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January 26, 2009

Chinese Will Build Modular High Temperature Nuclear Reactors Like Cans of Soda: in Eight Packs



A 60 slide presentation Chinese HTR Program: HTR-10 results & Work Progress on HTR-PM by Zuoyi ZHANG, Institute of Nuclear and new Energy Technology (INET), Tsinghua University, Beijing, 100084, China The Chinese High Temperature Reactors is one of the top 16 programs for the Chinese Government from 2006-2020. They figure that as they make their 13th to 31st pack of eight 200MW high temperature nuclear plants that cost will come down to 60% of the first one. Buying and building modular nuclear reactors like eight packs of beer or soda.

In order to meet energy demand in China, the high temperature gas-cooled reactor-pebble-bed module (HTR-PM) is being developed. It adopts a two-zone core, in which graphite balls are loaded in the central zone and the outer part is fuel ball zone, and couple with a steam cycle. Outer diameter of the reactor core is 4.0 m and height of the core is 9.43 m. The helium inlet and outlet temperature are 250 and 750 C, respectively. An earlier design of the reactor had thermal power of 380 MW. Preliminary studies show that the HTR-PM is feasible technologically and economically. In order to increase the reactor thermal power of the HTR-PM, some efforts have been made. These include increasing the height of reactor core, optimizing the thickness of fuel zone and better selection of the scheme of central graphite zone, etc.



They figure that as they make their 13th pack of eight 200MW electrical plants that cost will come down to 60-70% of the first one.












They are targeting 90% of the cost of a Pressure Water Reactor (PWR) but worst case the HTR figures to 120% of the cost of the PWR.












China plans to go to a very high temperature reactor design before 2020 and make hydrogen, switch to gas turbine and super-critical power cycle, and use spent fuel.




In 2006, they changed from a 458 MW thermal reactor design to two 250 MW thermal. They had technical uncertainties for the annual core:
* Dynamic annual core: reactivity control, helium outlet temperature, fuel flow demonstration, etc..
* Solid annual core: graphite replacement, pressure drop, fuel flow at the bottom, etc..
* Cost analysis indicates the difference between specific capital costs of 1×458 MWt and 2×250 MWt are limited.
* It is estimated that the specific costs of a ready-to-build 2×250 MWth modular plant will be only 5% higher than the specific costs of one 458 MWth plant. When considering the technical uncertainties of the latter, a 2×250 MWth modular plant seems to be more attractive.












The Chinese high temperature reactor powered down within 8 minutes without control rods.












The reactor was restarted in hours




The same Chinese researcher indicates that China should and probably plans to shift to breeder reactors in the 2025-2030 timeframe.





Uranium Distribution in the Earth's Crust
The following table is from Deffeyes & MacGregor, "World Uranium resources" Scientific American, Vol 242, No 1, January 1980, pp. 66-76.

The total abundance of Uranium in the Earth's crust is estimated to be approximately 40 trillian tonnes. The Rossing mine in Nambia mines Uranium at an Ore concentration of 300 ppm at an energy cost 500 times less than the energy it delivers with current thermal-spectrum reactors. If the energy cost increases in inverse proportion to the Ore concentration, shales and phosphates, with a Uranium abundance of 10 - 20 ppm, could be mined with an energy gain of 16 - 32. The total amount of Uranium in these rocks is estimated to be 8000 times greater than the deposits currently being exploited.
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