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Nuclear-plant performance
The Pattern of Prediction/Futures
necessity of the modern industrial state. For proof there is the lengthy scenario recently composed by Sir John Hackett and his associates in The Third World War August 1985: a Future History.
References
1. A. Grenfell Price, The Explorations of Captain James Cook (Melbourne, Georgian House, 1958), page 18. 2. Ibid, page 19 3. Charles Knight, Passages from a Working Life, 1864, volume 1, page 162. 4. Baron Georges de Cuvier, Recueil des dloges historiques, 1819, volume 1, page 20. 5. Lord Lytton, The Life of Edward Bulwer Lytton, 1913, volume 2, page 290. 6. Auguste Javary, De L’idke de progrt?, 1851, page 75.
Futures
Forum
245
7. Michael
Angelo Garvey, The Silent 1851, page 170. 8. H. C. Carey, The Past, the Present, and Revolution,
the Future, 1848, page 472. 9. Felix Bodin, Le Roman de l’avenir, 1834,
page 472. 10. M. de Lamartine, France and England, 1848, page 104. 11. Hansard, third series, 72, 1223-1234. 12. Rear-Admiral Bowles, Thoughts on National Defence, 1848; General Sir John Burgoyne, Observations on the possible results of a war with France, 1852 ; Captain Robert Fitz-Roy, On the Application of Steam to Ships of War, 1835; G. V. Gustafson, Observations on the Steam Navy of Great Britain, 1847; Captain C. Knox, The Defensive Position of England; J. D. Lang, The Prospect of Australia in the event of a War with France, 1848; Lord Viscount Ranelagh, Observations on the Present State of our National Defences, 1845.
Forum
NUCLEAR-PLANT
PERFORMANCE
P. M. S. Jones THE recent article in Futures by Surrey
and Thomas1 drew together published information on nuclear-power-reactor performance. Such exercises can be useful, particularly if they are matched with technical appraisals which identify the weak points in systems as a preliminary to corrective measures. As anyone who has worked in the field will know, the data are notoriously difficult to obtain on a consistent basisoperating experience over a run of years for the first large plants to be commissioned is only now becoming available. For example, refuelling outageperturbations are difficult to smooth out; problems unique to an individual reDr P. M. S. Jones is Head of Economics and Programmes
in the United Kingdom
Atomic
Energy Authority, 11 Charles II Street, London SWlY
4QP, UK.
FUTURES
June 1880
actor can distort the statistics for small samples; the reasons for outages may be uncertain and they may be used to advance maintenance schedules. Whilst the authors regarded their work as only a preliminary assessment, they nevertheless felt able to make remarkably strong comments on the whole question of reactor choice on the basis of provisional findings about performance alone. Performance is important but so are other factors: eg costs, safety, and environmental impact. Surrey and Thomas rightly point out that regression analysis has not proved a suitable method for establishing the major determinants of plant performance, although some interesting work of this type has been done elsewhere which confirms the comment by Surrey and Thomas that conditions in individual countries are a key
246
Futures Forum
fact0r.a The very lack of data and variability which have prevented researchers from obtaining respectable R” values in regression equations also hampers the less rigorous analysis which Surrey and Thomas perform. This leads them to rather subjective judgements on some of the data. For instance their statement that pressurised-water-reactor performance falls with increased coolant temperature is based upon a very slender temperature range well below those of conventional boiler practice and a marginal difference as shown in their in performance, fuller report. 3 As the authors point out in their Futures article (page 12)) low unplanned outage and low operating losses are the hallmarks of good performance: on this basis their own statistics show little difference between pressurised water reactors (1600 hours lost per reactor year during 1975-1977), pressurised heavy-water reactors (1850 hours lost), and gas-cooled reactors (1300 hours)-bearing in mind the large error bands quoted. The use of load factor based upon design output is a useful measure in many cases, but it is by no means the only measure and it would probably have been more appropriate to include results based upon the availability factor to reflect operational performance. On such a basis the operational reliability of gascooled reactors becomes apparent. It is perhaps surprising, given the fact that 75% of unplanned outages are reported to be due to equipment failures of which 75% is due to conventional subsystems (page 13), that the authors feel able to comment so strongly on reactor-type differences, particularly as they themselves comment (page 12) that it is not sufficient to choose reactors of the type and size which appear inherently more reliable: manufacturer and country of construction appear to be of considerable importance. Indeed, if the experience of the USA, Japan, and Sweden is set
aside, the pressurised water reactors in the remaining eight countries have ranging from average load factors 74.6% to 85.7% : this compares well with Canadian pressurised heavy-water reactors at 80.5%. The ‘findings’ listed by Surrey and Thomas could be paraphrased as: l
l
l
weigh up risk and consider the factors affecting reliability and performance before settling your reactor design; the importance of establishing the appropriate engineering expertise to ensure good results should not be underestimated; and pressurised heavy-water reactors are wonderful, they have no problems, and even if they did have these could be overcome easily.
The first two of these are dominant in the mind of the UK nuclear industry provided safety, environmental impact, and economic factors are also included and performance. under reliability Pressurised heavy-water reactors have to be judged against the same criteria and not on the basis of load factor alone, as the main text of the SPRU paper makes clear.3 The special advocacy of this system does not follow logically from the preceding analysis which merely reveals that CANDUs (the heavy-water Canadian pressurised reactors) can be very reliable, as can pressurised water reactors and gascooled reactors. References 1. J. Surrey and S. Thomas, “Worldwide nuclear-plant performance: lessons for technology policy”, Futures, February 1980, 12(l), pages 3-17. 2. N. J. D. Lucas and P. J. Thompson, “Age, size, and learning effects in light water reactor operation”, Department of Engineering. Imperial Mechanical College, London, July 1979. 3. J. Surrey and S. Thomas, “World-wide Science nuclear plant performance”, Policy Research Unit occasional paper 10, University of Sussex, Brighton, February 1980.
FUTURES
June W30
necessity of the modern industrial state. For proof there is the lengthy scenario recently composed by Sir John Hackett and his associates in The Third World War August 1985: a Future History.
References
1. A. Grenfell Price, The Explorations of Captain James Cook (Melbourne, Georgian House, 1958), page 18. 2. Ibid, page 19 3. Charles Knight, Passages from a Working Life, 1864, volume 1, page 162. 4. Baron Georges de Cuvier, Recueil des dloges historiques, 1819, volume 1, page 20. 5. Lord Lytton, The Life of Edward Bulwer Lytton, 1913, volume 2, page 290. 6. Auguste Javary, De L’idke de progrt?, 1851, page 75.
Futures
Forum
245
7. Michael
Angelo Garvey, The Silent 1851, page 170. 8. H. C. Carey, The Past, the Present, and Revolution,
the Future, 1848, page 472. 9. Felix Bodin, Le Roman de l’avenir, 1834,
page 472. 10. M. de Lamartine, France and England, 1848, page 104. 11. Hansard, third series, 72, 1223-1234. 12. Rear-Admiral Bowles, Thoughts on National Defence, 1848; General Sir John Burgoyne, Observations on the possible results of a war with France, 1852 ; Captain Robert Fitz-Roy, On the Application of Steam to Ships of War, 1835; G. V. Gustafson, Observations on the Steam Navy of Great Britain, 1847; Captain C. Knox, The Defensive Position of England; J. D. Lang, The Prospect of Australia in the event of a War with France, 1848; Lord Viscount Ranelagh, Observations on the Present State of our National Defences, 1845.
Forum
NUCLEAR-PLANT
PERFORMANCE
P. M. S. Jones THE recent article in Futures by Surrey
and Thomas1 drew together published information on nuclear-power-reactor performance. Such exercises can be useful, particularly if they are matched with technical appraisals which identify the weak points in systems as a preliminary to corrective measures. As anyone who has worked in the field will know, the data are notoriously difficult to obtain on a consistent basisoperating experience over a run of years for the first large plants to be commissioned is only now becoming available. For example, refuelling outageperturbations are difficult to smooth out; problems unique to an individual reDr P. M. S. Jones is Head of Economics and Programmes
in the United Kingdom
Atomic
Energy Authority, 11 Charles II Street, London SWlY
4QP, UK.
FUTURES
June 1880
actor can distort the statistics for small samples; the reasons for outages may be uncertain and they may be used to advance maintenance schedules. Whilst the authors regarded their work as only a preliminary assessment, they nevertheless felt able to make remarkably strong comments on the whole question of reactor choice on the basis of provisional findings about performance alone. Performance is important but so are other factors: eg costs, safety, and environmental impact. Surrey and Thomas rightly point out that regression analysis has not proved a suitable method for establishing the major determinants of plant performance, although some interesting work of this type has been done elsewhere which confirms the comment by Surrey and Thomas that conditions in individual countries are a key
246
Futures Forum
fact0r.a The very lack of data and variability which have prevented researchers from obtaining respectable R” values in regression equations also hampers the less rigorous analysis which Surrey and Thomas perform. This leads them to rather subjective judgements on some of the data. For instance their statement that pressurised-water-reactor performance falls with increased coolant temperature is based upon a very slender temperature range well below those of conventional boiler practice and a marginal difference as shown in their in performance, fuller report. 3 As the authors point out in their Futures article (page 12)) low unplanned outage and low operating losses are the hallmarks of good performance: on this basis their own statistics show little difference between pressurised water reactors (1600 hours lost per reactor year during 1975-1977), pressurised heavy-water reactors (1850 hours lost), and gas-cooled reactors (1300 hours)-bearing in mind the large error bands quoted. The use of load factor based upon design output is a useful measure in many cases, but it is by no means the only measure and it would probably have been more appropriate to include results based upon the availability factor to reflect operational performance. On such a basis the operational reliability of gascooled reactors becomes apparent. It is perhaps surprising, given the fact that 75% of unplanned outages are reported to be due to equipment failures of which 75% is due to conventional subsystems (page 13), that the authors feel able to comment so strongly on reactor-type differences, particularly as they themselves comment (page 12) that it is not sufficient to choose reactors of the type and size which appear inherently more reliable: manufacturer and country of construction appear to be of considerable importance. Indeed, if the experience of the USA, Japan, and Sweden is set
aside, the pressurised water reactors in the remaining eight countries have ranging from average load factors 74.6% to 85.7% : this compares well with Canadian pressurised heavy-water reactors at 80.5%. The ‘findings’ listed by Surrey and Thomas could be paraphrased as: l
l
l
weigh up risk and consider the factors affecting reliability and performance before settling your reactor design; the importance of establishing the appropriate engineering expertise to ensure good results should not be underestimated; and pressurised heavy-water reactors are wonderful, they have no problems, and even if they did have these could be overcome easily.
The first two of these are dominant in the mind of the UK nuclear industry provided safety, environmental impact, and economic factors are also included and performance. under reliability Pressurised heavy-water reactors have to be judged against the same criteria and not on the basis of load factor alone, as the main text of the SPRU paper makes clear.3 The special advocacy of this system does not follow logically from the preceding analysis which merely reveals that CANDUs (the heavy-water Canadian pressurised reactors) can be very reliable, as can pressurised water reactors and gascooled reactors. References 1. J. Surrey and S. Thomas, “Worldwide nuclear-plant performance: lessons for technology policy”, Futures, February 1980, 12(l), pages 3-17. 2. N. J. D. Lucas and P. J. Thompson, “Age, size, and learning effects in light water reactor operation”, Department of Engineering. Imperial Mechanical College, London, July 1979. 3. J. Surrey and S. Thomas, “World-wide Science nuclear plant performance”, Policy Research Unit occasional paper 10, University of Sussex, Brighton, February 1980.
FUTURES
June W30