scholarly journals Reactivity induced transient analysis when the occurrence of leakage in the dry irradiation channels of the Dalat Nuclear Research Reactor

2021 ◽  
Vol 8 (4) ◽  
pp. 1-9
Author(s):  
Duc Tu Dau ◽  
Minh Tuan Nguyen ◽  
Vinh Vinh Le ◽  
Ton Nghiem Huynh ◽  
Cuong Nguyen Kien ◽  
...  
Keyword(s):  
Water Column ◽  
Transient Analysis ◽  
Research Reactor ◽  
Nuclear Research ◽  
Point Of View ◽  
Operating Conditions ◽  
Nuclear Research Reactor ◽  
Calculation Results ◽  
Reactor Operating ◽  
Reactor Pool

The leakage from the reactor pool back into the dry irradiation channels due to corrosion or mechanics based reason is a postulated event that could occur under operating conditions of the Dalat nuclear research reactor (DNRR), especially the channel 7-1 which has been installed more than 30 years. When it occurs, the air space in these channels will be occupied by the water, subsequently a water column will appear in fuel region. The appearance of water column considerably enhances medium of neutron moderation for its surrounding fuel assemblies. As a result, a positive reactivity is inserted in the core and this event is classified as an insertion of excess reactivity. This event needs to be addressed by analysis and assessment from safety point of view and the results of analysis are also important for updating the reactor operating procedures. This paper presents assumptions, computer models and the results of analysis for such event in the DNRR by using MCNP5 code (code for neutronics analysis) and EUREKA-2/RR code (code for transient analysis). The calculation results include value of reactivity insertion, change in power of reactor, as well as surface temperature of the hottest fuel assembly. This research contributes to updating the reactor operating procedure.

scholarly journals Steady-State Thermal-Hydraulic Analysis of the LEU-Fueled Dalat Nuclear Research Reactor

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Kien-Cuong Nguyen ◽  
Vinh-Vinh Le ◽  
Ton-Nghiem Huynh ◽  
Ba-Vien Luong ◽  
Nhi-Dien Nguyen
Keyword(s):  
Research Reactor ◽  
Nuclear Research ◽  
Nucleate Boiling ◽  
Fuel Cladding ◽  
Hydraulic Analysis ◽  
The Core ◽  
Nuclear Research Reactor ◽  
Calculation Results ◽  
Enriched Uranium ◽  
Thermal Hydraulic Analysis

This paper presents results of steady-state thermal-hydraulic analysis for the designed working core of the Dalat Nuclear Research Reactor (DNRR) using the PLTEMP/ANL code. The core was designed to be loaded with 92 low-enriched uranium (LEU) VVR-M2 fuel bundles (FBs) and 12 beryllium rods surrounding a neutron trap at the core center, for replacement of the previous core with 104 high-enriched uranium (HEU) VVR-M2 FBs. Before using this code for thermohydraulic analysis of the designed LEU working core, it was validated by comparing calculation results with experimental data collected from the HEU working core of the DNRR. The discrepancy between calculated results and measured data was at the maximum about 0.8°C and 1.5°C of fuel cladding and outlet coolant temperatures, respectively. In the design calculation, thermohydraulic safety was confirmed through evaluation of the fuel cladding and coolant temperatures, as well as of other safety parameters such as Departure from Nucleate Boiling Ratio (DNBR) and Onset of Nucleate Boiling Ratio (ONBR). The calculation results showed that, in normal operation conditions at full nominal thermal power of 500 kW without uncertainty parameters, the maximum fuel cladding temperature of the hottest FB was about 90.4°C, which is lower than its limit value of 103°C, the minimum DNBR was 32.0, which is much higher than the recommended value of 1.5, and the minimum ONBR was 1.43, which is higher than the recommended value of 1.4 for VVR-M2 LEU fuel type. When the global and local hot channel factors were taken into account, the maximum temperature of fuel cladding at the hottest FB was about 98.4 °C, for global only, and 114.3°C, for global together with local hot channel factors. The calculation results confirm the safety operation of the designed LEU core loaded with 92 fresh VVR-M2 FBs.

scholarly journals Calculation Results for Enhancing Ability of I-131 Radioisotope Production Using Tellurium Dioxide Target on the Dalat Nuclear Research Reactor

2021 ◽  
Vol 9 (3) ◽  
Author(s):  
Cuong Nguyen Kien ◽  
Nghiem Huynh Ton ◽  
Vinh Le Vinh ◽  
Vien Luong Ba ◽  
Huy Pham Quang ◽  
...  
Keyword(s):  
Research Reactor ◽  
Nuclear Research ◽  
Computer Code ◽  
Total Activity ◽  
Radioisotope Production ◽  
Original Design ◽  
Operational Conditions ◽  
Safety Requirements ◽  
Nuclear Research Reactor ◽  
Calculation Results

The paper presents the calculation results in re-design of neutron trap of the Dalat Nuclear Research Reactor (DNRR) for I-131 radioisotope production using TeO2 target. The new design permits for loading more TeO2 capsules from 9 to 12, 15 and 18 in the neutron trap. The enhancement of radioisotope production was implemented by re-arrangement of the neutron trap without changing the dimension or geometry of irradiation capsules. By using neutronics computer code as MCNP6, the obtained calculation results of I-131 activity in 6 investigated cases showed that the new design by the re-arrangement of the neutron trap can be used effectively for radioisotope production with thermal neutron flux in average range from 5.3×1012 to 1×1013 n/cm2.s and the total activity of I-131 isotope was increased from about 19.2% to 38.8% comparing with the original design using 9 capsules. The negative reactivity insertion was from 0.60 βeff to 0.96 βeff when loading capsules that also met the safety requirements of operational conditions of the DNRR.

scholarly journals MCNP model of L-54M nuclear research reactor: validation by preliminary graphite radiological characterization

2019 ◽  
Vol 322 (3) ◽  
pp. 1341-1350
Author(s):  
Eros Mossini ◽  
Luca Codispoti ◽  
Giorgio Parma ◽  
Filippo Maria Rossi ◽  
Elena Macerata ◽  
...  
Keyword(s):  
Research Reactor ◽  
Nuclear Research ◽  
Nuclear Research Reactor ◽  
Radiological Characterization

State of the Art of Nuclear Reactor Instrument Automation

1974 ◽  
Vol 96 (4) ◽  
pp. 394-398
Author(s):  
M. Taeschner ◽  
R. Gariod
Keyword(s):  
High Performance ◽  
Nuclear Reactor ◽  
Research Reactor ◽  
State Of The Art ◽  
Nuclear Research ◽  
Automation System ◽  
Nuclear Research Reactor ◽  
High Investment

Due to its complexity, nuclear reactor instrument automation is a challenge to engineers. High investment and running costs of a nuclear research reactor imply the use of advanced equipment and concepts for instrument automation when striving for high performance, reliability, and operational convenience under budgetary pressure. The article describes a successfully operating instrument automation system stressing the important underlying concepts trying to avoid too much details on specific hardware which is dependent on the time when one must order things.

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