The load factor averages, total energy produced, total reactor years of operation and other data are presented in the tables overleaf for the four main reactor types and those vendors which have sold four or more of each respective type. Only units which have operated for a year or more qualify for inclusion. In addition, the overall figures for the 355 units which qualify have been included, whereas last year all the miscellaneous units were included in this one “all units” line only.

Vendors are listed with the original names and groupings under which the units were sold at the time. Reactors are divided into small, medium and large categories, defined as under 600MWe, 1000MWe and below, or rated at 1000MWe and above, all ratings being the gross values.

The history, and the fortunes of the ageing population of nuclear power reactors is reflected in the small table on p26. This divides the period since the oldest unit in the main table began operation, Bradwell 1 in July 1962 (Magnox units are included in this analysis since they still provide useful and continuous service) and the end of 1999 into three-year intervals plus one year, showing when electricity was first produced by those units surviving in the NEI tables to the end of 1999 (note that this summary does not include units that have been shut down permanently). The “all unit” line summarises all the units qualified as above, and continues to show a greatly increased figure, from 75.2% in 1998 to 78.2% in 1999 for the average annual load factor, and an improving lifetime performance, from 69.2% to 70.2% As far as maxima and minima are concerned, it is felt that a minimum figure of zero tells some of the story, but it is also interesting to record the minimum achievement of units that have not been shut down for the year, hence the minima of zero are recorded with an asterisk against the lowest achieved above zero.

Framatome’s reactors, the majority of which are operating in France, are penalised to an unprecedented extent by the high proportion of load-following in their daily operating cycle. As noted last year, even the minimum figures are commendable despite this imposition. The lifetime minimum for Framatome units has climbed to 59.6%, while the overall lifetime average climbed a little, from 768.8% to 69.1% Among PWRs, which had a fairly slow change in average performances compared with last year, Westinghouse units achieved a notable increase from 80.6% to 84.0% in the annual load factor averages. In the BWR table (and curves) it can be seen that the KWU and Toshiba units enjoyed notable increases (KWU by nearly 10% to 88.9% and Toshiba by 7.2% to 86.4%).

The Indian PHWRs continued to climb, reaching an overall annual average of 71.6% by the end of September, which dropped back a little to 68.7% by the year’s end, still up by 5.5% over last year’s improvements! Any particular advantage in smaller or medium units’ average performance has tended to disappear, any differences visible in one vendor’s results being offset by those of another design.