A3.01/00 TSO 2+2 - Enhancement of the safety assessment capabilities of the ANRA for licensing of Medzamor 2 safety improvements (follow up of projects AR/TS/03)

The Armenia NPP is the only nuclear power plant in the region, and consists of two units of the WWER/440/270 model Soviet type reactor that is a modified version of the WWER/440/230. Unit 1 began its commercial operation in 1976 and Unit 2 in 1980. Both units were shut down shortly after the 1988 Spitak earthquake. Because of critical situation with power supply in Armenia, the plant was restarted in November 1995 after re-commissioning works were performed from 1993 to 1995. Currently, only Unit 2 is in operation while the Unit 1 was closed down several years ago.
The Armenia NPP has received large international assistance with the objective to improve the plant operational and design safety. Since 1997, the European Union belongs to the major donors with the highest financial contribution to the safety improvement activities that were implemented throughout the TACIS nuclear safety programme, and since 2007, the Instrument for Nuclear Safety Cooperation (INSC).

The On-site assistance (OSA) programme is implemented by EU companies or consortia with experience of NPP operation in the EU that are contracted by the EC to work on site at a nuclear power plant of the Beneficiary country. The aim of OSA is to provide the Beneficiary nuclear power plant with support to 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 maintains a site presence and assists the plant management/operation in various safety aspects, such as the safety culture, safe operation and maintenance. In addition, the OSA Team assists the EC, End User and suppliers implementing the supply projects that deal with replacement of the old equipment which does 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 Armenia 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.

The activities to be implemented were organised under three general areas:

1) General Operational Assistance activities

• General management of the project
• General Operational Assistance in any safety related topic, on request of the End User
• General training and transfer of experience
• Training topics to be mutually agreed between the OSA Consultant and the End User, with approval of the EC Project Manager
• Assistance with licensing issues, including licensing related to the 'soft' assistance topics, where applicable
• Experience feedback on completed TACIS projects

2) Specific ('soft') activities for the transfer of safety culture

• Revision of the plant Event Oriented Emergency Operating Procedures (EOPs)
• A limited scope of reliability analysis to assess how already implemented projects contributed to the plant safety improvement
• Improvement of the plant technical specifications
• Preliminary Project Planning for equipment supply projects – Improvement of I&C at ANPP

3) Management of the implementation of ongoing specific equipment supply projects from the TACIS 96 programme

• A1.01/96A - Greifswald Main Generator Breakers installation
• A1.01/96 B - Medium Voltage and Low Voltage Circuit Breakers replacement
• A1.01/96 E - I&C Basic Engineering and Equipment Procurement involved a replacement of Steam generator water level measurement
• A1.01/96 I – Seismic hazard analysis
• A1.01/96 J – A confinement leak tightness Improvement

4) Support to Implementation of the Plant Improvement Project

A1.01/00A - Leak Before Break study (LBB). This project focused on applicability of LBB concept for Armenia NPP primary circuit piping.

A1.01/00B Improvement of the Instrumentation and Control system at ANPP; this project was divided in five sub-projects:

• Reactor vessel head venting
• Primary circuit pressure control
• Neutron flux source range instrumentation
• Radiological Instrumentation
• Primary and secondary water chemistry

A1.01/00C – Improvement of the Accident Localisation Safety System. The project was divided in two parts: part I. related to the feasibility study of the applicability of the Jet Vortex Condenser to the confinement of Armenian NPP, and part II. to the procurement of a Jet Vortex Condenser.
The work involved preparation / finalisation of the tender documents, tendering, contracting and implementation of the projects.

The OSA to Armenia NPP under the present contract was implemented by the Italian Utility SOCIETA GESTIONE IMPIANTI NUCLEARI PER AZIONI (SOGIN).

The General On-Site Assistance was performed in accordance with the requirements of the contract.

Specific ('soft') activities for the transfer of safety culture

Emergency Operating Procedures (EOPs).

The objective of this activity was to develop a new set of emergency operating procedures that would supplement the existing event oriented procedures. The importance of this activity underlines that fact that ANPP control room operators had only event based emergency operating procedures available that, in case of event cannot be easily identified or in case of multiple equipment failures could not provide the main control room operators with sufficient event response guidance. The OSA team subcontracted Atomservice in 2001, a local subcontractor, who possessed necessary knowledge of the ANPP design and operation. A final set of EOP was developed at the end of 2004 and first V&V was performed in December 2004 on the multifunctional Simulator. Based on the plant request, the EOP scope has been extended to include additional procedures (earthquake, complete loss of FW, service water break in boron mode, as well as the extension of already developed secondary circuit pipe breaks with malfunction of associated safety equipment). Because of this scope extension, completion of the EOP V&V was postponed to the future programmes.

Reliability analysis

OSA team performed a limited scope of reliability analysis to evaluate the safety contribution of TACIS safety improvement projects. The activities were completed with the evaluation how the plant safety was improved following implementation of TACIS projects for ANPP.

PSA Level 1 Study

This project aimed at development of the plant specific PSA study that was never done for ANPP before, and which helped to identify the plant failure modes and reveal latent weak points in the plant design and, partially, operation. With the help of PSA insights, ANPP could plan corrective measures to improve the plant safety level. The PSA level 1 study was performed in the framework of a complementary project co-financed by the Italian Government, Sogin, and the ANPP. The ANPP personnel took part in elaboration of some PSA tasks, was trained on use of the PSA technique and interpretation of the PSA results.

Improvement of the Accident Localisation Safety System

The project aimed at improvement of thermal hydraulic behaviour of the plant confinement. The Russian VNIIAES suggested installing a jet vortex condenser (JVC) in the confinement that would help reducing the confinement pressure following LOCA and thus ensure confinement integrity. The project was divided in two parts; Part I. related to the Jet Vortex Condenser feasibility study, and Part II. related to the procurement of JVC. Although the JVC equipment was delivered on site and the provisional acceptance was issued on the July 2005, it has been never installed, due to prevailing licensing related concerns about JVC functional performance characteristics.

Seismic Hazard Analyses

This project focused on re-evaluation of the site seismic spectra that are important source data for the reinforcement of the plant seismic design, i.e. structures and components important to safety. This project was included in the Amendment 1 of the OSA contract. The OSA team prepared the entire package of tender documentation. However, tendering of the project did not proceed because the IAEA launched a similar project involving the same activities as well as participation of the Armenian research institute.

Management of the ongoing specific equipment supply projects

The management and follow-up of ongoing specific equipment supply projects was performed in accordance with the requirements of the contract. A list of equipment projects at the time of completion of the OSA contract is given below.

The following equipment supply projects were completed during the Contract period:

• A1.01/96A - Greifswald Main Generator Breakers installation: the activity completed with the installation of the generator breakers in December 2002.
• A1.01/96 B - Medium Voltage and Low Voltage Circuit Breakers replacement: the project finally focused on procurement of Medium Voltage Circuit Breakers only. Final acceptance certificate was issued on March 2005.
• A1.01/96 E - I&C Basic Engineering and Equipment Procurement involved a replacement of Steam generator water level measurement. The first tender to procure equipment was unsuccessful. Based on Armenia NPP and the OSA Consultant request, the European Commission reprogrammed this project. A new tender was successful and the contract was signed in 2005. The equipment installation was foreseen during year 2006 outage (after the end of the present OSA contract).
• A1.01/96 J – A confinement leak tightness Improvement: the project involved delivery of a large compressor to enable performing the confinement leak tests. The Compressor was delivered on site in 2001.

Implementation of the Plant Improvement Project

The OSA team assisted the EC, End User and suppliers in implementation of the following plant improvement projects:

Leak Before Break study (LBB)

This project focused on applicability of LBB concept for Armenia NPP main primary circuit piping and the pressurizer surge line. The associated equipment (i.e. leak detection system, additional anchors and snubbers) originally envisaged to be procured within this project were postponed to the later programmes. The study showed that LBB concept is feasible for Armenia NPP; however, the pressurizer surge line would have required higher leak detection sensitivity than the leak detection systems available on the market could have provided. Later on, when IAEA completed a new seismic study for Armenia NPP site, and which concluded with different seismic spectra, another LBB study was performed in 2008 with consideration of the new seismic spectra, which eventually confirmed LBB applicability for the main primary circuit piping including the pressuriser surge line.

Reactor Vessel Head Venting System

The project focused on design modification of the reactor pressure vessel head venting system so that to allow for removal of the steam and non condensable gases from below the reactor pressure vessel head in accidental conditions; the equipment installation was completed in April 2006.

Neutron Flux source-range monitoring Instrumentation

The project focused on replacement of the source range neutron flux ex-core monitoring system with the new system satisfying requirements for similar equipment in EU. The plant capability to measure neutron flux especially in start up and shut down modes was increased significantly. The project was completed in March, 2006. ANPP

Radiological Instrumentation

This project focused on replacement of the obsolete radiation monitoring system at ANPP and comprised the new automatic monitoring system "8004" hardware to improve monitoring of aerosols, blow down water, and personal dosimetry. The project was implemented in December 2005.

Primary and secondary water chemistry

This project focused on the installation of a water chemistry monitoring system to perform the automatic measurement of the most important indicators of the quality of the primary and secondary circuit coolant, indication of the values of the measured parameters in the control room and signalling to the operator of any significant deviations from the normal values. Monitoring had previously been implemented by means of laboratory analysis of manually taken samples. The equipment was installed in September 2005.

Comments

(Quality of the results, Lesson learned, Recommendations for follow-up)

In the final report the OSA Consultant noted some experiences during project implementation from which lessons could be learned and for which recommendations were made. These were related to the need for better coordination among all project stakeholders, particularly in the project documentation development stage and related approvals, equipment suppliers to correctly follow the sequence of document approval before starting manufacturing or software development activities and to the need for better coordination of the equipment supply and related licensing processes, both of which are provided with TACIS funded EU support (the so-called '2+2' approach).

The OSA project, which was originally foreseen for 2 years, but was extended twice with the final project duration of 55 months (about 4,5 years).

Applicable lessons learned and accomplished results were considered in the programming of the new projects under the TACIS nuclear safety programme.