1) Background
At Zaporozhye NPP, turbine hall structure is made of steel beams, and does not fit with modern fire protection requirements, as it does not have a defined fire rating time. Buildings do not have their own outer wall with the required fire resistance in the areas of adjacent buildings. In addition, fire protection system was designed according to former USSR standards, not in line with modern requirements. Thus, in case of major fire in the turbine hall roof steel structure could collapse and induce collapse of neighbour building like electrical building, which contains electrical distribution system to the plant (emergency 6kV and 380V AC power busses, and DC power busses).
Experience feedback in Ukraine showed that such an event is likely: turbine hall at Chernobyl NPP unit 2 collapsed after a major fire in the turbine hall. Zaporozhye NPP experienced also important fires during unit 1 construction in turbine building electrical cable trays, and on unit 2 when a station transformer fire caused some damage in the electrical building attached to turbine hall.

2) Objectives
Projects U1.03/93C, U1.03/94A, 95A and 95A1 have to be considered as the same technical project dealing with coating of steel structures of turbine halls at Zaporozhye NPP units 1 to 6. They have been split into 4 TACIS project references for contracting and project management reasons:

• U1.03/93C deals with coating of turbine halls of units 1 to 5;
• U1.03/94A deals with continuation of U1.03/93C for units 1 to 5;
• U1.03/95A deals with continuation of U1.03/94A for units 1 to 5, plus extension to unit 6;
• U1.03/95A1 is part of U1.03/95A and deals with an extension of U1.03/94A scope with coating of turbine hall of unit 6 (decided later than units 1 to 5, as unit 6 has been commissioned in 1995).
Selected contractor issued a common completion report to these 4 TACIS projects.
The aim of these projects is to improve fire resistance of structural steelworks of turbine hall in order to allow the fire brigade to intervene efficiently and to extinguish a fire, with sufficient time span of stability of turbine hall.
For that, solution of coating of turbine hall steel structures by fire proof intumescent material has been chosen in TS (Technical Specification).
TS defined that coating must provide the following parameters of fire resistance:
• for trusses: not less than 30 minutes (preventable 45 minutes);
• for columns: not less than 45 minutes.

Incidentally steel structure must not be subjected to any internal changes in order to keep their structural strength during normal operation. Besides that, coating material must not be toxic, must not interact with active media and must possess high moisture resistance features and ability to stick to the surface of protected steel structure.
Turbine halls of all 6 units at Zaporozhye NPP have to be coated.

3) Project results–achievements
Preparatory phase
TS have been prepared in 1994-1995 in the frame of U1.03/93C and U1.03/94A, and tendering process happened in November 1995 in the frame of U1.03/94A. SVT Brandschutz und Umwelttechnik GmbH has been selected as contractor and supply contract has been signed in June 1996.
Implementation of the supply contract
Tasks to be performed by the contractor were the following:

• Establishment of a work plan and a quality assurance plan;
• Supply and erection of scaffolding by SVT and ASKEN: after completion of the works on all 6 units, scaffolding became property of Zaporozhye NPP;
• Storing of basic products for the intumescent material (protected from heating, frost, dust and humidity);
• Implementation of coating work with contractor’s supervisor and ASKEN team (Ukrainian subcontractor);
• Site infrastructure: staff accommodation and office including storing capacity for equipment and tools;
• Issuance of provisional and final acceptance;
• Support to licensing;
• Training;
• Writing and delivery of design and operational documentation.

Other partners have been involved in the implementation of the project, outside contractor’s scope:

• Zaporozhye NPP: validation of all steps of the project, licensing, qualification of scaffolding;
• Work safety authorities: acceptation of scaffolding;
• Goskomatom (now Energoatom): validation of all steps of the project, licensing;
• GKN (Gemeinschaftskernkraftwerk Neckarwestheim - OSA utility): general follow-up of the project, and general support;
• UNRA: licensing.

Time schedule of implementation phase:

• 1994-1995: writing, updating of TS, and approval by all counterparts of the project; launching of tendering process
• November 1995: technical and financial evaluation of bids. SVT Brandschutz und Umwelttechnik GmbH has been selected as contractor
• December 1995: contract negotiations between EC procurement agent and selected supplier
• June 1996: supply contract signature for units 1 to 5 (U1.03/94A)
• June-July 1996: coating of turbine hall of unit 3. Provisional acceptance was issued in November 1996 together with unit 2
• July - November 1996: coating of turbine hall of unit 2. Provisional acceptance was issued in November 1996
• November 1996-February 1997: coating of turbine hall of unit 1. Provisional acceptance was issued in March 1997
• February 1997-May 1997: coating of turbine hall of unit 4. Provisional acceptance was issued in May 1997
• May 1997-September 1997: coating of turbine hall of unit 5. Provisional acceptance was issued in September 1997
• June 1997: SVT Brandschutz und Umwelttechnik GmbH has been selected as contractor for an additional contract dealing with coating of turbine hall of unit 6 (U1.03/95A1). U1.03/94A has been continued into U1.03/95A
• September 1997-December 1997: coating of turbine hall of unit 6. Provisional acceptance was issued in December 1997
• Final acceptance of supply and services
• September 1998: issuance of completion report.

The whole supply projects U1.03/93C, U1.03/94A, U1.03/95A and U1.03/95A1 have been implemented in consistency with initial schedule, except for issuance of TS, which took rather long time.
Technical description of the supply
Scaffolding: it took a long time to establish a group of qualified scaffold workers. In addition, permanent modifications of scaffolding were needed. Scaffolds have been approved by corresponding Zaporozhye NPP experts and local authorities.
After installation of scaffolding, cleaning of steel structure to be coated was performed, as dust has accumulated. In addition, damages of steel structure due to corrosion have been mended.

Intumescent coating has been then applied to steel structure by airless-spray method:

• Several layers of "Pyro-safe Flammoplast SP-A";
• One final protecting layer “Decklack SP-2”.

Thickness of the layers was permanently measured (7000 measurements points).
The work was performed on a three-cycle shift routine for work on the critical paths. Other work was performed by a two-cycle shift routine in order to ensure the deadlines given in the contract. It was not allowed to perform coating activities during unit shutdowns.
For each turbine hall, the following areas were coated:

• Roof trusses: 7,200 m2;
• Supports: 12,580 m2.

No work accident occurred during whole duration of the projects.
Training
Training has been performed by contractor SVT during coating of turbine halls of units 2 and 3 in June - November 1996. 30 technical people who performed coating activities from SVT, ASKEN and Zaporozhye NPP have been trained in the following topics:
• Explanation of works instructions, technical documentation, schedule of working procedure, coating of structural steelworks;

• Examination of comprehension of work instructions within an examination discussion;
• Examination of executed coatings through SVT supervisor.
4) Comments
Good work safety provisions have been implemented, and no work accident occurred, which is remarkable for such a risky activity.
Further information
Further information on the project results could be sought from Energoatom and Zaporozhye NPP.
The Project Final report is available at the JRC-IE archive.