Energy From Thorium Discussion Forum

It is currently Jan 22, 2018 1:34 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 68 posts ]  Go to page 1, 2, 3, 4, 5  Next
Author Message
PostPosted: Aug 08, 2016 3:49 pm 
Offline

Joined: Dec 05, 2008 8:50 am
Posts: 337
Is it possible to start up a thorium breeder with a mix of low enriched uranium and/or plutonium from LWRs, considering that a large amount of uranium 233 is not currently available today ? And. in particular in the case of LWR pluonium, is it possible to achieve iso breeding (I think it' s not, but curious to know your opinion) ?


Top
 Profile  
 
PostPosted: Aug 09, 2016 5:03 am 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1326
Location: NoOPWA
Alex P wrote:
Is it possible to start up a thorium breeder with a mix of low enriched uranium and/or plutonium from LWRs, considering that a large amount of uranium 233 is not currently available today ? And. in particular in the case of LWR pluonium, is it possible to achieve iso breeding (I think it' s not, but curious to know your opinion) ?

You cannot isobreed a U/Pu cycle in a thermal spectrum. You can use a mixture of Pu and U to start up a LFTR. I am not sure what the max percentage of Pu can be because PuF3 isn't as soluable in FLiBe as UF4.

Gentles? More info please?

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
PostPosted: Aug 11, 2016 3:24 pm 
Offline

Joined: Dec 05, 2008 8:50 am
Posts: 337
So, what shall be the realistic approach ? Start with LEU or MOX-like LWR spent fuel, waiting for producing enough uranium 233 in the blanket and later run the reactor only with that U-233 in a pure thorium-uranium 233 cycle? Is that right ?


Top
 Profile  
 
PostPosted: Aug 11, 2016 6:06 pm 
Offline
User avatar

Joined: Dec 22, 2015 8:40 pm
Posts: 356
Location: Florida
Alex P,

I believe your last guess is right but others (Kirk, David L., Lars, Cyril, and others here) are better qualified to answer. As I understand it, Dr. Weinberg intended a breeding program with the MSBR. I imagine that the thorium fuel cycle would take time to get started just because the initial U-233 inventory in the first few (FE) LFTRs would be bred from other reactors. The MSRE was started with U-235 in 1965, and then later was charged with U-233 in 1968. It ran through to 1969 before it was shut down and I believe it successfully bred U-233. (The last of three fuel assemblies at Shippingport NPS had thorium and bred U-233.)

I'm not asking FE about specific FE LFTR technology because I believe it's wise FE keep its cards very close so why bother when the answer is no. But what I've learned so far from studying the ORNL materials, I believe prior to 1973 at ORNL directed by Dr. Weinberg, the MSBR goal was to to keep the salts clean by continuous chemical and physical processing to maximize breeding. But the rate to accumulate enough U-233 to start another reactor is how long?

What would be the thorium cycle big picture? It's why I am interested in the Transatomic Power (TAP) waste annihilating MSR (WAMSR) that might have a model designed with a thorium blanket for breeding U-233 and thus to work in concert with FE LFTRs.

I apologize for the armchair speculation. Kurt Sellner is better at this. (Well, it's not like you're an experienced nuclear engineer, Kurt. But you've been pretty thorough on this forum.)

_________________
"Those who say it can’t be done are usually interrupted by others doing it."

—James Arthur Baldwin, American novelist, essayist, playwright, poet, and social critic


Last edited by Tim Meyer on Aug 26, 2016 11:56 am, edited 1 time in total.

Top
 Profile  
 
PostPosted: Aug 12, 2016 4:56 pm 
Offline
User avatar

Joined: Oct 06, 2010 9:12 pm
Posts: 137
Location: Cleveland, OH
I believe that the idea for fissile for a LFTR is that each reactor would have an initial start-up fuel of U235 or possibly Pu239, and run as a converter to turn the Th232 in the blanket into enough U233 that the fuel would be switched over to U233. And do not forget that you will have a time lag as you wait for the Pa233 to decay into U233 (half life about 27 days). The key driver AFAIK is the enrichment level of U235 (or Pu239 if that is used) and your breeding ratio.

But as things stand now, the IAEA will only allow U235 enrichment of under 10% for a commercial reactor, and U233 has to be under 20%. If this does not change, I think that a reactor with a BR=1 would take 5 years to generate enough U233 to run on solely U233 and that is optimistic and design dependent. Also, some folks argue about adding the U233 to the fuel as it is generated versus accumulating it until it can solely be run on U233 but that may be a different thread topic.


Top
 Profile  
 
PostPosted: Aug 12, 2016 5:32 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1495
IAEA has no real authority to dictate reactor enrichment levels - especially not in a Nuclear Weapons state.


Top
 Profile  
 
PostPosted: Aug 13, 2016 12:12 pm 
Offline
User avatar

Joined: Dec 22, 2015 8:40 pm
Posts: 356
Location: Florida
What are the enrichment rules and if not the IAEA then who has enforcement authority?

About the Enrichment Limit for Research Reactor Conversion: Why 20%? is from 2005.

I thought one LFTR goal is to minimize formation of TRUs. If that is a goal, then how does it get achieved? Some pro-nuclear for clean energy and particularly pro-LFTR people who are not nuclear engineers (myself) imagine that this goal can best be achieved if, for example, a Transatomic Power (TAP) waste annihilating MSR (WAMSR) outfitted with a thorium blanket for breeding U-233 would begin utilizing SNF for 1) commercial energy production simultaneously reducing the high-level waste inventories, and 2) jump-starting the thorium fuel cycle by delivering a "pure" U-233 start charge to a Flibe Energy (FE) LFTR acting in concert. That seems an optimum goal and would constitute a great achievement.

_________________
"Those who say it can’t be done are usually interrupted by others doing it."

—James Arthur Baldwin, American novelist, essayist, playwright, poet, and social critic


Top
 Profile  
 
PostPosted: Aug 13, 2016 8:13 pm 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1495
National governments are responsible for enforcement of non proliferation within their territories.
IAEA just tries to define best practice in that regard.
The UN endeavours to enforce non proliferation across international boundaries - as seen in North Korea.


Top
 Profile  
 
PostPosted: Aug 14, 2016 9:05 am 
Offline
User avatar

Joined: Dec 22, 2015 8:40 pm
Posts: 356
Location: Florida
E: What are the enrichment rules in the UK? (If this was already defined in this forum, perhaps you know the internal link.)

World Nuclear Association: Safeguards to Prevent Nuclear Proliferation (Updated April 2016)

In order for so-called pro-nuclear pro-thorium pro-LFTR non-nuclear-engineers to sell this radioactive message to a very skeptical, ill-informed electorate (solar and wind advocates), straight and understandable answers to highly complex technical subjects are needed. The nuclear engineers and scientists who know better would be extremely patient and willing to offer explanations if they are in favor of paving the way to more productive nuclear policies assuming democracy (absence of authoritarian dictatorships or some other form of global catastrophe or total failure of the rule of law) and the possibility of electorates to become adequately informed.

See: Need Some Help Helping LFTR and Nuclear Energy Overall

Alex P's original question here presumes a pro-nuclear pro-thorium pro-LFTR position:
Alex P wrote:
Is it possible to start up a thorium breeder with a mix of low enriched uranium and/or plutonium from LWRs, considering that a large amount of uranium-233 is not currently available today? And, in particular in the case of LWR plutonium, is it possible to achieve isobreeding? (I think it's not, but curious to know your opinions.)
Opinions? Are these matters of opinion? What is the scientific method for investigating natural phenomena? (Alex P: Please forgive my copy edits and proofs of your writing.)

A relevant part of the answer might be that the first commercial solid-phase light water reactor, Shippingport Nuclear Power Station (PA), had its third and last fuel assembly installed with a thorium blanket that showed U-233 breeding upon shutdown and examination. Is the original ORNL U-233 inventory still in storage?

I just found 74 matches here on the string "isobreeding". One is by Dr. Darryl Siemer, retired INL chemist:

Another way that MSRs could "save the world"


1) "Fissile Startup in a LFTR" topic gets back to U-235 enrichment rules to prevent people from making nuclear weapons.

2) Here we have a forum that is not interested in making nuclear weapons; rather, the majority opinion is—naively foolish?—peaceful commercial clean energy-dense thorium nuclear power.

3) But the thorium fuel cycle cannot start without either natural U-235, or bred Pu-239 (others?) that has (have?) accumulated over years of nuclear marine propulsion, light water reactor spent fuel assemblies, decommissioned weapons, what else? (Answer: It's classified?)

4) If the thorium cycle could get started, U-233 would soon be driving the train and U-235/Pu-239 demand for breeding would begin tapering off?

5) But the U-235 enrichment rules don't work for U-233? Because, for example, a (FE) LFTR requires a 99% U-233 intermediate inventory, but by design the forming U-233 is dynamically consumed as it is formed?

6) And even a "pure" U-233 stored inventory spontaneously begins to develop U-232 and the cache begins (how soon?) setting up a gamma field from:

232U (alpha, 68.9 years)
228Th (alpha, 1.9 year)
224Ra (alpha, 3.6 day, 0.24 MeV) (at this point, the decay chain is identical to that of 232Th)
220Rn (alpha, 55 s, 0.54 MeV)
216Po (alpha, 0.15 s)
212Pb (beta-, 10.64 h)
212Bi (alpha, 61 m, 0.78 MeV)
208Tl (beta-, 3 m, 2.6 MeV) (35.94% branching ratio) <-- our worst offender
208Pb (stable)

And the U-233 gamma field is worse than for U-235/Pu-239 inventories?—the U-233 gamma field is so severe that bomb makers would overdose before they could build U-233 fissile weapons that would fail from the gamma damage? So U-233 is exempt from nonproliferation rules that came from the natural U-235/Pu-239 uranium fuel/weapons cycle?

7) Even if a (FE) LFTR is started with a "fresh" i.e., low U-232 content, U-233 charge, upon operation, the fuel salt begins accumulating U-234, 5, 6, Np-237, what else? with their neutron activation products?

8) Assuming permission to go forward with U-233 (FE) LFTRs, Pu-239 can be used to breed U-233 from thorium if the breeder reactor is built correctly (proper neutron moderation).

So the sales pitch to a working-class anti-nuclear voter is: "Believe me! LFTR is the answer. Trust me." Wow.

_________________
"Those who say it can’t be done are usually interrupted by others doing it."

—James Arthur Baldwin, American novelist, essayist, playwright, poet, and social critic


Last edited by Tim Meyer on Aug 14, 2016 11:16 am, edited 16 times in total.

Top
 Profile  
 
PostPosted: Aug 14, 2016 9:18 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1495
Tim Meyer wrote:
E: What are the enrichment rules in the UK? (If this was already defined in this forum, perhaps you know the internal link.)

There are no real hard enrichment rules in the UK - however must reactors constructed in the UK have and do use relatively low enrichment rates, even AGR fuel is only ~3% at most or so.
And we had a major reactor programme built on natural uranium fuel (Magnox) after all.
Even SGHWR was only predicated on ~2%.

Enrichment capacity for civil use was always considered too expensive and so on. Especially considering the British obsession with on load refueling that reduced the need for long fuel cycles


Top
 Profile  
 
PostPosted: Aug 14, 2016 9:25 am 
Offline
User avatar

Joined: Dec 22, 2015 8:40 pm
Posts: 356
Location: Florida
E Ireland wrote:
". . . however must reactors constructed in the UK . . .
[sic] Most reactors in the UK . . .

Thanks, E. Evidently, (a) this was not covered anywhere else in this forum, or (b) it was covered but you don't know where, or? The UK nuclear experience is vital to the global experience (that for thorium MSRs began at ORNL in the 1950s).

And the big picture beyond your shores? When I was sold on energy from thorium about a year ago by Kirk Sorensen and other members of the Thorium Energy Alliance (courtesy of Gordon McDowell's YouTube media) who are an extreme minority in the general populations, my impression was that energy from thorium is a great and worthy energy technology that depends upon support from the non-nuclear-engineering majority anti-nuclear electorates. What did I miss? I thought ALL the members in this forum have volunteered in the pro-nuclear pro-thorium pro-LFTR information efforts.

_________________
"Those who say it can’t be done are usually interrupted by others doing it."

—James Arthur Baldwin, American novelist, essayist, playwright, poet, and social critic


Top
 Profile  
 
PostPosted: Aug 15, 2016 4:10 am 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2233
In Shippingport experiment, U233 was created by irradiating Th in a LWR and reused as a Th-U233 fuel.Someone could replicate the initial steps and take the Th-U233 burning to an LFTR.


Top
 Profile  
 
PostPosted: Aug 17, 2016 2:43 am 
Offline

Joined: Dec 05, 2008 8:50 am
Posts: 337
Thanks Jim and Tim. If it's so, then the fissile start-up is not a big problem, simply we begin with LEU having at the same time a super high efficient converter reactor and eventually switch later, if needed, to a full thorium isobreeder - particurally if this may lead to more economic and less problematic salts (for example, for tritium problem)


Top
 Profile  
 
PostPosted: Aug 17, 2016 10:52 am 
Offline
User avatar

Joined: Dec 22, 2015 8:40 pm
Posts: 356
Location: Florida
Alex P, you're welcome! We're pro-LFTR that means pro-thorium that all recognizes nuclear is a better energy source than carbon—independent of our side of the isle and the veracity of climate change (right side says it's a hoax).

The tritium problem? From lithium-6 in the core neutron flux, as far as I know, but the LFTR off-gas handling system will be engineered to capture it. I wonder if pro-LFTR people (whether or not experienced nuclear engineers) are factoring in the surge in demand for lithium highly depleted in lithium-6 (HD Li).

Jim offered great perspective on this. I tried to encourage and organize the discussion: Re: FLiBe with 99.995% 7Li, the topic on using the LFTR to participate in lithium depletion. The reactor developers rejected the idea that other members (non-developers with no skin in the game) doggedly pursued for pages.

No one here with experience in chemical engineering has answered my question on the promise of reported ionic liquids processes for lithium depletion. The above link itself links to the Lithium-7 topic that is 14 pages long!
Jim L. wrote:
Tim,

I am optimistic that the ionic fluid method will work, and that several of the "build any kind of MSR RIGHT NOW" companies would use at least 7LiF in a heart beat. And be better off for doing so.
Jim, you're an experience mechanical engineer and not chemical?

I believe once a solid LFTR prototype goes online and starts proving itself as the experts knew it would, and industry people begin to salivate, the South American "white petroleum" companies will be particularly interested in non-mercury amalgam process!

_________________
"Those who say it can’t be done are usually interrupted by others doing it."

—James Arthur Baldwin, American novelist, essayist, playwright, poet, and social critic


Top
 Profile  
 
PostPosted: Aug 17, 2016 10:57 pm 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1326
Location: NoOPWA
Alex P wrote:
So, what shall be the realistic approach ? Start with LEU or MOX-like LWR spent fuel, waiting for producing enough uranium 233 in the blanket and later run the reactor only with that U-233 in a pure thorium-uranium 233 cycle? Is that right ?
I've generally thought that we should start with as pure reactor grade Pu as we can get with only enough HEU to reach criticality. Keep adding more of the Pu/HEU start-up mixture as needed. Then as soon as any U233 is bred, add it instead of adding more of the Pu/HEU start-up mixture. As the amount of U233 starts lifting the LFTR into the breeding level, add as much of the rest of the SNF Extract Fuel to keep the system at sustainment level. (sustainment = isobreeding).

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 68 posts ]  Go to page 1, 2, 3, 4, 5  Next

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