Nuclear Engineering Section



Prepare & Submit Calculation Form

The thermodynamic and transport properties of  light water can be calculated according to the property equations presented in:

[1] Keyes F.G., Keenan J.H., Hill P.G. and Moore J.G., "A Fundamental Equation for Liquid and Vapor Water", Proceedings of the 7th International Conference on the Properties of Steam, Tokyo, Japan 1968.

[2] Schmidt E., "Properties of Water and Steam in SI Units", Springer-Verlag, 1969.

[3] Sengers J.V. and Watson J.T.R., "Improved International Formulations for the Viscocity and Thermal Conductivity of Water Substance", Journal of Physical Chemistry Reference Data, 15(4):1291, 1986.

[4] Straub J., Rosner N. und Grigull U., "Oberflaechenspannung von Leichtem und Schwerem Wasser", Waerme- und Stoffuebertragung, 13:241, 1980.

Based  mainly on the above references  property equations have been  implemented in the LIGHT_WASP (LIGHT Water And Steam Properties) FORTRAN 77 code in the course of  the following PhD work (in Greek):

Petropoulos N.P., "THERMOPHYSICAL PROPERTIES OF NUCLEAR POWER REACTOR COOLANTS: COMPARATIVE STUDY AND CALCULATION CODES", Nuclear Engineering Section, Mechanical Engineering Department, National Technical University of Athens, 2000 (in progress).

The set of equations used provide reliable thermodynamic and transport properties results equivalent to the industrial standard formulation IFC-1967. The following validity range is covered:

Pressure: 0 - 1000 bar

Temperature: 0 -1000 oC


A small region at the vicinity of the critical point is excluded:


| - *| 10 ,      |/* - 1| 0.3


where T*= 647.27 K and *= 317.763 kg/m3

Calculable Properties:

Specific volume v in m3/kg  Density in kg/m3
Internal energy u in kJ/kg  Specific enthalpy h in kJ/kg
Entropy s in kJ/(kgK) Isobaric heat capacity cp in kJ/(kgK)
Isochoric heat capacity cv in kJ/(kgK)  Viscosity in kg/(ms)
Thermal conductivity in W/(mK) Surface tension  in N/m.

Code accepts the following input pair:

(P,T)  in bars and degrees Centigrate respectively.

Reported Bugs

This WWW page is maintained regularly to ensure best performance and error-free accurate calculations for the thermodynamic and transport properties of light (ordivary)  water. All efforts have been made to ensure that the present  code  is as accurate implementation as possible of the property equations included at the above literature. Authors welcome your comments and suggestions for further improvement along with any bug reports and they will acknowledge any reported bug in this very page under the link reported bugs regardless whether they are fixed or not. 

Please, contact:

Nick P. Petropoulos (

Research Assistant

Nuclear Engineering Section

Mechanical Engineering Dept.

National Technical University of Athens

15780 Athens, GREECE

tel: +302107722939

fax: +302107722914


However, authors will not try to fix all reported bugs promptly, and they will certainly not be ivolved in an effort to improve performance of the property equations in pressure - temperature regions, where their results are ambiguous or not to be trusted.   Furthermore, authors cannot accept ANY responsibility if some or all calculations based on this code may be proven wrong or inadequate.Visitors of this page, who would like to receive free copies of the source code for their own private use or for evaluating purposes are encouraged to place a request at, stating also their intented implementation platform (i.e. FORTRAN make & version, UNIX or Windows based application etc). Not all requests are to be granted. This version of the software is not commercially available.

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