The Beishan underground research laboratory for geological disposal of high-level radioactive waste in China:Planning, site selection,site characterization and in situ tests

With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories（URLs） play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China＇s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area,located in Gansu Province of northwestern China, has been selected as the final site for China＇s first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations,including borehole drilling,geological mapping, geophysical surveying,hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological,hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel（BET）, which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone（EDZ）, and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction.According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.

On area-specific underground research laboratory for geological disposal of high-level radioactive waste in China

Underground research laboratories （URLs）, including ＂generic URLs＂ and ＂site-specific URLs＂, are un- derground facilities in which characterisation, testing, technology development, and/or demonstration activities are carried out in support of the development of geological repositories for high-level radioactive waste （HLW） disposal. In addition to the generic URL and site-specific URL, a concept of ＂areaspecific URL＂, or the third type of URL, is proposed in this paper. It is referred to as the facility that is built at a site within an area that is considered as a potential area for HLW repository or built at a place near the future repository site, and may be regarded as a precursor to the development of a repository at the site. It acts as a ＂generic URL＂, but also acts as a ＂site-specific URL＂ to some extent. Considering the current situation in China, the most suitable option is to build an ＂area-specific URL＂ in Beishan area, the first priority region for China＇s high-level waste repository. With this strategy, the goal to build China＇s URL by 2020 mav be achieved, but the time left is limited.

Study on the residence time of deep groundwater for high-level radioactive waste geological disposal

Residence time of deep groundwater is one of the most important parameters in safety and performance assessment for high-level radioactive waste geological disposal. In this study, we collected the deep groundwater samples of Jijicao in Gansu Beishan pre-selected region. The deep groundwater residence time at two depths estimated by Helium-4 accumulation method were 3.8 ka and 5.0 ka respectively upon measurement and calculation, which indicates that the deep groundwater is not derived from the deep crust circulation process. Hence, deep groundwater is featured with long residence time as well as slow circulation and update rate, and such features are conductive to the safe disposal of high-level radioactive waste.

Key Scientific Challenges in Geological Disposal of High Level Radioactive Waste

The geological disposal of high level radioactive waste is a challenging task facing the scientific and technical world.This paper introduces the latest progress of high level radioactive disposal programs in the world,and discusses the following key scientific challenges:(1)precise prediction of the evolution of a repository site;(2)characteristics of deep geological environment;(3)behaviour of deep rock mass,groundwater and engineering material under coupled conditions(intermediate to high temperature,geostress,hydraulic,chemical,biological and radiation process,etc);(4)geochemical behaviour of transuranic radionuclides with low concentration and its migration with groundwater;and(5)safety assessment of disposal system.Several large-scale research projects and several hot topics related with high-level waste disposal are also introduced.

High-level radioactive waste disposal in China: update 2010

For geological disposal of high-level radioactive waste （HLW）, the Chinese policy is that the spent nuclear fuel （SNF） should be reprocessed first, followed by vitrification and final disposal. The preliminary repository concept is a shaft-tunnel model, located in saturated zones in granite, while the final waste form for disposal is vitrified high-level radioactive waste. In 2006, the government published a long-term research and development （R＆D） plan for geological disposal of high-level radioactive waste. The program consists of three steps： （1） laboratory studies and site selection for a HLW repository （2006-2020）; （2） underground in-situ tests （2021-2040）; and （3） repository construction （2041-2050） followed by operation. With the support of China Atomic Energy Authority, comprehensive studies are underway and some progresses are made. The site characterization, including deep borehole drilling, has been performed at the most potential Beishan site in Gansu Province, Northwestern China. The data from geological and hydrogeological investigations, in-situ stress and permeability measurements of rock mass are presented in this paper. Engineered barrier studies are concentrated on the Gaomiaozi bentonite. A mock-up facility, which is used to study the thermo-hydro-mechano-chemical （THMC） properties of the bentonite, is under construction. Several projects on mechanical properties of Beishan granite are also underway. The key scientific challenges faced with HLW disposal are also discussed.

Excavation of underground research laboratory ramp in granite using tunnel boring machine: Feasibility study

Underground research laboratory(URL)plays an important role in safe disposal of high-level radioactive waste(HLW).At present,the Xinchang site,located in Gansu Province of China,has been selected as the final site for China’s first URL,named Beishan URL.For this,a preliminary design of the Beishan URL has been proposed,including one spiral ramp,three shafts and two experimental levels.With advantages of fast advancing and limited disturbance to surrounding rock mass,the tunnel boring machine(TBM)method could be one of the excavation methods considered for the URL ramp.This paper introduces the feasibility study on using TBM to excavation of the Beishan URL ramp.The technical challenges for using TBM in Beishan URL are identified on the base of geological condition and specific layout of the spiral ramp.Then,the technical feasibility study on the specific issues,i.e.extremely hard rock mass,high abrasiveness,TBM operation,muck transportation,water drainage and material transportation,is investigated.This study demonstrates that TBM technology is a feasible method for the Beishan URL excavation.The results can also provide a reference for the design and construction of HLW disposal engineering in similar geological conditions.2020 Institute of Rock and Soil Mechanics,Chinese Academy of Sciences.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Current status of the geological disposal programme and an overview of the safety case at the pre-siting stage in Japan

In Japan,high-level radioactive waste and specific low-level radioactive waste which includes long-lived radionuclides are planned to be disposed of in the geological formations at depths greater than 300 m.The disposal site will be selected through a stepwise site investigation process that consists of a Literature Survey,Preliminary Investigation,and Detailed Investigation phases.In October 2020 a Literature Survey was launched in Japan at two municipalities in Hokkaido for the first time since NUMO initiated a nationwide call for volunteer municipalities in 2002,and the outcomes are currently being compiled.To enhance the public’s understanding of how to implement safe geological disposal in Japan based on the latest scientific knowledge and technology,NUMO,as the implementing organisation,developed and published a safety case for geological disposal at the pre-siting stage.This safety case provides multiple lines of arguments and evidence to demonstrate the feasibility of the geological disposal and a basic structure for a safety case that will be applicable to any potential sites in Japan.The safety case also presented some R&D challenges to enhance the technical confidence of the project,including the R&D topics related to rock mechanics.This report presents the current status of the geological disposal programme in Japan,together with the status of the Literature Survey phase and an overview of the NUMO safety case.

高放废物处置地下实验室现场试验数据管理顶层设计

我国高放废物地质处置研发已经进入地下实验室建设的关键阶段。在地下实验室建设和运行期间,将开展大量现场试验,这些试验数据具有传输距离长、采集周期长、数据类型多和数据量大等特点,同时数据质量、安全与可追溯性要求高,数据管理难度较大。通过分析我国高放废物地质处置北山地下实验室现场试验数据特点,以iS3智慧数据服务系统为基础,提出现场试验数据管理顶层设计方法,为现场试验和科研工作顺利开展提供重要的数据管理支撑。

我国高放废物地质处置新突破

2019年5月6日,国家原子能机构批复了我国高放废物地质处置地下实验室建设工程立项建议书。2021年6月17日,地下实验室工程正式开工建设,标志着我国高放废物地质处置进入一个新的阶段——地下实验室阶段,实现了新的突破。本文介绍近五年(2019-2024)来我国高放废物地质处置在法律法规、技术标准、场址评价、缓冲材料、工程技术、岩石力学、放射性核素迁移和安全评价等方面取得的新进展,重点介绍北山地下实验室工程建设及研究开发的新进展。

高放废物地下实验室岩壁吊车梁优化设计研究

北山高放废物地质处置地下实验室是中国首个研究高放废物地质处置的地下实验室。在该地下实验室-560 m的主试验水平内布置了起重量为5 t的电动单梁起重机岩壁吊车梁。本研究以相关设计规范为依据,阐述岩壁吊车梁的计算方法及设计步骤,并提出了对于起重机吨位较小的岩壁吊车梁的优化设计方案。优化方案可有效节省岩壁吊车梁的材料和宝贵的地下空间,本研究结果对小吨位起重机岩壁吊车梁设计有借鉴意义。

高放废物地质处置地下实验室开挖及精细探测关键技术

针对高放废物处置地下实验室工程建造面临的主要技术难题和挑战,以甘肃北山预选区新场-旧井地段为研究目标场址,建成了北山坑探设施工程并以此为研发平台,通过试验研究、理论建模和数值模拟等多重综合集成的研究方法,开展了地下实验室围岩含水结构面超前探测技术、地下实验室开挖方法及开挖损伤区评价技术、围岩开挖响应监测技术和围岩力学时效特性评价技术等研究,成功实施了不良地质体超前探测、围岩变形监测、光面爆破和开挖损伤区评价等11种现场试验,突破了地下实验室围岩含水结构面精细探测技术、低损高效破岩及评价技术、围岩位移全过程监测技术和围岩长期稳定性分析技术,掌握了高放废物地质处置地下实验室工程设计、建造有关的关键安全技术。相关成果为地下实验室设计和建造提供了重要的理论基础和技术支撑,显著提升了我国在高放废物处置领域的研发能力。

中国高放废物地质处置北山地下实验室重大进展

北山地下实验室是我国建设的首座高放废物地质处置地下实验室,是列入我国国民经济和社会发展“十三五”规划的国家重点项目。该项目于2019年5月获得立项批复、2021年6月正式开工、2022年5月主体工程正式开挖。这标志着我国高放废物地质处置工作全面进入全新的地下实验室建设及研发阶段。北山地下实验室位于甘肃省酒泉市西北的戈壁深处。主体工程由主竖井、螺旋斜坡道和两层试验水平组成。主竖井直径6 m,深590 m。螺旋斜坡道直径7.03 m,长约7.0 km,坡度10%,水平转弯半径255 m,采用隧道掘进机开挖,是世界上首条采用隧道掘进机开挖的螺旋斜坡道。自开工以来,关键设备建造、工程建设和相关科研工作取得了重大进展。用于螺旋斜坡道开挖的“北山1号”掘进机,也是世界首台大坡度小转弯隧道掘进机。该设备于2022年9月研制、制造成功,并于2022年12月正式开掘。截至2023年6月30日,主竖井开挖至280 m深,斜坡道掘进至1628 m,位于280 m深的水平试验巷道已经开挖完成100 m。与工程建设配套的科研工作,包括地质编录、水文地质编录、岩体质量评价、地下水监测和生态环境监测等均稳步推进。研究结果表明:地下实验室场址花岗岩完整、裂隙稀少、岩体质量好,开挖的地下巷道稳定。地下水稀少,主要赋存在裂隙密集带中,具有典型的干旱地区花岗岩裂隙地下水的特征。北山地下实验室预计于2027年建成,这将为填补我国在高放废物安全领域研发平台空白、攻克高放废物地质处置这一世界性难题提供试验平台和基础。

北山地下实验室斜坡道三维地质建模研究

基于KANTAN 3D和SKUA-GOCAD软件,对北山地下实验室斜坡道围岩岩性、节理和断层分布特征等巷道编录资料进行深入解译和分析,探讨建模思路与方法,以期整合各种地质特征,建立直观、科学的地下实验室巷道尺度三维地质模型,为岩石力学分析提供几何框架与地质参数。结果显示:北山地下实验室斜坡道前460 m岩性相对单一,以花岗闪长岩和片麻状二长花岗岩为主;斜坡道构造建模主要从单节理、节理(蚀变)带和断层(带)3个影响因素进行考量;节理总体走向以NNE向为主,倾向以SEE向为主,倾角集中在60°~90°之间;共发育4处节理蚀变带,规模小,未延伸至地表。随着地下实验室工程开挖和相关试验数据的不断丰富,对地下实验室斜坡道的地质建模方法和地质认识水平将不断提高,相关成果将为安全评价等研究提供重要基础。

北山地下实验室场址多尺度地壳形变观测系统的构建

在参考国外主要硬岩地下实验室场址地壳形变观测的经验,并结合我国高放废物北山地下实验室的定位和区域构造条件的基础上,构建了我国地下实验室场址多尺度地壳形变观测系统,该系统主要由跨断层、GNSS(Global Navigation Satellite System)和InSAR(Interferometric Synthetic Aperture Radar)形变观测3种手段组成,其中,利用跨断层和GNSS观测,给出地下实验室场址西侧关键构造(旧井断裂)的现今近场和远场的三维形变速率,评估断裂未来的活动趋势;GNSS观测以获得地下实验室场址所在新场岩体的水平形变特征;InSAR用以分析研究区最大LOS(Line of Sight)向的时序高分辨率形变速度场。以上3种手段的结合,初步实现了对地下实验室场址所在区域近场和远场范围多维度、多尺度的形变观测,观测对象囊括了场址区的主要断裂构造和大型岩体,该系统的建立填补了我国高放废物地下实验室场址形变观测的空白,为场址的适宜性评价奠定了良好的基础。

KAERI underground research laboratory: Overview of in-situ experiments

Social concerns regarding the safety of high-level radioactive waste have increased with growing public awareness of environmental issues and nuclear power.The performance assessment of deep geological disposal systems is crucial to reduce the uncertainties associated with high-level radioactive waste disposal and enhance the overall public confidence in nuclear safety.Accordingly,the Korea Atomic Energy Research Institute(KAERI)has undertaken various studies on the development of a deep geological disposal system for high-level waste and disposal safety evaluation.The KAERI Underground Research Tunnel(KURT),South Korea's only underground research laboratory dedicated to radioactive waste disposal,was constructed in 2006 and expanded in 2015.Since its construction,numerous in-situ experiments have been conducted and are currently underway in the KURT.The KURT plays a significant role in assessing the feasibility,safety,stability and appropriateness of a deep geological disposal system in South Korea and also provides an opportunity to revitalize industrial-academic-scientific cooperation between related institutions.This report summarizes two key in-situ experiments and international joint research conducted between 2007 and 2017 to assess the performance of the engineered and natural barriers of the KURT.The research experiences from the in-situ tests conducted at the KURT will provide crucial information on the safety and feasibility validation of the deep geological disposal system and will be an important contributor to the success of the Korean high-level radioactive waste disposal program in the future.

高放地下实验室紧急避险系统设计研究

高放地下实验室既是用来了解深部地质环境和地应力状况、获取深部岩石和水样品、在真实深部地质环境中验证工程屏障长期性能的试验设施,也是开发和验证处置库施工、建造、回填和封闭技术的重要手段,是高水平放射性废物处置工艺技术研发必不可少的关键平台。针对地下实验室可能存在的安全风险,开展了紧急避险系统建设原则、避险系统布置方案研究,旨在为地下实验室的安全运行提供可靠保障。

高放废物地质处置及其若干关键科学问题

如何安全处置高水平放射性废物是科学、技术和工程界所面临的挑战性问题。在介绍国内外最新研究进展的基础上,重点讨论高放废物地质处置的若干关键科学问题:处置库场址地质演化的精确预测、深部地质环境特征、多场耦合条件下(中(高)温、地壳应力、水力作用、化学作用、生物作用和辐射作用等)深部岩体、地下水和工程材料的行为、低浓度超铀放射性核素的地球化学行为与随地下水迁移行为及处置系统的安全评价。同时,介绍了国外若干重大科研项目和若干研究热点问题。

高放废物深地质处置及其研究概况

简要介绍了高放废物深地质处置的概念及其关键技术问题、高放废物工程屏障及其研究概况、高放废物处置库的选址因素及选址过程、处置库的主要岩石力学问题与候选主岩、地下实验室核素迁移示踪研究概况,最后,简要介绍了美、法、俄、韩、中等国在高放废物处置方面的研究计划与进展。

中国高放废物地质处置研究进展:1985～2004

如何安全处置高放废物是核工业可持续发展面临的挑战性问题.我国的高放废物深地质处置研究从1985年开始,提出的计划目标是:于21世纪中叶建成我国高放废物地质处置库,处置的对象是玻璃固化块、超铀废物和部分乏燃料,处置库为竖井-坑道型,候选围岩为花岗岩,位于饱和带中.在1985～2004的20 a中,我国高放废物地质处置研究取得了进展,已确定我国高放废物最终处置走'深地质处置',并且是'三步曲'式的技术路线,即处置库选址和场址评价-地下实验室-处置库.经过全国筛选对比,已初步选定甘肃北山地区为重点预选区,该区地处戈壁,地壳结构完整,地壳稳定,人烟稀少,地质条件和水文地质条件均有利.20世纪90年代初期,开展了地下实验室的选址工作,初步选择了北京郊区2处地点为我国高放废物地质处置'普通地下实验室'的场址.已确定使用膨润土作为处置库的回填材料,并初步确定内蒙古高庙子膨润土为我国高放废物处置库的首选缓冲回填材料.对膨润土的矿物学、岩土力学、物理力学性质和热学性质进行了研究.已获得一批放射性核素(主要是Np、Pu、Tc)在北山花岗岩和膨润土上的吸附分配比、扩散系数和弥散系数等参数,建立了低氧手套箱和模拟处置库温度、压力和氧化-还原条件的小型实验装置.高放废物中的关键核素的化学行为研究也取得进展.花岗岩接触带核素迁移、铀矿床中超铀元素迁移、青铜器腐蚀等天然类比研究取得了成果.还开展了高放废物地质处置系统总性能评价源项和生物圈模式的调研.概念设计研究仅在20世纪90年代初开展了部分研究.从1999年开始,与国际原子能机构开展了2期高放废物地质处置技术合作项目,极大地提高了我们的技术水平.20 a的科研工作为我国在21世纪完成高放废物地质处置奠定了一定基础.

中国高放废物地质处置地下实验室场址筛选

高放废物地质处置地下实验室建设项目是我国“十三五规划”的重点项目。文章介绍了我国首座高放废物地质处置地下实验室场址筛选的总体思路、筛选准则、候选场址特征、场址比选的定性和定量方法、比选过程和最终结果。我国首座地下实验室总体定位为第三代地下实验室,即特定场区型地下实验室。以此为指导,综合分析对比了甘肃北山、内蒙古、新疆三大预选区中9个预选场址(旧井西、新场、沙枣园、算井子、雅满苏、天湖东、阿奇山1号、塔木素、诺日公)的地质条件、未来自然变化、水文地质条件、人类活动、建造和工程条件、环境保护、土地利用、社会经济和人文条件等场址条件和特征,先筛选出新场、沙枣园、诺日公和雅满苏4个场址。在获得当地政府同意的基础上,经国家层面的专家评审会,最终确定甘肃北山新场为我国首座高放废物地质处置地下实验室场址。以新场场址为基础,完成了地下实验室的工程设计。2021年6月地下实验室正式开工建设。