Objectives
In the framework of the “Tacis Nuclear Safety Programme”, it was decided to improve the passive fire protection facilities of the BN-350 NPP (fast breeder) in Aktau, Kazakhstan. The project was divided into three lots. Lots 1 (Replacement of floor covering material and covering of cables) & 2 (Replacement of fire protective doors) were subject to a different call for tender (R1.07/95J Lots 1&2). Lot 3 consisted of three parts merged to one call for tender:

• Replacement of halon gas with substitute gases (“clean agents”)
• Replacement & improvement of fire detectors
• Supply of new equipment for the fire brigade.

The fire suppression system of the Aktau NPP covers all the controlled areas, which has a total volume of 8700 m3. The substitute gas needed to replace the initial halon gas and be a “clean agent”, i.e. have only low impact on the health of staff (no toxicity) & the environment (low global warming potential). It needed to be chosen in accordance with the common standards (NFPA 2001, ISO 14520, EPA environmental requirements). On the other hand it was required that the clean agent only has limited replacement impact on the existing fire suppression installation (i.e. containers, pipes, valves, nozzles, etc…) and is chemically compatible with the existing system. If replacement of components in the existing system was seen as necessary it was required that the supplier of the clean agent also chooses appropriate replacement components.
The supplied gas had to be in accordance with the total room volume mentioned above and its quantity had to be sufficient to extinguish fires in the two largest rooms of the NPP at the same time in a reasonable time (associated release time under 10s). The service life of the flooding clean agent system had to be at least 10 years.
The supplier was also responsible for all associated on-site work: Collection of data & performance of measurements for installation of the new fire suppression system and supervision of the installation activities inc. its documentation. The supplier was also requested to provide at least 10% of the installed components and another 5% of the clean agent as spare parts / reserve.
The new fire detection and alarm system embraced the following components: Fire detectors of various types (see below), fire alarm control panels, necessary quantity of cables for installation of fire detectors & control panels, specific tools for installation, testing & maintenance and supplies for testing the detectors. In addition the supplier was asked to provide the following services:

• on-site survey to collect all relevant data, measurements & information for the installation of the new fire detection system
• design & manufacturing of the new detection system including location identification for each sensor
• supervision of the installation activities.

The supplier was also asked to provide proper documentation, i.e. assembly drawings of the detection & alarm system, technical descriptions of the detection & alarm system, operating & maintenance manuals, etc…
The following types of fire detectors needed to be installed: Smoke detectors (ionizing; Type 1), smoke detectors (photo-electric; Type 2), heat detectors (rate-of-rise, Type 3), mixed detectors (smoke & heat, Type 4) and flame detectors (Type 5). The fire detection system panels needed to be energised at all times, so they all needed to be equipped with self-contained emergency batteries that provide energy for 12 hours in case of loss of normal power.
The mean time before failure of each detector had to be at least 50000 hours. The overall availability of the detection system had to be at least 97% assuming a mean time to repair of 4 hours. Faults which make the complete system totally unavailable should not occur within the first 10000 hours. Overall system availability had to be at least 99.5%. Availability of spare parts had to be ensured by the supplier for the entire life time of the system (expected life time 20 years). The fire detection & alarm system had to meet the following codes & standards: EN 54, NFPA 72, IAEA Safety Guide no. 50-SG-D2 and the standards EN 50081-2, 50082-2 and 50130-4 for electromagnetic compatibility.
The equipment for the fire brigade (approximately 96 persons with three shifts of 16 people) involves protective clothing, protective gloves, helmets with face shields, fire proof boots & suitable socks, special clothing for sodium fires inc. spare parts, self-contained breathing apparatus with face masks, portable lights with spare parts, tools for fire intervention (axes, electrical cutter, special hammers, etc…), fire powder portable extinguishers, fire hoses, fire exit signals, spray nozzles, knee boots, fire resistant ropes, portable general purpose survey meters to detect radioactivity inc. spare parts, portable radios with spare parts, battery chargers for 10 radios, two mobile radios for trucks & one fixed radio for radio station inc. spare parts, power supply for fixed station and antenna sets.
The breathing apparatuses needed to be of the open-circuit, self-contained type and had to provide a respirable atmosphere independent of the ambient environment. The breathing gas had to be contained in a breathing gas cylinder with a capacity of 800 litres of air at 20C and 1 bar.
The radios had to cope with the environmental conditions (maximum air humidity 95%, air temperature range -25C - 60C) and meet the following characteristics: minimum 40 programmable channels, voltage supply between 12-13.8 V dc for mobile radios and 7.2-13.8 V dc for portable radios, output power mobile at least 50 W (mobile), 2.5 W (portable on internal batteries) & 5 W (portable on external power 13.5 V dc), spurious emission < 60 dB, operating mode narrow frequency modulation (NFM), VHF coverage (both receiving & transmitting) 144 – 173 MHz and availability of noise reducing circuit. All radios had to be equipped with ear-phone adapters and the portable units needed to be flameproof and usable in explosive gas atmospheres.
The portable meters for radioactivity needed to measure the equivalent dose and/or contamination (measurement range: 0.1 Sv/h – 1000 mSv/h, range of dose: 1 Sv – 10 Sv, energy range: 45 keV – 3 MeV). They needed to run autonomously for more than 500 hours with chargeable or non-rechargeable batteries. The portable meters needed to have alphanumeric display with memory function for dose and maximal dose and provide threshold alarm. They had to be usable in all environments (outside, reactor building, auxiliary building), tight and easily decontaminable and provide temperature stability between -10C and 40C.
The equipment for the fire brigade needed to be tested and certified according to all applicable European and international standards, which are EN 469, 659, 443, 137, 345-2, and NFPA 1971. The supply of the equipment also included associated documentation (manuals, technical descriptions, project time schedule).
Project Results
The contract was awarded to Alstom Power Service S.A. on the 22nd April 2003 (effective contract date) and ended on the 25th October 2005 with the successful completion of the project.