Gaseous Sampling and Monitoring Cubicle Refurbishment

The combined particulate and Sulphur 35 (S-35) gaseous discharge monitoring system at Hinkley Point B Power Station was in need of an upgrade to provide additional alarm functions to the central control room and to address an inefficiency with its maintenance. The flow transmitters that formed an integral part of the system frequently needed removal for cleaning and recalibration, costing the station money and leading to undesired periods of system downtime.

Due to AMS’ expertise in the design and manufacture of environmental sampling systems and specialist instrumentation knowledge, AMS was contracted to carry out an inspection of the system and to recommend modifications that could be made to improve the efficiency of operating and maintaining the system.

AMS carried out a detailed inspection of the existing sampling system, looking at the existing instrument selection, power distribution, sampling connection, alarm philosophy and process pipework.

Recommendations were made that involved replacing the flowmeters for a different, more robust technology (a bespoke calibrated CS Instruments VA520  thermal mass flowmeter) and incorporating AMS’ mobile radionuclide samplers (Total Oxidation Units) that not only provided the S-35 sampling but also the additional alarms via an integrated Omniflex alarm annunciator.

The Total Oxidation Units (TOU) and associated trolleys were provided and installed to the outside of each sampling cubicle to provide the primary S-35 sampling capability. Each TOU performed the same function as the existing system, with the benefit of being easily exchanged when system maintenance was required, thus reducing system downtime.

AMS produced work packs and marked up system drawings detailing the installation method and materials required, so that site maintenance teams could undertake the system modifications.

The outcomes of the project were that:

• AMS provided the client with an upgraded Gaseous Sampling & Monitoring System that was implemented without any safety or quality events and within the client’s timescales and budget.

• The flowmeters that AMS recommended and supplied provide the station with a substantial cost saving in the long term, with their ability to be calibrated on site and easily removed and cleaned within a very short duration if required.

• AMS’ S-35 Total Oxidation Units greatly improved the reliability and functionality of the system

• Experience and knowledge base of implementing Radionuclide sampling systems within nuclear facilities.

• In depth instrumentation knowledge allowing the failure modes of the existing flowmeters to be properly understood and, therefore, a more appropriate technology to be selected.

• Ability to produce detailed design, manufacture and production documents in the format required for the client to safely and efficiently implement the upgrade.