Preliminary results of an on-Line, multi-spectrometer fission product monitoring system to support advanced gas reactor fuel testing and qualification in the advanced test reactor at the Idaho National Laboratory

Scates, Dawn M.; Hartwell, J.K.; Drigert, M. W.; Walter, John B.

doi:10.1109/nssmic.2007.4436445

“…The usual measurement protocol acquires gamma-ray spectra with counting times of eight hours. This gives adequate measurement sensitivity and provides three sets of results each day which are used to compute daily capsule release activity values [3,4,5]. Transport times from each capsule to its respective FPM are estimated using capsule-specific effluent flow rates and transport volumes, the volumes through which the effluent flows between the capsule and the FPM.…”

Section: Equipment and Measurementsmentioning

confidence: 99%

Quantity of <sup>135</sup>I released from the AGR-1, AGR-2, and AGR-3/4 experiments and discovery of <sup>131</sup>I at the FPMS traps during the AGR-3/4 experiment

Scates¹

2014

0

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A series of three Advanced Gas Reactor (AGR) experiments have been conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). From 2006 through 2014, these experiments supported the development and qualification of the new U.S. tristructural isotropic (TRISO) particle fuel for Very High Temperature Reactors (VHTR). Each AGR experiment consisted of multiple fueled capsules, each plumbed for independent temperature control using a mix of helium and neon gases. The gas leaving a capsule was routed to individual Fission Product Monitor (FPM) detectors. For intact fuel particles, the TRISO particle coatings provide a substantial barrier to fission product release. However, particles with failed coatings, whether because of a minute percentage of initially defective particles, those which fail during irradiation, or those designed-to-fail (DTF) particles, can release fission products to the flowing gas stream. Because reactive fission product elements like iodine and cesium quickly deposit on cooler capsule components and piping structures as the effluent gas leaves the reactor core, only the noble fission gas isotopes of Kr and Xe tend to reach FPM detectors. The FPM system utilizes High Purity Germanium (HPGe) detectors coupled with a thallium activated sodium iodide NaI(Tl) scintillator. The HPGe detector provides individual isotopic information, while the NaI(Tl) scintillator is used as a gross count rate meter. During irradiation, the 135m Xe concentration reaching the FPM detectors is from both direct fission and by decay of the accumulated 135 I. About 2.5 hours after irradiation (ten 15.3 minute 135m Xe half-lives) the directly produced 135m Xe has decayed and only the longer lived 135 I remains as a source. Decay systematics dictate that 135m Xe will be in secular equilibrium with its 135 I parent, such that its production rate very nearly equals the decay rate of the parent, and its concentration in the flowing gas stream will appear to decay with the parent half-life. This equilibrium condition enables the determination of the amount of 135 I released from the fuel particles by measurement of the 135m Xe at the FPM following reactor shutdown. In this paper, the 135 I released will be reported and compared to similar releases for noble gases as well as the unexpected finding of 131 I deposition from intentional impure gas injection into capsule 11 of experiment AGR-3/4. viii ix ACKNOWLEDGMENT

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“…Also, the reduced diffusion coefficients used in the PARFUME model are based on German fuel tests. The compact density in the German tests were 1.7 g/cm 3 while the compact density for the AGR-1 compacts is 1.3 g/cm 3 [20]. The greater open porosity might enhance diffusion.…”

Section: Fission Gas Release Modelsmentioning

confidence: 99%

“…One important measure of the fuel performance in these tests is quantification of the fission gas releases over the duration of each irradiation experiment. This important measurement is provided by the AGR Fission Product Monitoring System (FPMS) [2,3].…”

Section: Introductionmentioning

confidence: 99%

Fission Product Monitoring of TRISO Coated Fuel for the Advanced Gas Reactor-1 Experiment

Scates

¹

,

Hartwell

²

,

Walter

³

et al. 2008

Fourth International Topical Meeting on High Temperature Reactor Technology, Volume 1

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The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA.At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both highpurity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors.To quantify the fuel performance, release-to-birth ratios (R/B's) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

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Fission product monitoring of TRISO coated fuel for the advanced gas reactor-1 experiment

Scates

¹

,

Hartwell

²

,

Walter

³

et al. 2010

Nuclear Engineering and Design

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The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA.At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both highpurity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors.To quantify the fuel performance, release-to-birth ratios (R/B's) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

show abstract

Preliminary results of an on-Line, multi-spectrometer fission product monitoring system to support advanced gas reactor fuel testing and qualification in the advanced test reactor at the Idaho National Laboratory

Cited by 3 publications

References 5 publications

Quantity of <sup>135</sup>I released from the AGR-1, AGR-2, and AGR-3/4 experiments and discovery of <sup>131</sup>I at the FPMS traps during the AGR-3/4 experiment

Quantity of <sup>135</sup>I released from the AGR-1, AGR-2, and AGR-3/4 experiments and discovery of <sup>131</sup>I at the FPMS traps during the AGR-3/4 experiment

Fission Product Monitoring of TRISO Coated Fuel for the Advanced Gas Reactor-1 Experiment

Fission product monitoring of TRISO coated fuel for the advanced gas reactor-1 experiment

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