A nuclear powered world

“Nations sign on to the Global Nuclear Energy Partnership” ran the Sunday press release from politicos in Vienna. But, sign on to what, exactly? Oh yes, broad uptake of nuclear power without weapons proliferation etc, etc, but again, what exactly - at the nuts and bolts level?

To tease out an answer it was best to be, not hobnobbing with suave diplomats in Vienna's splendour on a balmy Sunday afternoon, but in deep discussion with front-line nuclear “grunts” at the Centre on the Grove, in Boise, Idaho for an intensive week.

For Idaho, home to a major US national nuclear laboratory and birthplace of commercial nuclear electricity, played host to more than 500 researchers from around the world attending “Global 2007”, this year's convention of the nuclear industry's premier conference series on advanced nuclear systems.

“Global”, which usually deals with far-off innovation, much of it only ready for implementation well after the presenters are dead, is traditionally hosted by rotation, and this year was not the US' turn. But US nuclear policymakers made a persuasive case that they needed a high profile venue to deliver their GNEP program to nuclear “insiders”. And so attendees were treated to a technical nuclear smorgasbord - from imminent, next-step reactors to on-the-horizon technologies - served up in a socio-economic/political milieu of third world development, energy/greenhouse concerns and constraints, and nuclear non-proliferation.

The mid-term advanced nuclear reactors at the heart of “Global” are these days tagged by the label "Generation IV". Intended to put the nuclear industry on a truly sustainable footing through the end of the 21st century and beyond, these reactors are unlike present-day commercial nuclear power reactors, which primarily "burn" the uranium 235 isotope. Rather, the Generation IV class - within which there is a number of design types - by completely “burning” all uranium, and also thorium, fuelstocks, together with long-lived in-reactor created byproducts - will enable the full utilisation of uranium and thorium resources, while at the same time massively reducing both the volume and the radioactivity of waste left over from the fission process.

It was clear from the conference presentations that, in many aspects, overseas researchers, whose robust funding has continued through the US nuclear power "doldrums" of recent decades, are well ahead of their US colleagues. This has significant impact on US ability to assert political leadership on the nuclear front.

The most evident example of international excellence is perhaps India's work on the thorium fuel cycle. India's presenter at Global said his country's energy needs, which track an ongoing GDP growth of 8-9 per cent per annum, were extremely large, and so energy security was of primary national concern. But India's population density precluded some alternative measures, such as using arable land to grow biofuel crops - food production would always take precedence. Hence India had a three-stage plan for indigenous development of nuclear power, culminating, in about 2040, in a principally thorium-fueled reactor suite, with uranium/plutonium fueled fast reactors used as fuel breeders.

India is poor in uranium resources but rich in thorium deposits, so the country's self-interest in pursuing thorium research is obvious. However, since thorium is roughly three times as abundant as uranium in the earth's crust, the promise of a viable thorium-fueled nuclear power system is of universal appeal.

Generation IV is an ambitious plan, matched only by the more immediate problem of how to achieve the transition. For though a simple leap to Generation IV would be preferable, the technology - fast neutron spectrum reactors which will breed U233 from thorium and Pu239 from uranium, then burn the products - will not be commercially ready until 2030 at the earliest, and probably not before 2040. Given an intervening period of projected rapidly escalating world energy demand in the face of exacerbating greenhouse conditions sans nuclear, the world simply can't wait for Generation IV.

Within the nuclear industry, present-day power reactors are referred to as "Generation II". To bridge the gap between this extant Generation II and sustainable Generation IV, much effort is being directed towards a nearer-term (circa 2010-12) roll-out of "Generation III/III+" systems. These will be "conventional" reactors, in the sense of principally burning uranium 235, plus plutonium obtained from spent fuel reprocessing. But for capital cost economy and enhanced operational reliability they will be standardised plants, and some of the designs will be tuned, not just towards electricity generation, but also towards water desalination, district heating, or the large-scale production of hydrogen for use as a transport fuel.

US Government policy with respect to both Generation III/III+ and Generation IV is twofold: advancement of US domestic energy security, and the promotion of nuclear power as an international energy solution without increasing the risk of nuclear weapons proliferation. It is the latter part of this policy which has given rise to the Global Nuclear Energy Partnership (GNEP): an initiative to provide developing countries with nuclear energy on a turnkey basis: that is, via total provision of reactors and fuel, with full takeback, by GNEP supplier members, of spent reactor fuel for reprocessing and storage.

The rationale is that the spread of material, technology and know-how considered to represent nuclear weapons proliferation risks can best be controlled by dividing the nuclear world into two tiers: those countries which already possess such means, the so-called nuclear suppliers, and those countries, the nuclear recipients, which would voluntarily eschew developing “trigger” steps in the nuclear fuel cycle.

At Global, the GNEP discussions were very detailed. Presentations were made on a variety of proliferation, accident and terrorism resistant reactor types suitable for turnkey delivery. These included three very small-scale designs - 50MW to 120MW - intended for aggregated-over-time hook-up to low grade electricity grids, and also for remote locations and/or safe, unattended operation. At least one of these designs will be small enough to be delivered - fully fueled - as an integrated unit, and removed the same way - years hence, when the fuel runs out.

The International Atomic Energy Agency delivered a draft report on its endeavours to find out what prospective nuclear power recipient countries actually wanted - as opposed to what the nuclear suppliers had in mind to deliver: they mostly wanted larger, centralised units. (The IAEA identified about 50 prospective recipients, and conducted in-depth research with eight “most likely” candidates for early uptake - the formal report is to be published in early 2008.) Simultaneously, other specialist groups delved into enhanced nuclear safeguards monitoring.

Security will perhaps be GNEP's Achilles heel: from three perspectives. First, it is not at all clear that a multiplicity (the developers' projected aggregate demand runs to hundreds of units) of dispersed small-scale reactors can be as economically protected as a single, larger power station.

Second, the US formal position - as reiterated in its presentation at Global - is that supplier countries would do their part towards non-proliferation by reprocessing plutonium only together with other in-reactor created transuranics: neptunium, americium, and so on. In this way, the “conventional” Generation III/III+ designs used to kick start GNEP could benefit from enhanced fuel utilisation, without nuclear suppliers expanding transient stocks of separated plutonium. (The constant caveat about the general unsuitability of power reactor produced plutonium - which includes some non-fissile Pu240, whereas a weapon requires high purity Pu239 - is too arcane a topic for elucidation here.) But Japan and France (plus also Russia and China) reprocess plutonium already.

Presumably recognising this, and regarding a US stand-alone policy as futile, at Global it was informally allowed that US policy was in process of being changed to adopt plutonium separation. (Since the presidency of Jimmy Carter - a former US navy nuclear engineer - the US has independently refrained from the reprocessing of plutonium from Generation II spent fuel, on the grounds of enhancing non-proliferation. US reversal of this policy is a very big step.)

Third, and perhaps most important from a developing-country perspective, energy security is inextricably tied to industrial progress, and full nuclear fuel cycle competence - which requires cadres of highly trained specialists across disparate, yet interlocking, disciplines - is equally seen as linked to the buildup of intellectual capital necessary to drive that progress.

“South Africa won't sign on to GNEP”, ran the Reuters newsflash - also emanating from Vienna, a mere two days after the positive Sunday pronouncement. Again, Global attendees were treated to a detailed country report. South Africa, having under its previous regime voluntarily admitted to and dismantled its former successful nuclear weapons program, is now determined to reap the benefit of its expensively-nurtured nuclear expertise in a legitimate way. It has independently matured a variant of one of the most promising Generation III+ types: the Pebble Bed Reactor, and identified the commercialisation of this design as a national strategic program. South Africa intends to be optionally self-sufficient in the nuclear fuel cycle, to deliver 30 per cent of its electricity from nuclear by 2030 (the present figure is 6 per cent), and to enter the nuclear marketplace as a reactor supplier.

The inferred message is clear: South Africa will not be autocratically relegated to second-class nuclear - and, by implication, industrial - status. It is extremely plausible that other former weapons developers - Brazil, for instance - as well as present-day nuclear novice nations will similarly see GNEP, not as an energy facilitator, but as an imposed retardation of their industrial growth. And as their economies mature, it might be expected that even some initially willing GNEP recipients will naturally, having emulated South Korea's recent blistering economic progress, chafe against nuclear constraints which they consider no longer reasonable, appropriate or acceptable.

Yet - disparaging whispers (and shouts) about US grasping for retrieved nuclear power hegemony aside - GNEP's essential purpose is benign: without early, broadscale adoption of nuclear power, unremitting world energy demand will make a mockery of greenhouse amelioration. The crucial question therefore becomes: can GNEP work as a 21st century stopgap, and can a post Generation IV reactor class be implemented in such a way that, eventually, no nation requires either uranium enrichment or ex-reactor spent fuel reprocessing? That is, can nuclear plant reach a stage of sophistication where natural fuel is fed in, and fissile-free waste comes out?

Of the six Generation IV technologies preselected in 2002 (and reaffirmed in 2006) by the Generation IV International Consortium, only one - the Molten Salt Reactor - has this potential. Much derided and mocked because it was originally, indeed during the 1950s and 60s, developed for aircraft propulsion, the MSR dissolves its fuel in a liquid salt solution which also acts as the reactor coolant. The potential of this liquid fuel design type is for continuous in-reactor recycling and burning of actinides, and for continuous waste extraction. MSR, though further along its development path than other Generation IV types, is not well funded under the Generation IV Roadmap, and received scant attention at Global 2007. MSR, perhaps eventually conceived in conjunction with an accelerator-driven neutron source to maintain criticality, might really be considered a “Generation V/V+” technology.

It is towards this nominally “Generation V+” end-point, well beyond the majority focus even of Global 2007, that nuclear fission technology must strive if GNEP's altruistic goal of a proliferation-free nuclear powered world is to be fully realised.