ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
P. V. Gilli
Nuclear Science and Engineering | Volume 22 | Number 3 | July 1965 | Pages 298-314
Technical Paper | doi.org/10.13182/NSE65-A20934
Articles are hosted by Taylor and Francis Online.
Heat transfer and pressure drop characteristics for the flow across banks consisting of plain (unfinned) helical tubes in a multistart arrangement with essentially uniform inclination angles, uniform longitudinal pitches and hence essentially equal heat loads per tube, but with tube pattern changing continuously around the perimeter, have been reduced analytically to the relatively well-known heat transfer coefficients and friction factors for the flow across banks of straight tubes with in-line and regularly staggered tube patterns. For this purpose, correction factors for the effects of tube inclination and of the number of tube rows are introduced. The effective average values of the free flow area—which determine the effective velocity and hence the effective Reynolds number—and the effective arrangement factors are obtained by integration of the local values. The apparent differences of the heat transfer and pressure drop correlations obtained by the two experimental investigations known—the Waagner-Biro experiments on the prototype tube bundle of the steam generators for the OECD High Temperature Reactor Project Dragon and the data of Glaser on regenerator inserts—have been explained quantitatively by the different approach employed for calculating the free flow area. Using the expressions for the effective average free flow area and the correction factors for tube inclination and tube row numbers, agreement of the heat transfer and pressure drop data of both experimental investigations with each other and, what is more, with straight-tube data is achieved. The suggested heat transfer and pressure drop correlations for banks of helical tubes are valid for gases and liquids with Prandtl numbers above 0.1. This range includes applications to steam generators of gas-cooled and liquid-cooled reactors (and cryogenic applications as well). For heat exchangers and steam generators of liquid-metal-cooled reactors—that is for Prandtl numbers of the order of 0.01—a different heat transfer correlation is developed, which is based on available data obtained with liquid metal flowing across banks of straight tubes.