atw 2018-04v6


atw Vol. 63 (2018) | Issue 4 ı April

whole condensation phenomena and

flow morphologies by using GENTOP

concept. Further to the AIAD concept

which considers two continuous

fluids, the GENTOP approach is a

three field two fluid model and considers

also a poly dispersed phase.


This project is an ongoing project in

Helmholtz-Zentrum Dresden Rossendorf

(HZDR), which is funded by Bundesministerium

für Bildung und Forschung

(BMBF) under grant number

02NUK041B in Germany.


[1] Hajal, J.El.; Thome, J.; Cavallini, A.

Condensation inside horizontal tubes,

part 1: two phase flow pattern map.

International Journal of Heat and Mass

Transfer 46: 3349-3363(2003).

[2] Thome, J.; Hajal, J.El; Cavallini, A.

Condensation inside horizontal tubes,

part 2: New heat transfer model based

on flow regimes. International Journal

of Heat and Mass Transfer 46: 3365-


[3] Kattan, N.; Thome, J.R.; Favrat, D. Flow

boiling in horizontal tubes:part2-New

heat transfer data for five refrigerants.

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[4] Lee, W. H. A Pressure Iteration Scheme

for Two-Phase Flow Modeling. Multiphase

Transport Fundamentals,

Reactor Safety, Applications: 407–432,


[5] Štrubelj, L.; Ézsöl, Gy. ; Tiselj, I. Direct

Contact Condensation Induced

Transition from Stratified to Slug Flow.

Nuclear Engineering and Design 240:

266–274 (2010).

[6] Lavieville, J.; Quemerais, E.; Boucker, M.;

Maas, L., NEPTUNE CFD V1.0 User Guide


[7] Coste, P. ; Pouvreau, J. ; Lavieville, J.;

Boucker, M. A Two-phase CFD approach

to the PTS problem evaluated on COSI

experiment. Proceedings of the 16 th

International Conference on Nuclear

Engineering ICONE16, USA, (2008).

[8] Banerjee, S.; A surface renewal model

for interfacial heat and mass transfer in

transient two-phase flow. International

Journal of Multiphase Flow, Vol.4:

571-573 (1978).

[9] Hughes, E. D.; Duffey, R. B. Direct

Contact Condensation and Momentum

Transfer in Turbulent Separated Flows.

Internal Journal of Multiphase Flow 17:

599–619 (1991).

[10] Egorov, Y. Validation of CFD codes with

PTS relevant test cases. Technical Report



[11] Apanasevich, P. ; Lucas, D.; Beyer, M.;

Szalinski, L. CFD based approach for

modeling direct contact condensation

heat transfer in two-phase turbulent

stratified flows. International Journal of

Thermal Sciences 95: 123-135(2015).

[12] Shen, L.; Triantafyllou, G.S.; Yue. D.K.P.

Turbulent diffusion near a free surface

Journal of Fluid Mechanics 407:

145–166 (2000).

[13] Ceuca, S. C. ; Macián-Juan R. CFD

Simulation of Direct contact Condensation

with ANSYS CFX using Locally

defined Heat Transfer Coefficient.

In ICONE-20, Anaheim, California, USA,

No. 54347 (2012).

[14] Goldbrunner, M.; Karl, J. ; Hein, D.

Experimental Investigation of Heat

Transfer Phenomena During Direct

Contact Condensation in the Presence

of Noncondensable gas by means of

Linear Raman Spectroscopy. In 10 th Int.

Symp. on Laser Techniques Applied to

Fluid Mechanics, Lisbon (2000).

[15] Krepper, E.; Frank, Th.; Lucas, D.; Prasser,

H.-M.; Zwart, P.J. The Inhomogeneous

MUSIG model for the simulation of

poly-dispersed flow. Nuclear Engineering

Design 238: 1690-1702 (2008).

[16] Höhne, T.; Deendarlianto; Lucas, D.

Numerical simulations of countercurrent

two-phase flow experiments in

a PWR hot leg model using an area

density model. International Journal

of Heat and Fluid Flow 31 (5):

1047-1056 (2011).

[17] Hänsch, S.; Lucas, D.; Krepper, E.;

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different scales of interfacial structures.

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Flow 47:171-182(2012).


Amirhosein Moonesi Shabestary,

Eckhard Krepper,

Dirk Lucas



P.O.Box 510119

01314 Dresden, Germany



The Decommissioning of the ENEA RB3

Research Reactor in Montecuccolino

F. Rocchi, C. M. Castellani, A. Compagno, I. Vilardi, R. Lorenzelli and A. Rizzo

The ENEA RB3 reactor was a 100 Wth research installation owned and operated by ENEA, in its center of Montecuccolino

near Bologna, from 1971 to 1989. It consisted of a cylindrical aluminium vessel, about 4.3 m high and 2.9 m in diameter,

which could host various types of fuel elements suspended from the top of a special adjustable rack and submerged into

moderating and cooling heavy water. Principal aim of the reactor was to provide neutronics data for the CIRENE NPP, a

SGHWR that was being designed and then partially built in Latina starting from 1979. The specific RB3 core, surrounded

by a graphite reflector and housed inside a concrete biological shielding, allowed to test easily very different fuel

element configurations by changing their pitches and by regulating the heavy water level inside the vessel. The reactor

design, similar to that of the ZED-II Canadian research facility, was originally developed by CEA for its Aquilon facility

in Saclay in 1956; in fact, through a special arrangement between ENEA and CEA, parts of the Aquilon facility were

ultimately donated to ENEA at the end of the 60s for the construction of RB3. In 1989, the RB3 reactor was shut down,

and in the late 2010 ENEA received by ministerial decree the authorization to its dismantling, with the aim of reaching

the “green field” status and with the unconditional release of its building, which is actually owned by the University of

Bologna. The dismantling activities started in May 2013 and were concluded at the end of 2014; after that, a campaign

for the radiological characterization of the building was initiated and concluded in June 2015. Now, all the necessary

site characterization activities are being conducted with the aim to present the results declaring the “green field” status

before the end of 2017. This paper will present the three main pillars of the decommissioning of RB3, namely the

strategy and methods for the dismantling, the strategy and methods for the radiological characterization of the building,

and finally the strategy and methods for the radiological characterization of the site. The radionuclide limits imposed

by the Italian Regulatory Body, together with the challenges encountered so far will be likewise shown and described.

Revised version of

a paper presented

at the Eurosafe,

Paris, France, 6 and 7

November 2017.

Decommissioning and Waste Management

The Decommissioning of the ENEA RB3 Research Reactor in Montecuccolino ı F. Rocchi, C. M. Castellani, A. Compagno, I. Vilardi, R. Lorenzelli and A. Rizzo

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