R2.03/03 (S) - Maintenance equipment for VVER primary loop - lot 2 (AP ref 7.1.2.3)

The present contract was based on a comprehensive project (R2.02/97 – see 30302) programmed in 1997. The purpose of the R2.02/97 project was to provide assistance in diagnostics and maintenance of VVER reactor coolant system (primary circuit loops). A part of the project was procurement and supply of maintenance tools aimed at improving quality of reactor coolant system (RCS) maintenance resulting in:
reduction of number and severity of observed RCS integrity problems
reduction of radiation doses received by maintenance personnel during RCS maintenance
a possible increase of rated power of the VVER-1000 reactor.
The equipment supply was divided in four lots. Equipment Technical Specifications for all the lots were developed within the R2.02/97 project. However, the equipment delivery could not be contracted within the original project, therefore a new equipment supply project R2.03/03 was established in 2003 including all four lots. The tenders for all the lots were opened to public in November 2005 and offers were made for each lot. Three separate contracts were finally concluded for the lots 1+4 (contract 114514), 2 (contract 76777) and 3 (contract 115574).

The general aim of the R2.03/03 project was to deliver to Rosenergoatom a set of modern tools for maintenance and repairs of RCS equipment of the VVER-1000/V320 reactors. This particular contract (76777) was concluded for delivery of the Lot 2 including one complete, hydraulically operated tool with accessories, suitable for bolt tightening at reactor coolant pumps (RCP), to be delivered to Novovoronezh NPP as an End User of the Lot 2. Although it was to be delivered to a specific NPP, the equipment was supposed to be available also to the other Rosenergoatom NPPs to take advantage of it. During the warranty period however, the equipment was to be used solely by the End User.

The contract for the equipment procurement and supply was signed with Wenutec (later on renamed to Siempelkamp Tensioning Systems) GmbH, Germany on 24 April 2006. Initially, the contract was concluded for 6 months. The factory acceptance tests were completed in September 2006 and Certificate of Origin for Transport was signed 16 November 2006.
But later on, the contract was extended by 31 months to total 37 months expiring on 25 May 2009. Finally, the contract was closed on 4 May 2010. The Provisional Acceptance Certificate was signed by the supplier Wenutec/Siempelkamp GmbH and the recipient Concern Rosenergoatom + Novovoronezh NPP on 22 August 2007. The Final Acceptance Certificate was signed on 10 December 2009.
The reason for the substantial contract extension were problems in communication between the involved Russian parties (including the Russian Humanitarian Aid Committee), which delayed the overall customs clearance procedure and hampered delivery of the equipment to the End User.
According to the TS, a complete, hydraulically operated tool suitable for simultaneous tightening of all 30 bolts at the RCP flange was to be delivered. The basic principle of the equipment has been to pre-stress (elongate) the flange-connecting bolts using hydraulic jacks and then slightly tighten the nuts onto the bolts. After releasing the tension from the bolts, the bolts would contract exerting the same tightening force to each bolt, thus ensuring a homogeneous tightening of the entire flange.
In the equipment, delivered by Wenutec/Siempelkamp GmbH, each bolt has had its own tensioning jack and the jacks, combined in two groups, have been commonly connected to two semi-circular hydraulic lines. The whole hydraulic system has been powered by its own electric pump independent of other plant auxiliary systems but the electric power supply. This bolt tightening system has reduced number of activities to be performed in the radiation controlled (restricted access) area and also decreased the time necessary to connect the jacks to the individual bolts. Consequently, the radiation doses received by the RCP maintenance personnel have been substantially reduced in accordance with the ALARA principle. According to the TACIS programme evaluation performed in December 2009, the previous procedure required two days of operation, while using the Wenutec/Siempelkamp equipment, the same task could be done in a few hours. The Beneficiary Rosenergoatom has therefore indicated its intention to order similar equipment for the other nuclear power plants in Russia, since transporting the equipment between the plants (after its use in the radiation controlled area) would be rather cumbersome.

Conclusions

The contract, however delayed in its implementation, has been successfully completed and has fully met its objectives.