[en] Operation criterions are used to decide if the reactor can continue to work when the fuel clad failure. The method for establish the limits is presented. The tolerated maximum of failure fuel rods for the reactor safety should be calculated by risk analysis. The parameters are determined which can not only reflect the quantity but also be measured directly. The relationship is set up between the amounts with the parameters. The data calculated corresponding to maximum of failure fuel element which the reactor safety can stand are technical limits used to decide if the reactor can work continually. (author)

[en] The computational model of radionuclide activities in reactor compartment was set up for the nuclear accident of nuclear ships. The effect on the reducing of radioactive concentration by emergency ventilator was calculated quantitatively. It showed that the emergency Ventilation had a significant effect on the reducing of the radiological consequence, the reduction effect depends on the ratio of ventilation flux to the net volume of the reactor compartment, and the greater the ratio, the faster the reduction. Within half an hour after the emergency exhaust operated, the activity in the reactor compartment can be reduced by 90%. (authors)

[en] The definition of clearance is introduced. The principles and dose criterion of clearance are also clarified. The main radionuclides in radioactivity waste and the radioactivity waste which can be cleared are investigated. The techniques for the measurement of radioactivity waste from the decommissioning of nuclear reactors are summarized. This paper provides the scientific criterion and methods for the management of radioactive waste, and lays the foundation for the treatment of radioactive waste from the decommissioning of nuclear reactor. (authors)

[en] Radiation Safety is of great importance for the combat effectiveness of nuclear-powered ships, while overemphasis on radiation safety could influence the performance of carriers negatively. As a result, the optimization of radiation protection is the crucial task in the design of nuclear-powered ships. To achieve this goal, the system of radiation safety for nuclear-powered ships is constructed. The function, main problems to be considered, the control index, the relations and cooperation from inside and outside is analyzed. (author)

[en] The paper deals with two methods to recognition nuclear explosion electromagnetic pulse based on neutral network and fuzzy. Firstly the feature value extraction for the sample of nuclear explosion signals and lighting signals is discussed. Secondly two mathematic models are established. Finally, we test the recognition efficiency of the two method with certain amount of samples, the recognition includes the classification between nuclear explosions and lighting and the classification between hydrogen bombs and atomic bombs

[en] Based on the model of nuclear ship equipment, the tracer diffusion experiments were conducted, with the related systems and facilities simulated in the actual conditions. SF_6 was used as tracer, simulating the radioactive source term. The tracer was released in the reactor cabin, and the concentration of cabins were monitored separately in two different conditions, i.e., with and without the operation of emergency ventilator. The results were compared and analyzed. The study shows that emergency ventilating could reduce greatly the radioactivity in the ship. The radioactivity in the reactor cabin was reduced over 99% after the ventilator worked 30 minutes, and the radioactivity in other cabins were almost reduced to zero after 5 hours, In comparison, the reduction of radioactivity were not obvious without the operation of the ventilator. (authors)

No abstract available

[en] Two different methods to test the reactor compartment airtightness have been set up, which are the pressure reduction and the indicator leakage. Measurement and analysis ways in the two methods have been separately presented according to their principle bases. Based on the theory analysis, SF₆ has been verified to act as the indicator in the indicator leakage test. (authors)

[en] The authors developed a method for discrimination between explosions and earthquakes at the zone. Three discriminant are picked out and put into use, i.e. the ratio of max amplitude in P and S (A_p/A_s), the max period in S waves (T_s), and the ratio of local magnitude to local signal duration magnitude (M_L/M_D). Fuzzy pattern recognition method is applied to events identification (include HeiBei events and ShanXi events), and the rates of correct discrimination are all over 90% without exception

[en] A large volume of slightly radioactive waste is produced during the operation, maintaining and decommissioning of pressurized water reactor. The type and characteristic of expected clearance waste are analyzed, the basis of clearance are supported by its final destination, and the method of clearance monitoring technology are researched in this paper. (authors)