Reactor Vessel Inspection with the MIS 7, Paluel Power plant Unit 2 (France) © AREVA

By Peter Taberner

The Areva Group, for example, stepped up its safety operations after the events of three years ago, and the new construction projects of their EPR reactors have passed through post-Fukushima security measures, through domestic safety organisations.

Another example of where this industry adaption has taken place is in Finland, where the local safety authority STUK in their final assessment of the Olkiluoto Nuclear Power Plant 3, says that the design functions on the plant are now strong enough to combat the possibility of earthquakes and flooding.

At the Taishan 1&2 plants in China, where Areva is progressing well with its construction in Guangdong province no issues have been reported for the EPR designs.
 

Advanced products

As regards to the existing fleets of nuclear plants, Areva have been in close contact with utility customers in supporting advancements in safety, through the “AREVA Safety Alliance” programme. This has been developed to offer nuclear utilities the most advanced products, services and integrated solutions, to maximise safety operations.

As of today, more than 225 projects have been launched in 19 countries and for 53 nuclear electricity producers.

To support the extension of current nuclear plant life, the “AREVA Forward Alliance programme” has also been launched to help utilities ensure the safe, long-term operation of the existing nuclear fleet.

The services that are provided are in line with the recommendations of the IAEA, including integrated plant assessment, aging management review by component, and supporting products and solutions.
 

New systems

Some of the latest techniques focus on database screening using the COMSY system, which allows the full observation of all the components of a nuclear plant.

Also, there is the FAMOSi fatigue monitoring system, which files historical data for components, new technologies for electric cable rejuvenation, concrete aging measurement diagnosis, and mitigation are also on offer from AREVA, resulting in the launch of 80 projects worldwide.

A spokesperson for the company reflects on what this means for the supply chain: “Regular updates of AREVA’s requirements for its suppliers are conducted in order both to comply with the evolving international standards and to guarantee our customers the up most level of safety.”

“However, no specific changes have been made to our requirements following Fukushima, as these standards already complied with the highest safety recommendations.”
 

Is France’s nuclear fleet ‘hard core’?

The 58 strong nuclear fleet in France is one standout example of how thorough safety measures have been put in place since the tsunami disaster, with a raft of measures that have been implemented.

In 2011, EDF took strong action to improve safety, by submitting 19 additional Safety Assessment reports to the French Nuclear Safety Authority (ASN), which encompassed all operational reactors alongside those that were under construction.

Many safety margins were reviewed, for example the extent of the risks from earthquakes and floods, that could result in the loss of cooling sources and all power supplies.

While the ASN was satisfied over safety levels, they insisted in the ‘hard core‘, concept, designed to strengthen nuclear plants’ structures, systems and components to withstand extreme situations.

Subsequently, the ASN made 19 decisions, which EDF plants would have to incorporate over six hundred new requirements.

In technical terms the ‘hard core’ principle would require plants to have “bunkerised” electrical resources in each unit, which must beready and installed before 2018.

Additionally, a temporary back-up diesel generator was fitted into all of France’s nuclear plants, which was completed in the first half of last year.

A further emergency power supply measure was included for the reactor coolant system relief valves that prepares the valves for depressurisation of the reactor coolant system to be opened, and kept open in the event of total loss of power, and emergency power.

As a testament to the rigorous safety process which is now in place, a total of 418 inspections were carried out across France’s nuclear plants throughout last year.

“The work undertaken in the wake of the Fukushima accident will extend over several years, and EDF will continue to mobilise its expertise and the resources of the industrial sector, to study and achieve

all of these improvements to meet the recommendations of the ASN," says an EDF spokesperson.
 

Tier 1 suppliers on the Horizon

Horizon nuclear power is one of the biggest nuclear power station developers in the UK, who directly manages several contracts with their “tier 1” suppliers, and have a stringent registration process in place, where any supplier will have to prove that they are competitive while ensuring safety.

Ben Russell, a spokesperson for Horizon Nuclear Power, explains: “In the UK, in terms of the safety of nuclear plants, there has been a perfectly sensible response after the Fukushima disaster, and the Weightman report concluded that there were no barriers to continuing with both our operating fleet and our nuclear new build programme.”

“Our chosen technology, Hitachi-GE’s UK ABWR, is currently progressing through the UK regulators’ Generic Design Assessment process and the reactor design incorporates lessons learned from Fukushima, including enhanced protection of core facilities, with watertight buildings and doors around back-up features, and diverse, and independent methods of power supply and core cooling.”

All signs are that the supply chain has adapted and is evolving for the good of the nuclear industry’s safety with the combined help and guidance of seasoned plant designers, operators, and component technology service companies within the supply chain.