IAEA reviews pre-operational safety at Slovakian unit

11 December 2019

Slovenske Elektrarne, the owner and operator of unit 3 of the Mochovce nuclear power plant in Slovakia, has shown a commitment to safety, an expert team from the International Atomic Energy Agency (IAEA) has concluded. The team also identified areas for further enhancements at the 471 MWe VVER unit, which is due to start up next year.

The four-unit Mochovce plant (Image: Slovenske Elektrarne)

A Pre-Operational Safety Review Team (Pre-OSART) concluded an 18-day mission to assess operational safety at Mochovce 3. The 17-member team comprised experts from Brazil, Canada, China, Czech Republic, Finland, France, Germany, Hungary, Romania, Russia and the UK, as well as two IAEA officials and observers from Austria, Italy and Russia.

Pre-OSART missions aim to improve operational safety by objectively assessing safety performance using the IAEA's Safety Standards and proposing recommendations for improvement where appropriate. The review covered the areas of leadership and management for safety; training and qualification; operations; maintenance; technical support; operating experience; radiation protection; chemistry; emergency preparedness and response; accident management; human, technology and organisational interactions; and commissioning.

The Pre-OSART mission team identified a number of good practices at Mochovce 3 that will be shared with the nuclear industry globally. These include that the plant has implemented a novel safety system to cool the reactor even when shut down. It has also developed and uses an online tool to support event classification and prognosis, in case of emergencies. The team also found the plant has adopted an effective way of communicating with external organisations and interested parties.

The mission made several recommendations to improve operational safety at Mochovce 3, including that plant managers should set high standards and expectations for plant operation and ensure they are rigorously applied. The plant should also fully develop and implement an integrated and strategic approach to support its safe commissioning.

"Before first starting up a new nuclear power plant, senior managers need to continuously demonstrate commitment to safety and engage employees at every level in this effort and the Pre-OSART team has observed such a commitment," said team leader Fuming Jiang, senior nuclear safety officer in the IAEA's Operational Safety Section. "The team also offered recommendations and suggestions to further improve the plant's operational safety performance."

"The mission provided valuable feedback, which will help us further improve the commissioning process and increase operational efficiency and safety of our new units," said Slovenske Elektrarne Chairman and CEO Branislav Strýček. "We will implement all proposals and recommendations of the Pre-OSART experts, and I believe that we will achieve our objective of becoming one of the best operators of VVER reactors in the world."

The mission team has submitted a draft report of its finding to the plant management. The management, together with the national regulator - the Nuclear Regulatory Authority of the Slovak Republic (UJD SR) - will be able to comment on the report, a final version of which will be submitted to the Slovakian government within three months.

Construction of the first two units at the four-unit Mochovce plant started in 1982. Work began on units 3 and 4 in 1986, but stalled in 1992. The first two reactors were completed and came into operation in 1998 and 1999 with a project to complete units 3 and 4 beginning ten years later. The final design includes many upgrades to safety and security, including increased aircraft impact protection and emergency management measures based on lessons from the Fukushima accident which were incorporated during the project.

UJD SR announced on 6 December that it had been informed of damage to the reinforced concrete channels and their covers in one of the Mochovce 3's two 125-metre-tall water cooling towers. The damage was caused by insufficient anchorage of the concrete covers during recent high-pressure pump tests. UJD SR said repairs are to be completed by the end of February and are "unlikely to negatively affect the schedule of unit 3 commissioning".

Researched and written by World Nuclear News