03/22/2007 - 07:00

Nuclear can help

Given Earth's inevitable and imminent climate change and the rapid development of previously
underdeveloped nations, humanity faces a novel challenge. Whether the climate will change slowly
enough that we can respond at familiar rates or the change will happen so abruptly that we need new
modes of adaptation, we don't know. Whether China, India, and other fast-developing nations can
find pathways to sustainable lifestyles is another unanswered question, but one that perhaps we can
help guide.

At the very least, given that we now live with these uncertainties, we can identify things that
we recognize as
necessary. But we certainly can't tell whether they're
sufficient to enable humanity as we know it to survive and continue improving. The core
issue is to find a way to use nature's resources that allows us to improve the human condition
globally. Naturally, the first resource on our list is energy.

The most obvious, universally accepted--but not universally adopted--action we can take is to
use energy more efficiently. Here, the problem is not whether to follow such a path but how to make
it happen. So another given is that we will somehow discover and adopt creative ways to use energy
efficiently.

The next problem is based on the unavoidable course that we've adopted to improve our lives
(nationally and globally) by using considerably more energy
per capita. Whether it's inevitable that per capita energy consumption will rise in
developed nations is open, even controversial. But there's no arguing the global need, if the human
condition is to improve everywhere.

From there, we move to the question of how to meet that need, which relates directly to the
efficiency of how much or how little we will need to supply. Perhaps it would be better to phrase
that question in terms of how much energy is needed if certain levels of efficiency were
attained--and if certain levels of improved living conditions were our goal.

Suppose we're able to make a rough prediction of how much energy we'd need to supply in 2015,
2025, and 2050. Suppose we're even able to set rough upper and lower limits on these estimates.
We'd then be in a position to rationally decide what energy source to choose. We have a list
already, including all of the available sources:

  • Coal, oil, and gas (with some means of avoiding carbon emissions);
  • Hydroelectric (with safe and environmentally acceptable dams);
  • Solar;
  • Environmentally acceptable wind;
  • Environmentally acceptable geothermal;
  • Possibly tidal;
  • Safe and secure nuclear.

But when would we have the information to make a well-guided, information-based decision? The
difficult problem now is that the world is changing faster than we can generate the information
needed to make well-guided decisions.

A kind of negative benefit-cost analysis could help deal with this dilemma. That is, we can
estimate benefits and costs of different pathways in the conventional way, and then go a step
further by estimating the costs of choosing a pathway
and making a mistake. For example, we can ask what the costs of pumping carbon dioxide
into underground storage wells would be if the wells were safe
and if the wells sometimes exploded. Likewise, we can estimate the costs of accidents at
nuclear plants if we made an incorrect assumption about their safety level. Such an analysis gives
us an "insurance" perspective to help guide choices.

This leads me to posit that the mix of energy sources for the next many, many years
must include a significant component of nuclear power--and much more than we have now. The
nuclear power issue divides naturally into a near- and long-term aspect. The near-term addresses
the question of how to reduce carbon emissions relatively soon (say in 10 or 15 years) in a way
that's at least as safe as the ways we provide energy now. The present generation of light water
reactors (LWRs) has proven more durable, efficient, secure, and safe than the LWRs from the 1960s
and 1970s. We will need to build many more LWRs during the next 20 or 30 years, while finding ways
to safely deal with their waste.

The long-term problem combines dealing with nuclear wastes and making more efficient use of
potentially fissionable nuclear materials. This is the challenge of reducing the volume of nuclear
wastes by orders of magnitude and increasing the energy derived from uranium by an equal
amount.

At present, there is a potential pathway to do this that looks very promising, but it's still
far from realization. This pathway would combine recycling nuclear fuel with reactors using fast
neutrons. (Our current reactors use slow, "thermal" neutrons.) This will require years of research
and development and takes into account safety and security from proliferation. In my view, this
makes nuclear power one of those necessary, but not sufficient, components of our energy future in
the near and long terms.