The control rod drop analysis is very important for safety analysis. A mathematical model of the control rod for the ETRR-2 reactor is presented. A computer program by the Engineering Equation Solver has been developed for investigation of the impact force and the final dropping velocity of the rod. Also, buckling deformation stresses have been simulated using commercial software, ABAQUS/CAE release 6.14-5. This paper describes the theoretical results required to obtain the von Mises stress at maximum impact force during the control rod drop. The control rod velocity after the rod reached the reactor core bottom has been predicted which reached up to 3.8 ms?1 after a drop time equal to 0.41 s at the end of the reactor core height. The results showed that the maximum and minimum von Mises stresses are 90 MPa and 6.345 MPa at maximum and minimum impact force of 6625 N and 755.73 N, respectively.
Clean areas nowadays are advanced technology solutions with very high standard and criteria applied on air quality level. Egyptian Radioisotopes Production facility (RPF) is a facility that requires clean area to produce technetium (Tc 99m ) isotope for medical purposes. The air cleanliness inside area is dependent on the air quality of supplied air, contaminant and pollutant sources, dedicated ventilation system in addition to rigorous precautions to sterilize space of the area and commitment to follow standard recommendations. Two main standard classes are available in production area, A and C according to ISO 14644-1. Our paper deals with class C in which isotope is produced and some tests are conducted to know particle counts in that area in addition to prediction of these counts by computer simulation Contam-CFD0 program, which predicts transient particles count behavior which compared with standard WHO values and measurements for validation. Biological tests are also implemented to monitor sterility of area to confirm cleanliness and validity for processing medical radioisotope. High efficiency particulate air filters with class H14 are dedicated for the clean area and equipped with pressure drop manometer for replacement in case of blockage. Simulation program is also used to predict particles concentration in case of filter contamination.
Heat pipes are passive heat transfer devices, of long lives. Material and testing reactors (MTRs) have residual heat after shutdown. Usually MTRs have also spent fuel storage tanks to compromise heat that need to be removed. Gravity assisted two-phase closed heat-pipe loop (GTPHL) covered by removal of decay heat (or heat after shutdown) with evaporator and condenser lengths each 100m helical coil shape with outer diameter 15 cm and 3 mm thickness as a passive cooling system for a nuclear spent fuel storage pool. This study proposes a completely passive cooling sys tem using thermosyphon loop for cooling and dissipation of the residual heat of wet spent fuel storage by running as main or alternative cooling system. The design focuses on heat removal from the spent fuel storage tank of a research reactor. The model considers natural convection by air for the condenser part of the heat-pipe loop to confine the residual heat. A numerical simulation, using special design of GTPHLs, was used to investigate the thermal performance of the GTPHL. The effects of heat loads were analyzed. Demineralized water was used as the GTPHL working fluid. The atmospheric air was circulated around the condenser as a cooling system. The thermal performance of the GTPHL is evaluated at heat input ranging from 25 to 15o kW with filling ratio of the working fluid of 100%. The results show that a good thermal performance is obtained at high evaporator heat load obtained from nuclear spent fuel storage tank.
A Super Critical Water-cooled Nuclear Reactor (SCWR) is a Generation IV concept currently being developed worldwide. Unique to this reactor type is the use of light-water coolant above its critical point. The number of SCWR components is reduced since steam separators and dryers are not required. This advantage drives down capital and maintenance costs. Safety is also increased, because a dry out phenomenon does not occur in SCW conditions; SCW remains in a single phase. A computer program by Engineering Equation Solver, (EES) has been produced for inquiry of the fuel, clad and coolant temperatures under supercritical conditions for supercritical water reactor powered by ThO 2 -UO 2 mixture as a fuel. In the calculation, uniform axial heat flux and average channel were considered. The bulk fluid, clad and fuel temperatures along fuel length were obtained for supercritical pressures 26, 30 and 40 MPa. Also, the UO 2 percentage added to ThO 2 was varied as, 4% and 10%. It was found that the maximum fuel temperature reached 1917 o C for a pressure of 26 MPa and 1896 o C for a pressure of 30 MPa in case of 4% UO 2 . However, the maximum temperature of the fuel was 1915 o C for a pressure of 26 MPa and 1894 o C for a pressure of 30 MPa in case of 10% UO 2 , which is surpasses the industry limit of 1850 o C.
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