Astrophysics of Molten Salt Breeder Reactors: Building a Nuclear Reactor Better than the Sun

Thu, Oct 29, 2015 at 4:00 pm

1 LeConte Hall

Frank Shu (UCSD)

Climate change is real, here, and potentially catastrophic in its effect. We argue that the scale of the transformation needed to mitigate climate change requires breakthroughs in current technologies, most importantly, in new forms of fission reactors that are:

(1) safe in their inherent design,

(2) sustainable in terms of meeting future energy demand for several

centuries as well as having an acceptable solution for nuclear waste disposal,

(3) secure in terms of weapons proliferation,

(4) superior in competitive cost relative to other alternatives.


We focus on one design – a two-fluid molten salt breeder reactor that uses the thorium fuel cycle – that has all four attributes, as well as a pathway to convert smoothly from our current unsustainable dependence on light-water reactors that use the once-through uranium fuel cycle. We argue how a spherical reactor can be understood in terms of astrophysical principles that govern the equation of state of the matter, mechanical structure, energy generation (with fission replacing fusion), and heat transport inside stars. An important difference is that engineering solutions can avoid evolution away from the so-called zero-age main-sequence. A subtext of the talk is that astrophysicists with a training in systems-thinking can bring unique technical insights to the challenges of climate-change mitigation and energy transformation. However, we also need to appreciate that the needed changes from business as usual are not only in scientific approach, but must deal with economic, political, and social realities. Climate change is a problem that affects all segments of society, and it cannot be solved without the cooperation of important stakeholders, in particular, the current suppliers of world primary energy (in descending order of market share in 2012): fossil fuels (81.7%), biofuels (10%), nuclear power (4.8%), hydropower (2.4%), and wind/solar/geothermal (1.1%).