Nuclear Production of Hydrogen, Fourth Information Exchange ...

THE CONCEPT OF NUCLEAR HYDROGEN PRODUCTION BASED ON MHR-T REACTOR
The following processes are considered as the basic processes for the chemical-technological
sector:
• steam methane reforming;
• high-temperature solid oxide electrochemical process of hydrogen production from water.
It should be taken into consideration that the selected hydrogen production process determines
not only chemical-technological sector solutions, but also to a great extent solutions of the MHR-T RP
and NPP as a whole, as individual equipment units. The methane reforming option (SMR technology)
allows to envisage a plant configuration with a two-circuit thermal diagram (Kostin, 2006; Ponomarev-
Stepnoi, 1983). Heat shall be transferred directly from primary coolant to chemical-technological sector
medium in a high-temperature heat exchanger. The key component of chemical-technological sector
medium circulating through the high-temperature heat exchanger is water steam. Temperatures at
the reactor outlet required to implement the above option shall not be less than 900°C (950°C is
adopted). The high-temperature electrolysis option allows considering the plant configuration both
with two- and three-circuit thermal diagram. Heat is transferred from the primary coolant in the
high-temperature heat exchanger to intermediate circuit helium and then to steam-hydrogen flow of
the chemical-technological sector that will require (in the option with intermediate circuit) increase of
reactor outlet temperature up to 950°C.
The chemical-technological sector with steam methane reforming is considered as the basic
option (for short-term perspective).
The MHR-T refers to HTGR facilities representing one of the advanced areas of new-generation
nuclear power development and having inherent safety feature. The technical concept is based on:
• modular helium-cooled reactors with typical high level of inherent safety;
• fuel cycle based on uranium dioxide in the form of multi-layer particles, high burn-up and
burial of fuel blocks unloaded from the reactor without any additional processing;
• direct gas-turbine power conversion cycle (Brayton cycle) with highly effective recuperation
and intermediate cooling of coolant;
• highly efficient gas turbines developed for aircrafts and electric power plants;
• electromagnetic bearings operating almost without friction and applied in various technical
areas;
• highly efficient high-temperature compact heat exchangers, strong casings made of heat
resistant steel.
Heat released in the reactor core is removed and transferred to the chemical-technological sector
in accordance with two- or three-circuit diagram (in the power conversion unit – in accordance with
one-circuit diagram) to produce electric energy in closed gas-turbine cycle. The main components of
each NPP module are arranged in isolated premises of the buried containment of the NPP main
building.
In the addition to the reactor plant, the main building modules accommodate also NPP key
systems supporting NPP operation.
The chemical-technological sector equipment is arranged outside the containment of the NPP
main building.
The MHR-T energy-technological complex is designed for a specific site on the basis of design
solutions selected with account of:
• typical climatic conditions of the site located in the middle of Russia;
• specific external impacts – seismicity, aircraft fall, shock air wave.
The basic operation mode of the MHR-T energy-technological complex is 100% power operation
with parallel production of hydrogen and electric energy (combined mode).
72 NUCLEAR PRODUCTION OF HYDROGEN – © OECD/NEA 2010