Lattice code choice effect and geometry and material uncertainties in core physics calculations

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Lattice code choice effect and geometry and material uncertainties in core physics calculations

Popis výsledku v původním jazyce

Full-core calculations often show significant differences from the measured reactor records and one of the most important questions is whether the difference is caused mostly by a methodology bias of the computation stack (basic nuclear data-lattice code model-lattice code-XS homogenization-XS parameterization-core physics code) or rather by inherent input data uncertainties. In other words: can we improve the agreement between calculation and measurement by improving our methods or are the observed differences below the effect of the uncertainties? In this paper we focus on the influence of material and geometry uncertainties. We use Monte-Carlo sampling approach: various parameters of the fuel assemblies (dimensions, enrichment etc.) have uncertainties or tolerances attached and we run hundreds of lattice code calculations and generate a large amount of macroscopic XS libraries. Afterwards, a sampling mechanism is used to run hundreds of full-core core physics calculations; the results are then gathered and statistically processed. In the end we obtain full-core results (critical boric acid concentration, peaking factors, spatial power distribution) with resulting uncertainties attached. This paper presents the methods we have used and the results obtained so far: impact of aforementioned factors on principal neutron-physical core characteristics (reactivity, power distribution, feedback coefficients) is quantified and evaluated.

Název v anglickém jazyce

Lattice code choice effect and geometry and material uncertainties in core physics calculations

Popis výsledku anglicky

Full-core calculations often show significant differences from the measured reactor records and one of the most important questions is whether the difference is caused mostly by a methodology bias of the computation stack (basic nuclear data-lattice code model-lattice code-XS homogenization-XS parameterization-core physics code) or rather by inherent input data uncertainties. In other words: can we improve the agreement between calculation and measurement by improving our methods or are the observed differences below the effect of the uncertainties? In this paper we focus on the influence of material and geometry uncertainties. We use Monte-Carlo sampling approach: various parameters of the fuel assemblies (dimensions, enrichment etc.) have uncertainties or tolerances attached and we run hundreds of lattice code calculations and generate a large amount of macroscopic XS libraries. Afterwards, a sampling mechanism is used to run hundreds of full-core core physics calculations; the results are then gathered and statistically processed. In the end we obtain full-core results (critical boric acid concentration, peaking factors, spatial power distribution) with resulting uncertainties attached. This paper presents the methods we have used and the results obtained so far: impact of aforementioned factors on principal neutron-physical core characteristics (reactivity, power distribution, feedback coefficients) is quantified and evaluated.

Druh

D - Stať ve sborníku

CEP obor

JF - Jaderná energetika

OECD FORD obor

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Projekt

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Návaznosti

N - Vyzkumna aktivita podporovana z neverejnych zdroju

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

International Congress on Advances in Nuclear Power Plants, ICAPP 2016 Volume 1, 2016

ISBN

978-151082594-9

ISSN

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e-ISSN

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Počet stran výsledku

9

Strana od-do

603-611

Název nakladatele

American Nuclear Society

Místo vydání

La Grange Park, Illinois, USA

Místo konání akce

San Francisco, USA

Datum konání akce

17. 4. 2016

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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