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Nuclear reactor stability
Ractm
sdcnec and Techaol~
(Journ
of Nuckar Energy. Parts A & Bh 1961, Vol. 14. p. 117. I’WQWIOD FTea Ltd. f’hUd
in Nodan
IrehId
BOOK REVIEW Reactor Stability, A. HITCHCOCK (Nucl. Engng. Monograph). Temple Press, 1960, x + 61 pp., 12.r.6d.
Nuckar
TWIUE titles in this series have now appeared and further are in preparation, which indicates the range of specialist subjects included in the complex of nuclear engineering. This monograph is concerned with the stability about quilibrium of the spatial distribution of power density and temperature within a reactor whose neutron balance is subject to small arbitrary fluctuations. This topic is now of considerable practical importance as well as bf academic interest. On the one hand it confronts the engineer engaged currently in the design and operation of large nuclear power reactors, whilst on the other hand it is an absorbing and advanced field of study for the applii mathematician. Chapter l-an introduction to the dynamics of power reactors-defines the coefficients of reactivity and indicates the magnitudes of the time constants of the associated reactor quantities. Possible sources of instability are given as moderator temperature, xenon-135 and voidage. Spatial instability is distinguished from a purely time-dependent process and the necessity for its control is emphasized when restrictions exist on local excursions in reactor variables. Chapter 2 outlines the analysis of stability of the system on the assumption that the partial differential equations which describe transport processes can be resolved into a set of coupled
ordinary differential equations in time. Thii resolution is made generally in terms of spatial modes or finite differences. Chapters 3,4 and 5 refer to the effects of temperature, xenon135 and voidage respectively, when control is treated as a constraint. A more detailed analysis is shown to be required for the axial direction when thii is associated with coolant flow and control rod action. Chapter 6 introduces control rods explicitly but in an ideal&d form. Two appendices deal with properties of ‘flattened’ reactors. It is inevitable in a text of such wide scope which is compressed into a short monograph that a number of points should invite comment. On p. 13 what is termed modal analysis might be considered to be harmonic analysis; on p. 15 the physical significance of neglected cross-coupling terms is not discussed; the boundary condition on p. 25 is inconsistent with that on p. 55; Fig. 5 on p. 40 is somewhat confusing; and the statement on p. 53 regarding stability analysis of a controlled reactor gives necessary rather than sutllcient criteria. None of these comments is intended to detract from .the merits of this valuable work. The monograph is to be welcomed as a most useful and comprehensive addition to thii series. It provides working rules, illustrated by numerical examples, for stability analysis as an integral part of reactor design calculations. It will undoubtedly stimulate further progress in this field particularly, one hopes, in the design of operational control units. A. Forma
117
sdcnec and Techaol~
(Journ
of Nuckar Energy. Parts A & Bh 1961, Vol. 14. p. 117. I’WQWIOD FTea Ltd. f’hUd
in Nodan
IrehId
BOOK REVIEW Reactor Stability, A. HITCHCOCK (Nucl. Engng. Monograph). Temple Press, 1960, x + 61 pp., 12.r.6d.
Nuckar
TWIUE titles in this series have now appeared and further are in preparation, which indicates the range of specialist subjects included in the complex of nuclear engineering. This monograph is concerned with the stability about quilibrium of the spatial distribution of power density and temperature within a reactor whose neutron balance is subject to small arbitrary fluctuations. This topic is now of considerable practical importance as well as bf academic interest. On the one hand it confronts the engineer engaged currently in the design and operation of large nuclear power reactors, whilst on the other hand it is an absorbing and advanced field of study for the applii mathematician. Chapter l-an introduction to the dynamics of power reactors-defines the coefficients of reactivity and indicates the magnitudes of the time constants of the associated reactor quantities. Possible sources of instability are given as moderator temperature, xenon-135 and voidage. Spatial instability is distinguished from a purely time-dependent process and the necessity for its control is emphasized when restrictions exist on local excursions in reactor variables. Chapter 2 outlines the analysis of stability of the system on the assumption that the partial differential equations which describe transport processes can be resolved into a set of coupled
ordinary differential equations in time. Thii resolution is made generally in terms of spatial modes or finite differences. Chapters 3,4 and 5 refer to the effects of temperature, xenon135 and voidage respectively, when control is treated as a constraint. A more detailed analysis is shown to be required for the axial direction when thii is associated with coolant flow and control rod action. Chapter 6 introduces control rods explicitly but in an ideal&d form. Two appendices deal with properties of ‘flattened’ reactors. It is inevitable in a text of such wide scope which is compressed into a short monograph that a number of points should invite comment. On p. 13 what is termed modal analysis might be considered to be harmonic analysis; on p. 15 the physical significance of neglected cross-coupling terms is not discussed; the boundary condition on p. 25 is inconsistent with that on p. 55; Fig. 5 on p. 40 is somewhat confusing; and the statement on p. 53 regarding stability analysis of a controlled reactor gives necessary rather than sutllcient criteria. None of these comments is intended to detract from .the merits of this valuable work. The monograph is to be welcomed as a most useful and comprehensive addition to thii series. It provides working rules, illustrated by numerical examples, for stability analysis as an integral part of reactor design calculations. It will undoubtedly stimulate further progress in this field particularly, one hopes, in the design of operational control units. A. Forma
117