacts of each event, determination of scenario generation criteria, scenario generation, safety assessment modeling, and model convergence check. Database on performance indicator, complementary safety indicator, and natural analogue was established on the basis of the documents published by international organization such as IAEA, OECD/NEA, and international project such as SPIN and PAMINA.

Besides, we investigated the complex behaviors of radionuclides in the interfaces of container/buffer/rock and then evaluated their effects on the radionuclide migration.

We developed a radionuclide migration model considering geochemical reactions at the canister/buffer interface using LBM and PHREEQC. Under the CFM joint international study which is being carried out in the Underground Research Laboratory of GTS(Grimsel Test Site) in Swiss, KAERI has performed a long-term in-situ experiment and then has compared the results with those from KAERI.

Results from the investigation of the long-term behaviors of uranium in KURT groundwater include the development/installation of a Time-Resolved Laser Fluorescence Spectroscopy (TRLFS) system, and quantitative analysis of the uranium concentration, identification of uranium species in the KURT groundwater.

Besides, in the long-term behaviors of uranium in the KURT fractured rock, we investigated the distribution, existing forms, and minerals of uranium, respectively, using the EPMA and developed a calculation code (KAERI-TCDBC). Consequently, we published a safety case report entitled ‘A Safety Case of the Conceptual Disposal System for Pyro-processing High-Level Waste Based on the KURT Site (AKRS-16)’ based on the research results which have been carried out for last years.

3. Development of technology for characterization of geological environment in KURT

The block scale hydrogeological model around KURT area was suggested. In order to construct the hydrogeological model including the major water conducting features around KURT area, the uncertainties on hydrogeological understandings, which were included in previous model, was identified. To access the hydrogeological change after KURT extension, the hydrogeologcal model including MWCF around KURT were constructed. Using hydrogeological model, numerical method was applied to understand hydraulic system around KURT area. Water head pressure, geochemical data and ground water samples through the depth were analyzed from the multi-packered monitoring boreholes in KURT. Geochemical characteristics were evaluated in respect of redox condition and reactions between water and fracture-filling minerals in MWCF. With the calculated cluster density, the correlation length for background fractures was estimated and suggested as an appropriate domain size for stochastic DFN modeling. To characterize the solute transport properties of MWCF, requisites for minimizing the experimental errors in a tracer test were introduced. Considering the introduced requisites, the tracer injection and sampling systems for a tracer test at MWCF were designed and manufactured. Considering the conclusions of the previous studies, tracer tests were conducted, and the transport characteristics of MWCF were evaluated. The in-situ hydraulic tests were carried out to obtain the hydrogeological properties of geological units which are components of geological model around KURT area. To validate groundwater flow modeling around KURT area, the results from modeling were compared with the results of in-situ hydraulic tests (long term interference test). The results from uranium isotope ratio analysis provide the strong evidence to determine more than 600m as a proper depth for radioactive waste disposal in KURT site. The results from hydrological model using particle backward tracking also showed the groundwater flow rate was negligible below 450m in KURT site.

Thus, both of approaches can be applied together to determine the depth or location for radioactive waste disposal based on geochemical and hydrological characteristics of KURT site.

4. Establishment of infrastructure in KURT for in-situ demonstration

KURT research fellows identified various in-situ tests and experiments and defined requirements for each tests. We carried out geological investigation to understand geology, geological structure, and hydrological properties of extension area. We constructed preliminary rock mechanical model based on the results of geological investigation. Optimum tunnel layout was determined based on the site investigation results also. We determined NATM as final excavation method. The contractor for construction was HYUNDAI construction co. Ltd. that is the world best construction company. There were two or three blasting events per day and about 3 m digging was attained by every blasting. We constructed 3-D rock mechanical model using data from construction to provide geological information to end users, system designer, and safety assessment team.

5. Long term in-situ investigation of repository system performance

The underground conditions were evaluated to select the location of in-DEBS.
Two locations in KURT were evaluated and six boreholes were drilled to investigate the underground conditions. Hydrological tests were performed at different depths and hydrological model was developed based on the data. The 1/2.3 scaled engineered barriers of A-KRS system with 116 THM sensors were constructed in-situ condition. The heat container with 6 divides were invented to minimize the difference in heat distribution. The automatic monitoring control system were developed to sustain for long term under in-situ underground condition to accumulate monitoring data. The dataset was used to simulate THM behaviors of engineered barriers using TOUGH-FLAC program, which is FLAC3D coupled TOUGH2.

(출처 : SUMMARY 19p)

목차 Contents

• 표지 ... 1
• 제출문 ... 3
• 보고서 요약서 ... 5
• 요약문 ... 7
• SUMMARY ... 17
• CONTENTS ... 25
• 목차 ... 27
• 표목차 ... 31
• 그림목차 ... 33
• 제1장 연구개발과제의 개요 ... 39
• 제1절 연구개발 필요성 ... 41
• 제2절 연구개발 목표 ... 42
• 제3절 연구개발 내용 ... 42
• 제2장 국내외 기술개발 현황 ... 46
• 제1절 시스템 설계 및 공학적방벽 개발 분야 ... 48
• 제2절 핵종거동 및 처분안전성 평가 분야 ... 52
• 제3절 천연방벽 지질환경특성 평가 분야 ... 55
• 제4절 지하연구시설 구축 및 실증시험 분야 ... 57
• 제3장 연구개발수행 내용 및 결과 ... 61
• 제1절 공학적방벽 성능향상 기술 개발 ... 63
• 1. 고성능 완충재 개발 ... 63
• 2. 고성능 처분용기 개발 ... 68
• 3. 실험실 규모 공학적방벽 열-수리 복합거동 시험 ... 72
• 4. 공학적방벽 열-수리 복합거동 시험 해석 ... 76
• 5. KURT 기반 열-수리-역학적 복합거동 실증 시험 ... 80
• 6. 열-수리-역학적 복합거동 해석 기법 개발 ... 84
• 7. 공학적방벽 전단거동 특성 ... 89
• 8. 처분용기 부식 해석 ... 93
• 9. 처분시스템 개발 ... 98
• 제2절 처분안전성 신뢰도 향상 기술 개발 ... 103
• 1. 처분장 안전성평가 및 Safety Case 개발 ... 103
• 2. 처분환경에서 핵종의 복합거동 특성 평가 ... 115
• 3. 우라늄 장기 유사거동 연구 ... 125
• 4. KURT 기반 Safety Case 보고서 작성 ... 136
• 제3절 KURT 지질환경 특성평가 기술 개발 ... 145
• 1. KURT의 MWCF 특성조사 및 정량화 기술개발 ... 145
• 2. KURT 수리지질/지구화학모델 개발 ... 155
• 3. KURT의 MWCF 지하수 유동모델 개발 ... 164
• 4. MWCF 추적자 시험 및 이동경로 특성 평가 ... 172
• 5. KURT 부지특성 통합모델 개발 ... 178
• 제4절 KURT 현장검증 기반 구축 ... 186
• 1. KURT 확장 최적안 설계 ... 186
• 2. KURT 확장 공사 ... 192
• 3. KURT 확장구간 지질정보 및 현장검증 기반 구축 ... 200
• 제5절 처분시스템 성능 장기 현장시험 ... 208
• 1. KURT THM 복합거동 현장 시험조건 평가 ... 208
• 2. 공학적방벽-자연방벽 반응평가 ... 213
• 3. THM 복합거동 현장 시험장치 구축 ... 220
• 4. 현장 시험조건을 반영한 THM 복합거동 특성 예비평가 ... 226
• 제4장 목표달성도 및 관련분야에의 기여도 ... 231
• 제1절 목표 달성도 ... 233
• 제2절 관련 분야에의 기여도 ... 242
• 제5장 연구개발결과의 활용계획 ... 247
• 제1절 국가 현안사업 기술 지원 ... 249
• 제2절 타연구에의 응용 ... 252
• 제3절 추가 연구의 필요성 ... 253
• 제4절 기업화 추진 방안 ... 256
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ... 258
• 제1절 시스템 설계 및 공학적방벽 개발 분야 ... 260
• 제2절 핵종거동 및 처분안전성 평가 분야 ... 261
• 제3절 천연방벽 지질환경특성 평가 분야 ... 263
• 제4절 지하연구시설 구축 및 실증시험 분야 ... 265
• 제7장 연구개발성과의 보안등급 ... 272
• 제8장 연구장비의 구축 및 활용 결과 ... 276
• 제1절 액체섬광계수기 및 자외-가시광선 분광광도계 ... 278
• 제2절 기상․수리․지화학 장기모니터링 시스템 ... 280
• 제3절 MWCF 추적자 시험 장치 ... 282
• 제9장 연구개발과제 수행에 따른 연구실 등의 안전 조치 이행 실적 ... 284
• 제10장 참고문헌 ... 288
• 부록. 저온분사코팅 구리 처분용기개발 영문 종합보고서 ... 296
• 끝페이지 ... 389