Background

The Smolensk Nuclear Power Plant (SmNPP), located in the Smolensk region of Russia, comprises 3 power units. The site lies 3 km away from the nearby town of Desnogorsk on the bank of an artificial lake situated on the river Desna. Unit 1 was commissioned in 1982, Unit 2 in 1985 and Unit 3 in 1990. All three units have reactors of the RBMK-1000 boiling water graphite moderated type and were still in operation at the time of this contract.

One of the many recommendations of the RBMK Safety Review (see contract 21720) was that the main steam safety relief valves (SRVs) should be replaced by better quality equipment. The existing safety relief valves for the protection of the primary circuit of RBMK-1000 units had a high leak rate, did not possess sufficient operational reliability and did not satisfy requirements of the latest Russian norms PNAEG-7-008-89 and OTT-87.

In the framework of the TACIS 1994 Nuclear Safety Programme, the European Commission and SmNPP agreed on a project to procure replacement pilot-operated safety relief valves for 3 units of SmNPP.

Objective

The objective of introducing the replacement units was to provide enhanced reliability and performance over the existing valve design, thus improving the safe operation of the plant. The SRVs were to be installed by the End User using procedures provided by the Supplier of the valves.

The scope of work included the design and design justification of the SRV system and all ancillary equipment for installation, operation and maintenance/testing. Documentation and procedures for the installation of the valve systems within the predefined terminal points were to be provided. Support during installation, testing and commissioning also had to be provided. Operating, maintenance and testing instructions were required in addition to production of a full manufacturing documentation package. The scope of supply also included a set of manufacturer's recommended spare parts.

Each RBMK-1000 Unit is fitted with 8 SRVs. The project budget was not sufficient to procure new valves to replace all valves at all three units. The scope of supply included 4 tandem-type, pilot-operated valves. These were to be installed at the three units in accordance with the End User preference.

The scope of work/supplies included the design, manufacture, testing, packing, transport, supervision of installation and commissioning, documentation, training of the End User's personnel in the installation, operation, maintenance and testing of the equipment.

Results

The contract was signed on 28 February 2001. Manufacturing was completed and the equipment was tested at the supplier's premises in September 2002. Delays were experienced due to problems with customs paperwork which were solved in April 2003. The equipment was delivered to site, installed and tested. The Provisional and Final Acceptance Certificates were issued on 15 August 2003.