Shattered Pellet Injection experiments at JET in support of the ITER Disruption Mitigation System design

2021 ◽  
Author(s):  
Stefan Jachmich ◽  
Uron Kruezi ◽  
Michael Lehnen ◽  
Matteo Baruzzo ◽  
Larry R Baylor ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
System Design ◽  
Thermal Load ◽  
Runaway Electron ◽  
Load Control ◽  
Large Parameter ◽  
Disruption Mitigation ◽  
Pellet Injection ◽  
Series Of Experiments ◽  
Injection Strategies

Abstract A series of experiments have been executed at JET to assess the efficacy of the newly installed Shattered Pellet Injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and runaway electron energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme.

Post-thermal-quench shattered pellet injection for runaway electron seed depletion in ITER

2021 ◽  
Author(s):  
Eric Nardon ◽  
Akinobu Matsuyama ◽  
Di Hu ◽  
Fabian Wieschollek
Keyword(s):  
Runaway Electron ◽  
Injection Rate ◽  
Disruption Mitigation ◽  
Pellet Injection ◽  
Present Design

Abstract The possibility of using shattered pellet injection after the thermal quench of an ITER disruption in order to deplete Runaway Electron (RE) seeds before they can substantially avalanche is studied. Analytical and numerical estimates of the required injection rate for shards to be able to penetrate into the forming RE beam and stop REs are given. How much material could be assimilated before the Current Quench (CQ) becomes too short is also estimated. It appears that, if hydrogen pellets were used, the required number of pellets to be injected during the CQ would be prohibitive, at least considering the present design of the ITER Disruption Mitigation System (DMS). For neon or argon, the required number of pellets, although large, might be within reach of the ITER DMS, but the assimilated fraction would have to be very small in order not to shorten the CQ excessively. This study suggests that other injection schemes, based for example on small tungsten pellets coated with a low Z material, may be worth exploring as an option for an upgrade of the ITER DMS.

Feasibility of thermal load control from electrochromic windows for ground coupled heat pump optimization

2021 ◽  
Vol 40 ◽  
pp. 102339
Author(s):  
Connor Dacquay ◽  
Hikari Fujii ◽  
Ed Lohrenz ◽  
Hartmut M. Holländer
Keyword(s):  
Heat Pump ◽  
Thermal Load ◽  
Load Control ◽  
Ground Coupled Heat Pump ◽  
Electrochromic Windows

Suppression of runaway electron generation by massive helium injection after induced disruptions on TEXTOR

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
A. Lvovskiy ◽  
H. R. Koslowski ◽  
L. Zeng ◽  
Keyword(s):  
Time Delay ◽  
Runaway Electron ◽  
Critical Density ◽  
Runaway Electrons ◽  
Electron Generation ◽  
Disruption Mitigation ◽  
Order Of Magnitude ◽  
Short Time ◽  
Short Time Delay

Disruptions with runaway electron generation have been deliberately induced by injection of argon using a disruption mitigation valve. A second disruption mitigation valve has been utilised to inject varying amounts of helium after a short time delay. No generation of runaway electrons has been observed when more than a critical amount of helium has been injected no later than 5 ms after the triggering of the first valve. The required amount of helium for suppression of runaway electron generation is up to one order of magnitude lower than the critical density according to Connor & Hastie (1975) and Rosenbluth & Putvinski (1997).

Comparison of disruption mitigation by shattered pellet injection to massive gas injection on J-TEXT

2021 ◽  
Author(s):  
You Li ◽  
Zhong yong Chen ◽  
Wei Yan ◽  
Yu Wei ◽  
Ruihai Tong ◽  
...  
Keyword(s):  
Gas Injection ◽  
Disruption Mitigation ◽  
Pellet Injection

Design and performance of shattered pellet injection systems for JET and KSTAR disruption mitigation research in support of ITER

2021 ◽  
Author(s):  
Larry R Baylor ◽  
Steve J Meitner ◽  
Trey E Gebhart ◽  
John B. O. Caughman ◽  
Daisuke Shiraki ◽  
...  
Keyword(s):  
Disruption Mitigation ◽  
Pellet Injection ◽  
And Performance

Energy dissipation by vertically placed screens

2007 ◽  
Vol 34 (4) ◽  
pp. 557-564 ◽  
Author(s):  
Zafer Bozkus ◽  
Pinar Çakir ◽  
A Metin Ger
Keyword(s):  
Energy Dissipation ◽  
Froude Number ◽  
Hydraulic Jump ◽  
Large Range ◽  
Hydraulic Structure ◽  
Flow Depth ◽  
Supercritical Flow ◽  
Series Of Experiments ◽  
Upstream Flow

Screens can be utilized efficiently for dissipating energy of water. In this study, water flowing beneath a gate is used to simulate the flow downstream of a small hydraulic structure, and vertically placed screens are used as an alternative tool for energy dissipation. Investigations are conducted using a series of experiments. The porosity, thickness, and location of the screens are the major parameters together with the Froude number of the upstream flow. The experiments cover a range of supercritical Froude numbers between 5.0 and 18.0, porosities between 20% and 60%, and screen locations up to 100 times the undisturbed upstream flow depth. The thicknesses of the screens used are in the order of the undisturbed upstream flow depth. The results show the importance of each parameter in the energy-dissipating performance of the screens and the system. It is observed that screens dissipate significantly more energy than a conventional hydraulic jump within the large range of Froude numbers covered in the study. The results are also in agreement with the results of an earlier similar study.Key words: screen, energy dissipation, hydraulic jump, porosity, supercritical flow.

Adaptive Robust Operation of Multi-Energy Microgrids with Thermal Load Control

2020 ◽  
Author(s):  
Bin Du ◽  
Haizhu Wang ◽  
Kaiwen Zeng ◽  
Jianing Liu ◽  
Bin Lin ◽  
...  
Keyword(s):  
Thermal Load ◽  
Load Control
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