Design and performance of the helically coiled boilers of two AGR power stations in the United Kingdom

The Hartlepool and Heysham-I AGR stations have been commissioned and operating since 1983. The main features, of the design of the helical once-through boilers raising the steam for power generation, are outlined. The modifications to the feed inlet flow ferrules, necessary to improve the boiler performance and optimize the power output, have been described. Comparisons between the thermal and hydrodynamic performance of the boilers before and following these alterations are given. The improvements in the computer code predictions of the plant performance have also been presented. (author)