Supercritical Transient Analysis for Ramp Reactivity Insertion Using Multiregion Integral Kinetics Code

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.

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A coupled neutronic/thermal–hydraulic module for the transient analysis of VVER-1000 reactor during reactivity insertion accidents

Progress in Nuclear Energy ◽

10.1016/j.pnucene.2020.103249 ◽

2020 ◽

Vol 121 ◽

pp. 103249

Author(s):

Mona Ajami ◽

Mahdi Zangian ◽

Abdolhamid Minuchehr ◽

Ahmadreza Zolfaghari

Keyword(s):

Transient Analysis ◽

Reactivity Insertion

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REACTIVITY INSERTION ACCIDENT ANALYSIS OF KARTINI REACTOR

GANENDRA Majalah IPTEK Nuklir ◽

10.17146/gnd.2011.14.2.40 ◽

2011 ◽

Vol 14 (2) ◽

Author(s):

Tegas Sutondo

Keyword(s):

Steady State ◽

Temperature Increase ◽

Transient Analysis ◽

Power Level ◽

Transient Condition ◽

Accident Analysis ◽

Fuel Temperature ◽

Severe Condition ◽

Start Up ◽

Reactivity Insertion

REACTIVITY INSERTION ACCIDENT ANALYSIS OF KARTINI REACTOR. A transient analysis of reactivity insertionaccident of Kartini reactor during start up from the minimum critical condition has been performed to estimate the effect onthe fuel temperature increase. Two cases of reactivity insertion limits had been assumed in this study i.e. the reactivityinsertions were limited by the actuation of overpower trip system (110 %) for the 1st case and by manual scram when thecontrol rod reached the 100 % UP position, assuming the overpower trip system was failed to function for the 2nd case.Adiabatic condition was assumed in this study, to get the most severe condition. The result shows that based on theassumed power level of trip setting for the 1st case, the total reactivity insertion was 0.82 $, corresponding to the reactorperiod of about 2 s and causing the maximum fuel temperature increase of around 11 oC or the maximum fuel temperature of45 oC. For the 2nd case the total reactivity insertion at the trip point was 1.367 $, resulting in the maximum fuel temperatureincrease of about 103 oC or maximum fuel temperatur of around 137 oC which is still far below the defined design limit of1115 oC for transient condition and 700 oC for steady state as well. This result concludes that by limiting the available coreexcess of reactivity at reasonably low, it could prevent the fuel from possible of undergoing an excessive temperatureincrease, during the postulated reactivity insertion accident.Keywords: Transient analysis, reactivity insertion, accident, reactor kartini, fuel temperature.

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