1) Background
The issue of the integrity of the cable penetrations in relation to fire was identified by the IAEA and ranked level 3. Moreover, the ZNPP received in 1995 a licence conditions for operation from SNRC.
One concern is that redundant equipment, components and cable support structures with their laid-on cables of safety important systems, were, in some areas, located without sufficient physical separation and are not protected against a spreading fire. This results from deficiencies such as:
Redundant cable bundles run too close to each other;
Absence of passive fire resistant partitions in areas of approaching, parallel course and crossing of cables, belonging to different safety systems;
Cable penetration sealing and fire stops were not compliant with the existing requirements;
Insufficient requirements concerning fire resistance for compartmentalisation of cables as well as of barriers and fire stops;
Lack of fire resistance of overlayers covering the cables, e.g. inflammable insulation on the cables shall be used.
Thus a fire could lead to the loss of more than one redundancy of safety important systems.
This project was started by GKN under Tacis 96 with the preparation of the technical specification. In 1996 it was decided to combine both projects, the U1.03/96C and the U1.03/97C. The issue of fire protection at Zaporozhye is also covered by the projects U1.03/93C, 94A, 95A, 95A1 (see relevant PRS) where, among other measures, coating of all structural steelworks at all Units was funded.
The tender took place in February 1999, followed by the bid evaluation in September 1999. The result of this evaluation was rejected by the EC for administrative reasons. Therefore, it was decided to modify the technical specification and to re-start the tender process. The process of review of the Technical Specifications ended in December 2001. However, due to the new Ukrainian regulations on fire protection, in January 2002 it was decided to revise the technical specifications. The tender was launched in October 2002.
2) Objectives
The project aimed at supplying new cable penetrations for all the safety related cables in Units 1-5, according to the state-of-the-art fire safety requirements. In particular, the fire protection of the cables had to be improved through cable coating, wrapping of cables and/or of the whole cable support structure including the penetration through walls and ceilings, as well as the replacement of a number of Fire Dampers and Fire Stops.
3) Project results–achievements (with reference to the TORs)
The equipment arrived at the ZNPP on 10 November 2003. On the same day the support of the supplier for the implementation started, i.e. supervision, training, recommendations. Everything was completed on 14 November 2003. The ZNPP and Biblis (OSA Team) signed the Provisional Acceptance Certificate on 2 December 2003 and the warranty period of 2 years started.
The Supplier provided the manufacturing of the components, workshop tests for the confirmation of the material characteristics, certification, delivery, warranty period, as well as the plant personnel training. The work on cable coating with fire protection materials was performed by the plant as well as the work on removal of the old materials. The supplier delivered the materials for the fire stops, and the plant (the qualified company based on the agreement with the plant) manufactured them. The Supplier carried out a site visit for the examination of the work areas and the elaboration of recommendations concerning the work execution. This visit was combined with the plant personnel training. A 2nd visit took place after the delivery of materials to check the results of the work done.
More specifically, the following was carried out:
All locations of cable passage through walls and ceilings independent of their design were sealed.
Along with sealing of locations of cable passage through walls and ceilings, permanent fire stops were installed in metal ducts in vertical runs after each 20 m, in horizontal runs after each 30 m. Fire stops with the same requirements were installed also in pathless reinforced concrete channels. Metal cable ducts were fabricated based on technical conditions and installed in compliance with the approved procedures. The type of cable lay on (open on cable support structures, in ducts, in cable support structures, etc.) was specified by the design organization.
Cable in technological passages and rooms were laid on based on the condition that the volume of polymer materials at each cable structure (shelf, tray, pannier, etc.) did not exceed 7 liter per 1 m. The longest distance between individual structures in rooms, passages and cable facilities was checked to be in compliance with the Ukrainian norms. If the volume of polymer materials on cable structure exceeded 7 liter per 1 m, cables were coated with fire protection materials during cable lay on in passages and rooms of the NPP which were not equipped with automatic fire extinguishing units.
In control rooms (central control room, main control room, standby control room), as well as in rooms with electronic and electrical equipment, fire protection coating of combustible cables was laid on between panels in ducts or in the lower part of panels.
Power cables, control cables, communication cables in turbine halls as well as power cables running in these areas were coated with fire protection material in locations where the external fire could potentially impact cables (within the boundaries of the mentioned equipment plus 10 m in each direction). For multiple-layer lay on in cable ducts, the upper layer of cables was coated.
There were cable rooms where cables of different safety systems were closed or crossing each other on different levels. The plant identified those cables of different systems and power cables so that these cables could be protected separately.
The minimum time for fire resistance of cable penetrations through walls and ceilings shall be 90 minutes. In some areas there were many cable penetrations where the “Camum” method material was used and on top of it some other material was laid on. Those penetrations were cleaned up completely, the old material was removed and the new approved material, licensed in Ukraine, was put in place instead of it.
The OSA Team monitored the warranty period until the end of the reporting period: no claims were reported by ZNPP.
4) Comments (quality of the results, lesson learnt, recommendations for follow-up)
The project met the objectives stated in the TORs.
Further Information
Further information on the project results could be sought from the beneficiary organization.