Chernobyl 30 Years On: Key Remediation And Safety Projects Are ‘On Track’

Posted by NucNet on 26 April 2016 in NucNet

Tagged with: Chernobyl, New Safe Confinement, Ukraine.

Thirty years after the accident at Chernobyl, key remediation and safety projects at the site in Ukraine are on track and construction of the vital €1.5bn ($1.6bn) New Safe Confinement (NSC) is almost finished with commissioning scheduled for November 2017, the company in charge of construction and the European Bank for Reconstruction and Development (EBRD) told NucNet.

A spokesman for Novarka, a 50:50 joint venture formed by French multinationals Vinci Construction and Bouygues Travaux Publics, said since the preliminary design for the NSC was approved in 2013 the project “has always been on track”.

And Vince Novak, director of the EBRD’s nuclear safety department, said “most projects” are on schedule and nearing the commissioning stage.

Novarka said the NSC’s main crane system has been installed and power systems will be fitted before the huge arch-shaped structure is slid into position over the Unit 4 reactor, which exploded on 26 April 1986. The placement of the NSC – which will cover the existing temporary shelter, known as the sarcophagus – is scheduled for the end of 2016, the spokesman said.

The NSC is the most high profile and expensive element of the €2.15bn Shelter Implementation Plan (SIP), a framework developed to overcome the consequences of the accident, which was the most severe in the history of the nuclear power industry, causing a huge release of radionuclides over large areas of Belarus, Ukraine and Russia.

The EBRD told NucNet the SIP is expected to be completed by 2017 and “we do not project any further increases or additional cost”. It is being funded by contributions from more than 40 countries and organisations.

Novarka and the EBRD both confirmed that the €1.5bn budget element for the NSC has already been covered with donor governments are making their payments “on a regular basis”. There is no shortfall in funding for the NSC, thanks also to a €500m contribution by the EBRD.

The EBRD’s involvement in nuclear safety began in 1993 with the establishment of the Nuclear Safety Account (NSA) for urgent safety upgrades of Soviet-type reactors in operation in Bulgaria, Lithuania and Russia.

The EBRD said the biggest task at Chernobyl was to overcome the legacy of the 1986 accident with the destroyed reactor enclosed only in a temporary structure, known as the sarcophagus, erected in the immediate aftermath of the explosion under extremely hazardous conditions. The vicinity of the plant had to be evacuated due to heavy contamination and a 30km exclusion zone was declared which remains in place to this day.

To help Ukraine in making the site of the shelter stable and environmentally safe, the international community led by the G-7 and the European Commission established the Chernobyl Shelter Fund (CSF) in 1997. The EBRD was commissioned to become the new fund’s administrator.

The first task of the CSF was to take stock and develop a work programme of how to transform Chernobyl into an environmentally safe and secure environment. Vince Novak, who joined the EBRD after a visit to Chernobyl in 1997 and today is director of its nuclear safety department, said: “The task was so enormous that the most difficult challenge was to define the project.”

Based on recommendations by Ukrainian and international experts, this strategy was outlined in the SIP, a step-by-step approach on how to make the accident site safe.

The plan defined five central safety goals, one of which led to the design and construction of the NSC. However, long before work on the structure could begin, extensive preparations had to be made and implemented ranging from research and engineering for conceptual designs to the development of the site infrastructure and procedures for worker protection.

Overall, the SIP includes more than 300 sub-projects that have been completed, with the exception of those related to the finalisation of the NSC. The sub- projects include creating the infrastructure for the construction of the NSC, the successful stabilisation of the existing shelter, the removal of the heavily contaminated vent stack, radiological protection and safety measures for the workforce and permanent monitoring and risk assessment for all activity on the site.

The most visible, prominent and final element of the SIP is the NSC, which will make the site safe and allow for the eventual dismantling of its aging structure, the EBRD said.

When completed, the NSC will prevent the release of contaminated material from the existing shelter and at the same time protect the structure from external impacts such as extreme weather.

To minimise the risk of workers’ exposure to radiation, the NSC is being assembled about 300 metres from Unit 4, where radiation levels are significantly lower than near the damaged reactor, and will be slid into position.

The huge structure will eventually rise to a height of 110 metres, will be 165 metres long, have a span of 260 metres and a lifetime of a minimum of 100 years. It will provide “a safe working environment” equipped with heavy duty cranes for the future dismantling of the shelter and waste management, the EBRD said.

Another key element of the work being carried out at Chernobyl, the interim spent fuel storage facility known as ISF2, is in the final phase of construction. ISF2 will process, dry and cut more than 21,000 fuel assemblies from Chernobyl Units 1-3, which will then be placed in double-walled canisters and stored in concrete modules on site. The spent fuel will then be stored safely and securely for a minimum of 100 years.

Completion of the facility, designed and built by the US company Holtec, is scheduled for 2017.

Once all fuel has been transferred to the ISF2 the current storage can be decommissioned. The EBRD said this will represent “a major step forward in increasing nuclear safety at the site”.

The EBRD said: “Decommissioning any nuclear power plant is a challenge. In Chernobyl, where the last unit was shut in 2000, it is further complicated by the fact that it takes place in a contaminated area.”

Novarka said personnel working onsite are fitted out with appropriate personal protective equipment chosen according to the working area and two dosimeters.

The data recorded from the dosimeters is checked twice daily by radioprotection technicians and analysed in a laboratory. If allowable limits are reached – which is in principle impossible, given the prevention procedures – personnel may be prevented from working onsite, Novarka said. “Additional specific protocols include such procedures as systematic analysis of the data by a radioprotection specialist.”

Novarka said its maximum annual authorised dose for workers is 14 millisievert a year. The standard set by the French nuclear authorities is 20 mSv/year.

Helen Rycraft, senior nuclear safety officer at the International Atomic Energy Agency, said the Chernobyl accident was “a watershed” for the nuclear industry, particularly its impact on nuclear safety.

She said Chernobyl showed that technology alone could not be relied upon to ensure safety – and that the attitudes and behaviour of management and employees have a vital role to play as part of something that came to be called “safety culture”.

Ms Rycraft said: “Safety culture is about people. It addresses the human tendency towards complacency and taking things for granted.”

She said the IAEA’s work on safety culture has helped give rise to stronger legislative frameworks in member states, which use IAEA standards to develop and improve their safety practices.

“In the early years after Chernobyl, the focus was on safety culture at nuclear power plants, but the concept is now being used to enhance safety at all types of nuclear facilities and for activities in which radiation and radioactive sources are used.”

NucNet’s Chernobyl Fact File

For an in-depth look at the Chernobyl accident, download NucNet’s Chernobyl Fact File, originally published in February 2006, and updated for the 30th anniversary of the accident.

The 24-page publication, which includes references to the most relevant international studies, provides nuclear communications professionals and journalists with a single, comprehensive resource that brings together the facts about Chernobyl, including the reasons for the accident, the aftermath, the health effects and the lessons learned.

Details online.