Successfully completed Periodic Safety Review (PSR) project for SUNPP Unit 1

Background

Periodic Safety Review (PSR) project for SUNPP Unit 1 has been one of the largest and most significant cooperation projects in the field of nuclear safety enhancement between Sweden and Ukraine.

In 2007 the National Energy Generating Company, being the operator of all the nuclear power facilities in Ukraine addressed SSM for assistance in involving Swedish experts in the evaluation of Periodic Safety Review reports to be developed for Unit 1 of South-Ukraine NPP (SUNPP) which was selected as a pilot facility for an independent international assessment. The same year a bilateral project was initiated involving SSM, international experts, SUNPP, Energoatom and Ukrainian Contractor Energorisk.

The main goal of the project was to assist SUNPP in performing the Periodic Safety Review by the transfer of the international expertise and methodology and review the developed PSR reports for the compliance with the international safety standards.

The project was implemented under the supervision of State Nuclear Regulatory Inspectorate of Ukraine (SNRIU) and the results of the review were submitted to SNRIU for evaluation.

South-Ukraine Nuclear Power Plant

South-Ukraine NPP is located near the town of Yuzhnoukrainsk in Nikolaev province approximately 350 kilometers south of Kiev and is one of the five nuclear power plants in Ukraine. The nuclear power plant has three VVER-1000 reactors and a net generation capacity of 2,850 megawatts (MW) which comprises 20% of the total capacity produced by the nuclear power facilities of the country.

Unit 1 of SUNPP was commissioned in December 1982 and the license to operate it expires by the end of 2012. The results of the PSR project will lay ground for the decision by SNRIU regarding further operation of the facility.

PSR in Ukraine

Similarly to other countries and in line with the current regulatory requirements all the nuclear facilities in Ukraine are expected to carry out Periodic Safety Review every ten years of their operation in order to demonstrate that the facility operates in compliance with its design, within the safety limits and meeting the requirements of the current national and international standards and regulations in nuclear and radiation safety. The review should be based on the data provided in Safety Analysis Report (SAR) or previous PSR with due regard to the modernizations and upgrades implemented at the facility during the reporting period as well as new scientific and engineering research and the results of the modern operating practice.

Project implementation

The implementation phase started with a series of meetings between SSM and NNEGC Energoatom/SUNPP in order to establish the scope of the project, select a project group and plan activities in both short-time and long-time perspective.

The project group identified the scope of the review by selecting fourteen safety factors to be evaluated in line with the IAEA standards and international practices:

•  (SF01) Plant design
• (SF02) Actual condition of SSCs
• (SF03) Equipment qualification
• (SF04) Ageing
• (SF05) Deterministic safety analysis
• (SF06) Probabilistic safety analysis
• (SF07) Analysis of internal and external impacts
• (SF08) Operational safety
• (SF09) Use of experience from other plants and research findings
• (SF10) Organization and management
• (SF11) Operating documentation, procedures
• (SF12) The human factor
• (SF13) Emergency planning and preparedness
• (SF14) Radiological impact on the environment

The identified Safety Factors were grouped into five main review areas and five working groups comprising Ukrainian specialists and SSM reviewers were established to take care of the report development and review process.

Each safety factor was presented and assessed in a separate report with a format common for all the safety factor reports; at the final stage of the project an overall safety assessment report was developed on the basis of the review of each individual safety factor.

The actual work started with the development of Technical Guidelines (TG) for each specific safety factor. The Technical Guidelines were intended for the developers of the PSR reports and stipulated the scope of work, analysis methodology and the requirements to the structure of the reports regarding the fourteen safety factors as well as the overall safety factor assessment. The Technical Guidelines were reviewed by the SSM experts.

Regular Working Group meeting at SUNPP

To provide practical assistance in the process of the report development at an early stage SSM organized a seminar at Ringhals NPP in Sweden where the Ukrainian project group met with the experts of Ringhals facility and discussed the PSR development process.

At the next stage the SSM experts developed International Requirements and Recommendations (IRR) for each safety factor which contained a comprehensive list of the applicable requirements of the IAEA Safety Standards as well as other relevant IAEA documents to be used for the assessment of the safety factors.

After that the specialists of SUNPP together with the Ukrainian contractor started developing safety factor reports based on the Technical Guidelines and International Requirements and Recommendations. After the internal review at SUNPP and the evaluation by NNEGC Energoatom the safety factor reports were submitted to the SSM experts for assessment. A number of unclear issues and questions were identified during the review process for each individual safety factor and were discussed and clarified at the regular Working Group meetings. The results of the assessment and discussions were formulated in the Evaluation Reports developed separately for each safety factor. The final versions of the Evaluation Reports signed by the reviewers and SSM were submitted to SUNPP to be further handed over to SNRIU.

The experience of similar work performed by Rivne NPP in the framework of the lifetime extension project of Rivne NPP for Units 1 and 2 was taken into account in the process of the development of the PSR for SUNPP Unit 1.

During the project implementation specific safety concerns that arose from the Fukushima accident were also addressed.

Main conclusions

Finalizing the assessment of the safety factor reports, SSM experts concluded that the majority of the reports were comprehensive and met the intent of the requirements of IAEA Safety Standards. As a result of the evaluation a number of comprehensive safety enhancement measures were proposed to be implemented.

It was also pointed out that the decision regarding continued operation should be based on the Current Licensing Basis including national regulatory requirements, updated safety analysis reports, probabilistic safety analysis and other documents as applicable.

Finally it should be mentioned that the PSR SUNPP Unit 1 project was implemented in the spirit of efficient collaboration, based on mutual respect and understanding and opened opportunities for new areas of cooperation.

PSR SUNPP Unit 1 in facts

Short historical outline

Companies participated in the project

NNEGC Energoatom, Ukraine

South-Ukraine NPP, Ukraine

Energorisk, Ukraine

Ukrenergosnab, Ukraine

ES-konsult, Sweden

Inspecta, Sweden

Pronova Energy, Sweden

Scandpower, Sweden

Vattenfall, Sweden

Emarcon, Sweden

Resco, Check Republic