Energy From Thorium Discussion Forum

It is currently Feb 22, 2018 12:22 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 31 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
PostPosted: May 30, 2014 6:43 am 
Offline

Joined: Sep 22, 2013 2:27 pm
Posts: 262
Hi E Ireland...

The MCFR (Molten Chloride Fast Reactor) is my favorite since years.

A salt mixture UCl3 - PuCl3 - NaCl-MgCl2 is indeed an option. According to Benes the MgCl2 addition will not reduce the melting temperature of the mixture significantly.

As KCl is more stable than MgCl2 I would prefer the mixtures:

NaCl 42,8% KCl 22,8% UCL3 25,5% PuCl3 4,6% and FpClx 4,3% Fission zone
NaCl 44,72% KCl 24,72%UCL3 29,1% PuCl3 1,24% and FpClx 0,22% Fertile zone

with liquidus temperatures of 525°C and 530°C.


Top
 Profile  
 
PostPosted: May 30, 2014 10:12 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1502
Potassium has serious neutron activation problems though.
(40K with a billion year halflife).

Magnesium's induced activity is gone with in 90 minutes (27Mg).

While the former is not going to be particularily active we need to reduce the production of activation products wherever possible.

This paper from ORNL seems to suggest that an MgCl-UCl-NaCl-(TRU)Cl mixture would be usable at temperatures of ~500C. [See page 26 of the PDF].


Top
 Profile  
 
PostPosted: May 30, 2014 5:04 pm 
Offline

Joined: Sep 22, 2013 2:27 pm
Posts: 262
Dear E. Ireland,

as long as radioactivity is demonized there will be no revival of nuclear power. If risks and disadvantages are seen from a realistic point of view there will be a revival.

The concept I aim for is based on a technical/commercial optimization.

Within this context the necessary fuel treatment (degassing, noble metals plate out, low boiling chlorides) is done within the power plant and the fuel reprocessing is done external with a commercially optimized efficiency. The remaining waste fractions will contain fission product chlorides some remaining actinides as americiumchlorides, plutoniumchlorides, and some carrier salts. The total waste is about 1-2m3/yr. The ideal place for it is the antarctica or a deep salt mine as it is done with several 100.000to chemical waste/yr. without media attention. The 40K is very low radioactive and will not increase costs significantly nor it is a danger for human being.


Top
 Profile  
 
PostPosted: May 30, 2014 6:50 pm 
Offline

Joined: Jul 28, 2008 10:44 pm
Posts: 3069
You have a lot of radioactive potassium inside you - if you didn't you'd be dead. I can't imagine potassium activation is a problem.


Top
 Profile  
 
PostPosted: May 30, 2014 8:18 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1502
Well I could have consumed only isotopically seperated potassium.....

The problem is that 40K is likely to be produced in sufficient amounts to significant increase the long lived radioisotope production of the reactor.
Also magnesium has the advantage that the (albeit small) measurable energy contained in the activation products is released in the reactor where it can be of use.

Various studies I have read seem to indicate that the eutectic temperatures are not dissimilar which leaves little else to chose between them on.


Top
 Profile  
 
PostPosted: May 30, 2014 8:19 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1502
HolgerNarrog wrote:
. The ideal place for it is the antarctica or a deep salt mine as it is done with several 100.000to chemical waste/yr. without media attention. The 40K is very low radioactive and will not increase costs significantly nor it is a danger for human being.


Emplacing the waste like that sounds like it is going to be very expensive if the WIPP is any indication.
The best way to 'dispose' of nuclear waste is to gather it in concrete casks placed on a disused airfield's runways.


Top
 Profile  
 
PostPosted: May 31, 2014 5:40 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2239
Disused air strips may be too visible and could be used for other things. Mined out mine pits are better used for any type of permanent storage. They could be covered with earth and planted over.


Top
 Profile  
 
PostPosted: May 31, 2014 9:18 am 
Offline

Joined: Aug 29, 2008 4:55 pm
Posts: 496
Location: Idaho Falls, Idaho
The problems at WIPP at self made for the most part. both in the way the problem drum was prepared at LANL and in the way the mine operator responded to the leak event. The recovery is also being mismanaged, in my opinion. Another contractor would have found the problem drum within 3 weeks instead of 3 months. Now the recovery will be extended as well. You have a contractor and the local DOE office that is inexperienced.
As far as putting anything in Antarctica I see nothing but problems in doing that. Shipping alone would be a night mare. I would think any dry area in a reasonable latitude would be better. Western Australia, Gobi desert ect.


Top
 Profile  
 
PostPosted: May 31, 2014 12:09 pm 
Offline

Joined: Sep 22, 2013 2:27 pm
Posts: 262
In many places of the world salt domes exist since some 100 mio. years. Usually they are surrounded by water tight clay layers otherwise they would not have existed for hundreds of million years.

Salt domes behave plastic under pressure and closes cracks. A salt dome is a perfect barrier against water and the biosphere. The heat conductivity is pretty well. That are the reasons that salt domes are from the geological point of view the best places for chemical and high radioactive waste.

The costs to create an underground mine some 700m below the surface including infrastructure are acc. to informations from annual reports from Xstrata (today a part of Glencore) 1 - 2 Bn $. If you use it for 50 NPP for 60 years it is less than 0.003 c/kWh.

The main costs of a nuclear waste site are created by politics and plenty of documentation, licensing....A government starts ahead..the next one stops it...the following one starts again from 0

Best regards

Holger


Top
 Profile  
 
PostPosted: May 31, 2014 12:46 pm 
Offline

Joined: Sep 22, 2013 2:27 pm
Posts: 262
E. Ireland...

I would suggest that if you eat (40K) potassiumchloride you would die from the salt long before there are any impact from radioactivity.


Top
 Profile  
 
PostPosted: May 31, 2014 8:43 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1502
Unfortunately people will demand continuous monitoring of emplaced materials and likely demand replacement of canisters when they eventually fail. So there is little point emplacing them in the first place - changing a dry cask on the surface is far cheaper than doing it underground.

Also we must avoid all mention of 'permanent' storage - localities do not like the idea of 'waste dumps'.
'Intermediate storage' and 'Storage with research' facilities are apparently far more acceptable.

Also we do not want to preempt technologies that may allow further concentration of the waste in the future (enhanced secondary processing or even low cost isotopic seperation).


Top
 Profile  
 
PostPosted: Jun 01, 2014 2:57 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2239
One problem with chlorides is that 35Cl absorbs more neutrons than the 37Cl. There may be a need to get isotopically pure 37Cl.


Top
 Profile  
 
PostPosted: Jun 01, 2014 6:38 am 
Offline

Joined: Sep 22, 2013 2:27 pm
Posts: 262
Jagdish...the only potential risk known to me from 35Cl is the n -> p reaction that creates corrosive sulphur. As soon as I find the time I will try to quantify the created sulphur.


Top
 Profile  
 
PostPosted: Jun 01, 2014 10:28 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1502
36Cl is a nasty radioisotope that is highly mobile in the environment with a half life of ~308k yrs.
So not exactly something we want.


Top
 Profile  
 
PostPosted: Jun 02, 2014 11:06 am 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3427
Location: Alabama
E Ireland wrote:
36Cl is a nasty radioisotope that is highly mobile in the environment with a half life of ~308k yrs.
So not exactly something we want.


With that half-life and with 36Cl being a beta-emitter, I don't think it's too much to worry about. The specific radioactivity level (curies/gram) will be rather low.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 31 posts ]  Go to page Previous  1, 2, 3  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group