US-based Holtec International announced on 23 September that it had completed pre-commissioning cold testing at the €380m ($416m) ISF-2 interim used fuel processing and storage facility at the Chernobyl nuclear plant in Ukraine.
The principal contractors for the ISF-2 were Ukraine's UTEM, Germany's BNG and Italy's Maloni. The project, supported by the Nuclear Safety Account (NSA) and managed by the London-headquartered European Bank for Reconstruction and Development (EBRD), will provide for the processing and storage of the used nuclear fuel from Chernobyl 1-3.
Holtec said cold testing, which began on 6 May and was completed on 29 August, had demonstrated the “full functionality” of the facility. Completion of cold testing was confirmed by the State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) on 6 September. The tests involved a range of scenarios which could be faced by the operator, including regular operation, remotely executed maintenance, and response to incidents and emergencies. Hot testing using real fuel is scheduled to begin at the end of November and will take three months. ISF-2 can formally begin commercial operation once Chernobyl NPP receives the necessary operating permit from the SNRIU.
Holtec took over the ISF-2 project in 2011 after demonstrating to EBRD and SNRIU that it had the technologies to deal with Chernobyl’s RBMK fuel. The project had begun in 1998 but stalled when the technology provided by Areva was shown to be inadequate. Holtec took over the project 13 years later and started work to develop a fully functional facility using the legacy systems, structures and components supplied by Areva, and by acquiring new replacement systems from France, Germany, Italy, the USA, and elsewhere.
"The seemingly endless slog of modifying and developing replacement SSCs that could work within the constraints of the partially built and ageing facility, followed by qualifying, licensing, manufacturing and testing them turned out to be an interminably long and tedious process," Holtec said. "The site acceptance tests involving 110 individual and 46 integrated tests including an astonishingly large number of SSCs (more than a thousand), punctuated by the discovery of hidden defects and obsolescent parts, was finally completed by April of this year."
According to EBRD, the facility will process, dry and cut more than 21,000 fuel assemblies from Chernobyl 1, 2 and 3. They will then be placed in double-walled canisters and stored in concrete modules onsite for at least 100 years.
The project is jointly funded by the EBRD and the NSA. The 18 NSA donors have committed more than €280m to safety projects at Chernobyl, and the EBRD has provided more than €200m of its own funding for the ISF-2.
Chernobyl’s RBMK reactors were shut down permanently after unit 4 was destroyed by an explosion in the April 1986 accident. Unit 1 closed in 1996, unit 2 in 1991, and unit 3 in 2000.
Sergiy Tarakanov, General Manager of Holtec Ukraine and ISF-2 Programme Manager, noted: “Chernobyl’s wet storage facility, where the entire massive inventory of used fuel is presently stored, is working beyond its design life. It is critical that this enormous inventory of fuel be moved to dry storage in the fastest possible time.”
Photo: Operability tests at ISF-2 (Credit: Holtec International)