Atmospheric Dispersion and Deposition of Radionuclides (¹³⁷Cs and ¹³¹I) Released from the Fukushima Dai-ichi Nuclear Power Plant

The Lagrangian Particle Dispersion Model (LPDM) in the 594 km× 594 km model domain with the horizontal grid scale of 3 km×3 km centered at a power plant and the Eulerian Transport Model (ETM) modified from the Asian Dust Aerosol Model 2 (ADAM2) in the domain of 70° LAT × 140° LON with the horizontal grid scale of 27 km×27 km have been developed. These models have been implemented to simulate the concentration and deposition of radionuclides (137Cs and 131I) released from the accident of the Fukushima Dai-ichi nuclear power plant. It is found that both models are able to simulate quite reasonably the observed concentrations of 137Cs and 131I near the power plant. However, the LPDM model is more useful for the estimation of concentration near the power plant site in details whereas the ETM model is good for the long-range transport processes of the radionuclide plume. The estimated maximum mean surface concentration, column integrated mean concentration and the total deposition (wet+dry) by LPDM for the period from 12 March to 30 April 2011 are, respectively found to be 2.975 × 102 Bq m-3, 3.7 × 107 Bq m-2, and 1.78 × 1014 Bq m-2 for 137Cs and 1.96 × 104 Bq m-3, 2.24 × 109 Bq m-2 and 5.96 × 1014 Bq m-2 for 131I. The radionuclide plumes released from the accident power plant are found to spread wide regions not only the whole model domain of downwind regions but the upwind regions of Russia, Mongolia, Korea, eastern China, Philippines and Vietnam within the analysis period.

Atmospheric radionuclides from Fukushima Dai-ichi nuclear accident detected in Lanzhou, China

After the Fukushima Dai-ichi nuclear power plant accident on March 11,2011,the radioactivity released from the accident was transported around the globe by atmospheric processes.The radioactivity monitoring program on atmospheric particulate in Lanzhou,China was activated by GSCDC to detect the input radionuclides through atmospheric transport.Several artificial radionuclides were detected and measured in aerosol samples from March 26 to May 2,2011.The peaked activity concentrations(in m Bq/m3)were:1.194(131I),0.231(137Cs),0.173(134Cs)and 0.008(136Cs),detected on April 6,2011.The average activity ratio of131I/137Cs and134Cs/137Cs in air were 13.5 and 0.78.The significant increase of137Cs activity concentration,one order of magnitude higher than pre-Fukushima accident levels,in ground level aerosol was observed in 2013,as its resuspension from soil.The back-trajectory analysis simulated by NOAA-ARL HYSPLIT shows a direct transfer of the air masses released from Fukushima to Lanzhou across the Pacific Ocean,North America and Europe at the height close to 9000 m AGL.The value of effective dose for inhalation is close to one millionth of the annual limit for the general public.

Experimental investigation on effective aerosol scavenging using different spray configurations with pre-injection of water mist for Fukushima Daiichi decommissioning

During the decommissioning of the Fukushima Daiichi nuclear power plant,it is important to consider the retrieval of resolidified debris both in air and underwater configurations.For the subsequent retrieval of debris from the reactor building,the resolidified debris must be cut into smaller pieces using various cutting methods.During the cutting process,aerosol particles are expected to be generated at the submicron scale.It has been noted that such aerosols sizing within the Greenfield gap(0.1-1μm)are difficult to remove effectively using traditional spraying methods.Therefore,to improve the aerosol removal efficiency of the spray system,a new aerosol agglomeration method was recently proposed,which involves injecting water mist to enlarge the sizes of the aerosol particles before removing them using water sprays.In this study,a series of experiments were performed to clarify the proper spray configurations for effective aerosol scavenging and to improve the performance of the water mist.The experimental results showed that the spray flow rate and droplet characteristics are important factors for the aerosol-scavenging efficiency and performance of the water mist.The results obtained from this study will be helpful for the optimization of the spray system design for effective aerosol scavenging during the decommissioning of the Fukushima Daiichi plant.

Establishing a mechanism for international cooperation for Fukushima nuclear-contaminated water monitoring

The Japanese government’s unilateral decision to discharge the nuclear-contaminated water from the Fukushima nuclear power plant into the ocean has caused immense nuclear safety risks.Monitoring the unclear contaminated water is a starting point to combat these risks and seek remedies for the rights and interests of all concerned parties.The establishment of a mechanism for international cooperation in this respect is necessary to handle the risks of the Fukushima nuclear-contaminated water and to lay the foundation of a framework for tackling any future disposal of nuclear-contaminated water following Japan’s example.At present,the international legal systems in the spheres of nuclear safety and security,marine environmental protection,and other areas,as well as the questioning of the monitoring reports of the International Atomic Energy Agency(IAEA)by the relevant parties,the monitoring practices of historical nuclear accidents,and numerous radioactivity monitoring mechanisms have provided the institutional and practical basis for constructing such a mechanism.The mechanism can be promoted by the IAEA through its existing mechanisms or be jointly initiated by China,the Russian Federation,the Republic of Korea,the Democratic People’s Republic of Korea,and the Pacific Island countries,among other stakeholders.Specifically,this mechanism should consist of three levels:first,the framework of the basic legal system,including the cooperative principles of national sovereignty,interest-relatedness,and procedural fairness,and the signing of the Framework Convention on the Monitoring of Fukushima’s nuclear-contaminated water and its Optional Protocol;second,the organizational structure and its responsibilities,which may include the Conference of Parties as the decision-making body,the Secretariat as the central coordinating body,and the monitoring committees in various fields as specific implementing agencies;and third,specific administrative arrangements,which involve the standardization of monitoring,the management system of monitoring networks and stations,the rules for monitoring procedures,and the rules for the utilization of the monitoring data,etc.With the urgent need for the scientific and fair monitoring of Fukushima’s nuclear-contaminated water,China,as a stakeholder country,can promote the establishment of such a mechanism for monitoring nuclear-contaminated water through the following paths:①It is necessary to clarify the factors affecting the construction of an international cooperation mechanism for monitoring nuclear-contaminated water so as to ascertain the standpoints of the stakeholders,claims of their interests,contents of their cooperation,and the relevant international relations.②On the basis of existing practices,China should consider improving the monitoring mechanism to cope with the risks of the discharge of Fukushima’s nuclear-contaminated water by formulating targeted policies and systems,setting up specialized monitoring institutions,and establishing a systematic monitoring network system.③This is an effective way for China to actively promote the participation of stakeholders in the construction of an international cooperation mechanism for monitoring nuclear-contaminated water in Fukushima by further innovating the dissemination mechanism to address the risk of Fukushima’s nuclear-contaminated water discharging into the sea and facilitating the identification of issues for international cooperation in monitoring Fukushima’s nuclear-contaminated water based on the concept of a community with a shared future for mankind.

The comparison of ensemble or deterministic dispersion modeling on global dispersion during Fukushima Dai-ichi nuclear accident

Ensemble forcasting,originally developed for weather prediction,is lately being extended to atmospheric dispersion applications,which is a new,effective methodology for improving the atmospheric dispersion numerical modeling.In March 2011,due to the massive 9.0 earthquakes and ensuing tsunami that struck off the northern coast of the island of Honshu,the Fukushima Nuclear Plant I had the substantial leak of radioactive materials into surrounding environment and atmosphere.To aim at the global dispersion modeling of atmospheric radionuclides from Fukushima Nuclear Accident,this paper presents two approaches of atmospheric dispersion forecasting:ensemble dispersion modeling(EDM) and deterministic dispersion modeling(DDM),conducts the globally dispersion modeling cases for Fukushima nuclear accident,and analyzes and evaluates the simulation results using observation data.In this paper,EDM includes three different perturbation methods:meteorological perturbation method,turbulence perturbation method,and physical parameterization ensemble forecasting method.The simulation results show that the trajectories from EDM have a better performance,which is in better agreement with the atmospheric circulation and observation data; the spread from DDM is slower and not as far as EDM.Additionally,the results from EDM display a better performance in the modeling of transport from Japan to China East Sea on April 4.The reasons for these results are:the techniques of MET and TUR are performed by adding perturbations on mean wind and turbulent velocity,respectively; the various different flow fields will result in far spreading in horizontal and the simulation results closer to observation; PHY is performed by using different diffusion physical parameterizations and produces the perturbations on vertical wind,which results the spreading in smaller range and discontinuous in horizontal.Finally,the comparative analysis between modeling results and observation data shows that all cases results are in good agreement with trends of observed radionuclides surface concentration; however,the modeling surface concentration is smaller than observation,especially in DDM and PHY.Furthermore,the EDM results show that MET and TUR are of more evolutionary advantage than PHY in modeling of average and maximum concentration.Therefore,this study can serve as a reference to atmospheric dispersion and environmental emergency response(EER).

日本核污水排海海洋生态损害责任的法理性审视及应对策略

日本核污水排海引发了国际社会对全球海洋生态损害的广泛关注与担忧。该行为不但违反了国际公约的相关规定,也反映了日本政府及其东京电力公司极端不负责任的态度。日本核污水排海海洋生态损害责任的归责以及责任主体成为后续事态发展的研究重点。就归责原则而言,日本核污水排海的海洋生态损害责任应当适用严格责任原则。就责任主体认定而言,虽然日本政府和东京电力公司应当共同承担核污水排海的海洋生态损害赔偿责任,但责任主体实质上归属于日本政府。鉴于核污水对海洋生态损害的长期性和不可逆性,应重视推广海洋跨界环境影响评价制度、引入预防性海洋环境公益诉讼制度、推动建立国际海洋生态损害赔偿制度等,以促进全球海洋环境治理转型、维护相关利益国正当海洋权益。

日本福岛来源^(134,137)Cs在海洋多介质体系中演变特征解析——以福岛港口区为例

日本福岛核事故以来,大量人工放射性核素持续泄漏进入海洋,造成严重海洋核污染。福岛来源人工放射性核素也可作为示踪剂,指示核素在海洋中的迁移转化规律。本研究聚焦福岛核事故后污染最严重的福岛第一核电站港口区,系统分析日本经济产业省、日本原子能规制委员会、东京电力公司等1 000多份监测报告,同时重建2011年4月至2023年10月期间港口区海水、沉积物、鱼类等多介质中^(134,137)Cs的演变历史,提出海水三阶段演变、沉积物四阶段演变、鱼类三阶段演变模式,计算不同阶段^(134,137)Cs活度水平和有效半衰期。本文发现了沉积物中^(134,137)Cs长期记忆效应及其对鱼类的持久影响,揭示了不同介质中高度一致的福岛来源^(134,137)Cs初始活度比值特征指纹,并解析了海洋鱼类对^(137)Cs富集吸收动力过程,可以为福岛核电站修复进程和核污水排海评估提供一定的科学参考。

基于海洋放射性核素时空演化体系的海洋核安全评估技术

本文指出全面构建海洋中放射性核素本底基线的时空演化体系是海洋核安全评估的基石,提出本底基线法、活度限值法和剂量限值法三种海洋核安全评估技术,并应用于福岛核事故后污染最严重的核心海区——港口区,定量剖析港口区的海洋核污染历史与现状,有利于评估过去12年以来日本福岛核电站修复进程中相关修复措施的有效性。之后,本文在利用海洋数字孪生技术的基础上,针对上述三种海洋核安全评估技术对应提出从寻找人类核活动历史的可靠“档案馆”、健全海洋放射性核素的基准/标准限值和探索长期低剂量生物辐射效应与风险三个角度展望未来海洋核安全评估技术需求与发展方向,以期为国内外新形势下我国海洋核安全评估与管理提供一定借鉴。

Addressing Japan’s disposal of nuclear-contaminated water from the perspective of international human rights law

The discharge of nuclear-contaminated water containing radionuclides into the ocean by Japan will lead to its integration into the entire ecosystem through processes of circulation and biomagnification,eventually entering the human body via the food chain.This poses a substantial risk of irreversible damage to both the ecosystem and human health,a situation that will worsen with the ongoing discharge of such water.The respect and protection of human rights represent an international consensus,and safeguarding fundamental human rights is a substantial obligation that states must undertake in accordance with both international and domestic law.Since the Fukushima nuclear disaster,Japan has continuously violated its international legal obligations to protect human rights in several areas,including the resettlement of disaster victims,the reduction of nuclear radiation levels,and the handling of contaminated water.Such actions have compromised and will continue to compromise the basic human rights of not only its citizens but also those of people worldwide,including environmental rights,the right to life,development rights,and food rights.In the aftermath of the Fukushima meltdown,the public and workers involved in handling nuclear contaminants have been continually exposed to high radiation levels,endangering their rights to life,development,and health.Japan’s inadequate efforts in victim resettlement and environmental restoration have jeopardized the environmental and food rights of its citizens to live healthily and access food in an environment unaffected by nuclear radiation.The release of nuclear-contaminated water poses a risk of Japan’s nuclear pollution to the people of neighboring countries and the global population at large.The principle of human rights underpins the theory of a community with a shared future for humanity,and human rights are a crucial area of China’s active participation in United Nations affairs and global governance.By voicing concerns over Japan’s potential human rights violations globally,China demonstrates its role as a responsible major country.In response to Japan’s breach of legal obligations and human rights violations,China can adopt a reasoned and beneficial approach,including calling on the international community to hold Japan criminally accountable for crimes against humanity under the Rome Statute and advancing scholarly discussions on ecocide and crimes against the marine environment.Furthermore,China should persist in seeking advisory opinions from the International Court of Justice and strive for substantive accountability,utilizing the mechanisms of international human rights organizations to make its voice heard.

日本福岛核污染水排放危害及对策

目的 探寻日本核污染水排放对人体的危害,研究应对措施。方法 通过搜集文献资料总结核污染水的危害,参照应急处置办法和经验,结合我国当前的特点提出应对措施。结果 核污染水会通过吸入、食入和皮肤沾染照射等途径对人体造成躯体和遗传的辐射效应。应对措施包括三个方面:摸清排放源项,做到心中有数;运用扩散模型,提高风险预判;建立应急预案,确保有备无患。结论 核污染水对人体有辐射损害,应科学预案和应对,做好综合防护措施。

Accident at Fukushima Dai-lchi Nuclear Power Plant--Lessons Learned for the Czech Republic

Accident at Fukushima Dai-ichi nuclear power plant significantly affected the nuclear industry at time when everybody was expecting the so called nuclear renaissance. There is no question that the accident has at least slowed it down. Research on this accident is taking place all over the world, in this paper, we present the findings of research on Fukushima nuclear power plant accident in relation to the Czech Republic. The paper focuses on the analysis of human performance during the accident. Lessons learned from the accident and main human errors are presented. First, the brief factors affecting the human performance are discussed. They are followed by the short description of activities on units 1-3. The key human errors in the accident mitigation are then identified. On unit 1, the fuel damage was probably impossible to prevent, however, on units 2 and 3, it could be probably prevented.

日本福岛核污水排海的监督困境及其对策——以环境法中的“风险预防”原则为视角

日本核污水排放活动不仅引发了许多国家的高度关切,而且国际原子能机构也介入其中,但现实情况却是国际社会无法对其实施有效的监督。主要原因在于日本有步骤地采取了混淆排放行为性质,选择标准限制较低的排放方式以及主动适用尚不完善的部门法律等方法。对此,有必要跳出当前国际原子能法的框架束缚,将日本的排污行为还原为国际环境法下的规制对象,着重运用“风险预防”原则加以应对。该原则不仅在合作义务方面具有更强的约束力,而且包括更加完善的责任承担机制。通过分析国际环境法中“风险”的内涵、阈值以及与污染形式间的关系,足以证立日方排海行为应受到“风险预防”原则的严格约束。

福岛核污染水排海引发的两次舆情事件分析研究

本文针对福岛核污染水排海事件进行长期跟踪研究,以事件在公布和正式实施两次时间节点所引发的舆情事件为切入点,梳理归纳了排海事件的进程,以及我国、日本、韩国等国家的应对和舆情变化,基于舆情态势进行了深入分析,提出了应对建议。本文可为进一步的研究提供基础和线索。

核电厂严重事故日常管理经验总结与发展建议

福岛核事故后,核电厂高度重视严重事故的应对。核电厂为维持和提升应对严重事故的能力,加强了设备、人员和文件的管理措施,并落实到相应的管理程序中。在严重事故日常管理中,核电厂发现了燃油标号不满足要求、应急移动泵无定期试验项目、钥匙管理不规范和未开展移动设备充足性评价等典型问题,并提供了相应的改进措施。本文针对严重事故管理导则电子化、移动设备接入系统试验、移动设备操作错配和严重事故管理导则框架更新等当前仍然存在的问题进行了探讨,并给出了建议。

The Price of Engineering Ethics, a Personal Story

There are costs for doing the right thing,but regret is not one of those costs.I learned this lesson the hard way throughout a 42-year engineering career.As a young engineer,raising a family,I was more adaptable to management mandates,i.e.,I was more willing to be unethical to keep my job to make money and have health insurance for my family.As I grew in age,experience,and stamina,I was less adaptable,i.e.,I was more ethical.This article tells this story through events at various times in my engineering career1.Ethics define how we do the right thing.

Elevated airborne beta levels in Pacific/West Coast US States and trends in hypothyroidism among newborns after the Fukushima nuclear meltdown

Various reports indicate that the incidence of congenital hypothyroidism is increasing in developed nations, and that improved detection and more inclusive criteria for the disease do not explain this trend entirely. One risk factor documented in numerous studies is exposure to radioactive iodine found in nuclear weapons test fallout and nuclear reactor emissions. Large amounts of fallout disseminated worldwide from the meltdowns in four reactors at the Fukushima-Dai-ichi plant in Japan beginning March 11, 2011 included radioiodine isotopes. Just days after the meltdowns, I-131 concentrations in US precipitation was measured up to 211 times above normal. Highest levels of I-131 and airborne gross beta were documented in the five US States on the Pacific Ocean. The number of congenital hypothyroid cases in these five states from March 17-December 31, 2011 was 16% greater than for the same period in 2010, compared to a 3% decline in 36 other US States

Changes in confirmed plus borderline cases of congenital hypothyroidism in California as a function of environmental fallout from the Fukushima nuclear meltdown

Radiation exposure has been linked to increased risk of congenital hypothyroidism (CH) for decades. CH is a relatively uncommon condition, occurring in about 1 of 2000 US births. Thyroid Stimulating Hormone (TSH) levels for each child born in California permitted an analysis of combined confirmed and borderline CH cases. Borderline/confirmed CH cases are more than seven times greater than just confirmed cases. Airborne levels of gross beta nuclear radiation in the US were elevated in the period starting several days after the Fukushima nuclear meltdown, especially in west coast states like California. The borderline/confirmed CH rate for newborns during the last 9.5 months in 2011 (exposed to Fukushima in utero) vs. births during other periods in 2011 and 2012 (not exposed) was significantly elevated, suggesting that adverse health effects to the newborn thyroid were not restricted to just a small number of confirmed CH cases. The sensitivity of the fetus to radiation exposure, plus the presence of thyroid-seeking radioiodine, suggest further analysis of Fukushima’s potential to cause adverse health effects in newborns is needed.

A numerical investigation into the long-term behaviors of Fukushima-derived ^(137)Cs in the ocean

The Fukushima nuclear accident in 2011 released large amounts of radionuclides, including ^（137）Cs, into the Pacific Ocean. A quasi-global ocean radioactive transport model with horizontal grid spacing of 0.5°×0.5° and 21 vertical layers was thereafter established to study the long-term transport of the Fukushima-derived ^（137）Cs in the ocean.The simulation shows that the plume of ^（137）Cs would be rapidly transported eastward alongside the Kuroshio Current and its extensions. Contaminated waters with concentrations lower than 2 Bq/m3 would reach the west coast of North America 4 or 5 years after the accident. The ^（137）Cs tends to be carried, despite its very low concentration, into the Indian and South Pacific Oceans by 2016 via various branches of ocean currents.Meanwhile, the ^（137）Cs concentrations in the western part of the North Pacific Ocean decrease rapidly with time. Up to now the highly contaminated waters have remained in the upper 400 m, showing no evidence of significant penetration to deeper layers.

Sleep and Stress of Late Middle Age Males Who Are Forced to Live in Emergency Temporary Houses and Post-Earthquake Public Houses for a Long Period Due to the Fukushima Daiichi Nuclear Power Station Accident

It has been revealed that prolonged shelter life caused by Fukushima Daiichi Nuclear Power Station accident in conjunction with the Great East Japan Earthquake influences sleep and mental health of the residents, and therefore its influence on their physical and emotional health has become a concern. Therefore, in this study, the authors aimed at clarifying actual situations of sleep and stress of middle age males living in shelters for a long period in each of emergency temporary houses and post-earthquake public houses. For 5 males who moved from emergency temporary houses to post-earthquake public houses, their objective and subjective sleep states were measured with Actigraph and PSQI, respectively. Furthermore, their objective and subjective stresses were measured with saliva stress biomarkers and GHQ28, respectively. Their data were analyzed by paired t-test. As result, in comparison between the life in the emergency temporary houses and post-earthquake public houses, significant variation was not recognized in their objective sleep states and saliva stress biomarkers though their subjective sleep and subjective stress were significantly worsened after moving to the post-earthquake public houses.

Monitoring long-term ecological impacts from release of Fukushima radiation water into ocean

After 10 years of the Fukushima Nuclear Accident,Japan decided to release the nuclear wastewater into the Pacific Ocean on 13 April 2021.It is apparent that Japan has chosen the most cost-efficient way to deal with the contaminated water,however,great opposition and concerns have been raised internationally due to the ecotoxicological features of radioactive materials and their harmful impacts on the environment.Here we an-alyze the ecological impacts caused by the nuclear accident and the potential impacts of releasing the nuclear wastewater into the ocean.Science-based solutions are proposed through a third-party evaluation and strict envi-ronmental assessment,multi-stakeholder public participation,integrated monitoring of the neighboring coastal countries,long-term international collaborative research,and setting up international convention for ecological compensation.