Downscaling a supercritical water loop for experimental studies on system stability

Rohde, M.; Marcel, Christian Pablo; T’Joen, Christophe; Class, Andreas G.; Hagen, T.H.J.J. van der

doi:10.1016/j.ijheatmasstransfer.2010.09.063

Cited by 18 publications

(7 citation statements)

References 19 publications

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“…The non-dimensional fluid properties agree well, with a maximum deviation of 8% for the density far away from the pseudo-critical point . Through linear stability analysis of a channel with supercritical water and of its scaled R23 counterpart, it was shown that the scaling rules result in the same stability behaviour, confirming the proposed scaling procedure and fluid selection (see Rohde et al [35]). This finding was also highlighted by Ambrosini [27], who found a very strong agreement between the stability boundary for different supercritical fluids provided the scaling was done correctly.…”

Section: Experimental Setup: Delightsupporting

confidence: 65%

“…(8)) and used the conditions at the inlet of the tube as reference values. This procedure was later modified by Rohde et al [35] to include friction scaling. They also used the pseudo phase change number and defined a subcooling number (Eq.…”

Section: Resultsmentioning

confidence: 99%

“…The corresponding property data is listed in Table 1. Rohde et al [35] describe the scaling procedure and derive a number of scaling factors based on the selected scaling fluid and the conservation of the Froude number and the friction distribution. It was shown that the friction distribution, rather than the actual value determines the linear stability behaviour.…”

Section: Experimental Setup: Delightmentioning

confidence: 99%

“…These values were obtained from [40], but because of the time scaling in the facility, the decay constants need to be divided by the time scaling factor 0.438 ( [35]). The mean generation Λ gen was set to 22 µs, this is the scaled equivalent of a BWR value, [15].…”

Section: Experimental Setup: Delightmentioning

confidence: 99%

“…The time constant was set to 6 seconds, which is based on earlier experimental work on the ESBWR fuel rods ( [42]). Note, that this value of 6 seconds isthen scaled in the DeLight setup, by multiplying it with 0.438, to account for the time-scaling ( [35]). The precise value of the fuel time constant is related to the actual size of the fuel rod and the gap, and as such it can vary significantly, being as low as 2 seconds ( [42]- [43]).…”

Section: Experimental Setup: Delightmentioning

confidence: 99%

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Experimental study of the coupled thermo-hydraulic–neutronic stability of a natural circulation HPLWR

T’Joen

Rohde

2012

Nuclear Engineering and Design

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The HPLWR (High Performance Light Water Reactor) is the European concept design for a SCWR (SuperCritical Water Reactor). This unique reactor design consists of a three pass core with intermediate mixing plena. As the supercritical water passes through the core, it experiences a significant density reduction. This large change in density could be used as the driving force for natural circulation of the coolant, adding an inherent safety feature to this concept design. The idea of natural circulation has been explored in the past for boiling water reactors (BWR). From those studies, it is known that the different feedback mechanisms can trigger flow instabilities. These can be purely thermo-hydraulic (driven by the friction -mass flow rate or gravity -mass flow rate feedback of the system), or they can be coupled thermo-hydraulic -neutronic (driven by the coupling between friction, mass flow rate and power production). The goal of this study is to explore the stability of a natural circulation HPLWR considering the thermo-hydraulic -neutronic feedback. This was done through a unique experimental facility, DeLight, which is a scaled model of the HPLWR using Freon R23 as a scaling fluid. An artificial neutronic feedback was incorporated into the system based on the average measured density. To model the heat transfer dynamics in the rods, a simple first order model was used with a fixed time constant of 6 seconds. The results include the measurements of the varying decay ratio (DR) and frequency over a wide range of operating conditions. A clear instability zone was found within the stability plane, which seems to be similar to that of a BWR. Experimental data on the stability of a supercritical loop is rare in open literature, and these data could serve as an important benchmark tool for existing codes and models.

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Section: Experimental Setup: Delightsupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Experimental Setup: Delightmentioning

confidence: 99%

Section: Experimental Setup: Delightmentioning

confidence: 99%