26 Nov (NucNet): An International Atomic Energy Agency team of experts says safety has improved in recent years at Russia’s Novovoronezh nuclear station, but further improvements are needed such as completing work to bring the station’s various quality arrangements into a single integrated management system.
The Operational Safety Review Team (Osart) today concluded a 19-day mission to assess operational safety at Novovoronezh-5, one of the station’s three commercially operating reactors. The team said safety has been improved by, for example, using “innovative techniques” to reduce the facility’s impact on the environment.
Good practices identified by the team include the use of advanced chemistry techniques to “significantly enhance” removal of radioactive elements from water discharged from the site.
Advanced analysis of the primary coolant is used to estimate the likely age of any of fuel assembly in the core that develops a minor defect during power operation, which enables swifter replacement of damaged fuel, the team said.
The plant’s full scope simulator is able to model normal, abnormal and severe accident conditions, and has been developed in a way that improves training and communications for staff operating equipment on the site as well as from the main control room.
The team made a number of proposals to improve operational safety at the plant, including integrating the plant’s quality, environment and health and safety requirements into a single management system.
The plant’s ability to respond rapidly to changes in chemistry conditions should be improved, for example by removing the reliance on manual sampling and updating the automatic sampling system, the team said.
The team called for “a more rigorous and questioning approach” to dose control practices to be adopted to reduce the overall radiation dose.
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 IAEA said the Novovoronezh station’s first unit started operating in 1964, and since then four other units have operated at the site. Units 1 and 2 are being decommissioned, while Units 3, 4 and 5 are operating.
Unit 5, which began commercial operation in 1981, was the first 1,000-megawatt VVER pressurised water reactor to enter operation in Russia. Two additional units are under construction, the first of which will start operating in the next few months, the IAEA said.
In October Russia’s regulator extended the operational licence for Novovoronezh-5 by 10 years until 2025, state nuclear corporation Rosatom said. The unit’s initial lifetime operating period of 30 years expired on 25 September 2010 and the reactor was shut down for modernisation. Work was carried out on improving safety and most of the thermo-mechanical and electrical equipment has been replaced.
The 15-member Osart team comprised experts and observers from 13 countries and two IAEA staff members.
The review, which began on 9 November, covered the areas of leadership and management for safety; training and qualification; operations; maintenance; technical support; operating experience; radiation protection; chemistry as well as accident management.
