Armenia :	|	Operating History	|	Technical Activities	|	Accomplishments	|

Technical/Upgrading Activities

The operating staff of Unit 2 includes one trained Russian operator on each shift.

After the fire in 1982, several modifications were made, including installation of an additional control panel, fitting of an additional independent emergency power cable network, improved separation of safety-related cabling and the implementation of numerous fire protection measures.

The main backfits approved by Armenian regulators include hardware modifications of: primary circuit, protection and control systems; emergency cooling systems; thermal insulation; and fire and explosion protection.

Specific upgrades carried out or under way include new seismic-resistant storage batteries from Germany, an additional DC panel to provide backup power, a new diesel generator hookup that provides twice the redundancy of the original configuration, and rerouting of power lines to separate trains. In addition, all monitoring equipment has been replaced, and additional reactor protection system shutdown logic installed for water levels in the steam generators and for water and steam levels in the pressurizer. Sealing gaskets and other components providing isolation in the system's confinement were upgraded using materials and technology from a U.S. company, and the reactor hall sprinkler system was modernized. Following an inspection of the unit's steam generators, 1-2 percent of the tubes were plugged.

According to the plant manager, over 500 tons of equipment needed to refurbish and upgrade the unit--most of it from Russia--was airlifted to the site because of the land-route blockade by neighboring Azerbaijan.

A system of five large basins is under construction at the plant site to upgrade the essential service water supply. It is expected to begin operating in 1997.

In addition, the following upgrades (mostly seismic) have been reported:

• The main building and its equipment have been seismically upgraded.
• Reactor coolant pumps now have flywheels to increase coast-down time.
• The reactor trip system includes a seismic trip.
• Blocking devices automatically separate major systems to lessen the consequence of a pipe rupture during an earthquake.
• Main equipment in the primary system (i.e., reactor coolant pumps, isolation valves, etc.) is supported by hydro-shock absorbers.
• There are two additional secondary cooling systems, both high- and low-pressure.