READER ENQUIRIES PRESS ENQUIRIES

Bob Kingman / Bryan Richardson
ABB Automation Ltd / Richardson Public Relations
Howard Road / 38 Mayfield Crescent
St Neots / Brighton
CAMBS PE19 3EU / East Sussex
Tel: (01480) 475321 / BN1 8HQ
Fax: (01480) 218361 / Tel: 01273 506667
e-mail: / Fax: 01273 551756
ABB-KT/552 / 5th December, 2001.

ABB DEVELOPS AUTOMATIC HYDROGEN LEAKAGE

DETECTION FOR FRENCH NUCLEAR POWER STATIONS

Collaborative engineering from ABB operations in France and the UK has provided the French national power authority, Electricité de France (EDF), with an automatic early warning system for hydrogen leakage prevention in the alternators of its nuclear power stations.

Inside the power generator’s alternator the rotating windings are cooled by pure hydrogen while the stationary elements - the stators - are water cooled. Should the internal stator circuit become defective, hydrogen is likely to leak into the cooling waters and will need to be replaced in order to maintain pressure in the system. Quick detection of such leakage is vital to preserving the plant’s operational efficiency and cost-effectiveness.

The solution - currently being applied to more than 50 alternators in nuclear power stations throughout France - has combined ABB’s IndustrialIT product and applications engineering expertise to provide continuous on-line hydrogen monitoring and leakage detection. The system integrates advanced katharometers - purity analysers based on gas thermal conductivity - mass flowmeters, computing controllers, regulation valves and operator displays.

(1) More......

ABB-KT/552 Continued......

Each system is packaged in two cubicles for safe and hazardous area locations. The hazardous area cubicle houses an explosion-proof sampling pump, sample delivery system and an ABB katharometer analyser system. The safe area cubicle houses the katharometer power supply, an ABB COMMANDER 301 Controller and an ABB MOD 30 ML multi-loop process controller.

Stators cooling water circulating around the system leaves the alternator and enters a receiver vessel where a constant flow rate of air separates any leaked hydrogen. Gaseous samples are then conveyed to the katharometer analyser system where the hydrogen concentration is measured against the known flow rate of air. The ABB COMMANDER 301 controller linearises the hydrogen measurement to provide a digital display and a linear re-transmission signal to the ABB MOD30 ML controller which computes the hydrogen leakage rate. This multi-loop controller also performs closed loop control of the constant flow rate of air which is monitored by a mass flowmeter.

The hydrogen leakage detection system provides a reliable early warning for power plant preventive maintenance personnel and is assembled at ABB’s Stonehouse factory in Gloucestershire.

END

Note to editors: ABB ( serves customers in manufacturing, process and consumer industries, the utilities and the oil, gas and petrochemicals sector. More than 160,000 people are employed in more than 100 countries.

(2)