Meeting fuel temperature limits in an HTR-Module Reactor during depressurized core heat-up

Sensitivity and Uncertainty Analysis of the Maximum Fuel Temperature under Accident Condition of HTR-PM

“…is leads to a conservative 2% uncertainty of the operation power, i.e., the 2 standard deviation value of the operation power is 2%. It is different with the value used in the cited paper [3], in which 5% is too conservative, and same as the value for the PBMR analysis [4].…”

“…Furthermore, the basic nuclear data, the "multipass" fuel refueling scheme, spatial distribution of decay heat of the zone where the fuel temperature reaches to the maximum value, decay heat production rate, effective conductivity coefficient of the pebble bed, conductivity of graphitic matrix material, specific heat capacity of the fuel elements, effective conductivity and specific heat capacity of the reflector graphite, measurement of the initial temperature, the thermal property parameters of the core structures and outer components, and the heat transfer between pressure vessel and surface cooler all have an influence on the maximum fuel temperature, and these influences are different. In the cited paper [3], the preliminary uncertainty analysis of the maximum fuel temperature under DLOFC accident condition of the HTR-module reactor [14] due to most of the uncertainty sources mentioned above was performed and the numerical results indicate that the appearance of a higher peak power density when the operational power transients, the inadvertently full insertion of the absorber rod, the measurement of initial temperature, the thermal property parameters of the core structures and outer components, and the heat transfer between pressure vessel and surface cooler have a relatively small or only a marginal influence on the maximum fuel temperature under DLOFC accident condition. erefore, these uncertainty parameters are not considered in our work and the basic uncertainty information of some parameters is requantified based on our previous studies.…”

“…At the same time, the probability distribution types and variation range of each uncertainty source should be determined based on the experimental data or material characteristics or numerical simulation results. In this work, eight important uncertainty sources are selected based on some related papers [3,4], preliminary sensitivity analysis via a homedeveloped thermal-hydraulic code ATHENA for HTGR, and our previous studies [5,6].…”

Thermal–hydraulic feasibility analysis on uprating the HTR–PM

“…Increasing the decay heat generation rate by 2.85%, which is an average standard deviation according to German standards (Kohtz and Haque, 1992), causes a maximum fuel temperature 25 • C higher than that with nominal decay heat generation.…”

The impact of design on the decay heat removal capabilities of a modular pebble bed HTR

“…For the material properties such as thermal conductivities, emissivities and specific heat capacities of helium, graphite, carbon and steel standard correlations or values have been used which were also applied in the HTR-MODULE case (Kohtz and Haque, 1992). The effective heat conductivity of the pebble bed was evaluated according to the model of ZehnerSchlünder.…”