Richard Fidler, Graham Taylor, Bob Clayton -ASTEC Associates

During the 1980s and 90s, the nuclear industry in the UK was a firm target of the environmental lobby. Nuclear energy was seen as dirty, an opinion greatly strengthened by the events at Chernobyl. However, as the environmental and scientific communities became concerned that carbon emissions could be presenting a greater risk than any nuclear legacy, the industry is now seen as having to play a substantial role in minimising the country’s carbon footprint. Thus, the nation’s nuclear generating capacity needs to grow beyond its past peak of the 23% share of the electricity market that was reached in 1998.

At the same time, the issues of decommissioning and waste management are still missions that need to be successfully deployed; though re-assuring the public could still be a harder task than the technical and engineering challenges.

Decommissioning work involves dismantling plant and buildings, processing and immobilising the radioactive materials, decontaminating the site and returning it to a usable condition.  The NDA’s estimate for the UK decommissioning programme of £70 billion makes it a globally attractive market and nuclear businesses from around the world are seeking to secure a slice of the pie.

Although much of the work is being carried out by companies based overseas, all the work is subject to the UK’s nuclear regulatory regime, and the licensing arrangements of the Nuclear Installations Inspectorate.  The UK’s nuclear regulatory arrangements are significantly different from much of the rest of the world, requiring the operator to justify the proposal on its own merits, rather than meeting a prescriptive set of targets.  At present however, one consequence of the lean years has been the decline in the numbers of graduates entering the nuclear profession, resulting in a substantial skills shortage, particularly in areas that are specific to the UK industry.

So with the huge amounts of money in the decommissioning market and the potential resource issues being encountered, how much has the nuclear power industry changed in its transition from generating into decommissioning? What is it like to work on a decommissioning site? And how much different is it to work on a decommissioning site compared with a generating site?

When considering a nuclear power station as it approached the end of its generating life, many in the industry believed that the transition would be both massive and rapid – the control rods would go in, reactors would be quickly defuelled and the bulldozers would arrive at the gate leaving staff numbers to dwindle to a handful because there was very little left for anyone to do. 

In reality, however, planning the site clean-up commenced up to three years before the final shut-down. Defuelling is the first priority because of the strategy to remove the higher hazards early so that the site can operate under a less stringent regulatory regime thereafter. 

First the irradiated fuel has to be removed from the reactors and dispatched to Sellafield.  The general feeling around the industry was that this would not be a problem.  After all, fuel had routinely been removed from reactors since electricity generation began.  Few had recognised that large amounts of fuel, being removed quickly from each decommissioning reactor would have to compete with other sites being defuelled, as well as with the routine throughput of the stations that are still operating.  The huge demand for reprocessing capacity repeatedly threatened to overwhelm an already constrained Sellafield. 

Secondly, even though some stations went ‘cold and dark’, the fuel remained on-site, and in the eyes of the regulators, there was very little change to the site hazard.  The NII, EA and SEPA all gave the same level of scrutiny as when the sites were generating and consequently so did the companies’ own processes as a necessity. 

Thus, during defuelling almost the same level of engineering is required to support, produce and manage safety cases and to ensure the maintenance of appropriate technical standards.  Currently, this is a valuable opportunity to rebuild and rejuvenate some of the UK’s nuclear skill base, such that the UK’s nuclear industry can benefit from future expansion.  This was recognised by the Government and the Skill Councils in developing programmes under the KNOO (Keeping the Nuclear Option Open) banner.  However, many in the industry had the same view of dwindling staff numbers as described above, and there were redundancies as well as large numbers being tempted into other sectors.  With oil prices rising and other large engineering projects on the go, retention of key skills became a major issue.

The required levels of operational staff remained higher during de-fuelling than was envisaged.  Shift cover remained in place to keep the hazard under surveillance, and there has been the same requirement to provide manning for emergency arrangements that were no different from those that had existed during generation. As engineering and operations staff numbers remained high, so did those of technical support, administration, and business support. 

OK, so defuelling was a glitch.  Surely when the last fuel left the site, so could most of the staff; then the bulldozers could move in and proper decommissioning could begin in earnest.

If the paradigm turned out to be wrong for defuelling then it has similarly turned out to be wrong for decommissioning.  While 99% of the hazard had left the site, the remaining 1% would prove hard to shift.  Large volumes of intermediate level waste – fuel element debris, reactor components, and radioactive resins from pond water treatment plants, for example – would need to be processed and retained on site in newly designed and built ILW stores until UK radioactive waste policy had been formalised and put into practice. 

Operational staff, albeit at reduced levels, will continue to remain on shift to watch over the hazard and engineering staff will still be needed to ensure the risk is as low as is reasonably practicable.    

The conclusion of this is that decommissioning sites are, in many ways, not vastly different from generating sites: The Nuclear Installation Act Licence Conditions still apply, the same regulatory framework exists and the same levels of management and effort are expended in the scrutiny and control of environmental and industrial safety.  However, some things have changed and in particular two things are very different: money and time.

The attitude to money is what someone on a generating site would have seen change the most in the transition from generating, through defuelling and into decommissioning.  When generating electricity and earning the income from its sale; the differential between income and expenditure is colossal.  The generating income of a Magnox station would be hundreds of thousands of pounds a day.  While attention may have been paid to cost cutting, the reality always is that it is worth spending a lot of money to keep generating.  Generation almost always covers the costs by a large margin.  Once power generation has stopped, everything becomes cost and to people who have generated most of their working lives this change is often hard to come to terms with.

The money for decommissioning comes from the Nuclear Decommissioning Authority which has brought a national discipline to decommissioning.  What money is available is being spent predominantly to address the greatest hazard, with sufficient funding at least to occupy a core of staff and to allow progress to be made.  This, of course, feeds into the time equation.  Expenditure to ensure continued or extended generation is urgent; after all when electricity output has been lost, it’s a lost opportunity.  In contrast, money for hazard reduction can be spent more flexibly.  If a hazard is identified as secure where it is, then waiting to do anything about it can be acceptable. Delaying the work still requires a safety case and sometimes that can be more time-consuming to prepare than one which actually justifies removing the hazard.

Changes in expenditure priority have, not surprisingly led to flexible staffing.  On decommissioning sites operational staff numbers have, by and large, fallen in line with reducing hazard, but professional engineering staff – safety case engineers, project managers and project engineers for example, have reduced in line with the level of funding available to the site.  When additional funding is available it is normal to go to the agency market to secure the resource to utilise that funding.

Time-flexibility has enabled some sites to change their staffing policies and to gain access to a bigger pool of available expertise – both in-house staff and agency.  By moving to a 4 day week it has proved much easier to utilise remotely based people.  Whilst shift operational staff still need to reside locally, day staff do not, as many more are prepared to work for 3 nights away from home.  Now on many decommissioning sites, it is impossible to differentiate between station staff and contractors and similarly impossible to differentiate between someone who lives locally and someone who lives 200 miles away.

It seems that equilibrium is being reached and decommissioning sites are learning how to make the most of the money that is available to them.  The sites are securing enough of their own staff to maintain control of their destinies and using the still viable pot of experienced, but ageing agency engineers, who cut their teeth mainly on generating stations, to give flexibility in delivery. 

Without any perturbation in the nuclear business this would probably be OK.  As the hazard declines over the next few years on most sites, the number of available trained and skilled engineers required would probably keep pace with demand.  However, new build may have an enormous impact and if it does one wonders how the UK nuclear engineering base will cope.