During Covid, remote diagnostics achieves troubleshooting of feed water pump

Every two years, nuclear customer Cofrentes (Iberdrola) has a planned outage to refuel the reactor and maintain the plant. The customer is one of the largest nuclear PP (1X 1102MW) power provider in Spain near Valencia, originally commissioned in 1984. For reference, a power plant producing 1,000+ MW can provide power tomore than 1 million homes.

A few weeks before the regularly scheduled service, the team could not mobilize due to the risk of COVID-19, and the travel restrictions existing in Spain at the time.

The customer contacted Bently Nevada’s local team to decide on the best approach, and agreed the problem could be addressed 100% remotely.  With access to the data, the MDS team was able to perform a detailed analysis of an adverse trend identified while monitoring one of the plant’s feedwater pumps.

Bently Nevada’s MDS team recommended the installation of balancing weights during the upcoming outage, and supported the customer with the preparation and supervision of the field works. Customer staff was able to solve the issue in 48 hours with the remote support of the MDS team and be prepared for the upcoming outage.

The plant is a BWR-type nuclear power station (boiling water reactor). In a BWR, the reactor core heats water, which turns into steam and then drives a steam turbine. The feed water pump are non-safety related components, whose performance is essential to enable the power generation.

Cofrentes has two feed water pumps and when both of them perform correctly, the station can work at its maximum power rating, producing electricity for more than a million homes. If one of the feed water pumps were out of service, the reactor output would need to be reduced.

Due to the importance of these components, the plant’s operations team monitor them very thoroughly, and so, they were able to early identify an adverse trend in the vibration values of the feed water pump “A”. The customer anticipated a maintenance intervention to ensure maximum reliability.

Bently Nevada’s team provided short noticed implementation and around the clock remote support leveraging ADRE- Bently Nevada’s multi-channel data acquisition system, video conferencing,and pictures. ADRE is a field-proven data acquisition system, enabling users to spend minimal time reducing machinery data and more time interpreting it.

MDS Engineers analyzed actual and historical data and found the unbalance of the pump shaft. Using Bently Balance (balancing software capable of calculation for multiple solution points, both speed and load ones, in multiple correction planes), the balancing scenarios were tested. The solution using the available coupling plane was applied reducing shaft and casing vibration below alarm levels in full range of operation. MDS recommended to the End User to complement this intervention with additional improvement actions in the next planned overhaul, and to restore operation of a permanent data acquisition system.