International Activities on Used Fuel Reprocessing

More than once on the first two days of this meeting, I heard comments made to the effect that we need to begin discussions (first as an industry and then later much more widely as a nation) about the "higher than zero" chance that the eventual introduction of advanced or Gen-IV reactors in the United States might best be accomplished along with a resumption of used nuclear fuel reprocessing, in order to obtain the best advantages of the Gen-IV designs (not the least of which is the reduction in volume of the final HLW or High Level Waste to be permanently stored in a repository.)  Because this seems likely to me, I decided to attend a technical session entitled "International Activities on Spent Fuel Reprocessing" here at the ANS Winter Meeting.

In an interesting technical achievement, Josquin Vernon of the French nuclear regulator ASN delivered a paper via telephone all the way from France -- nine hours out from Las Vegas time!  Vernon's presentation centered around the regulatory processes in France; his aim was to describe the regulatory process that would have to be undertaken to build a new fuel reprocessing facility.  Of course, France does reprocess fuel - but its facilities were built under a now-obsolete regulatory framework.

Vernon described the fact that ANS's task is really to ensure that the operator of a facility is safe; he said that "ANS controls the efficiency of the licensee in controlling the safety of its plant."  ASN controls nuclear and industrial safety aspects at French nuclear facilities, he said, and has no control over security measures.  But he reminded the assembled crowd that the prime responsibility for safety rests with the plant operator and "cannot be delegated."  This of course applies to fuel reprocessing facilities as well as nuclear power plants.

In France, Vernon said, the process to actually construct such a facility is quite different from that one might see in the United States, but this reporter found some similarities.  For example, the first step in France (with an essentially top-down system) is the political decision to construct a new facility.  ASN is not involved in this step.  Then, an authorization decree for creation of a facility is developed; at this point ASN can be consulted for input on the safety measures of the facility, but its input is 'suggestion only' at this phase.  When this process (which has other parallel administrative functions occurring as well) finishes the operator has permission to build the facility. Finally, a commissioning and operating license must be obtained from ASN, after a thorough technical assessment of the license application file.  ASN may also enact additional requirements or 'license conditions' for the plant's commissioning and operation.

In the United States, where spent fuel reprocessing is all but dead, a political decision would have to lead the way as well -- a decision that would carry with it discussions of safety, of nonproliferation, of cost and naturally of the final waste to be stored.

Mr. Vernon then told the attendees that the process, from political decision to construction of a new fuel reprocessing plant in France would likely take more than 15 years.  The signal here is that the discussion about reprocessing, and then the design, construction and licensing of a reprocessing facility might well take enough time to only just be ready when Gen-IV reactors are ready.  The major implication then is that these discussions need to begin very soon.

It was also stated that ASN considers it necessary in licensing a new facility to consider, before construction, the final disposition of all of the waste streams generated by the facility. He also noted that originally ASN's predecessors didn't think of fuel reprocessing plants in exactly the same ways as nuclear plants, but today's world demands that they be considered the same so that, for example, age related degradation of components is continuously considered from the regulatory point of view.  Further, he told the group, the applications for new facilities in France actually include the decommissioning plan.  He said that "it helps to have the designers of the facility think about the decommissioning while they are designing and building the facility, which helps with the inherent loss of institutional knowledge about the construction features that you'll naturally have over the life span of the facility."

I. Le Bars of the firm IRSN then addressed the meeting on hazard analysis and control at spent fuel reprocessing facilities.  He noted that in a major reprocessing plant, there may be as many as 3000 cells (chambers, etc.) each of which has some form of 'nuclear risk' which must be analyzed and controlled, and that many of these have specific operations and equipment unique to that cell.  He added that there are many types of processes going on in such a plant as well - chemical, mechanical, thermal - that need to be managed to ensure worker safety and nuclear safety.  Just as an example of one process, he described moving used fuel from a storage pool (chemical and thermal concerns as well as criticality concerns) to a dissolution process (chemical process concerns) and then the extraction of fission products (more chemical processes) and so on until the materials have been completely divided into output streams.  He said that the major hazards of containment, criticality, radiation health, thermal or heat release, and human factors all together contributed to a highly complex process quite difficult to manage from a regulatory standpoint.

Le Bars said that safety of such facilities is ensured by a conventional 'defense in depth' approach, as well as the case by case safety measures that are proposed to the regulator by the operator.  Because 100% guarantee of permanent safety of all aspects is impossible, Le Bars said, the target for any one process is "as safe as reasonably achievable."  Further, the continuous assessment of these processes ensures that there is a continuous technical dialogue ongoing between all stakeholders.

Finally, he noted that a fuel reprocessing plant might have 50,000 identified items or processes important to safety.  These, he said, cannot all realistically be considered as being equally important, and that the only rational way to address this large number of potential safety risks is to develop a ranking system for them.  To that end, the French, he said, are in the process of developing extra ASN technical guides specific to the contexts of fuel cycle / reprocessing plants.

Finally, Fiona Rayment, Director, Fuel Cycle Solutions, National Nuclear Laboratory (UK) spoke on reprocessing in the UK.  She began by noting that while the UK has had a variety of commercial power reactor systems (sodium cooled fast reactor, gas cooled reactors of multiple types, and pressurized water reactor) that it has only been reprocessing fuel from the gas cooled types (primarily the MAGNOX fleet.)  She added that the UK intends to end fuel reprocessing in 2020, concurrent with the end of MAGNOX operations.  The nation will then clean up all the fuel reprocessing sites.

While the present plan in the UK is to move to the open (permanent used fuel repository) fuel cycle, she noted that the UK is planning some 75 GWe of new light water reactors to be on line by about 2050.  To that end the nation has not fully shut the door on the idea of returning to reprocessing, but this time of course (eventually) of LWR fuel.

Rayment then went on to describe what she feels are the absolutely vital points for ensuring site safety for a newly designed and built fuel reprocessing plant.  They are:

1. A robust design with appropriate limits on and conditions for operations.

2. A rigorous operating regime that includes peer checking, self assessment, professional training accreditation and solid internal oversight.

3. An experienced regulatory interfacing group within the facility licensee's organization.

4. External peer reviews of the licensee on a continuing basis (by bodies such as WANO and the IAEA.)

5. The oversight of a strong, competent, independent and external nuclear regulator.

Rayment added that the defense in depth concept (first, that there be no faults; second, that if there are any faults they are controlled; and third, that if protection fails, there are systems in place to limit the consequences, as she described it) is the other pillar of safety of such facilities and must be rigorously adhered to.

The session ended with some Q&A, and was well attended and interactive.  Clearly, there is a lot of thought in other nations being put into the future of used nuclear fuel reprocessing - thought that the US might do well to borrow on.