Modernising Loviisa, learning from LARA1 January 2015
Loviisa’s first attempt at a full upgrade of its I&C systems, a project called LARA, proved unsuccessful because of the complexity and sheer scale of the undertaking. Building on the painful lessons of that experience a new project, ELSA, with new contractors, is underway. The scope is somewhat reduced, but the project remains ambitious and the schedule tight, with completion by 2018.
Loviisa's first attempt at a full upgrade of its I&C systems, a project called LARA, proved unsuccessful because of the complexity and sheer scale of the undertaking. Building on the painful lessons of that experience a new project, ELSA, with new contractors, is underway. The scope is somewhat reduced, but the project remains ambitious and the schedule tight, with completion by 2018.
Author: Ulf Linden, Fortum, Loviisa power plant, Finland
Loviisa unit 1 has been in operation since 1977 and unit 2 since 1980. The plant has operating licences for 50 years, which means for unit 1 until 2027 and for unit 2 until 2030.
Loviisa employs two VVER-440 pressurised water reactors of Russian design. The reactors, turbines, generators and other main components were imported from the former Soviet Union, while the steel containment and its related ice condensers were manufactured using Westinghouse licences.
The safety, control and automation systems also employ Western technology, including Siemens Simatic and Teleperm for normal process control and Siemens safety automation for ESFAS (engineered safety feature actuation systems), while the reactor trip system, reactor controller, control rod limitation system and neutron flux measurement system are of Russian origin.
When Loviisa 1 was taken into operation in 1977 it was one of the most automated nuclear power plants in the world, but for some years it has been clear that continuing operation with the original automation systems would be challenging from both a technical and economic point of view. The main driver for the modernisation of these systems is therefore to ensure safe and reliable operation to the end of plant lifetime.
The scope of work has also been increased recently due to new nuclear safety regulatory guides released in 2013 by the Finnish Radiation and Nuclear Safety Authority, coming into effect on 1 December 2013. The new requirements are stricter than the old ones and some changes to the automation systems are being carried out to further enhance safety. These are being done as part of the modernisation programme.
Some additional plant modifications are also being done reflecting post-Fukushima lessons, eg building of new cooling towers for residual heat removal using air (in addition to the existing sea water cooling) and improving of temperature measurements and cooling of fuel pools.
The present automation upgrade project started in May 2014, and is the second attempt to renew the automation at Loviisa power plant. The first project, LARA (Loviisa Automation RenewAl), which was awarded to a consortium of Areva and Siemens, started in 2005. It was terminated in early 2014 when both parties (supplier and purchaser) agreed that due to its large scope and considerable complexity the project would be significantly delayed. The LARA project scope included renewal of all automation systems across both units. It also included renewal of control rooms and simulators.
The new project, called ELSA, for which Rolls-Royce was selected as main contractor, has a more limited (although still ambitious) scope, decreasing the functions and systems to be renewed with the aim of making the implementation more manageable.
ELSA (so-named because the project kick- off date was 14 October, which in Finland is the "name day" of Elsa) is confined to renewal of the automation systems for reactor protection, reactor control, reactor power limitation and for the most important safety functions. The scope also includes improvements to the short and long term accident management systems.
For the ELSA project Rolls-Royce will deliver all the new safety-classified automation systems, while Metso is subcontracted to Rolls-Royce as provider of monitoring systems and normal process control systems (employing Metso DNA for operational instrumentation & control).
Safety system automation will be implemented on Rolls-Royce's Spinline platform.
The Rolls-Royce scope includes planning, testing and installation. It will also provide a hardwired backup for accident management, reactor trip system and ESFAS. The Metso scope includes field design and on-site installation.
Learning from LARA
The new project aims to fully take on board experience gained with the LARA project, which was thoroughly analysed. An extensive body of material describing LARA lessons learned was assembled and ELSA project participants have been trained using this lessons-learned material. The main recommendations included:
• focus on change and configuration management;
• reduce the scope;
• avoid implementing unnecessary upgrades and improvements in old but well functioning automation systems;
• freeze the design;
• minimise changes at the plant and in the project.
Despite benefitting from building on these lessons from LARA, the ELSA project of course remains challenging. Challenges include:
• Interface between new and old systems, as the automation systems are only being partly renewed. A lot of effort is going into the investigation of the interface (old cabinets and marshalling racks).
• The tight schedule. The plan is to complete the automation renewal on both units in three stages during the normal planned annual outages in 2016, 2017 and 2018.
• Change and configuration management. Changes are made all the time to the plant and during automation upgrade implementation further small changes may be made. In the system and detailed design phase of the new automation changes may also have to be made to the scope, because it is not possible to implement functions in the new digital automation systems exactly as they were done in the analogue systems. The project and plant teams may also propose "small" improvements to the new automation system and the system supplier may suggest modifications because all requirements cannot be fulfilled. Experience with LARA highlighted these challenges.
In addition there are many other upgrade projects ongoing at the plant, eg turbine modifications and post Fukushima-projects, including provision of additional air cooling, as already noted, and impacts on the automation renewal must be carefully analysed.
Well-functioning instrumentation & control systems installed by Siemens/ Areva in phase one of the LARA project - including waste water process control systems on both units, monitoring and control of the 110kV/20kV switchyard and significant safety automation on both units (control rod control and indication systems, preventive protection safety functions and modifications in control rooms and training simulators) - will be retained and interfaces to the new Rolls-Royce Spinline platform will be provided.
Current status of ELSA
Implementation of the ELSA project is envisaged to be in three stages:
• Stage 1: Renewal of preventive protection functions to create clear defence-in-depth lines (normal process control - preventive protection - reactor trip - manual backup). In the implementation, the principles of redundancy, diversity and physical separation must be fully taken into account in the defence-in-depth-lines and between the defence-in-depth lines. This preventive protection part of the project will be completed at the plant in 2016.
• Stage 2: Accident management systems. Implementation planned for 2017.
• Stage 3: Renewal of the reactor protection system, together with the reactor control and reactor power limitation system. This stage will also include renewal of the neutron flux measurement system. Implementation is planned for 2018.
ELSA started smoothly in May 2014, greatly helped by being able to make use of the LARA project organisation, which was already in place and ready.
During the power plant outages of August and September 2014, interfaces with the existing automation system were investigated and the basic design of the new systems for stage 1 has now been completed, as scheduled, before the end of 2014. This will allow the first stage to be implemented on both units during 2016, subject to approval of the basic design concept by the regulatory authority.
Pre-installation work for stage 1 will be done in 2015, with final installation in 2016.
Design work in support of the second and third stages of the project is underway and the whole project will be completed by the end of 2018.
(Originally published in MPS January 2015)