Post scriptum:

Let us assume the Chinese could build a SMR that fulfills all economic promises of the SMR (I even think that is possible).

But should then the German Federal Government to build a Chinese SMR in Bavaria, Markus Söder would be the one in first row of every protest against it.

In summary:

• There are no physical reasons why a SMR cannot work.
• There is no working prototype for a SMR.
• The cost advantages of a SMR will never be realized.

This does not mean SMRs will not be built. As long as the tax payers foots the bill, the political resistance against nuclear power will be a larger obstacle than economic senselessness.

6/6

Gate 3: Economy / Scaling

The real trouble starts here.

The intention of the SMR is to use the modular design to bring down the costs by building the modules in large numbers.

This would require the design to be shared among many countries.

But politicians love nuclear reactors as 90% of the costs can end up locally. Buy using a shared design, a lot of the value created would be foreign.

If the SMR comes, every country/block will come up with it's own design. The claimed saving will never realized and nuclear energy will be as expensive as before.

5/x

Gate 2: Engineering

The problems appear at this stage. Russia and China are said to have reactors of said type. Though both installation fall short of the "modular" part.

The idea of the "modular" part is to drive down the costs of a nuclear reactor by building a lot of them based on a joint modular design and therefore achieving economies of scale.

So at this gate has not been passed or at least on a level that I consider satisfactory.

4/x

Gate 1: Physics

The proposed designs are based on rather well understood nuclear physics.

They are no magic machines, so most of them past this test rather easily.

There are some designs that deviate from the classic nuclear reactor that they may require more physical understanding for them to get them work.

But overall I do not object on this gate.

3/x

One problem about the SMR is that there are so many proposed designs of them.

There is no single SMR type. The suggested types go from down-scaling classic reactor types to complete new installations.

2/x

Gate 3: Does it work economically at scale?

A technology can be physically valid and technically feasible but still fail because the business case collapses when it is scaled. Costs of materials, energy, logistics or maintenance can kill an otherwise solid idea.

Examples of failures

• Supersonic passenger air travel (Concorde): The aircraft worked and did not violate physics, but the economics of fuel burn, noise restrictions and maintenance made the business unviable.
• Vertical farming for commodity crops: The biology and engineering work, but current energy and infrastructure costs make it far more expensive than field agriculture for low margin crops like wheat or rice.
• Hydrogen cars: Physics and engineering are fine, but storage, distribution and fuel cell costs made battery EVs far more competitive at scale.

5/5

Gate 2: Does a working prototype exist and are the engineering problems solved?

Even when a concept does not violate physics, the gap between an idea and a working system can be enormous. Some technologies fail because no one manages to build a prototype that performs as promised.

Examples of failures

• The Lilium Electric Aircraft: The physics of VTOL is real, but the company never produced a reliable, certified prototype despite years of promises.
• Theranos blood testing: No physical laws were violated, but the engineering requirements for accurate multi-analyte testing from tiny blood volumes were never solved. The prototypes never worked as announced.

4/5

Gate 1: Does it match physical realities and laws?

Before anything else, a technology must obey known physics. Ideas that violate conservation laws, thermodynamics or basic material limits usually fail long before money or engineering enter the picture.

Examples of failures

• Perpetual motion machines: Countless patents were filed that attempted to produce free energy. All violated the first or second law of thermodynamics. None worked.
• The Dean Drive: and similar “reactionless” propulsion concepts. They claimed thrust without expelling mass, which contradicts conservation of momentum.
• Cold fusion as initially announced in 1989: The Fleischmann and Pons experiment proposed fusion at room temperature but the claimed reaction rates contradicted known nuclear physics and could not be replicated.

3/5