SEU-Th MOX for CANDU?

E Ireland
Posts: 1565
Joined: Jun 19, 2013 11:49 am

SEU-Th MOX for CANDU?

Post by E Ireland » Apr 03, 2014 10:48 am

Well I've been thinking about this for quite a while.
1.2% enriched uranium fuel in a CANDU can obtain a burnup of ~21GWd/t according to studies done by the Romanians.
Does this mean that some sort of fuel containing the same amount of 235U in the form of 20% LEU diluted with Thoria would give comparable performance? I understand that you would probably have to break the irradiation up into a series of smaller campaigns (perhaps 3 7GWd/t ones to match NU fuel handling requirements?) to allow Pa to decay and keep the fuel's reactivity up but as I understand it the thermal cross section of Thorium is larger than that of 238U and thus it should be possible to get a fuel with similar breeding properties.

You might even have to add a diluent to keep the absorption by fertile material down at similar levels to Uranium... perhaps BeO for some minor neutron multiplication effects if the increased handling problems for fresh fuel are worth it. For example roughly 6% 20%LEU-dioxide and ~94% Thoria by mass.

Would this have any benefits over a simple SEU cycle once-through other than suppressing nasty transuranic production?

jagdish
Posts: 2304
Joined: Apr 19, 2008 1:06 am

Re: SEU-Th MOX for CANDU?

Post by jagdish » Apr 06, 2014 9:28 am

There is an Indian DAE paper on the subject
http://dae.nic.in/writereaddata/.pdf_38
CANDU as well as other reactors are covered. Refer to pages 11-14 on PHWR.

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