[en] For the operating characteristics of HFETR, the numerical model of HFETR was established by RELAP5/MOD3 to analysis the maximal natural circulation capacity. Combining with the reactor running condition, the influence of the system pressure was analyzed by ascending power in step method and the pool water temperature on natural circulation characteristics was analyzed by integral power method. The results show that the natural circulation capacity are 0.9 and 2.0 MW separately under low pressure and high pressure, the natural circulation capacity increases as the running pressure increases, however the natural circulation capacity decreases as the coolant temperature increases in the pressure vessel. Based on the computational result and the theoretical deduction, a correlation was proposed to predicate the relationship between the natural circulation mass flow and the core power under different coolant temperatures. (authors)

[en] Whole plant blackout is one of most serious accidents. So, in order to ensure the safety of a reactor after a whole plant lost power supply, the power system must have an emergency power. For the purpose, there are two sets of DC motor-AC generator, to which power is supplied with batteries, and two sets of diesel generators in the power system of this reactor plant. The aims of the test are, after the whole plant blackout, to measure the action time of the safety and control system, the starting time of an emergency pump and the time of beginning to supply flow to the primary loop, to measure the transient change of the main parameters, and to analyze the safety, so as to supply the sure data for developing the instruction of dealing with accidents. Moreover, the safety of the reactor at 250 kW thermal power after loss of power supply, when an emergency pump stopped and reverse flow took place, was studied. Three times of blackout test, the testing method, the test results, and the safety analysis are reported. As the result, it was confirmed that the safety of the reactor can be ensured by the protection system, power system and cooling system. (Kako, I.)

[en] The author introduces the strategy, organization, procedure and management of maintenance which have been formed from the eighteen year's operation of High-Flux Engineering Test Reactor (HFETR). The training design and training of the maintenance is systematically researched and summarized in it. The analysis result of the operation annual report and maintenance process indicate that the maintenance work for HFETR is reliability

[en] Frameworks of criteria is proposed for the assessment of risk from accidents in nuclear reactors, including the limits and objective values for individual and societal risks. It is suggested that the limit for occupational individual risk in site is 10^-4/man · a, 10^-5/man · a for the public outside the site boundary and 10^-4-10^-5/man · a for the public on the site boundary. The nominal objective values could be taken as 10% of above. The limits and objective values for societal risk adopted D. J. Higson's suggestion should be reasonable

[en] In the flow reverse of High Flux Engineering Test Reactor (HFETR), the change of the reactor core's thermal parameters affects the safety of the reactor operation. So the model of HFETR by the RELAP5/MOD3 code was established and relevant research was conducted. The study results indicate that the maximum permissible power for the conversion from forced circulation to natural circulation is 850 kW, the time for the conversion from natural circulation to forced circulation is decided by the upper coolant temperature. The results show that the recent operating mode can guarantee the safe operation of the reactor, and the data provide the support for the more perfect operation mode in the future. (authors)

[en] The attenuation of the fast neutron flux at the pressure vessel has been estimated through the method of the fast neutron removing cross section. The gamma-induced internal heating in the stainless steel rod has been computed by DOT3.5 Code. The wall temperate and centre temperature has been computed under the design status and current operating status of High-Flux Engineering Test Reactor (HFETR). The safety evaluation of the lattice sheet and the analysis of the core performance have been done. These results show that the core safety is not variation, and the fast neutron flux at the pressure vessel will be decreased greatly after replacement of the aluminium rod by the stainless steel rod as the outermost reflector of the core for HFETR

[en] Some of practical experiances obtained from the decadal operation of HFETR are described, such as the simplifide calculation method of the maximum permissible power, interference effect and relative efficiency calibration of control rods. Features of improved primary coolant system, loss of coolant monitoring during operation and so on are presented. Also, accident analysis and treatment are briefly introduced

[en] The author emphasizes the presentation of the quality control and management of implement process. Owing to the strict and scientific organizing, the field implement was completed only in 4 months, and comprehensive operation test of reactor was successful at one go. The management target that is safety, high efficiency and high quality, success at one go, was hit

[en] The author introduces the confirming, classifying, reporting and handling of all kinds of the operation abnormality and event of High-Flux engineering test reactor (HFETR) based on nuclear safety law. The analysis results of typical prototype's operation events and part of operation date are given, and some weakness links of technology are presented. At last, some suggestion are given in order to observe the nuclear safety law system and strengthen supervision and management of operation better

[en] The performance of 80 and 60 fuel assemblies cores for High Flux Engineering Test Reactor (HFETR) has been compared with theoretical analysis and operating results. These results show that the core performance of 80 fuel assemblies is the same as that of 60 fuel assemblies in the following aspects: the permission power of core, the irradiation test of materials, the transmutation doping of single crystalline silicon, the production of Mo-Tc isotopes, etc. The core of 80 fuel assemblies is more convenient in operation after 500 kw test loop installed, and in greatly raising the production of ⁶⁰Co source with high specific radioactivity and the usage of fuel. As compared to the production of ⁶⁰Co source of 60 fuel assemblies core, the benefit of 80 fuel assemblies core can increase more than 3.8 millions RMB yuan per year. (2 refs., 2 tabs.)