Dow Goes Nuclear

It has been announced that Dow and X-Energy will be building a nuclear power plant to feed Dow’s 4700 acre Seadrift, TX, manufacturing facility. The plant will be comprised of a 4 pack of Xe-100 80 Megawatt (electric) High Temperature Gas Cooled Reactor (HTGR) pebble bed reactors. The reactors are spec’d to each produce 200 MW thermal and 80 MW electric. The design is referred to as a small modular reactor facility and is part of the U.S. Department of Energy’s (DOE’s) Advanced Reactor Demonstration Program (ARDP).

According to Wikipedia, the history of pebble bed reactor operation is checkered by design and operational problems, many of which relate to the tennis ball sized graphite pebbles themselves. During operation of the pebble bed, radioactive graphite dust is generated leading to eventual contamination problems. Pebbles getting stuck within the equipment are difficult to dislodge and can lead to fracturing in doing so. The reactor needs fire protection because the hot pebbles are combustible when exposed to air.

The HTGR pebble bed design has many features that are very positive. The spaces between the pebbles duct the cooling gas, avoiding the need for coolant piping in the reactor. The absence of water prevents the formation of hydrogen by neutron collisions with the water. Hydrogen generated in a reactor will migrate into metal components and cause embrittlement leading to possible component failure. Overall, the design of a HTGR pebble bed reactor is considered to be much less complex than a water moderated reactor due to the lack of an elaborate water cooling system.

Despite the happy talk about their technology the maker of the system, X-Energy, will have to show how past problems with the pebble bed design have been overcome. Their website gives no clues about overcoming problems encountered in the past. The Nuclear Regulatory Commission is a tough crowd and both Dow and X-Energy will have to provide a strong case for safe operation.

I wish them success.