Supercritical water reactor

The supercritical water reactor combines the established technologies of the supercritical steam generator (typically used to generate electricity from fossil fuels) with the boiling water reactor (BWR), to achieve a design that is simpler and more efficient than a BWR, by operating at a higher pressure.

The development of SCWR systems is considered a promising advancement for nuclear power plants because of its high thermal efficiency (~45 % vs. ~33 % for current LWRs) and simpler design.

Also, by avoiding boiling, SCWR does not generate chaotic voids (bubbles) with less density and moderating effect.

In a LWR this can affect heat transfer and water flow, and the feedback can make the reactor power harder to predict and control.

Although supercritical fossil fuel plants have much experience in the materials, it does not include the combination of high temperature environment and intense neutron radiation.

It is an advantage in managing water chemistry and stress corrosion cracking of structural materials.

The water inventory in the top dome of the reactor vessel serves as an in-vessel accumulator.

There was an error in the water level signal in the Three Mile Island accident and the operators shut down the ECCS.

However, a LWR type design, reactor pressure vessel inner wall is cooled by the inlet coolant as PWR.

[11] However, a LWR type SCWR design adopts water rods in the fuel assemblies as BWRs.

This is an advantage in managing water chemistry and Stress corrosion cracking of structural materials.

LWRs are the dominant design with the largest share of nuclear power generation and are the current offering for new construction in the world.

[15] However, chemical shim cannot be used in SCWRs as well as BWRs, due to the positive coolant void coefficient.