The 99 nuclear power plants on US soil provide nearly 20 percent of the country's energy needs and have been operating at an increasingly high capacity, from 50 percent in the early 70s, to 70 percent in the early 90s, and keeping above 90 percent since 2002. However, according to new research from MIT and the Argonne National Laboratory, throttling down the capacity of nuclear power plants and adapting their output dynamically to compensate for the unpredictability of renewable sources could lead to savings for both consumers and nuclear plant owners.

According to the study, nuclear power plants do not need to operate at maximum capacity to maximize their efficiency. Rather, by adapting their output dynamically to compensate for the unpredictability of clean energy sources, they could create a symbiotic relationship that can minimize greenhouse gas emissions while also decreasing the cost of electricity to consumers as well as the cost of operations to power plant owners.

The researchers, led by principal investigator Francesco Ganda, developed a mathematical representation of the operational constraints of nuclear reactors and then used simulation models to estimate the cost of electricity generation, market prices, and the revenues to power plants.

"Nuclear power plants are governed by a different set of principles compared to other generators, and our approach enables the representation of these relationships in the analysis of power systems and electricity markets," said Ganda.

In particular, the study found that one of the most limiting constraints to flexible operations in nuclear power plants is the increased concentration of xenon (an effective neutron poison that lowers nuclear fuel reactivity) following every reactor power drop.

Despite this, the researchers conclude that nuclear plants can not only be efficient when not operating at full output, but they are also also fully capable of responding dynamically to hourly electricity market prices and second-to-second frequency regulation needs.

A paper describing the study appeared in a recent issue of the journal Nuclear Technology.