R1.07/04D - PIP Novovoronezh - “Steam Generator Emergency Feed-Water System at Novovoronezh NPP (NvNPP ) Lots 3 and 4

The emergency feedwater system (EFWS) at Novovoronezh NPP Unit 5 (VVER-1000/V187) is used to supply feedwater to its four steam generators (SG) in emergency situations and also in start-up and shutdown conditions.

Before the project implementation, all three EFWS pumps were located in one common compartment close to each other, which posed a considerable risk of their simultaneous failure due to a common cause (a fire, flooding, etc. of the compartment). Moreover, the emergency feedwater was distributed to the four SGs through an emergency feedwater header and emergency feedwater lines that were not fully physically separated from the normal operating feedwater system.

Such a configuration imposed elevated risk of the entire feedwater system failure due to a common cause resulting in deterioration of residual heat removal from the reactor in case of a serious accident. This possible loss of a basic safety function (reactor residual heat removal) has been identified by the IAEA as a safety issue of category III.

In the frame of the Novovoronezh NPP Unit 5 Safety Enhancement Programme, an additional EFWS that would meet current safety requirements was to be installed. The EFWS installation project included construction of a separate building for the system housing, installation of the new system equipment, its connection to the existing systems, necessary checks and tests, preparation of the operational and maintenance documentation and system commissioning.

The EFWS had to consist of three redundant trains with each train including:

demineralised water tank of 1000 m3 volume
pump set supplying up to 150 m3/h of water into SG at related pressure
low-pressure and high-pressure pipelines
associated valves
sensors and other instrumentation
independent essential power supply.
The main EFWS equipment had to be supplied through the R1.07/04D project established within the TACIS Nuclear Safety Programme and financed by the European Commission. The equipment supply was divided into 4 lots and implemented under three separate contracts:

supply contract number 99580 on Lot 1
supply contract number 129848 on Lot 2
supply contract number 129486 on Lot 3 and Lot 4.

The objective of the 129486 contract was delivery, installation and testing of EFWS equipment within the following two lots.

1. Lot 3 on stainless steel pipelines including:

About 420 m of pipes DN 150, DN 50 and DN 15 mm for 9.8 MPa and max 120°C including a flowmeter of DN 150 mm
About 440 m of pipes DN 150 and DN 100 mm for 7.8 MPa and max 300°C including a flowmeter of DN 150 mm
About 125 m of pipes DN 200, DN 50 and DN 15 mm for 0.15 MPa and max 90°C
About 710 m of auxiliary pipes DI 100, DI 80 and DI 50 mm for 1.25 MPa and 40°C (DI = Diameter Internal)
Standard supporting and hanging elements
Special equipment for welding, assembly and repair
2. Lot 4 on electrical and instrumentation-and-control (I&C) equipment including:

3x SF6 trolley-type 6 kV circuit breaker of the EFW pumps including spare parts for 4 years of operation
Cables including
1500 m of a 6 kV power cable
2200 m of a 1 kV power cable
700 m of a 1 kV control cable
18.8 km of 0.66 kV control cables of 5 various types
Cable connecting and terminating elements
Sensors including
o 3x pressure sensor 0-0.4 MPa
o 6x pressure sensor 0-16 MPa
o 18x flow sensors 0-160 m3/h
o 3x flow sensors 0-250 m3/h
o 6x level detector 0-10 m
o 18x level detector 0-4 m
Equipment for installation, repair, adjustment and verification of the sensors
6 sets of automatic SG level control instrumentation including necessary spare parts (2 sets per one EFW pump)
4x auxiliary power distribution switchgear 380/220V AC to supply EFWS auxiliary loads (lighting, ventilators, etc.) up to 10 kW including
Specific equipment required for installation, operation, maintenance and repair
4x set of spare parts for 4 years of post-warranty operation
A part of the contract were factory and site acceptance tests, contractor’s assistance in on-site installation, pre-commissioning functional tests and EFWS integration tests, delivery of design, operating and maintenance documentation, necessary certificates, delivery of spare parts and after-sales services (maintenance support).

This contract was concluded with the Scientific and Production Company Atomtechnoprom. The contract value was € 3,505,987.

The contract was signed on 12.9.2007 and the implementation started on 13.9.2007; the place of equipment acceptance was Novovoronezh NPP. The Kick-off Meeting of the contract took place on 9.10.2007. According to the original contract, the equipment had to be delivered within 16 months; by the Contract Addendum 3 signed on 28.8.2009, the delivery time limits were extended up to 23 months for the Lot 3 equipment and up to 29 months for the Lot 4 equipment.

By the Contract Addendum 4 signed on 19.5.2010, the time limits for delivery were further extended up to 33 months for the Lot 3 equipment and up to 37 months for the Lot 4 equipment. By the same addendum, the supply of the trolley-type 6kV circuit breaker was removed from the Lot 4 and replaced by improved controllers, providing an enhanced automatic SG level control function, and a sensor calibration bench. The contract value remained unchanged.

The equipment of the Lot 3 was fully delivered and installed in June 2010. The Provisional Acceptance Certificate (PAC) was issued on 25.6.2010. The Final Acceptance Certificate on the Lot 3 was issued after expiry of the 1-year warranty period on 15.11.2011.

The equipment of the Lot 4 as fully delivered in July 2011 and installed in August 2011. The Provisional Acceptance Certificate was issued on 27.9.2011. The Final Acceptance Certificate on the Lot 4 was issued after expiry of the 1-year warranty period on 27.9.2012.