Ultimate Safe Reactor

A big part of overcoming fear of all things nuclear is to design and build reactors that have certain characteristics. One of these characteristics is “continuous on-line fission product removal”, which means that the split atoms are removed from the reactor and the remaining fuel as they are created by the fissioning of the fuel.

Molten Salt Reactors have been (and are being designed) with this in mind.  Without getting all technical, this means that there is no reason to require an evacuation plan for the public surrounding the plant, ever.  The waste in not concentrated in the fuel or at the plant during operation. Because the fuel is liquid, the fission products can be removed continuously and dealt with, either as eventual industrial materials or long term storage, which has many technical and practical solutions.

Of course, the NRC would have to change its rules. But without the source term in the reactor (fission products) there is nothing to disperse in the even of an accident, Thus, no evacuation plan should be required. This does a lot to alleviate the public’s fears about the plant.

Some other characteristics are:

Safety is absolute, inherent, and passive, cannot be tampered with

After heat is reduced to benign level

Criticality is inherently controlled

Technology, basics are developed and have been demonstrated

Proliferation and Diversion Resistant

Size, expected to have great size flexibility

Economy, potential for being economic due to advantages

Future variations are possible to adjust to future needs

BTW, this type of reactor and some of these design considerations were exercised half a century ago (yes, 50 years!) with the Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Lab (ORNL).

Uri Gat of ONRL called this the Ultimate Safe (US) Reactor. (I guess he was very patriotic in the naming.) Here is the abstract of one of his papers that discuss the concept:

The Ultimate Safe (U.S.) Reactor is based on a novel safety concept. Fission products in the reactor are allowed to accumulate only to a level at which they would constitute a harmless source term. Removal of the fission products also removes the decay hears – the driving force for the source term. The reactors has to excess criticality and is controlled by the reactivity temperature coefficient. Safety is inherent and passive. Waste is removed from the site promptly.

These are worthy design goals!


Leave a Reply

Your email address will not be published. Required fields are marked *