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The safety characteristics and potential hazards of reprocessing facilities are different from those of nuclear power plants (NPPs). Emergency action level (EAL) development is an important aspect of emergency preparedness, and EAL is an important basis for emergency response of reprocessing facilities. EAL quantitative research can enhance its operability. At present, the domestic and foreign literature, generally only gave the principle method for EAL development. There are no operational guidance documents for specific EAL quantification in reprocessing facilities. According to the features of the functions and configurations of the reprocessing facilities, two additional categories EAL, E category for the spent fuel pool accident and W category for the high level liquid waste tank accident, have been added. Meanwhile, four categories-S, F, A, H are retained with similar implication as NPPs. On the basis of existing principles and practical experience, specially the reference from DOE G 151.1-1A, EAL quantification was developed according to the characteristics and symptoms related to the safety of reprocessing facilities. EAL quantification for several accidents was developed, and it was with good maneuverability. The study for EAL quantification in reprocessing facilities shows that, quantitative, indicative, practical EALs can make emergency response more accurate and efficient, and ongoing research is strongly requisite.

Fukushima accident shows again that the probability of reactor accident exists even though it is extremely small. In case of emergency in nuclear power plant, emergency condition of the reactor plays an important role in decision making. During emergency response, especially early stage of severe accident with large release of radioactive nuclides, decision making for protection actions should be based on emergency condition in NPPs. If emergency condition could be prognosed, more time could be bought for decision making and emergency response. In this paper, method for prognosis of large break loss of coolant (LBLOCA) initiated severe accident progression was established based on transient analysis for M310 reactor. Mass and energy conservation equations are the basis of the method. Separated flow model is used for prognosis of emergency condition for large break loss of coolant accident initiated severe accident. These conservation equations are solved approximately in order to significantly increase calculation speed. The active core is divided into 4 radial rings and 10 axial levels, which means there are 40 cells. Heat transfer calculation in the core is done using four experimental correlations. Based on the method established in this paper, a code using for prognosis of LBLOCA initiated severe accident emergency condition was developed. Research on method for prognosis of other severe accidents are being conducted.

For the aim of helping the development of robots used in Radiological Emergency Planning and Preparedness, the Total Ionizing Dose (TID) effects on the threshold voltage shift (ΔVth) of different kinds of Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) with different geometry and different scaling technology was compared. The different gate width and length dependent between bulk Complementary Metal-Oxide-Semiconductor Transistor (CMOS) process and nanowire (NW) MOSFET as well as higher and lower technology node is noticed. The reason of this difference is explained from the aspects of Radiation Induced Narrow channel effect (RINCE) and Radiation Induced Short channel effect (RISCE). It is found that some studies in recent years have corrected the influence of negative bias temperature instability (NBTI) when considering radiation effects. The TID effects on ΔVth of several kinds of new devices such as MOSFETs with new layout geometry as well as Ge-channel and GaN channel MOSFETs are described which can be investigated more deeply.

According to China’s nuclear power development plan, the demand for construction of more large-scale spent fuel reprocessing plant (RP) is increased. Nuclear safety is very important in the whole process of nuclear fuel cycle, and the safety supervision of RPs mainly draws lessons from the safety supervision of nuclear power plants (NPPs). The industry had come to realize that it could not eliminate all risks through its defense-in-depth principle and design basis accident methodologies. All nuclear power countries with advanced reprocessing industry such as the United Kingdom, France and Japan have carried out probabilistic safety assessment (PSA) research for RPs. This paper takes Chinese pilot RP as the research object. First, failure mode and effect analysis (FMEA) and master logic diagram (MLD) methodologies were adopted to identify initiating events (IEs), and then IEs were grouped. After that, fault tree (FT) analysis was performed to various accidents - red oil explosion, fire and criticality. Reliabilities of public systems - power and water and compressed air supply systems were modelled and analysed with GO methodology. And then, consequences of typical accidents were assessed. Finally, application of risk-informed technology in the reprocessing facility was investigated. In brief, PSA for a pilot RP was explored in this paper, and the results could be used as reference for Chinese commercial RP.

Emergency Assessment and Decision Support System has become an important tool to effectively respond to a nuclear emergency in nuclear power plant, the system mainly used to on-line assessment the real-time reactor conditions, calculate the source term released to the environment, and suggest the protection actions taken to protect the public and emergency workers. This paper describe the development of the system, analysis the business flow chart of nuclear assessment, introduce details of several functional modules, such as core damage assessment, source term calculation and radiological consequence assessment. The system’s data structure and data interface also be describe in detail.

Great interest in severe accident has been motivated since Fukushima accident, which indicates that the probability of severe accident exists even though it is extremely small. Emergency condition is important in decision making in case of severe accident in NPP. Although many studies have been conducted for severe accident, there was necessary to investigate emergency condition of severe accidents that could possibly happen and haven’t been sufficiently analyzed. Since station blackout (SBO) happened in Fukushima accident, a number of studies in severe accidents initiated by SBO have been carried out. Off-site power is assumed to be lost during large break loss of coolant accident (LBLOCA), but there is few study to find out emergency condition during LBLOCA if both of off-site and on-site power are lost. A hypothetical severe accident initiated by LBLOCA along with SBO in a China three-loop PWR was simulated in the paper using MELCOR code. Emergency condition was obtained including start of core uncover, start of zirconium-water reaction, failure of fuel cladding and failure of the lower head. Thermal-hydraulic response of the core during the accident was also analyzed in the paper. The model for this study consists of 46 control volumes (27 in primary loop, 17 in secondary loop, 1 in containment and 1 in environment) and 52 flow paths. High pressure safety injection (HPSI) and low pressure safety injection (LPSI) are lost because of loss of on-site and off-site power, and simultaneously main feed water and auxiliary feed water of the steam generators are lost for the same reason. The accumulator can inject water into the core since it is passive and doesn’t need any power. Results of the study will be useful in gaining an insight into detailed severe accident emergency condition that could happen in a China three-loop PWR and may provide basis for severe accident mitigation.

Operation intervention level (OIL) is a type of action level that can be used immediately and directly (without further assessment) to determine the appropriate protective actions and other response actions on the basis of an environmental measurement. OIL is used to implementation actions to protect the public due to the severe conditions at a nuclear power plant. This paper presents an integrated solution that integrates remote access and remote support over the Internet. The system real-time acquire the data of source term, meteorological, off-site monitoring points, monitoring vehicles, execute operation intervention level calculation, protective action decision-making to public based on data from database or input by user. The system simultaneous input multiple monitor data, and protection of the public action based on the results of multiple OIL decisions. The system display off-site monitoring points, protection of the public area of operations and administrative village using WebGIS.