Energy From Thorium Discussion Forum

It is currently Nov 16, 2018 12:58 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 7 posts ] 
Author Message
PostPosted: Jul 11, 2018 10:44 pm 
Offline

Joined: Apr 25, 2011 10:01 pm
Posts: 47
I have an opponent who claims that spontaneous wigner energy releases cause graphite fires.

Is this applicable to a LFTR?

How can I best rebuke claims that this is a valid safety concern for LFTRs?

Thanks for all your help.


Top
 Profile  
 
PostPosted: Jul 12, 2018 3:59 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1554
almost all graphite moderated power reactors keep the graphite sufficiently hot that the amount of Wigner energy that can build up will be extremely small.
This is especially true for an MSR because the graphite temperature will be well over 500C


Top
 Profile  
 
PostPosted: Jul 12, 2018 8:14 am 
Offline

Joined: Apr 25, 2011 10:01 pm
Posts: 47
Thank you for pointing me in the right direction. I was able to dig up a lot of material that confirms this.


Top
 Profile  
 
PostPosted: Jul 12, 2018 10:25 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1554
matthewwight wrote:
Thank you for pointing me in the right direction. I was able to dig up a lot of material that confirms this.


You're welcome.
The fun thing is that earlier Magnox stations (like the UKAEA reactors at Calder Hall and Chapelcross, and the first CEGB station at Bradwell) had provision to shutdown the reactors for a Wigner annealing, and the reactors at Bradwell were originally to be built with special modifications to the fuel channels to increase graphite temperature (sleeves to reduce gas exposure to the graphite), before improving heat transfer temperatures made it all redundant.


Top
 Profile  
 
PostPosted: Jul 28, 2018 1:32 pm 
Offline

Joined: Dec 09, 2017 4:31 pm
Posts: 20
Please bear with me, for I am nothing but an enthusiastic amateur at best, but does nuclear/reactor grade graphite even burn?

There are many contrasting opinions and viewpoints across a variety of sources, my understanding is that you won't burn graphite even with oxy-ace torches. It just doesn't want to cooperate.

Of course people may get confused with accidents like the Windscale fire where it was the fuel (and probably some of the cladding) that burned.


Top
 Profile  
 
PostPosted: Jul 28, 2018 3:57 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1554
modifiedgenes wrote:
Please bear with me, for I am nothing but an enthusiastic amateur at best, but does nuclear/reactor grade graphite even burn?

There are many contrasting opinions and viewpoints across a variety of sources, my understanding is that you won't burn graphite even with oxy-ace torches. It just doesn't want to cooperate.

Of course people may get confused with accidents like the Windscale fire where it was the fuel (and probably some of the cladding) that burned.


It won't "burn" as such, but smouldering oxidation is a significant threat.
The rate of oxidation, whilst relatively low, is sufficiently high that it can cause the core to overheat in an accident.


Top
 Profile  
 
PostPosted: Jul 31, 2018 6:41 pm 
Offline

Joined: Dec 09, 2017 4:31 pm
Posts: 20
That explains that for me, thank you.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


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