We can’t power world on “only solar”, solar needs either trans-global transmission or massive energy storage, or base load power backup.
Molten Salt Reactor Advantages
(Scroll to see all) Molten Fuel; Salt Cooled; Inherent Safety; Easy Construction & Siting; Lower Cost; Industrial Heat
Molten Fuel - Fuel circulates through the reactor, fission products get removed, for over 99% fuel use (vs. LWR ~3%). No long-term radioactive waste.
Salt Cooled - Coolant far below boiling point, so reactor operates near atmospheric pressure. Molten fuel chemically bound to stable salt; and no water; so no loss of coolant accident possible. No need for high-pressure safety systems.
High Inherent Safety - No water, no high pressure, nothing that could propel radioactive materials into the environment. Thermal expansion/contraction of molten fuel-salt strongly regulates fission rate; MSR is a very stable reactor. Simple safety systems work even if no electricity or operators.
Easy Construction and Siting - Low pressure operation, so no high-pressure safety systems. No water, so no steam containment building, no need for a river. Fuel salt quickly cools to solid, doesn't dissolve in water, can't spread in environment. Reactor and all eqipment would be factory assembled, with modern quality control, sensors and communication.
Lower Cost - Even with exotic materials, construction costs will be dramatically lower than LWR — factory construction, minimal manual on-site preparation. No long-term radioactive waste, so no long-term storage.
High Temperature Operation - Heat to generate electricity, desalinate water, produce CO2-neutral vehicle fuel, make cement or fertilizer, and other industrial uses.