1. Experimental and Computational Investigations of Plenum-to-Plenum Heat Transfer and Gas Dynamics Under Natural Circulation in a Prismatic Very High Temperature Reactor
I. A. Said[1], M. M. Taha[1], S. Usman[2], and M. H. Al-Dahhan[1]
Department of Chemical Engineering, Missouri S&T, Rolla.
Department of Mining and Nuclear Engineering, Missouri S&T, Rolla.
Presenting Author: Mahmoud Taha Moharam (M. M. Taha)

2. Presentation Outline Introduction Motivation Objectives Work plan
Missouri S&T Scaled-down Facility (MSTF)
Proposed sophisticated techniques
Acknowledgement

3. Introduction
The International forum in 2000 have released the Very High Temperature Reactors (VHTRs) is one of the most leading candidate for Next Generation Nuclear Plants (NGNPs).
The design has high fuel efficiency for electricity production and because of the high gas coolant outlet temperature is optimal for industrial applications or commercial hydrogen production.

4. Introduction “cont.” There are two versions of VHTRs:
Pebble Bed Reactor (PBR)
Prismatic Modular Reactor (PMR)
The Gas-Turbine Modular Helium-cooled Reactor (GT-MHR), also termed Modular High Temperature Gas Reactor (MHTGR) is a candidate for the DOE-funded NGNPs prismatic modular reactors.
Outlet coolant temperature and NGNPs applications

5. Introduction “cont.” MHTGR (prismatic modular) design features:
Coolant flow during normal and upset conditions
Natural circulation efficiency as a passive safety system
Figure 2. Core of prismatic CHTR
(LaBar et al. 2004, Southworth et al. 2004)
Figure 1. Features of Prismatic VHTR
(yoon et al. 2011)

6. Motivation
Computational Fluid Dynamics (CFD) has received a great deal of attention for understanding and predicting the flow behavior in VHTR, BUT sufficient validation of these codes has not been carried out. (Lee et al. 2014, McVay et al. 2015)
Lack in a detailed experimental study in the open literature for experimental work that addresses the gas dynamics and heat transfer in the prismatic core during natural circulation by using advanced novel techniques. (DOE 2016 Solicitation)

7. Objectives
Design and develop a separate-effects experimental setup mimicking prismatic modular reactor.
Advance and address experimentally and computationally the gaps in scientific and engineering knowledge of natural circualtion.
“benchmark data is needed to validate CFD simulations while there were no experimental test facilities to provide this”
McVay et al. 2015

8. Objectives
Provide benchmark data for validation of CFD commercial codes.
“benchmark data is needed to validate CFD simulations while there were no experimental test facilities to provide this”
McVay et al. 2015
- Show the function of each technique

9. Work plan Preliminary CFD simulations Experimental setup construction
Refine design / collecting benchmark data

10. Missouri S&T Facility (MSTF)
The same scaling criteria used for building the High Temperature Test Facility (HTTF) at Oregon State University (OSU) with reference to MHTGR are employed.
These scaling criteria have shown a successful similarity between HTTF and MHTGR. (Brian M. King 2012, R.R. Schultz et al. 2010)

11. Table 1. Dimensions of MSTF
MSTF “cont.”
MS&T dual-channel Facility “Phase-I” is a 1:4 scaled down facility based on OSU-HTTF design as shown below.
Table 1. Dimensions of MSTF

12. Figure 3. Physical picture of MSTF Figure 4. Schematic diagram of MSTF
MSTF “cont.”
- Explain the flow inside the reactor
Figure 3. Physical picture of MSTF
experimental setup
Figure 4. Schematic diagram of MSTF

13. Sophisticated Measurement Techniques
There are many invasive and noninvasive techniques available in the Dr. Al-Dahhan labs such as:
Radio-isotopes noninvasive techniques
Gamma Ray Computed Tomography (CT)
Radioactive Particle Tracking (RPT)
Gamma Ray Densitometry (GRD)

14. Sophisticated Measurement Techniques
2. Non-Radioisotopes based invasive and noninvasive techniques
1-point, 2-point and 4-point optical probes
Advanced dynamic gas and liquid tracer
Heat transfer probes
Hot wire anemometry (Constant Temperature Anemometer - CTA)

15. Sophisticated Measurement Techniques
In the current study the following techniques are planned to be used:
Heat transfer sensors.
Hot wire anemometry
Dynamic gaseous tracer

16. Heat Transfer sensors
Figure: Schematic diagram of proposed location of heat transfer probes
Figure: Sample of time-series heat transfer data

17. Figure: Calibration results Figure: CTA used in the current study
Hot Wire Anemometry
Figure: Calibration results
Figure: CTA used in the current study

18. Dynamic Gas Tracer Pump PC TCD Amplifier
Figure: Sample of gas tracer results
Figure: Gaseous tracer data acquisition system and data analysis

19. Outcomes/Impact
Developing flexible, separate-effects experiments to investigate intra-core natural circulation which complement the experiments of HTTF.
Developing an integrated sophisticated techniques that are implemented for the first time in such a study.
Obtaining detailed benchmark data for CFD codes validation.
Advance the knowledge and understanding of P2P natural circulation thermal hydraulic phenomena.

20. Acknowledgment
The authors acknowledge the financial support provided by the U.S. Department of Energy project number (NEUP (DE-NE )) for the 4th generation nuclear energy, which made this work possible.

21. M.H. Al-Dahhan (Project PI)
Thank You …
Team members s
I.A. Said
M.M. Taha
S. Usman
M.H. Al-Dahhan (Project PI)