The Armenian Nuclear Power Plant (ANPP) consists of two units of the WWER/440/270 model Soviet type reactor that is a modified version of the WWER/440/230 in view of special seismic design considerations. Unit 1 started its commercial operation in 1976 and Unit 2 in 1980. Both units were shut down shortly after the 1988 Spitak earthquake. Re-commissioning works were performed from 1993 to 1995 and in November 1995 Unit 2 restarted operation, and has been operational since then.
The ANPP design is similar to other WWER/440/230 NPPs and has the same generic safety issues and inherent safety features as other plants of this type. In addition, this plant has specific problems, some of which were resolved during the re-commissioning phase while others were either resolved since then or are still in the evaluation and upgrading processes.
The European Commission, in the frame of TACIS 1996 programme, allocated budget for On-site assistance to Armenia Nuclear Power Plant (ANPP) in order to address several urgent design and operational safety issues that were earlier identified in the IAEA Issue book for WWER/440/230 reactors.
The On-site assistance (OSA) programme was implemented by EU companies or consortia with experience in NPP operation in the EU that were contracted by the EC to work on site at a nuclear power plant of the Beneficiary country. The aim of OSA was to provide the Beneficiary nuclear power plant with support in different areas i.e. safety culture, quality assurance, maintenance, management and training, etc. and to upgrade the safety of the plant through the supply of equipment. The OSA team maintained a site presence and assisted the plant management/operation in various safety aspects, such as the safety culture, safe operation and maintenance. In addition, the OSA Team assisted the EC, End User and suppliers implementing the supply projects that dealt with replacement of the old equipment which did not meet safety requirements or installation of the new equipment based on its safety importance.
The aim of the On-Site Assistance programme at Armenia NPP (ANPP) was to combine the experience of the OSA Consultant with the experience and needs of the Nuclear Power Plant (NPP) operator in order to:
improve the operational safety of the Armenian NPP through the transfer of know-how and operational best practice;
identify, prepare and implement safety related specific projects which include the tendering and procurement of equipment required to improve the safety of the power plant.
In order to prepare a short term safety improvement programme for ANPP, i.e. to identify most urgent projects and set up priorities, an exploratory mission was carried out in 13-23 October 1996 with the objective to visit the plant, meet the Armenian organizations involved in the plant operation and discuss with them the main technical aspects related to the implementation of TACIS On-site assistance project.
The exploratory mission has been carried out by experts provided by ENEL, RWE Energie, and TRACTABEL. The mission objective was to conduct a plant walk down, meet the Armenian organizations involved in operation and discuss with them the main technical aspects related to safety improvement of ANPP.
The following activities were carried out:
1. Presentation of TACIS specific projects to be implemented
2. Analysis of safety measures requested by European Bank for Reconstruction and Development (EBRD) funded assistance programme
3. Definition of the regulatory framework in which the projects have to be developed, with particular focus on nuclear liability issue, the licensing aspects and the code and standards to be followed in the design implementation
4. Collection of necessary information for detailed definition of the general On-site assistance programme, in particular a time schedule for implementation of each specific project
5. Identification and definition of interfaces between plant staff and Western utilities, roles and responsibilities for each project
6. Verification of availability of the relevant plant documentation and initial data collection of the most important data
7. Evaluation of the plant status with particular attention to system, structures and components to be subject of improvement
8. Discussion of possible transfer of equipment and spare parts from Greifswald NPP
9. Examination of logistical aspect, i.e. office accommodation on site, interpretation and translation services, office and computer equipment, etc.
The Exploratory mission proposed an implementation programme for two general areas:
• General Operational Assistance activities
• Implementation of specific supply projects
1) For the General on-site assistance the following areas were identified:
Review and improvement of normal and emergency operating procedures. The objective of this task was elaboration and /or improvement of following documents:
a. Alarm sheets for most important Main Control Room alarms
b. Seven new normal operating procedures and improvement of six existing
c. Plant operating limits and conditions in a way to reorganize the document to a similar format as it is used at Western NPPs
Improvement of operating experience review programme
Analysis of I & C weaknesses, in particular identification and prioritization of the most urgent corrective measures to be implemented.
Analysis of internal hazards and common cause failures
Elaboration and establishment of the Quality assurance programme
Enhancement of personnel safety culture, especially organizing number of training courses for ANPP management, operation and maintenance personnel
Improvement of office facilities, in particular procurement of office equipment, a LAN network, printers and copiers, etc.
Licensing activities, in particular activities following 2+2 approach according to process set up for Armenia.
2) For the implementation of specific equipment supply projects
The team also noted number of non-conformances related to obsolete equipment, its vulnerability to the plant internal events (fire safety, steam and water jet, flooding, submergence, high temperature, seismic loads, etc.). Most of the equipment was without appropriate environmental qualifications too. Besides that, the equipment reliability was also noted as an urgent safety issue because of number equipment malfunctions that reduced the plant reliability and in many cases lead to a reactor trip.
The following equipment projects were identified to address the most urgent issues:
Replacement of Main Generator Circuit Breakers (house load operation,
Replacement of Medium Voltage and Low Voltage Circuit Breakers (reliability and fire prevention)
Replacement of Steam generator water level measurement
Installation of a Leak detection system between primary and secondary system (Steam generator tube rupture)
Replacement of pressurizer safety valves
Replacement of steam generator safety valves
Besides that, several design and operational safety issues were identified as follows:
Verification of integrity of reactor coolant system piping
Performance of a comprehensive seismic hazard analysis
Improvement of confinement leak tightness
Improvement of main control room operator training
For the above mentioned safety issues, corresponding TACIS projects were proposed. A Memorandum of Understanding (MoU) was signed between the EC, ANPP and Ministry, Department of Atomic Energy. This MoU listed the safety improvement projects that were agreed during the mission and which involved both the safety culture improvement and equipment supply projects. In this framework a two year General On-site assistance programme to ANPP Project A1.01/96 was formally established in order to assist the ANPP in implementing general OSA as well as specific equipment supply projects.
As it was shown later, this near term safety improvement programme was too ambitious to be implemented at ANPP within two years. Therefore, several projects from TACIS 96 that were not fully implemented during OSA 96 programme were transferred to TACIS 97, some of these even to TACIS 2000 OSA contract.