[ RadSafe ] Molten Salt Reactor

Mon Aug 18 15:24:40 CDT 2014

Having fuel that solidifies instead of melts is often touted as a safety feature, and it seems like a pretty good one.  Also, the entire fuel loop can be run at atmospheric pressure, so there is less of driver if containment is lost.  On the other hand, the reactor runs much hotter than a LWR, so if there is a breach there are a number of fission fragments that would happily leave in a gaseous form.  This includes the krypton and xenon isotopes (obviously), all of the iodines, and probably some others.  Interaction between the molten salt and water, even just water vapor in the air, could be exciting.  

One of the claims the thorium people like to make is that these kind of reactors do not make material that could be used in nuclear weapons.  I am not sure this is a valid statement.  U233 can be used in weapons.  As I understand it (I am just an old, run-of-the-mill plutonium weapons guy; I never dealt with U233) the big disadvantage with making bombs out of U233 is that it will be contaminated with U233, which will make it dangerously radioactive.  On the other hand, anyone who is stealing used nuclear fuel to process out material for weapons probably is not risk adverse.  

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brad Keck
Sent: Monday, August 18, 2014 12:43 PM
To: The International Radiation Protection (Health Physics) Mailing List
Cc: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Molten Salt Reactor

I am not sure what the exact design is from Transatomics, but molten salt designs are pretty well developed conceptually.  In very broad strokes, a mixture of fluoride salts is used to contain the fissile material and this can become critical when flowing through the moderated core (perhaps with reflectors as well) ; the salt also serves as the heat transfer medium to the primary cooling loop.  If cooling capacity is interrupted, a "freeze plug" melts and allows the molten salts with fuel to flow into holding tanks away from the core, and these tanks have adequate passive cooling to allow the salt to solidify, thus containing the entire mixture as a solid with minimal releases, and removing the salt/fuel from the moderator, thus terminating criticality.  

This will of course require a bit of operational flexibility to accommodate various mixtures of transuranics, but has a lot of potential to turn spent fuel back to kWe! 

Bradly D. Keck

Sent from my iPad

> On Aug 17, 2014, at 10:14 PM, Jeff Terry <terryj at iit.edu> wrote:
> 
> I believe in the transatomic design the molten salt solution gets dumped into a tank in a noncritical geometry. The salt cools and eventually solidifies. I think that might be a misquote. 
> 
> Jeff
> 
> Sent from my iPad
> 
>> On Aug 17, 2014, at 8:59 PM, "Dahlskog, Leif" <Leif.Dahlskog at health.wa.gov.au> wrote:
>> 
>> I don't get this sentence in the article.
>> 
>> "Since salt's melting point is higher than the core temperature, even if power is lost and no one is around to fix things, the reaction will eventually stop on its own."
>> 
>> I though the salt was meant to be in a molten state. Anyone able to help me understand this ?
>> 
>> Leif Dahlskog
>> Radiation Health Branch
>> 
>> Grace Vaughan House|227 Stubbs Terrace|Shenton Park WA 6008
>> 
>> 
>> -----Original Message-----
>> From: radsafe-bounces at agni.phys.iit.edu 
>> [mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of Sander Perle
>> Sent: Sunday, 17 August 2014 10:49 PM
>> To: The International Radiation Protection (Health Physics) Mailing 
>> List
>> Subject: [ RadSafe ] Molten Salt Reactor
>> 
>> Here is a link I posted on LinkedIn last night:
>> http://www.extremetech.com/extreme/187917-startup-gets-funding-for-it
>> s-molte n-salt-nuclear-reactor-that-eats-radioactive-waste
>> 
>> This morning CNN¹s Fareed Zakaria GPS TV interviewed Dr. Leslie Dewan, CEO, Transatomic Power Corporation. She graduated from MIT with a Ph.D. in nuclear engineering, with a research focus on computational nuclear materials. She also holds S.B. degrees from MIT in mechanical engineering and nuclear engineering. Before starting her Ph.D., she worked for a robotics company in Cambridge, MA, where she designed search-and-rescue robots and equipment for in-field identification of biological, chemical, and nuclear weapons. Leslie has been awarded a Department of Energy Computational Science Graduate Fellowship and an MIT Presidential Fellowship. She was named a TIME Magazine "30 People Under 30 Changing the World" in December 2013, an MIT Technology Review "Innovator Under 35" in September 2013, and a Forbes "30 Under 30" in Energy in December 2012.
>> 
>> I recommend that if you have the time, you should review the article as well as the interview.
>> 
>> Regards,
>> 
>> Sandy Perle
>> Retired, Consultant
>> 
>> 
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