Characterization of gamma field in the JSI TRIGA reactor

Ambrožič, Klemen; Radulović, Vladimir; Snoj, Luka; Gruel, A.; Guillou, M. Le; Blaise, Patrick; Destouches, C.; Barbot, L.

doi:10.1051/epjconf/201817004001

Cited by 5 publications

(4 citation statements)

References 33 publications

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“…Second, for shutdown mode, dose rates were calculated based on the response of a calibrated ionization chamber together with the power reading of the reactor as measured in the linear channel. 32 A factor of 14250 Gy s −1 W 1− was determined for γray-irradiated samples in the triangular channel with an uncertainty of ∼10%. Groups of samples were irradiated for a specified time depending on the dose quality and desired absorbed doses.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Nuclear Cogeneration of Methanol and Acetaldehyde from Ethylene Glycol Using Ionizing Radiation

Plant,

Kos,

Jazbec

et al. 2023

Ind. Eng. Chem. Res.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Nuclear Cogeneration of Methanol and Acetaldehyde from Ethylene Glycol Using Ionizing Radiation

Plant,

Kos,

Jazbec

et al. 2023

Ind. Eng. Chem. Res.

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“…Measurements of nuclear reactor gamma ray fields have included spectroscopy outside of the reactor shielding [10], and in-core measurements of fluxes using ionization chambers [11]- [13]. A recent focus has been the determination of delayed gamma contributions measured with mixed neutron-gamma flux measurements in research reactors [14], [15]. To the knowledge of the authors, no direct measurements of in-core gamma spectra have hitherto been performed.…”

Section: Introductionmentioning

confidence: 99%

First in-core gamma spectroscopy experiments in a zero power reactor

et al. 2021

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Gamma rays in nuclear reactors, arising either from nuclear reactions or decay processes, significantly contribute to the heating and dose of the reactor components. Zero power research reactors offer the possibility to measure gamma rays in a purely neutronic environment, allowing for validation experiments of dose estimates, computed spectra, and prompt to delayed gamma ratios. The resulting data can contribute to models, code validation and photo atomic/nuclear data evaluation. To date, most experiments have relied on flux measurements using TLDs, ionization chambers, or spectrometers set in low flux areas. The CROCUS reactor allows for flexible detector placement in and around the core, and has recently been outfitted with gamma detection capabilities to fulfill the need for in-core gamma spectroscopy, as opposed to flux. In this paper we report on the experiments and accompanying simulations of gamma spectrum measurements inside a zero power reactor core, CROCUS. It is a two-zone, uranium-fueled light water moderated facility operated by the Laboratory for Reactor Physics and Systems Behaviour (LRS) at the Swiss Federal Institute of Technology Lausanne (EPFL). Herein we also introduce, in detail, the new LEAF system: A Large Energy-resolving detection Array for Fission gammas. It consists of an array of four detectors – two large ø 127 254 mm Bismuth Germanate (BGO) and two smaller ø 12 50 mm Cerium Bromide (CeBr3) scintillators. We describe the calibration and characterization of LEAF followed by first in-core measurements of gamma ray spectra in a zero power reactor at different sub-critical and critical states, and different locations. The spectra are then compared to code results, namely MCNP6.2 pulse height tallies. We were able to distinguish prompt processes and delayed peaks from decay databases. We present thus experimental data from hitherto inaccessible core regions. We provide the data as validation means for codes that attempt to model these processes for energies up to 10 MeV. We finally draw conclusions and discuss the future uses of LEAF. The results indicate the possibility of isotope tracking and burn-up validation.

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“…However, many nuclear data libraries do not include all relevant prompt or delayed emission data [8] in order to provide the full picture [9]. As the delayed contribution of the total gamma flux, or delayed gamma fraction, is typically of the order of 30% [3,[10][11][12], the knowledge and accurate experimental determination of this fraction can aid in validating these codes.…”

Section: Introductionmentioning

confidence: 99%

Delayed gamma fraction determination in the zero power reactor CROCUS

Pakari

Mager

Lamirand

et al. 2021

EPJ Nuclear Sci. Technol.

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Gamma rays are an inextricable part of a nuclear reactor’s radiation field, and as such require characterization for dose rate estimations required for the radiation protection of personnel, material choices, and the design of nuclear facilities. Most commonplace radiation transport codes used for shielding calculations only included the prompt neutron induced component of the emitted gamma rays. The relative amount of gamma rays that are emitted from delayed processes – the delayed gamma fraction – amount to a significant contribution, e.g. in a typical zero power reactor at steady state is estimated to be roughly a third. Accurate predictions of gamma fields thus require an estimation of the delayed content in order to meaningfully contribute. As a consequence, recent code developments also include delayed gamma sources and require validation data. The CROCUS zero power research reactor at EPFL is part of the NEA IRPhE and has therefore been characterized for benchmark quality experiments. In order to provide the means for delayed gamma validation, a dedicated experimental campaign was conducted in the CROCUS reactor using its newly developed gamma detection capabilities based on scintillators. In this paper we present the experimental determination of the delayed gamma fraction in CROCUS using in-core neutron and gamma detectors in a benchmark reactor configuration. A consistent and flexibly applicable methodology on how to estimate the delayed gamma fraction in zero power reactors has hitherto not existed – we herein present a general experimental setup and analysis technique that can be applied to other facilities. We found that the build-up time of relevant short lived delayed gamma emitters is likely attributed to the activation of the aluminium cladding of the fuel. Using a CeBr3 scintillator in the control rod position of the CROCUS core, we determined a delayed gamma fraction of (30.6±0.6)%.

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Characterization of gamma field in the JSI TRIGA reactor

Cited by 5 publications

References 33 publications

Nuclear Cogeneration of Methanol and Acetaldehyde from Ethylene Glycol Using Ionizing Radiation

Nuclear Cogeneration of Methanol and Acetaldehyde from Ethylene Glycol Using Ionizing Radiation

First in-core gamma spectroscopy experiments in a zero power reactor

Delayed gamma fraction determination in the zero power reactor CROCUS

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