Design

ThorCon design is a game changer in the nuclear industry and a disruption technology to the energy sector

Low-cost zero carbon complete 500 MW power plant in a barge fast to build and fast deploy which can act as baseload or load follower with blackstart capability

Thorcon Overview

TMSR500 is an offshore type plant where all 500 MW generators are packaged on a ship body, all of which are built on shipyard, pulled to nearshore or offshore site with a water depth of 0 to 10 meters, balanced to the seafloor, and need to be surrounded by waves breakers. ThorCon can handle a peak ground acceleration up to 1g, which could handle earthquakes much better than conventional nuclear power plant making ThorCon potentially could be place in almost any sites in Indonesia.

Fission Island

ThorCon is divided into 250 MWe power modules or PMODs. Each module contains two replaceable reactors in sealed Cans. The Cans sit in silos. At any one time, just one of the Cans of each module is producing power. The other Can is in cooldown mode. Every four years the Can that has been cooling is removed and replaced with a new Can. The fuelsalt is transferred to the new Can, and the Can that has been operating goes into cool down mode.

Drain Tank

The cold-wall is what makes the ThorCon work.

1. The cold-wall allows us to keep the Can interior below 350C during normal operation and keeps the Can from over-heating after a drain. The fact that the cold-wall is always operating is an important safety feature. If a problem develops in the cooling wall loop, we will find out before a casualty occurs rather than during.

Power Conversion

ThorCon employs four loops for converting fission heat to electric power:

1. The primary loop inside the Can

2. The secondary salt loop

3. A solar salt loop

4. A supercritical steam loop

Safety

Totally passive, totally unavoidable shutdown and cooling. ThorCon combines a strongly negative temperature coefficient with a massive margin between the operating temperature of 700C and the fuelsalt’s boiling temperature (1430C). As the reactor temperature rises, ThorCon’s power output drops. This is an intrinsic, immutable property of the reactor physics. In any casualty that raises the temperature of the salt much above operating level, ThorCon will shut itself down.

If the high temperature persists, the freeze valve will thaw and drain the fuel from the primary loop to the drain tank, where the silo cold-wall will passively handle the decay heat.

Thorcon Overview

TMSR500 is an offshore type plant where all 500 MW generators are packaged on a ship body, all of which are built on shipyard, pulled to nearshore or offshore site with a water depth of 0 to 10 meters, balanced to the seafloor, and need to be surrounded by waves breakers. ThorCon can handle a peak ground acceleration up to 1g, which could handle earthquakes much better than conventional nuclear power plant making ThorCon potentially could be place in almost any sites in Indonesia.

ThorCon requires no new technology. ThorCon requires sound engineering, but nothing we don’t already know how to do. ThorCon uses only commercially available components and materials, such as SUS316 steel, but avoiding unobtainable lithium-7 for molten salt. ThorCon feeds its heat to the same standard super-critical steam cycle used by coal plants around the world for decades. The result is nil power loop development risk and sourcing from competitive suppliers.

The high-temperature, low-pressure liquid fuel leads to low cost and intrinsic safety. The reactor itself is in a Can that is replaced on a four-year service schedule. Molten fluoride salt with dissolved thorium and uranium fuel is similarly removed and replaced, on an eight-year cycle. Shipyards can rapidly fabricate 500 MW power plants on hulls to be towed to near-shore sites. A prototype could begin testing in four years.

ThorCon is a molten salt fission reactor. Unlike all current nuclear reactors, the fuel is in liquid form. It can be moved around with a pump, and passively drained in the event of a casualty.ThorCon’s reactor operates at about the same pressure as your garden hose. Standard nuclear reactors operate at up to 160 bar (2300 psi). They require 9 inch thick pressure vessels and massive piping. The key forgings can only be done by a few specialized foundries. Worse, if there is a big piping failure, the pressurized water explodes into steam, which might spray radioactivity all over the place. This means the reactor, heat exchangers and pumps must be entombed in a massive, reinforced concrete mausoleum, where they are extremely difficult to repair or replace. Therefore, we pretend they will need little or no maintenance for the life of the plant. Reinforced concrete construction is horribly slow, nearly impossible to automate, difficult to inspect, and even more difficult to repair. In contrast, ThorCon uses normal piping thicknesses and easily automated, ship-style steel plate construction. 

Fission Island

ThorCon is divided into 250 MWe power modules or PMODs. Each module contains two replaceable reactors in sealed Cans. The Cans sit in silos. At any one time, just one of the Cans of each module is producing power. The other Can is in cooldown mode. Every four years the Can that has been cooling is removed and replaced with a new Can. The fuelsalt is transferred to the new Can, and the Can that has been operating goes into cool down mode.

The Can is ThorCon’s heart. The Can contains the reactor, which we call the Pot, a primary loop heat exchanger (PHX), and a primary loop pump (PLP). The pump takes liquid fuelsalt — a mixture of sodium, beryllium, uranium and thorium fluorides — from the Pot at 704C, and pushes the fuelsalt over to the PHX at a rate of just under 3000 kg/s. Flowing downward through the PHX, the fuelsalt transfers heat to a secondary salt, and is cooled to 565C in the process. The fuelsalt then flows over to the bottom of the Pot, and rises through the reactor core, which is mostly filled with graphite blocks, called the moderator. This graphite slows the neutrons produced by the fissile uranium, allowing a portion of the uranium in the fuelsalt to fission as it rises through the Pot, heating the salt to 704C, and (indirectly) converting a portion of the thorium to fissile uranium. It’s just that simple; and just that magical.

The Pot pressure is 3 bar gage, about the same as a garden hose. The outlet temperature of 704C results in an overall plant efficiency of 46%, and a net electrical output per Can of 250 MW. To produce this power, the Can requires only 39 litersof uranium per year enriched to 19.7%. The Can is a cylinder 11.6 m high and 7.3 m in diameter. It weighs about 400 tons. The Can has only one major moving part, the primary loop pump.

Drain Tank

The cold-wall is what makes the ThorCon work.

1. The cold-wall allows us to keep the Can interior below 350C during normal operation and keeps the Can from over-heating after a drain. The fact that the cold-wall is always operating is an important safety feature. If a problem develops in the cooling wall loop, we will find out before a casualty occurs rather than during.

2. The wall allows us to capture any tritium permeating through the Can or drain tank in the inert gas in the annulus between the Can/FDT and the walls.

3. The wall cools more rapidly as the Can/FDT tank heats up, but more slowly as the Can/drain tank cool down, which is exactly what we want to handle both emergencies and avoid salt freeze ups.

4. The wall maintains a double barrier between the fuelsalt and the cold-wall water, even if the primary loop is breached.

5. And the cold-wall does all this without any penetrations into the Can or the fuelsalt drain tank.

Power Conversion

ThorCon employs four loops for converting fission heat to electric power:

1. The primary loop inside the Can

2. The secondary salt loop

3. A solar salt loop

4. A supercritical steam loop

Salt piped through heat exchangers converts Pot heat to steam. The secondary salt is a mixture of sodium and beryllium fluoride containing no uranium or thorium. Hot secondary salt, depicted in green, is pumped out of the top of the Primary Heat Exchanger to a Secondary Heat Exchanger where it transfers its heat to a mixture of sodium and potassium nitrate commonly called solar salt from its use as an energy storage medium in solar plants. The solar salt, shown in pink, in turn transfers its heat to a supercritical steam loop, shown in red and orange. The solar salt loop captures any tritium that has made it to the secondary loop, and more importantly ensures that a rupture in the steam generator creates no nasty chemicals and harmlessly vents to the Steam Generating Cell via an open standpipe.

Unlike almost all current nuclear reactors, ThorCon is a high temperature reactor. This translates to thermal efficiency of 46% compared to about 33% for a standard light water reactor. This reduces capital costs and cuts cooling water requirements by 60%. It also allows us to use the same steam cycle as a modern coal plant.

Safety

Totally passive, totally unavoidable shutdown and cooling. ThorCon combines a strongly negative temperature coefficient with a massive margin between the operating temperature of 700C and the fuelsalt’s boiling temperature (1430C). As the reactor temperature rises, ThorCon’s power output drops. This is an intrinsic, immutable property of the reactor physics. In any casualty that raises the temperature of the salt much above operating level, ThorCon will shut itself down.

If the high temperature persists, the freeze valve will thaw and drain the fuel from the primary loop to the drain tank, where the silo cold-wall will passively handle the decay heat.

There is no need for any operator intervention. Not in 3 days, not in 300 days, not in 3000 days. Nor are there any valves that must be realigned by either system or operator control as in some so called passive systems. In fact there is nothing the operators can do to prevent the shutdown, drain, and cooling.

Release resistance. ThorCon has three gas tight barriers between the fuelsalt and the atmosphere. Here is a sectional view of the hull in way of the fission island. The structure is similar to the cargo hold section of a large tanker with a 3 meter wide double bottom and double sides. In addition, a 3m deep double roof is provided in way of the fission island. The double sides and roof are filled with sand or concrete. This is an extremely strong structure. It will not be penetrated by a Boeing 777 engine in a perpendicular impact at 400 knots. The hull, which is a double barrier, is only one of at least three gas tight barriers between the the fuel salt and the atmosphere. The Can silo is a gas tight structure; and the Can itself is a gas tight structure. All these must be breached to allow a release.

But even if they were, there is no internal dispersal mechanism. The ThorCon reactor operates at near-ambient pressure. In the event of a primary loop rupture, there is little pressure energy and no phase change. The spilled fuelsalt merely flows to the drain tank where it is passively cooled.

Moreover, the most troublesome fission products, including iodine-131, strontium-90 and cesium-137, are chemically bound to the salt. They will end up in the drain tank as well.