Top Drop Menu


Picow Engineering Group have successfully completed the design, build, test and inactively commission stages of an active ventilation monitoring system to support decommissioning operations at a Nuclear site in North Wales.


Operations at Trawsfynydd Power Station in Snowdonia ceased in 1993 and decommissioning activities have now commenced. The site is currently in Phase Two of decommissioning and one of the requirements of this is the decommissioning of active waste facilities, including the emptying and post-operative clean-out of existing Resin Vault 1, which contains several cubic metres of ion exchange resin, irradiated during ponds water clean-up campaigns over the last few decades.

In support of the Decommissioning Safety Case, a fail-safe vent flow monitoring and alarm annunciation system was required to alert personnel working in and around the plantroom area in the event of a ventilation system fault. A supervisory control panel, located in the manned control area gave a continuous readout of the extract air velocity, and a network of audio-visual alarm towers at boot barriers and in the ventilated area give a concise and clear dynamic indication of whether safe entry or occupancy is possible, by means of a universally understood “traffic light system”.

Due to the philosophy of having a modular approach to cabling, allowing full fabricating and comprehensive testing of the whole system, from sensor to field alarm, the system was commissioned at the clients site within minutes of the installation being completed.



 Phil Miller - Magnox Senior EC&I Engineer - "Many thanks for your sterling efforts in the timely design, development, build, test and delivery of an active ventilation monitoring system for the Trawsfynydd site. The construction standard was high, and the modular concepts you engaged allowed for comprehensive acceptance testing  to be done off-site, dramatically minimising downtime and active commissioning on site. Your technical and quality arrangements ensured a “right first time” solution, and the system was duly running and protecting personnel several weeks ahead of schedule. We look forward to continued support from you as our decommissioning operations progress"