Reactivity insertion transient analysis for KUR low-enriched uranium silicide fuel core

Analysis of the steady-state and reactivity insertion accident is very important for the safety of reactor operations. In this study, steady-state and reactivity insertion accident analysis when the low enriched uranium foil target is irradiated in the reactor core has been carried out. The analysis is carried out by the best estimate method by using a coupled neutronic, kinetic, and thermal-hydraulic code, MTR-DYN. The MTR-DYN code is based on the 3-D multigroup neutron diffusion method. The cell calculations for the target are carried out by the WIMSD/5 and MTR-DYN code. After reactivity insertion, the coolant, fuel, and clad temperature are observed. The calculation results for the initial power of 1 W showed that the maximum temperature of the coolant, clad, and fuel are 49.76?C, 65.01?C, and 65.26?C, respectively. Meanwhile, when the reactivity insertion at the initial power of 1 MW, the maximum temperature of the coolant, clad, and fuel are 72.23?C, 140.79?C, and 141.97?C, respectively. Based on those calculation results during irradiation low enriched uranium foil target, the temperature in the steady-state and reactivity insertion accident does not exceed the allowable safety limit.

Download Full-text

Investigations of Rod Positions for Treat M8CAL Analyses

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4038929 ◽

2018 ◽

Vol 4 (3) ◽

Cited By ~ 1

Author(s):

Zachary Weems ◽

Sedat Goluoglu ◽

Mark D. DeHart

Keyword(s):

Significant Role ◽

Transient Analysis ◽

Boron Concentration ◽

Three Dimensional ◽

Test Facility ◽

Initial Transient ◽

Reactor Test ◽

Experimental Values ◽

Reactor Models ◽

Reactivity Insertion

The transient reactor test facility (TREAT), a graphite moderated experimental reactor, is scheduled to restart in late 2017. There is now renewed interest in development of capabilities to model and simulate the TREAT transients using three-dimensional coupled physics. To validate existing transient analysis tools as well as those under development, several temperature-limited transients have been modeled and analyzed. These transients are from the M8 calibration (M8CAL) experiment series, a set of experiments performed to calibrate the reactor detectors for the planned M8 series of fuel tests. Detailed reactor models were prepared that were then used to calculate the pretransient and post-transient keff values as well as corresponding reactivity insertions. Alterations to modeled values of shutdown and initial transient rod insertion depths were made to better match the reported experimental values of reactivity insertions assuming just critical pretransient states. It was found that two of the altered media inputs, fuel and Zircaloy-3 cladding, had significant effects on the keff. In addition, increasing shutdown rod insertion by 3–5 cm and decreasing initial transient rod insertion by 1–2 cm gave perfect pretransient keff and total reactivity insertion values. However, the revised positions are as much as a factor of 3–20 different from reported uncertainty of 0.762 cm. This suggests that boron concentration uncertainties may play a significant role in accurately modeling the TREAT transients and should be investigated thoroughly.

Download Full-text

Study on Transmutation of Minor Actinides as Burnable Poison in VVER-1000 Fuel Assembly

Science and Technology of Nuclear Installations ◽

10.1155/2019/5769147 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12

Author(s):

Vinh Thanh Tran ◽

Hoai-Nam Tran ◽

Huu Tiep Nguyen ◽

Van-Khanh Hoang ◽

Pham Nhu Viet Ha

Keyword(s):

Fuel Assembly ◽

Spent Nuclear Fuel ◽

Calculation Model ◽

Minor Actinide ◽

Minor Actinides ◽

Reference Case ◽

Burnable Poison ◽

Uranium Fuel ◽

Enriched Uranium ◽

Reactivity Insertion

Thermal reactors have been considered as interim solution for transmutation of minor actinides recycled from spent nuclear fuel. Various studies have been performed in recent decades to realize this possibility. This paper presents the neutronic feasibility study on transmutation of minor actinides as burnable poison in the VVER-1000 LEU (low enriched uranium) fuel assembly. The VVER-1000 LEU fuel assembly was modeled using the SRAC code system, and the SRAC calculation model was verified against the MCNP6 calculations and the available published benchmark data. Two models of minor actinide loading in the LEU fuel assembly have been investigated: homogeneous mixing in the UGD (Uranium-Gadolinium) pins and coating a thin layer to the UGD pins. The consequent negative reactivity insertion by minor actinides was compensated by reducing the gadolinium content and boron concentration. The reactivity of the LEU assembly versus burnup and the transmutation of minor actinide nuclides were examined in comparison with the reference case. The results demonstrate that transmutation of minor actinides as burnable poison in the VVER-1000 reactor is feasible as minor actinides could partially replace the functions of gadolinium and boric acid for excess reactivity control.

Download Full-text

Transient behaviour of low-enriched uranium silicide plate-type fuel for research reactors during a reactivity-initiated accident

International Journal of Nuclear Energy Science and Technology ◽

10.1504/ijnest.2008.020534 ◽

2008 ◽

Vol 4 (2) ◽

pp. 97 ◽

Cited By ~ 3

Author(s):

Kazuaki Yanagisawa

Keyword(s):

Research Reactors ◽

Transient Behaviour ◽

Enriched Uranium ◽

Type Fuel ◽

Plate Type ◽

Uranium Silicide

Download Full-text