LarsJorgensen

vor 12 Jahrendiscuss

It will be rather intensely radioactive. A person cannot approach it. A cleanup like this would have be done robotically. If the spill is contained in the can then the whole can is designed to be sealed and shipped back to the can recycling center where there are facilities for cleaning up the can. The main point though is that the spill is contained within the building and does not spread to the environment. A worst case accident becomes an economic loss of the reactor rather than a mass evacuation.

LarsJorgensen

vor 12 Jahrendiscuss

No we are not in production. Yes we do need funding but this is not on a kickstarter scale though. This will require hundreds of millions of dollars to become real so we do need to involve a large corporation or some wealthy folks.

LarsJorgensen

vor 12 Jahrendiscuss

The design choices have been specifically made to allow for a short development cycle and rapid deployment. There is no need to enrich thorium as virtually all thorium in the world is Th232.

LarsJorgensen

vor 12 Jahrendiscuss

The challenge with metallurgy for MSRE was two fold. First was the neutron interaction with nickle forming helium that migrated to the grain boundaries. We avoid this problem altogether by having a single fluid design with a protective shield of B4C absorbing neutrons before they hit the wall.

The second problem was with tellerium penetrating the Hastalloy and weakening it at the grain boundaries. This isn't a problem with stainless steel.

The stainless steel planned is SS316 which is available from multiple sources.

The primary loop does not have insulation surrounding it but it does have a 1m thick graphite reflector to bounce most of the neutrons back to the core then a layer of B4C to absorb the rest before they get to the vessel.

The MSRE was shutdown decades ago and recently had its fuel salt removed. The vessel and piping are still in Oak Ridge inside its concrete silo.

LarsJorgensen

vor 12 Jahrendiscuss

The primary loop (that contains all the fuel salt and fission products) is inside a can so if we get a leak in the primary loop the salt will be contained inside the can. The can drains to the fuel dump tank (FDT). Both the can and FDT get passively cooled by the membrane and all entrance pipes come in from above so there is no weakness at the bottom.

These in turn are inside a silo, which is inside the silo hall. All total there are four barriers to break through before we get radioactive release.

Further, the fission products are combined with fluoride upon forming (when you fission UF4 the uranium is split into two fission products and the F4 is available for recombining with the fission products). Most of the fission products like to stay in the salt so even if the salt gets spilled the fission products won't wander farther than the salt spill.

LarsJorgensen

vor 12 Jahrendiscuss

The design has two passive cooling systems. The first uses natural circulation through the heat exchangers to the normal primary cold sink. The second uses radiative heat to the membrane to a pond intended specifically for decay heat. Either one alone is sufficient - so if something (like a tsunami) takes out the primary cold sink we can still cool the core. If despite this the core overheats then it drains to the fuel drain tank. There we have passive cooling using the membrane.

If the drain between the core and the drain tank fails AND the both other passive cooling methods fail to keep the core cool enough then yes eventually the core vessel will fail. In that case, the fuel escapes the first containment (the primary loop) into the can. The can drains to the fuel drain tank so we still provide cooling.

LarsJorgensen

vor 12 Jahrendiscuss

The high temperature limits the materials we can choose from. We've elected to stick with known materials (stainless steel) for the first generation to keep our schedule short. As someone noted below highly corrosive depends on the material you are in. The fuel salt is actually pretty modestly corrosive as long as the chemistry is kept right. Specifically, we have to keep the fuel salt reducing - we don't want any free fluorine running around. We keep a balance between UF3 and UF4 (roughly 99% UF4). It's like keeping the chemical balance in your swimming pool. Under those conditions the vessel will last a very long time indeed (>60 years). But it takes a long time to prove this and we have to swap out the graphite anyway so we swap out all critical components every four years. They get disassembled, cleaned, and normally put back into service with a new graphite load. This is kindof like your laser printer cartridge.

LarsJorgensen

vor 12 Jahrendiscuss

There are many different thorium designs based on different objectives. The original designs assumed that we would run out of uranium so the primary objective was breeding. It is clear now that we have much more uranium than they thought.

We should start with an understanding of how much waste is there currently from today's reactors. Roughly one coke can would hold all the waste generated from one person's electricity (European standards roughly 1kW) for a lifetime. We can reduce the volume of waste readily by removing the uranium and re-enriching it. This can be done with virtually all reactors including todays reactors. This will remove 90% of the waste volume but does nothing to reduce the hazards of the waste.

We can remove the elements that are heavier than uranium (transuranics or TRUs). This is the long term hazard. This material can be recycled into a reactor to be fissioned (destroyed forever not simply buried). This can be done to a very limited extent in some of today's reactors. But either IFR or molten salt reactors would really be the appropriate way to eliminate the long term hazards of nuclear waste. Such a process will be limited by our ability to separate the TRUs from the fission products. We expect to achieve around 99% separation so to reduce the long term hazard 100 fold.

The near term hazard comes from the fission products. These will decay in a reasonable time. Every 30 years the radioactivity will decay by half. So by 300 years you are back to roughly background radiation. 300 years is short enough we know how to build containers to last that long.

LarsJorgensen

vor 12 Jahrendiscuss

We expect to be around 1/8th the capital cost for the reactor itself. We plan to use off-the-shelf turbines&generators marketed for coal so those costs are pretty well known. You still have to add in the switch yard and transmission lines which we won't provide any advantage in. Overall, though we expect to come in below the cost of coal and natural gas including the cost of capital. One can always use the regulatory system to drive up costs like has been done in the US.

LarsJorgensen

vor 12 Jahrendiscuss

Yes it is based on their work. MSRE was a successful experiment that gathered a lot of data. MSBR and DMSR were follow paper designs based on MSRE. We've combined elements of each. A major difference though is that we are not trying to be a breeder yet. Our first priority is to be very safe and lower cost than coal as soon as possible. We'll leave breeding and absolute minimal waste production for a second generation.

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