atw 2018-04v6

inforum

atw Vol. 63 (2018) | Issue 4 ı April

TBM conditions. The high prompt

component of the SPD signal is

attributed to the interaction of high

energy photons which are produced

in the detector and surrounding

materials. Charged particles emitted

in fast neutron reactions and contributions

from wires and signal cable

contribute to the high positive signal.

Parasitic reactions in non-emitter

materials also play an important role.

These effects need to be studied

explicitly and compared for understanding

of the overall currentgeneration

mechanism. Optimization

of design, dimensions and material

combinations is underway to realize

SPD flux monitors for application in

European ITER TBMs.

Acknowledgement

The work leading to this publication

has been funded partially by Fusion

for Energy under the Specific

Grant Agreement F4E-FPA-395-1.

This publication reflects the views

only of the authors, and Fusion for

Energy cannot be held responsible for

any use which may be made of the

infor mation contained therein.

References

[1] ITER Organization – Homepage. [Online].

Available: https://www.iter.org/.

[2] P. Calderoni, Status of the HCLL and

HCPB Test Blanket System instrumentation

development, 21 st Top. Meet.

Technol. Fusion Energy (TOFE), 9-13

Nov. 2014, Anaheim, CA, USA.

[3] N. P. Goldstein and W. H. Todt, A Survey

of Self-Powered Detector - Present and

Future, IEEE Trans. Nucl. Sci., vol. 26,

no. 1, pp. 916–923, 1979.

[4] P. Raj, M. Angelone, U. Fischer, and

A. Klix, Self-powered detectors for test

blanket modules in ITER, in 2016 IEEE

Nuclear Science Symposium, Medical

Imaging Conference and Room- Tem perature

Semiconductor Detector Workshop

(NSS/MIC/RTSD), 2016, pp. 1–4.

[5] M. Angelone, A. Klix, M. Pillon, P.

Batistoni, U. Fischer, and A. Santagata,

Development of self-powered neutron

detectors for neutron flux monitoring in

HCLL and HCPB ITER-TBM, Fusion Eng.

Des., vol. 89, no. 9–10, pp. 2194–2198,

2014.

[6] R. A. Forrest, FISPACT-2007: User

manual, EASY Doc. Ser. UKAEA

FUS 534, 2007.

[7] Low Level Measurements Handbook –

7 th Edition: Precision DC Current,

Voltage, and Resistance Measurements.

Keithley- A Tektronix Company.

Authors

Prasoon Raj

Axel Klix

Institute for Neutron Physics and

Reactor Technology (INR)

Karlsruhe Institute of Technology

(KIT)

Hermann von Helmholtz Platz 1

76344 Eggenstein-Leopoldshafen

(Germany)

RESEARCH AND INNOVATION 249

Nanofluid Applied Thermo-hydrodynamic

Performance Analysis of Square

Array Subchannel Under PWR Condition

Jubair Ahmed Shamim and Kune Yull Suh

1 Introduction Efficient engineered design of heat transfer and fluid flow with enhanced heating or cooling

requires two pivotal aspects that must be taken into consideration for extracting thermal energy from nuclear fission

reactions in order to save energy, reduce process time, raise thermal rating and increase the operating life of a reactor

pressure vessel. Hence, one of the major challenges in designing a new nuclear power plant is the quantification of the

optimal flow of coolant and distribution of pressure drop across the reactor core. While higher coolant flow rates will

lead to better heat transfer and higher Departure from Nucleate Boiling (DNB) limits, it will also result in higher pressure

drop across the core, therefore additional demand of pumping powers as well as larger dynamic loads on the core

components. Thus, thermal hydraulic core analysis seeks to find proper working conditions with enhanced heat transfer

and reduced pressure drop that will assure both safe and economical operation of nuclear plants.

Recently, nanofluid has gained much

renewed attention as a promising

coolant for pressurized water reactors

(PWRs) due to its enhanced thermal

capabilities with least penalty in pressure

drop. The improved heat transfer

of nanofluids results from the fact that

the nanoparticles increase the surface

area and heat capacity of the fluid,

improve the thermal conductivity of

the fluid, cause more collisions and

interactions between the fluid, particles

and surfaces of the flow passages,

and enhance turbulence and mixing

of the fluid.

Pak & Cho [1] experimentally

observed the turbulent friction and

heat transfer of dispersed fluids in a

circular pipe using two different

metallic oxide particles, γ-alumina

(Al 2 O 3 ) and titanium dioxide (TiO 2 )

with mean diameters of 13 and 27 nm,

respectively. The results revealed

that the Nusselt number Nu for the

dispersed fluids increased with

increasing volume concentration as

well as the Reynolds number Re. But

at constant average velocity, the

convective heat transfer coefficient for

the dispersed fluid was 12% less than

that for pure water. They proposed a

new correlation for Nu under their

experimental ranges of volume concentration

(0-3%), Re (10 4 -10 5 ), and

the Prandtl number Pr (6.54-12.33)

for the dispersed fluids γ-alumina

(Al 2 O 3 ) and titanium dioxide (TiO 2 )

particles as

(1)

Xuan and Li [2] observed the flow

and convective heat transfer of the

Cu-water nanofluid flowing through

a straight brass tube of the inner

diameter of 10 mm and the length of

800 mm. They noted that suspended

nanoparticles can remarkably enhance

heat transfer given the velocities.

For instance, the heat transfer

coefficient of nanofluids containing

2.0 vol % Cu nanoparticles was increased

by as much as 40 % compared

to that of water. The conventional

Research and Innovation

Nanofluid Applied Thermo-hydro dynamic Performance Analysis of Square Array Subchannel Under PWR Condition ı Jubair Ahmed Shamim and Kune Yull Suh

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