A pile noise experiment in the reference core of the nuclear research reactor LR-0

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F26722445%3A_____%2F23%3AN0000039" target="_blank" >RIV/26722445:_____/23:N0000039 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0306454923001524" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0306454923001524</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.anucene.2023.109833" target="_blank" >10.1016/j.anucene.2023.109833</a>

Jazyk výsledku

angličtina

Název v původním jazyce

A pile noise experiment in the reference core of the nuclear research reactor LR-0

Popis výsledku v původním jazyce

For safety reasons, it is important to simulate precisely the kinetic behavior of light water nuclear reactors (LWR) in nominal or incidental situations. In the point kinetic approximation, a few integral parameters allow describing the reactor's behavior. It is of interest to measure those parameters, such as the delayed neutron fraction and delayed neutron abundances, in low power research reactors loaded with benchmarked fuel con-figurations to compare with simulations results. In this context, Commissariat a` l'' Energie Atomique et aux ' Energies Alternatives (CEA) and Centrum Rez (CVR) have been collaborating towards measuring the delayed neutron fraction of LR-0, a VVER-type research reactor operated by CVR. This paper presents the first estimation of the delayed neutron fraction of the reactor loaded with six fuel assemblies, arranged in a small hexagonal lattice with a center cavity accessible for instrumentation. This configuration was chosen because it was very close to the so-called reference configuration with seven fuel assemblies, the one that was benchmarked in the NEA IRPheP Handbook. The measurement was performed in July 2021 using the CEA-developed acqui-sition system SPECTRON dedicated to pile noise experiments. Pile noise refer to a set of techniques which focus on the correlations induced by the fission process in the signals of neutron detectors. The experimental campaign was designed to meet two objectives: first to provide an estimation of the delayed neutron fraction; second to study the impact of the location of the neutron detectors on the quality of the results. Two fission chambers were used, one was fixed and located in the core center and the second was placed in various locations in the reflector. Several configurations were tested with the mobile detector progressively moved up to 20 cm from the closest fuel element. The reactor fission rate was obtained thanks to gamma spectrometry on metal foils (gold, nickel and iron). Simulations with TRIPOLI-4 (R) and JEFF33 libraries were performed to convert the saturated activities into fission rates. The delayed neutron fraction was estimated at 782 +/- 10 pcm and the generation time was measured at 39.1 +/- 0.5 mu s. The uncertainty balance is as follows: 2 % associated to the Diven factor and 1.5 % associated to the core's integral fission rate and 0.5 % for the statistical uncertainty. The reproducibility of the experiments was found very good, with a negligible dispersion amongst experiments (0.2 %). These results are valuable complements to the characterization of LR-0 reference neutron benchmark field.

Název v anglickém jazyce

A pile noise experiment in the reference core of the nuclear research reactor LR-0

Popis výsledku anglicky

For safety reasons, it is important to simulate precisely the kinetic behavior of light water nuclear reactors (LWR) in nominal or incidental situations. In the point kinetic approximation, a few integral parameters allow describing the reactor's behavior. It is of interest to measure those parameters, such as the delayed neutron fraction and delayed neutron abundances, in low power research reactors loaded with benchmarked fuel con-figurations to compare with simulations results. In this context, Commissariat a` l'' Energie Atomique et aux ' Energies Alternatives (CEA) and Centrum Rez (CVR) have been collaborating towards measuring the delayed neutron fraction of LR-0, a VVER-type research reactor operated by CVR. This paper presents the first estimation of the delayed neutron fraction of the reactor loaded with six fuel assemblies, arranged in a small hexagonal lattice with a center cavity accessible for instrumentation. This configuration was chosen because it was very close to the so-called reference configuration with seven fuel assemblies, the one that was benchmarked in the NEA IRPheP Handbook. The measurement was performed in July 2021 using the CEA-developed acqui-sition system SPECTRON dedicated to pile noise experiments. Pile noise refer to a set of techniques which focus on the correlations induced by the fission process in the signals of neutron detectors. The experimental campaign was designed to meet two objectives: first to provide an estimation of the delayed neutron fraction; second to study the impact of the location of the neutron detectors on the quality of the results. Two fission chambers were used, one was fixed and located in the core center and the second was placed in various locations in the reflector. Several configurations were tested with the mobile detector progressively moved up to 20 cm from the closest fuel element. The reactor fission rate was obtained thanks to gamma spectrometry on metal foils (gold, nickel and iron). Simulations with TRIPOLI-4 (R) and JEFF33 libraries were performed to convert the saturated activities into fission rates. The delayed neutron fraction was estimated at 782 +/- 10 pcm and the generation time was measured at 39.1 +/- 0.5 mu s. The uncertainty balance is as follows: 2 % associated to the Diven factor and 1.5 % associated to the core's integral fission rate and 0.5 % for the statistical uncertainty. The reproducibility of the experiments was found very good, with a negligible dispersion amongst experiments (0.2 %). These results are valuable complements to the characterization of LR-0 reference neutron benchmark field.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20305 - Nuclear related engineering; (nuclear physics to be 1.3);

Projekt

<a href="/cs/project/LM2023041" target="_blank" >LM2023041: České mezinárodní centrum výzkumných reaktorů</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

Annals of Nuclear Energy

ISSN

0306-4549

e-ISSN

1873-2100

Svazek periodika

189

Číslo periodika v rámci svazku

September

Stát vydavatele periodika

CZ - Česká republika

Počet stran výsledku

8

Strana od-do

1-8

Kód UT WoS článku

000982373600001

EID výsledku v databázi Scopus

2-s2.0-85153520100