Decrease the Volume of Boric Regulation of the Reactivity when Using the Burnable Absorber on the Basis of (GD2O3) in the Fuel Reactor WWER-1200

Sondos, M. A. Abu; Demin, V. M.; Savander, V. I.

doi:10.26583/gns-2019-03-06

Cited by 9 publications

(4 citation statements)

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“…After that, the spectral and density components of the overall temperature reactivity coefficient for all considered life du- The results of the computational studies agree with the conclusion that a longer life and a larger initial concentration of boron in the coolant affect adversely the density reactivity coefficient reducing it to negative values for a 24-month life. When erbium is used, the initial concentration of boron in the coolant decreases and the density reactivity coefficient grows linearly reaching substantially positive values (up to 50 to 70% of its value in a purely uranium-water system) which meets the EOL core composition (Abu Sondos et al 2019).…”

Section: Computational Analysismentioning

confidence: 96%

Use of erbium as a burnable absorber for the VVER reactor core life extension

Alassaf¹,

Savander²,

Hassan³

2020

NUCET

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The paper presents the results of a computational and theoretical analysis concerned with the use of erbium as a burnable absorber in VVER-type reactors. Partial refueling options for the reactor life extension to 18 and 24 months is considered, the refueling ratio being equal to three for the 18-month life and to two for the 24-month life. Erbium is expected to be present in all fuel elements in the FA with the same weight content. The influence of the erbium weight content on such neutronic characteristics of the reactor and fuel as burn-up, reactivity coefficients, residual volume of “liquid" control, and amounts of the liquid radioactive waste (LRW) formed was assessed. The calculations were performed using a simplified model of refueling without FA reshuffling. An infinite array of polycells consisting of FAs with different in-core times was considered. The escape of neutrons from the core was taken into account by selecting the critical value K∞ at the end of life. Erbium does not burn up in full for the lifetime which affects the fuel burn-up as compared with the liquid excessive reactivity compensation system. The reduction is 0.7% per 0.1% of the erbium weight load in the fuel elements. This, however, also reduces the maximum content of the boron absorber in the coolant and the LRW accumulation in the ratio of 5% per 0.1% of the erbium weight load. Erbium influences the spectral component of the coolant temperature reactivity coefficient which turns out to be negative even with its minor weight fraction in fuel elements, and a reduction in the boron absorber fraction leads to a positive value of the density reactivity coefficient. As a result, the overall coolant temperature reactivity coefficient has a negative value throughout the lifetime.

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Section: Computational Analysismentioning

confidence: 96%

Use of erbium as a burnable absorber for the VVER reactor core life extension

Alassaf¹,

Savander²,

Hassan³

2020

NUCET

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“…The multiplying coefficient of this polycell is described as the arithmetic mean of the multiplication values of each specific fuel assembly. It is considered that TVS (FA) consists of individual polycells, in the middle of this poly-cells there is a tweg (UO 2 +Gd), and around is the number of fuel rods [4,5]. A full-scale fuel assembly (FA) consists of 331 rods.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

Burnable absorber element (Gd and Er) use in the WWER-type reactor to increase the refueling time

Rahman,

Uvakin,

Hossen

2024

GNS

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In a WWER-type pressurized water reactor, high-neutron-absorbing materials can compensate for the excess reactivity. Theoretical and computational analyses were conducted in this article to use burnable absorbers placed in a fuel rod to reduce the reactivity margin for extending refueling time for WWER-type reactors. To investigate the reduction of the reactivity margin, the fuel burnup calculation was performed without a burnable absorber and with a combination of a variety of burnable absorbers, namely natural Gadolinium (Gd) and Erbium (Er), applying a simplified GETERA program. The calculation found that the variation of the quantity of the burnable absorber (Gd, Er) inside the fuel assemblies governs the reactivity margin for the fuel burnup and increases the efficiency of Uranium fuel (UO2). The combined use of Gd and Er leads to a smoother decrease in reactor reactivity due to a smaller Er absorption cross section, which makes it possible to reduce the total mass of Gd in the fuel element and reduce the blocking effect. In the calculation, Gd concentrations employed in the computation at 1.5% and 3%, while Er concentrations were used within the range of 0.1%–0.6%.

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“…После этого простым варьированием температуры тепло Результаты расчетных исследований соответствуют выводу о том, что повышение длительности кампании и увеличение начальной концентрации бора в теплоносителе отрицательно влияют на плотностной коэффициент реактивности, снижая его до отри цательных значений для двухгодичной кампании. При использовании эрбия начальная концентрация бора в теплоносителе снижается и плотностной коэффициент реактивно сти линейно возрастает, достигая существенно положительных значений (до 50 -70% от его величины в чисто уран водной системе), которая отвечает составу активной зоны в конце кампании [10].…”

Section: расчетный анализunclassified