Nuclear Production of Hydrogen, Fourth Information Exchange ...

CONCEPTUAL DESIGN OF THE HTTR-IS NUCLEAR HYDROGEN PRODUCTION SYSTEM
Table 1: Major specifications of the HTTR-IS system
Item
Value
Reactor power
30 MWt
Thermal load of IS process
Ca. 8 MWt
Reactor outlet temperature 950°C
Primary Reactor inlet temperature 395°C
cooling system Reactor inlet pressure
4.0 MPa
Reactor inlet flow rate
10.1 kg/s
IS process inlet temperature 880°C
Secondary IS process outlet temperature 253°C
cooling system IHX inlet pressure
4.0 MPa
IHX inlet flow rate
2.5 kg/s
Figure 2 shows a schematic diagram of the helium pressure control system in the HTTR-IS system.
The primary coolant pressure is controlled by the primary helium pressure control system at about
4.0 MPa with actuating valves of the helium storage and supply system. Secondary coolant pressure is
controlled higher than primary helium pressure at about 0.07 MPa by primary-secondary differential
pressure control system in order to prevent radionuclide transportation from the primary to secondary
cooling system with actuating valves of the secondary helium storage and supply system. The flow
meter is installed at the inlet and outlet of the primary and secondary helium storage and supply
systems. In the current HTTR, the integral flow rate of the primary helium gas supply is calculated by
the software in order to detect the leakage rate of primary cooling system.
Figure 2: Schematic diagram of the helium pressure control system in the HTTR-IS system
Primary He
pressure control
system
1
Secondary He
storage & supply
system
Primarysecondary
differential
pressure
control system
Primary He
storage &
supply
system
Secondary He
purification
system
2
Primary He
purification
system
2
? P
IS process
IHX
Auxiliary
heat
exchanger
Reactor
P
1
PPWC
Description of IHXTR
In the current HTTR, the whole secondary cooling system is involved in the CV so that there is no
need for considering radionuclide transportation outside of the CV in case of IHXTR. Also, the safety
analysis result showed that there are no significant impacts on reactor cooling ability and therefore
the scenario is not identified as a selected event in the safety evaluation.
NUCLEAR PRODUCTION OF HYDROGEN – © OECD/NEA 2010 389