Case study | Training & recruitment
Valve actuator training24 January 2011
Computer-controlled actuators are being installed on 20- and 30-year old valves in the UK’s AGR fleet to keep the stations up to date. Actuator manufacturer Auma has supported their installation with product-specific training
Training divisions at each of British Energy’s UK power stations (Dungeness, Hartlepool, Heysham, Hinkley Point, Hunterston and Torness, all advanced gas-cooled reactors) have a remit encompassing practical issues, human performance and nuclear professionalism. Engineering and operational training is also included.
At Heysham, the training department consists of four technical tutors: two for electrical and one each for mechanical and control & instrumentation. The training department supports around 1000 employees, including the 160 maintenance personnel that are each allocated 8-10 days of training per year. Training is also arranged for the station’s 48 apprentices.
Heysham’s training department responds to requests for education triggered by the power station’s systems and department heads. One of the key prompts for tuition is gap analysis. A large proportion of training at Heysham is carried out by in-house specialists. However, when new equipment is installed on site, manufacturers are invited to conduct the training.
When Auma’s modular electric actuators for valve automation were installed at Heysham 2 in mid-2010, gap analysis identified a training requirement. More than 400 Auma actuators have been installed at BE’s UK plants, partly for its obsolescence programme (British Energy is part of EDF Energy).
Heysham was the fourth BE plant to run Auma’s training programme, after Hinkley B, Dungeness B and Hunterston B. In outline, the course content begins with consideration of different valve/actuator designs. Attendees are educated in practical topics including sizing and installation issues along with maintenance education including removal of limit switches and motor/circuit board replacement. The training also features instruction in commissioning and set-up procedures. Eighteen staff members attended the training. To ensure that everyone that participated was able to benefit from a hands-on experience, the session was broken down into four teams.
“It was the first time that our technicians had seen Auma’s actuators: this meant that there was a lot of new content to take on board,” said John Plackett, BE technical training instructor, electrical. “However, the highly vocational style of instruction meant that the presentation was informative and engaging. Auma’s hands-on approach to education mirrors British Energy’s preferred training style.”
Steve Farrow, Training Manager for Auma Actuators Ltd said:
“As an actuator manufacturer, our training primarily focuses on our modular actuation technology. However, we recognise that it is essential to take a more rounded approach and acknowledge that valve integrity and life expectancy is paramount to the smooth running of a plant. We therefore begin our training course with an overview of basic valve knowledge and provide an understanding of the differences that exist between designs. Having set the scene, we go on to focus not only on actuator maintenance and repair but also to emphasise that correct commissioning procedures play a significant role in extending valve life.
“The need to set actuators in the context of differing applications can be illustrated with the example of a drain valve. Historically, parallel slide valves have been selected to fulfill this role, with the occasional use of globe valves. More recently we have seen a rise in the popularity of ball valves. The difference between a parallel slide and ball valve is relatively clear, allowing straightforward commissioning choices. However, when confronted with a fully lagged installation where the valve body is not visible, it may not be easy to visually identify if a globe or parallel slide is present. During our training programme, we therefore highlight the importance of maintenance technicians identifying the valve, as two very different commissioning procedures are required. Whilst it is unlikely that incorrect settings will adversely affect the actuator’s integrity, they will undoubtedly result in a reduction in valve performance during plant operation.
Straightforward explanations of the anatomy of an actuator are given with overviews of typical components including connectors, motor controls, gear cases and valve interfaces. Key ancillary issues, such as tripping torque and limit switches can also be considered worthy of additional comment. (A limit switch feeds back when the valve has reached a pre-determined position – usually fully open or fully closed. It can be mechanical or electronic in nature and is usually fitted within the actuator).
“Delivering training with foundations formed from the relationship between valve and actuator can alleviate many of the most common concerns: these can include valve damage caused by incorrect torque settings or the programming of the actuator to close on limit rather than torque as might be required. Process problems can be caused by valves either closing too slowly, or not at all, and valve spindle and or seat damage may arise as a result of incorrect commissioning procedures.”
In partnership with British Energy, Auma’s aim is to equip the utility’s staff with the necessary skills to address situations including the re-setting, repairing and commissioning of valves and actuators. Safety and operational integrity of valves is a primary objective of the training to support the smooth running of the plant. The actuator manufacturer’s aim is to ensure that the on-site team is as capable and independent as possible, although Auma’s service team is available if needed. Feedback forms are circulated at the conclusion of each training session and these confirm that Auma’s courses give engineers the knowledge and practical skills to assess on-site maintenance requirements.