Background
The Armenian Nuclear Power Plant (ANPP) consists of two units of the VVER/440/270 model Soviet type reactor that is a modified version of the VVER/440/230 in view of special seismic design considerations. Unit 1 started its commercial operation in 1976 and Unit 2 in 1980. Both units were shut down shortly after the 1988 Spitak earthquake. Re-commissioning works were performed from 1993 to 1995 and in November 1995 Unit 2 restarted operation.
The ANPP design is similar to other VVER/440/230 NPPs and has the same generic safety issues and inherent safety features as other plants of this type. In addition, this plant has specific problems, some of which were resolved during the re-commissioning phase while a number of others, requiring evaluation and upgrading measures, were implemented during the subsequent years of plant operation.
The Tacis 96 On-site assistance for Armenia NPP envisaged, amongst other activities, an improvement of fire protection system. The contract included the following activities in this area:
1. Elaboration of fire hazard analysis to identify fire risks in plant areas with significant fire load (electrical cable corridors, liquid fuel and lubricants tanks, battery rooms, turbine building, etc.).
2. Elaboration of procurement technical specifications for fire protection equipment needed, and
3. Implementation of improvements at the plant.
The plant was lacking a systematic fire hazard analysis. In order to identify issues in the plant fire safety, a deterministic Fire Risk Analysis (FRA) was elaborated as a first step. The FRA investigated and quantified the risks for internal fires in the plant areas most relevant for the safety.
The FRA identified a number of deficiencies in the fire safety at the plant such as lack of effective spatial separation of redundant trains of systems important to safety (cables), absence of emergency control room that could be used for safe plant shut down in case of fire at the main control room, inadequate fire detection and alarm system, some areas with large fire loads not properly separated by fire resistant barriers, fire resistance of existing fire barriers was not proven, extensive use of a flammable coating material at corridors in radiation controlled area, and the installed stationary fire extinguishers were mostly foam type with automatic actuation.
The above fire concerns were thoroughly evaluated and a list of short-term improvement measures, also indicating their priorities, was prepared. This led to the need for purchase of a range of fire related equipment, which is the subject of the present project and is described in the following sections.
In addition, fire safety continued to be the subject of follow up evaluation. Based on the FRA, the OSA team prepared a medium-term fire safety improvement programme, which particularly focused on (i) improving the physical separation and fire protection of the equipment important to safety, (ii) reducing the fire loads, and (iii) enhancing the plant capabilities for the detection and suppression of fires during accidental conditions.
Objectives
In order to implement the short term (most urgent) fire safety improvement measures identified in the above mentioned study, the following fire related equipment was identified for procurement:
1. A heat shield (coating material) on the steel structure of the turbine building,
2. Radio communication equipment for the plant fire brigade,
3. Medium and low voltage electrical circuit breakers, and
4. Fire doors at the main control room.
The purchase of the equipment associated with the first three items in the above list (see the 3 separate entries in this database for project A1.01/96B), plus the scaffolding required for application of the fire resistant coating (See project A1.01/96B1), was financed by the Tacis programme through four separate contracts. The description below covers all four contracts.
The equipment selected for procurement was chosen to address the most urgent short term measures. In addition, a medium term fire safety improvement programme was outlined, i.e. to focus on improving the physical separation and fire protection of equipment important to safety, reducing the fire loads, and enhancing the capabilities for fire detection and suppression in the accident conditions.
The OSA team developed three sets of procurement technical specifications and tender dossiers for purchase of the fire resistant coating material for steel structures, communication equipment for the plant fire brigade, and medium and low voltage electrical circuit breakers. The respective suppliers were selected through an open tender procedure. Following tender evaluation and contract placement, the equipment was delivered and installed at the plant.
All elements of the A1.01/96B project were implemented in several stages. In order to apply the fire resistant coating material on steel structures at the turbine hall and emergency diesel rooms, new reliable scaffolding had to be procured in a separate project (A1.01/97B1).
Project Results
The communication equipment to the plant fire brigade was procured and delivered on site in December 2000.
Following delivery of the scaffolding to site, the works on coating the steel structures of the turbine hall and emergency diesel buildings started in March 2001.
Replacement of the medium and low voltage electrical circuit breakers was, however, delayed; the first tender was unsuccessful and had to be repeated. The tender evaluation was successfully performed in August 2002. The project was completed in 2005. All medium and low voltage breakers in the scope were replaced, and final acceptance certificate was issued on March 2005.
A medium-term fire safety improvement programme has determined specific fire safety improvement activities that were included in the subsequent On-site assistance programmes to Armenia NPP. The fire safety improvement programme was implemented in parallel with other safety improvement measures at Armenia NPP.