Is SSTAR Program Still Alive?

[joelupchurch]

Is the Small, Sealed, Transportable, Autonomous Reactor program at Lawerence Livermore still going? I haven't found any recent updates on it.

http://en.wikipedia.org/wiki/SSTAR"

It seems to me that a design like this would be ideal for providing power in the 3rd world, since it doesn't have to built onsite or refueled. After 30 years you haul it off and put in a new one.

Having local power grids with 100mw plants would avoid a lot of the expense of setting up major power grids we use. It would be almost like how cell phones let the 3rd world leapfrog setting up the communication grids.

Even in the US, it might be cheaper for a smaller utility company to buy one SSTAR every year than a 1GW unit every 10, since it would tie up less capital for shorter periods of time.

 

[hagopbul]

SSTAR is an acronym for the "small, sealed, transportable, autonomous reactor" - being primarily researched and developed in the USA by Lawrence Livermore National Laboratory. It is designed as a fast breeder nuclear reactor that is passively safe. It has a self-contained fuel source of Uranium-235 containing also Uranium-238 which will be partly consumed by fast-neutron fission and, more importantly, converted into more fissile material ("breeding" Plutonium). It should have an operative life of 30 years, providing a constant power source between 10 and 100 megawatts.

the word Plutonium is the reason why it is not for 3rd word countries

 

[joelupchurch]

I think the Pu-239 gets burned up in situ, so you can't actually crack open the reactor and get enough Pu-239 for a bomb. I've also seen some discussion of using the design for a Thorium reactor. U-233 is much less suitable for weapons than Pu-239.

The high burnup is an essential part of the design, since the reactor is delivered prefueled and runs for 30 years and then is taken down and replaced. That way you don't have nuclear fuel that could be diverted to a weapons reactor.

Has anyone ever actually used a power reactor to produce weapons material? The wikipedia article make weapons reactor sound a lot different.

http://en.wikipedia.org/wiki/Pu_239"

It sound like to have a harvest the Pu-239 frequently before it picks up additional neutrons and you end up with too much Pu-240 etc.

 

[Morbius]

Has anyone ever actually used a power reactor to produce weapons material? The wikipedia article make weapons reactor sound a lot different.

http://en.wikipedia.org/wiki/Pu_239"

It sound like to have a harvest the Pu-239 frequently before it picks up additional neutrons and you end up with too much Pu-240 etc.

joelupchurch,

If by "power reactor" you mean a typical LWR - light water reactor - then the answer is no - nobody
regularly uses LWRs to produce weapons material.

However, if you turn the question around and ask, "Has anyone used a weapons production reactor
to produce power" - then the answer to that is yes. Years ago, when the USA was still making
plutonium at Hanford, one of the reactors, the newest of the Hanford reactors which started operation
in the early '60s; was the Hanford "N Reactor". [ Production reactors were named with letters,
"B Reactor", "K reactor"...]. The Hanford "N Reactor' was unique in that the plant incorporated
an electric power production plant. All other production reactors at Hanford simply dumped their
waste heat into the Columbia River. The "N Reactor" used that heat to produce power - and the
waste heat from the Rankine cycle was dumped into the Columbia.

You are correct that one has to harvest the Plutonium frequently. If your main purpose for the
reactor plant is generating electricity - and you have an LWR - then frequent shutdowns in which
you have to cool down the reactor, unbolt and remove the head; all to harvest Plutonium is a big
job for a task that isn't your primary purpose. It's easier to operate the LWR for a year to 18 months
before you have to open it up.

On the other hand, if your main job is producing weapons material and you are going to start / stop
the reactor anyway - then you may as well add the Rankine cycle to make use of the energy you
produce. As I recall, the Hanford "N Reactor" was a 4 Gw(t) reactor and just dumping that much
energy as heat would be wasteful.

http://www.hanford.gov/?page=345&parent=326

http://en.wikipedia.org/wiki/Hanford_Site

The RBMK reactors at Chernobyl were also dual use reactors - they produced weapons material
in addition to electric power.

Dr. Gregory Greenman
Physicist