2.1.3.1 Project development stage

The original Russian project with type WWER-440/V-230 units dates from the late 1960s and early 1970s.

With respect to the gradual upgrading of V-1, it was decided to develop project and safety-related documentation in two steps:

Step 1: Basic Engineering and Preliminary Safety Report

Owing to the importance and extent of upgrading works on NPP V-1, several foreign companies were invited to submit bids. Satisfactory bids were received from the companies WESTINGHOUSE and SIEMENS in early 1993, being draft bids for a principal upgrading of NPP V-1; these were rewritten in December 1993 to represent bids for gradual upgrading of NPP V-1. The selection of bids was finished in the first quarter of 1994, and the award went to SIEMENS KWU. The contract on Basic Engineering was made on 5 May 1994 (the first stage of project documentation - at the level lower than Initial Project) for gradual upgrading of NPP V-1.

It was mainly SIEMENS KWU that took care of the development of the BASIC ENGINEERING project for the gradual upgrading of NPP V-1, in cooperation with Slovak companies such as VÚJE, VÚEZ Tlmače, PPA Bratislava, EZ Bratislava, and others.

BASIC ENGINEERING dealt with the upgrading of the following areas, systems and subsystems:

1. Reactor coolant system integrity improvement
2. Upgrading of the emergency core cooling system.
3. Upgrading of the pressurizer safety valves.
4. Reinforcement and integrity improvement of the containment, including addition of isolation valves and flaps on technological and air-conditioning pipes crossing the containment boundaries.
5. Addition of the accident localization system within the containment, including hydrogen monitoring and disposal.
6. Addition to containment filtered ventilation system.
7. Upgrading of the containment spray system.
8. Installation of a new service water system for cooling of safety-related systems.
9. Upgrading of electric systems in:

   	uninterruptible electric supply 6kV, 0.4kV, 220 V DC, 220 V AC, 24 V DC - upgrading of distribution lines and buses,
   	replacement of motor generators,
   	modification of diesel generator control system,
   	installation of an additional off-site power source of house consumption,
   	provision for two independent power supply systems for safety systems.

10. I&C upgrading concerning:

    	upgrading of reactor protection system and engineered safety features actuation system, including reactor power control and limitation system (two redundancies),
    	upgrading of neutron flux monitoring systems,
    	upgrading of and additions to the post-accident monitoring system (PAMS),
    	completion of the setting up of the emergency control room,

11. Installation of additional system of emergency feed water supply.
12. Installation of additional steam generators relieve valves to the atmosphere.
13. Improvement of fire protection in existing compartments.
14. Upgrading of air conditioning systems in safety related systems compartments.
15. Modification of existing structures and construction of new buildings for:

    	emergency feed water system,
    	essential service water system,
    	air conditioning systems for electric and I&C systems compartments.

Under the contract on BASIC ENGINEERING, the following areas were also tackled:

	preliminary Safety Analysis Report (PSAR),
	system of individual equipment labeling,
	setting up of a set of standards, regulations and directives relevant with respect to gradual upgrading of NPP V-1,
	seismic capacity of the equipment,
	requalification of the existing NPP V-1 equipment.

Basic Engineering was completed in November 1996.

The outputs submitted by the developers were reviewed and commented upon by SE-EBO as well as by independent organizations, and submitted to ÚJD for approval.

Step 2: Executive projects and Safety Report drafted according to approved outputs from Basic Engineering and the Preliminary Safety Report for the individual systems. The drafting of the executive projects and of the safety report was under responsibility of the General Contractor, the REKON Consortium comprising the Consortium leader - Siemens KWU and the Slovak institution VÚJE.

ÚJD approved projects for the individual functional systems for construction permits, preliminary safety reports, executive projects, as well as individual plans of quality assurance.